ResearchPad - immune-deficiency https://www.researchpad.co Default RSS Feed en-us © 2020 Newgen KnowledgeWorks <![CDATA[Safety of tunneled central venous catheters in pediatric hematopoietic stem cell recipients with severe primary immunodeficiency diseases]]> https://www.researchpad.co/article/elastic_article_14693 Tunneled central venous catheters (TCVCs) provide prolonged intravenous access for pediatric patients with severe primary immunodeficiency disease (PID) undergoing hematopoietic stem cell transplantation (HSCT). However, little is known about the epidemiology and clinical significance of TCVC-related morbidity in this particular patient group. We conducted the retrospective analysis of patients with severe PID who received percutaneous landmark-guided TCVC implantation prior to HSCT. We analyzed 92 consecutive TCVC implantations in 69 patients (median [interquartile range] age 3.0 [0–11] years) with severe combined immune deficiency (n = 39, 42.4%), chronic granulomatous disease (n = 17, 18.4%), and other rare PID syndromes (n = 36, 39.2%). The median length of TCVC observation was 144.1 (85.5–194.6) days with a total of 14,040 catheter days at risk (cdr). The overall rate of adverse events during catheter insertion was 17.4% (n = 16) and 25.0% during catheter dwell period (n = 23, catheter risk [CR] per 1000 cdr = 1.64). The most common complication was TCVC-related infection with an overall prevalence of 9.8% (n = 9, CR = 0.64), followed by late dislocation (n = 6, 6.5%, CR = 0.43), early dislocation (n = 4, 4.3%) and catheter dysfunction (n = 4, 4.3%, CR = 0.28). TCVCs are safe in children with severe PID undergoing HSCT with relatively low rates of TCVC-related infection.

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<![CDATA[Mucosal-Associated Invariant T (MAIT) Cells Are Impaired in Th17 Associated Primary and Secondary Immunodeficiencies]]> https://www.researchpad.co/article/5989da80ab0ee8fa60b9a66e

The recently described Mucosal Associated Invariant T (MAIT) cells mediate specific recognition of bacterial and fungal vitamin B2 metabolites. As innate T cells, they possess broad effector responses, including IFN- including Iproduction, that are comparable to conventional T cell responses. Immunodeficiencies associated with systemic Th17 deficiency may also be compounded by defects in MAIT immunity. We evaluated Th17 immunity in this innate T cell compartment in primary (AD-HIES) and secondary immunodeficiency (thymoma) patients with conventional Th17 deficiency and susceptibility to fungal and bacterial disease. Our results suggest that MAIT cells are both reduced and functional deficient in STAT3 deficiency and thymoma patients with IL-12/23 autoantibodies. In contrast, thymoma patients without autoantibodies preserved the normal number and functional MAIT cells.

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<![CDATA[IL-12Rβ1 Deficiency in Two of Fifty Children with Severe Tuberculosis from Iran, Morocco, and Turkey]]> https://www.researchpad.co/article/5989da9fab0ee8fa60ba5191

Background and Objectives

In the last decade, autosomal recessive IL-12Rβ1 deficiency has been diagnosed in four children with severe tuberculosis from three unrelated families from Morocco, Spain, and Turkey, providing proof-of-principle that tuberculosis in otherwise healthy children may result from single-gene inborn errors of immunity. We aimed to estimate the fraction of children developing severe tuberculosis due to IL-12Rβ1 deficiency in areas endemic for tuberculosis and where parental consanguinity is common.

Methods and Principal Findings

We searched for IL12RB1 mutations in a series of 50 children from Iran, Morocco, and Turkey. All children had established severe pulmonary and/or disseminated tuberculosis requiring hospitalization and were otherwise normally resistant to weakly virulent BCG vaccines and environmental mycobacteria. In one child from Iran and another from Morocco, homozygosity for loss-of-function IL12RB1 alleles was documented, resulting in complete IL-12Rβ1 deficiency. Despite the small sample studied, our findings suggest that IL-12Rβ1 deficiency is not a very rare cause of pediatric tuberculosis in these countries, where it should be considered in selected children with severe disease.

Significance

This finding may have important medical implications, as recombinant IFN-γ is an effective treatment for mycobacterial infections in IL-12Rβ1-deficient patients. It also provides additional support for the view that severe tuberculosis in childhood may result from a collection of single-gene inborn errors of immunity.

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<![CDATA[Loss of NK Stimulatory Capacity by Plasmacytoid and Monocyte-Derived DC but Not Myeloid DC in HIV-1 Infected Patients]]> https://www.researchpad.co/article/5989da89ab0ee8fa60b9d71a

Dendritic cells (DC) are potent inducers of natural killer (NK) cells. There are two distinct populations in blood, myeloid (mDC) and plasmacytoid (pDC) but they can also be generated In vitro from monocytes (mdDC). Although it is established that blood DC are lost in HIV-1 infection, the full impact of HIV-1 infection on DC-NK cell interactions remains elusive. We thus investigated the ability of pDC, mDC, and mdDC from viremic and anti-retroviral therapy-treated aviremic HIV-1+ patients to stimulate various NK cell functions. Stimulated pDC and mdDC from HIV-1+ patients showed reduced secretion of IFN-α and IL-12p70 respectively and their capacity to stimulate expression of CD25 and CD69, and IFN-γ secretion in NK cells was also reduced. pDC activation of NK cell degranulation in response to a tumour cell line was severely reduced in HIV-1+ patients but the ability of mDC to activate NK cells was not affected by HIV-1 infection, with the exception of HLA-DR induction. No differences were observed between viremic and aviremic patients indicating that anti-retroviral therapy had minimal effect on restoration on pDC and mdDC-mediated activation of NK cells. Results from this study provide further insight into HIV-1 mediated suppression of innate immune functions.

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<![CDATA[KIR-HLA Genotypes in HIV-Infected Patients Lacking Immunological Recovery despite Effective Antiretroviral Therapy]]> https://www.researchpad.co/article/5989db28ab0ee8fa60bd0b52

Background

In HIV-infected individuals, mechanisms underlying unsatisfactory immune recovery during effective combination antiretroviral therapy (cART) have yet to be fully understood. We investigated whether polymorphism of genes encoding immune-regulating molecules, such as killer immunoglobulin-like receptors (KIR) and their ligands class I human leukocyte antigen (HLA), could influence immunological response to cART.

Methods

KIR and HLA frequencies were analyzed in 154 HIV-infected and cART-treated patients with undetectable viral load divided into two groups: ‘immunological non responders’ (INR, N = 50, CD4+ T-cell count <200/mm3) and full responders (FR, N = 104, CD4+ T-cell count >350/mm3). Molecular KIR were typed using polymerase chain reaction-based genotyping. Comparisons were adjusted for baseline patient characteristics.

Results

The frequency of KIR2DL3 allele was significantly higher in FR than in INR (83.7% vs. 62%, P = 0.005). The functional compound genotype HLA-C1+/KIR2DL3+, even at multivariable analysis, when adjusted for nadir CD4+ T-cell count, was associated with reduced risk of INR status: odds ratio (95% Confidence Intervals) 0.34 (0.13−0.88), P = 0.03.

Conclusions

Reduced presence of the inhibitory KIR2DL3 genotype detected in INR might provoke an imbalance in NK function, possibly leading to increased immune activation, impaired killing of latently infected cells, and higher proviral burden. These factors would hinder full immune recovery during therapy.

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<![CDATA[Estimating Implementation and Operational Costs of an Integrated Tiered CD4 Service including Laboratory and Point of Care Testing in a Remote Health District in South Africa]]> https://www.researchpad.co/article/5989d9f4ab0ee8fa60b6fb8b

Background

An integrated tiered service delivery model (ITSDM) has been proposed to provide ‘full-coverage’ of CD4 services throughout South Africa. Five tiers are described, defined by testing volumes and number of referring health-facilities. These include: (1) Tier-1/decentralized point-of-care service (POC) in a single site; Tier-2/POC-hub servicing processing <30–40 samples from 8–10 health-clinics; Tier-3/Community laboratories servicing ∼50 health-clinics, processing <150 samples/day; high-volume centralized laboratories (Tier-4 and Tier-5) processing <300 or >600 samples/day and serving >100 or >200 health-clinics, respectively. The objective of this study was to establish costs of existing and ITSDM-tiers 1, 2 and 3 in a remote, under-serviced district in South Africa.

Methods

Historical health-facility workload volumes from the Pixley-ka-Seme district, and the total volumes of CD4 tests performed by the adjacent district referral CD4 laboratories, linked to locations of all referring clinics and related laboratory-to-result turn-around time (LTR-TAT) data, were extracted from the NHLS Corporate-Data-Warehouse for the period April-2012 to March-2013. Tiers were costed separately (as a cost-per-result) including equipment, staffing, reagents and test consumable costs. A one-way sensitivity analyses provided for changes in reagent price, test volumes and personnel time.

Results

The lowest cost-per-result was noted for the existing laboratory-based Tiers- 4 and 5 ($6.24 and $5.37 respectively), but with related increased LTR-TAT of >24–48 hours. Full service coverage with TAT <6-hours could be achieved with placement of twenty-seven Tier-1/POC or eight Tier-2/POC-hubs, at a cost-per-result of $32.32 and $15.88 respectively. A single district Tier-3 laboratory also ensured ‘full service coverage’ and <24 hour LTR-TAT for the district at $7.42 per-test.

Conclusion

Implementing a single Tier-3/community laboratory to extend and improve delivery of services in Pixley-ka-Seme, with an estimated local ∼12–24-hour LTR-TAT, is ∼$2 more than existing referred services per-test, but 2–4 fold cheaper than implementing eight Tier-2/POC-hubs or providing twenty-seven Tier-1/POCT CD4 services.

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<![CDATA[Early Divergent Host Responses in SHIVsf162P3 and SIVmac251 Infected Macaques Correlate with Control of Viremia]]> https://www.researchpad.co/article/5989db0aab0ee8fa60bc9cc4

We previously showed intravaginal inoculation with SHIVsf162p3 results in transient viremia followed by undetectable viremia in most macaques, and some displayed subsequent immunity to superinfection with pathogenic SIVmac251. Here we compare early T cell activation, proliferation, and plasma cytokine/chemokine responses in macaques intravaginally infected with either SHIVsf162p3 or SIVmac251 to determine whether distinct differences in host responses may be associated with early viral containment. The data show SIVmac251 infection results in significantly higher levels of T cell activation, proliferation, and a mixed cytokine/chemokine “storm” in plasma in primary infection, whereas infection with SHIVsf162p3 resulted in significantly lower levels of T cell activation, proliferation, and better preservation of memory CD4+ T cells in early infection which immediately preceded control of viremia. These results support the hypothesis that early systemic immune activation, T cell proliferation, and a more prominent and broader array of cytokine/chemokine responses facilitate SIV replication, and may play a key role in persistence of infection, and the progression to AIDS. In contrast, immune unresponsiveness may be associated with eventual clearance of virus, a concept that may have key significance for therapy and vaccine design.

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<![CDATA[Hematological Changes as Prognostic Indicators of Survival: Similarities Between Gottingen Minipigs, Humans, and Other Large Animal Models]]> https://www.researchpad.co/article/5989d9f9ab0ee8fa60b71231

Background

The animal efficacy rule addressing development of drugs for selected disease categories has pointed out the need to develop alternative large animal models. Based on this rule, the pathophysiology of the disease in the animal model must be well characterized and must reflect that in humans. So far, manifestations of the acute radiation syndrome (ARS) have been extensively studied only in two large animal models, the non-human primate (NHP) and the canine. We are evaluating the suitability of the minipig as an additional large animal model for development of radiation countermeasures. We have previously shown that the Gottingen minipig manifests hematopoietic ARS phases and symptoms similar to those observed in canines, NHPs, and humans.

Principal Findings

We establish here the LD50/30 dose (radiation dose at which 50% of the animals succumb within 30 days), and show that at this dose the time of nadir and the duration of cytopenia resemble those observed for NHP and canines, and mimic closely the kinetics of blood cell depletion and recovery in human patients with reversible hematopoietic damage (H3 category, METREPOL approach). No signs of GI damage in terms of diarrhea or shortening of villi were observed at doses up to 1.9 Gy. Platelet counts at days 10 and 14, number of days to reach critical platelet values, duration of thrombocytopenia, neutrophil stress response at 3 hours and count at 14 days, and CRP-to-platelet ratio were correlated with survival. The ratios between neutrophils, lymphocytes and platelets were significantly correlated with exposure to irradiation at different time intervals.

Significance

As a non-rodent animal model, the minipig offers a useful alternative to NHP and canines, with attractive features including ARS resembling human ARS, cost, and regulatory acceptability. Use of the minipig may allow accelerated development of radiation countermeasures.

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<![CDATA[Mannose-Binding Lectin Deficiency Is Associated With Smaller Infarction Size and Favorable Outcome in Ischemic Stroke Patients]]> https://www.researchpad.co/article/5989db08ab0ee8fa60bc94e6

Background

The Mannose-binding lectin (MBL) pathway of complement plays a pivotal role in the pathogenesis of ischemia/reperfusion (I/R) injury after experimental ischemic stroke. As comparable data in human ischemic stroke are limited, we investigated in more detail the association of MBL deficiency with infarction volume and functional outcome in a large cohort of patients receiving intravenous thrombolysis or conservative treatment.

Methodology/Principal Findings

In a post hoc analysis of a prospective cohort study, admission MBL concentrations were determined in 353 consecutive patients with an acute ischemic stroke of whom 287 and 66 patients received conservative and thrombolytic treatment, respectively. Stroke severity, infarction volume, and functional outcome were studied in relation to MBL concentrations at presentation to the emergency department. MBL levels on admission were not influenced by the time from symptom onset to presentation (p = 0.53). In the conservative treatment group patients with mild strokes at presentation, small infarction volumes or favorable outcomes after three months demonstrated 1.5 to 2.6-fold lower median MBL levels (p = 0.025, p = 0.0027 and p = 0.046, respectively) compared to patients with more severe strokes. Moreover, MBL deficient patients (<100 ng/ml) were subject to a considerably decreased risk of an unfavorable outcome three months after ischemic stroke (adjusted odds ratio 0.38, p<0.05) and showed smaller lesion volumes (mean size 0.6 vs. 18.4 ml, p = 0.0025). In contrast, no association of MBL concentration with infarction volume or functional outcome was found in the thrombolysis group. However, the small sample size limits the significance of this observation.

Conclusions

MBL deficiency is associated with smaller cerebral infarcts and favorable outcome in patients receiving conservative treatment. Our data suggest an important role of the lectin pathway in the pathophysiology of cerebral I/R injury and might pave the way for new therapeutic interventions.

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<![CDATA[Impact of Rituximab on Immunoglobulin Concentrations and B Cell Numbers after Cyclophosphamide Treatment in Patients with ANCA-Associated Vasculitides]]> https://www.researchpad.co/article/5989dacfab0ee8fa60bb5ae5

Objective

To assess the impact of immunosuppressive therapy with cyclophosphamide (CYC) and rituximab (RTX) on serum immunoglobulin (Ig) concentrations and B lymphocyte counts in patients with ANCA-associated vasculitides (AAVs).

Methods

Retrospective analysis of Ig concentrations and peripheral B cell counts in 55 AAV patients.

Results

CYC treatment resulted in a decrease in Ig levels (median; interquartile range IQR) from IgG 12.8 g/L (8.15-15.45) to 9.17 g/L (8.04-9.90) (p = 0.002), IgM 1.05 g/L (0.70-1.41) to 0.83 g/L (0.60-1.17) (p = 0.046) and IgA 2.58 g/L (1.71-3.48) to 1.58 g/L (1-31-2.39) (p = 0.056) at a median follow-up time of 4 months. IgG remained significantly below the initial value at 14.5 months and 30 months analyses. Subsequent RTX treatment in patients that had previously received CYC resulted in a further decline in Ig levels from pre RTX IgG 9.84 g/L (8.71-11.60) to 7.11 g/L (5.75-8.77; p = 0.007), from pre RTX IgM 0.84 g/L (0.63-1.18) to 0.35 g/L (0.23-0.48; p<0.001) and from pre RTX IgA 2.03 g/L (1.37-2.50) to IgA 1.62 g/L (IQR 0.84-2.43; p = 0.365) 14 months after RTX. Treatment with RTX induced a complete depletion of B cells in all patients. After a median observation time of 20 months median B lymphocyte counts remained severely suppressed (4 B-cells/µl, 1.25-9.5, p<0.001). Seven patients (21%) that had been treated with CYC followed by RTX were started on Ig replacement because of severe bronchopulmonary infections and serum IgG concentrations below 5 g/L.

Conclusions

In patients with AAVs, treatment with CYC leads to a decline in immunoglobulin concentrations. A subsequent RTX therapy aggravates the decline in serum immunoglobulin concentrations and results in a profoundly delayed B cell repopulation. Surveying patients with AAVs post CYC and RTX treatment for serum immunoglobulin concentrations and persisting hypogammaglobulinemia is warranted.

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<![CDATA[TRAM Is Involved in IL-18 Signaling and Functions as a Sorting Adaptor for MyD88]]> https://www.researchpad.co/article/5989da8eab0ee8fa60b9ef48

MyD88, a Toll/interleukin-1 receptor homology (TIR) domain-containing adaptor protein, mediates signals from the Toll-like receptors (TLR) or IL-1/IL-18 receptors to downstream kinases. In MyD88-dependent TLR4 signaling, the function of MyD88 is enhanced by another TIR domain-containing adaptor, Mal/TIRAP, which brings MyD88 to the plasma membrane and promotes its interaction with the cytosolic region of TLR4. Hence, Mal is recognized as the “sorting adaptor” for MyD88. In this study, a direct interaction between MyD88-TIR and another membrane-sorting adaptor, TRAM/TICAM-2, was demonstrated in vitro. Cell-based assays including RNA interference experiments and TRAM deficient mice revealed that the interplay between MyD88 and TRAM in cells is important in mediating IL-18 signal transduction. Live cell imaging further demonstrated the co-localized accumulation of MyD88 and TRAM in the membrane regions in HEK293 cells. These findings suggest that TRAM serves as the sorting adaptor for MyD88 in IL-18 signaling, which then facilitates the signal transduction. The binding sites for TRAM are located in the TIR domain of MyD88 and actually overlap with the binding sites for Mal. MyD88, the multifunctional signaling adaptor that works together with most of the TLR members and with the IL-1/IL-18 receptors, can interact with two distinct sorting adaptors, TRAM and Mal, in a conserved manner in a distinct context.

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<![CDATA[CD46 Protects against Chronic Obstructive Pulmonary Disease]]> https://www.researchpad.co/article/5989da20ab0ee8fa60b7eb7d

Background

Chronic obstructive pulmonary disease and emphysema develops in 15% of ex-smokers despite sustained quitting, while 10% are free of emphysema or severe lung obstruction. The cause of the incapacity of the immune system to clear the inflammation in the first group remains unclear.

Methods and Findings

We searched genes that were protecting ex-smokers without emphysema, using microarrays on portions of human lungs surgically removed; we found that loss of lung function in patients with chronic obstructive pulmonary disease and emphysema was associated with a lower expression of CD46 and verified this finding by qRT-PCR and flow cytometry. Also, there was a significant association among decreased CD46+ cells with decreased CD4+T cells, apoptosis mediator CD95 and increased CD8+T cells that were protecting patients without emphysema or severe chronic obstructive pulmonary disease. CD46 not only regulates the production of T regulatory cells, which suppresses CD8+T cell proliferation, but also the complement cascade by degradation of C3b. These results were replicated in the murine smoking model, which showed increased C5a (produced by C3b) that suppressed IL12 mediated bias to T helper 1 cells and elastin co-precipitation with C3b, suggesting that elastin could be presented as an antigen. Thus, using ELISA from elastin peptides, we verified that 43% of the patients with severe early onset of chronic obstructive pulmonary disease tested positive for IgG to elastin in their serum compared to healthy controls.

Conclusions

These data suggest that higher expression of CD46 in the lungs of ex-smoker protects them from emphysema and chronic obstructive pulmonary disease by clearing the inflammation impeding the proliferation of CD8+ T cells and necrosis, achieved by production of T regulatory cells and degradation of C3b; restraining the complement cascade favors apoptosis over necrosis, protecting them from autoimmunity and chronic inflammation.

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<![CDATA[Copy Number Analysis of Complement C4A, C4B and C4A Silencing Mutation by Real-Time Quantitative Polymerase Chain Reaction]]> https://www.researchpad.co/article/5989da3eab0ee8fa60b89165

Low protein levels and copy number variation (CNV) of the fourth component of human complement (C4A and C4B) have been associated with various diseases. High-throughput methods for analysing C4 CNV are available, but they commonly do not detect the most common C4A mutation, a silencing CT insertion (CTins) leading to low protein levels. We developed a SYBR® Green labelled real-time quantitative polymerase chain reaction (qPCR) with a novel concentration range approach to address C4 CNV and deficiencies due to CTins. This method was validated in three sample sets and applied to over 1600 patient samples. CTins caused C4A deficiency in more than 70% (76/105) of the carriers. Twenty per cent (76/381) of patients with a C4A deficiency would have been erroneously recorded as having none, if the CTins had not been assessed. C4A deficiency was more common in patients than a healthy reference population, (OR = 1.60, 95%CI = 1.02–2.52, p = 0.039). The number of functional C4 genes can be straightforwardly analyzed by real-time qPCR, also with SYBR® Green labelling. Determination of CTins increases the frequency of C4A deficiency and thus helps to elucidate the genotypic versus phenotypic disease associations.

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<![CDATA[Deficiency of adaptive immunity does not interfere with Wallerian degeneration]]> https://www.researchpad.co/article/5989db5aab0ee8fa60bdf55d

Following injury, distal axons undergo the process of Wallerian degeneration, and then cell debris is cleared to create a permissive environment for axon regeneration. The innate and adaptive immune systems are believed to be critical for facilitating the clearance of myelin and axonal debris during this process. However, immunodeficient animal models are regularly used in transplantation studies investigating cell therapies to modulate the degenerative/regenerative response. Given the importance of the immune system in preparing a permissive environment for regeneration by clearing debris, animals lacking, in part or in full, a functional immune system may have an impaired ability to regenerate due to poor myelin clearance, and may, thus, be poor hosts to study modulators of regeneration and degeneration. To study this hypothesis, three different mouse models with impaired adaptive immunity were compared to wild type animals in their ability to degenerate axons and clear myelin debris one week following sciatic nerve transection. Immunofluorescent staining for axons and quantitation of axon density with nerve histomorphometry of the distal stump showed no consistent discrepancy between immunodeficient and wild type animals, suggesting axons tended to degenerate equally between the two groups. Debris clearance was assessed by macrophage density and relative myelin basic protein expression within the denervated nerve stump, and no consistent impairment of debris clearance was found. These data suggested deficiency of the adaptive immune system does not have a substantial effect on axon degeneration one week following axonal injury.

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<![CDATA[Reconstitution of Intestinal CD4 and Th17 T Cells in Antiretroviral Therapy Suppressed HIV-Infected Subjects: Implication for Residual Immune Activation from the Results of a Clinical Trial]]> https://www.researchpad.co/article/5989d9f4ab0ee8fa60b6f7ef

Introduction

During HIV infection the severe depletion of intestinal CD4+ T-cells is associated with microbial translocation, systemic immune activation, and disease progression. This study examined intestinal and peripheral CD4+ T-cell subsets reconstitution under combined antiretroviral therapy (cART), and systemic immune activation markers.

Methods

This longitudinal single-arm pilot study evaluates CD4+ T cells, including Th1 and Th17, in gut and blood and soluble markers for inflammation in HIV-infected individuals before (M0) and after eight (M8) months of cART. From January 2010 to December 2011, 10 HIV-1 naïve patients were screened and 9 enrolled. Blood and gut CD4+ T-cells subsets and cellular immune activation were determined by flow-cytometry and plasma soluble CD14 by ELISA. CD4+ Th17 cells were detected in gut biopsies by immunohistochemistry. Microbial translocation was measured by limulus-amebocyte-lysate assay to detect bacterial lipopolysaccharide (LPS) and PCR Real Time to detect plasma bacterial 16S rDNA.

Results

Eight months of cART increased intestinal CD4+ and Th17 cells and reduced levels of T-cell activation and proliferation. The magnitude of intestinal CD4+ T-cell reconstitution correlated with the reduction of plasma LPS. Importantly, the magnitude of Th17 cells reconstitution correlated directly with blood CD4+ T-cell recovery.

Conclusion

Short-term antiretroviral therapy resulted in a significant increase in the levels of total and Th17 CD4+ T-cells in the gut mucosa and in decline of T-cell activation. The observation that pre-treatment levels of CD4+ and of CD8+ T-cell activation are predictors of the magnitude of Th17 cell reconstitution following cART provides further rationale for an early initiation of cART in HIV-infected individuals.

Trial Registration

ClinicalTrials.gov NCT02097381

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<![CDATA[Human FOXN1-Deficiency Is Associated with αβ Double-Negative and FoxP3+ T-Cell Expansions That Are Distinctly Modulated upon Thymic Transplantation]]> https://www.researchpad.co/article/5989da2eab0ee8fa60b838c1

Forkhead box N1 (FOXN1) is a transcription factor crucial for thymic epithelium development and prevention of its involution. Investigation of a patient with a rare homozygous FOXN1 mutation (R255X), leading to alopecia universalis and thymus aplasia, unexpectedly revealed non-maternal circulating T-cells, and, strikingly, large numbers of aberrant double-negative αβ T-cells (CD4negCD8neg, DN) and regulatory-like T-cells. These data raise the possibility that a thymic rudiment persisted, allowing T-cell development, albeit with disturbances in positive/negative selection, as suggested by DN and FoxP3+ cell expansions. Although regulatory-like T-cell numbers normalized following HLA-mismatched thymic transplantation, the αβDN subset persisted 5 years post-transplantation. Involution of thymus allograft likely occurred 3 years post-transplantation based on sj/βTREC ratio, which estimates intrathymic precursor T-cell divisions and, consequently, thymic explant output. Nevertheless, functional immune-competence was sustained, providing new insights for the design of immunological reconstitution strategies based on thymic transplantation, with potential applications in other clinical settings.

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<![CDATA[Targeted sequencing identifies a novel SH2D1A pathogenic variant in a Chinese family: Carrier screening and prenatal genetic testing]]> https://www.researchpad.co/article/5989db4fab0ee8fa60bdbb8f

X-linked lymphoproliferative disease type 1 (XLP1) is a rare primary immunodeficiency characterized by a clinical triad consisting of severe EBV-induced hemophagocytic lymphohistiocytosis, B-cell lymphoma, and dysgammaglobulinemia. Mutations in SH2D1A gene have been revealed as the cause of XLP1. In this study, a pregnant woman with recurrence history of birthing immunodeficiency was screened for pathogenic variant because the proband sample was unavailable. We aimed to clarify the genetic diagnosis and provide prenatal testing for the family. Next-generation sequencing (NGS)-based multigene panel was used in carrier screening of the pregnant woman. Variants of immunodeficiency related genes were analyzed and prioritized. Candidate variant was verified by using Sanger sequencing. The possible influence of the identified variant was evaluated through RNA assay. Amniocentesis, karyotyping, and Sanger sequencing were performed for prenatal testing. We identified a novel de novo frameshift SH2D1A pathogenic variant (c.251_255delTTTCA) in the pregnant carrier. Peripheral blood RNA assay indicated that the mutant transcript could escape nonsense-mediated mRNA decay (NMD) and might encode a C-terminal truncated protein. Information of the variant led to success prenatal diagnosis of the fetus. In conclusion, our study clarified the genetic diagnosis and altered disease prevention for a pregnant carrier of XLP1.

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<![CDATA[Enhanced Neointima Formation Following Arterial Injury in Immune Deficient Rag-1−/− Mice Is Attenuated by Adoptive Transfer of CD8+ T cells]]> https://www.researchpad.co/article/5989dae4ab0ee8fa60bbcc59

T cells modulate neointima formation after arterial injury but the specific T cell population that is activated in response to arterial injury remains unknown. The objective of the study was to identify the T cell populations that are activated and modulate neointimal thickening after arterial injury in mice. Arterial injury in wild type C57Bl6 mice resulted in T cell activation characterized by increased CD4+CD44hi and CD8+CD44hi T cells in the lymph nodes and spleens. Splenic CD8+CD25+ T cells and CD8+CD28+ T cells, but not CD4+CD25+ and CD4+CD28+ T cells, were also significantly increased. Adoptive cell transfer of CD4+ or CD8+ T cells from donor CD8−/− or CD4−/− mice, respectively, to immune-deficient Rag-1−/− mice was performed to determine the T cell subtype that inhibits neointima formation after arterial injury. Rag-1−/− mice that received CD8+ T cells had significantly reduced neointima formation compared with Rag-1−/− mice without cell transfer. CD4+ T cell transfer did not reduce neointima formation. CD8+ T cells from CD4−/− mice had cytotoxic activity against syngeneic smooth muscle cells in vitro. The study shows that although both CD8+ T cells and CD4+ T cells are activated in response to arterial injury, adoptive cell transfer identifies CD8+ T cells as the specific and selective cell type involved in inhibiting neointima formation.

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<![CDATA[T-Lymphocytes Enable Osteoblast Maturation via IL-17F during the Early Phase of Fracture Repair]]> https://www.researchpad.co/article/5989dae0ab0ee8fa60bbbc29

While it is well known that the presence of lymphocytes and cytokines are important for fracture healing, the exact role of the various cytokines expressed by cells of the immune system on osteoblast biology remains unclear. To study the role of inflammatory cytokines in fracture repair, we studied tibial bone healing in wild-type and Rag1−/− mice. Histological analysis, µCT stereology, biomechanical testing, calcein staining and quantitative RNA gene expression studies were performed on healing tibial fractures. These data provide support for Rag1−/− mice as a model of impaired fracture healing compared to wild-type. Moreover, the pro-inflammatory cytokine, IL-17F, was found to be a key mediator in the cellular response of the immune system in osteogenesis. In vitro studies showed that IL-17F alone stimulated osteoblast maturation. We propose a model in which the Th17 subset of T-lymphocytes produces IL-17F to stimulate bone healing. This is a pivotal link in advancing our current understanding of the molecular and cellular basis of fracture healing, which in turn may aid in optimizing fracture management and in the treatment of impaired bone healing.

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<![CDATA[Placental Transfer of Maternally-Derived IgA Precludes the Use of Guthrie Card Eluates as a Screening Tool for Primary Immunodeficiency Diseases]]> https://www.researchpad.co/article/5989dad5ab0ee8fa60bb7903

There is a need for neonatal screening tools to improve the long-term clinical outcome of patients with primary immunodeficiency diseases (PID). Recently, a PCR-based screening method for both TRECs and KRECs using Guthrie card samples has been developed. However, the applicability of these excision circle assays is limited to patients with severe T or B cell lymphopenia (SCID, XLA and A-T), whereas the most common forms of PID are not detected. Absence of serum IgA is seen in a major fraction of patients with immunological defects. As serum IgA in newborns is considered to be of fetal origin, eluates from routinely collected dried blood spot samples might thus be suitable for identification of children with PID. To assess the applicability of such screening assays, stored Guthrie card samples were obtained from 47 patients with various forms of primary immunodeficiency diseases (SCID, XLA, A-T, HIGM and IgAD), 20 individuals with normal serum IgA levels born to IgA-deficient mothers and 51 matched healthy newborns. Surprisingly, normal serum IgA levels were found in all SCID, XLA, A-T and HIGM patients and, additionally, in all those IgAD patients born to IgA-sufficient mothers. Conversely, no serum IgA was found in any of the 16 IgAD patients born by IgA-deficient mothers. Moreover, half of the IgA-sufficient individuals born by IgA-deficient mothers also lacked IgA at birth whereas no IgA-deficient individuals were found among the controls. IgA in neonatal dried blood samples thus appears to be of both maternal and fetal origin and precludes its use as a reliable marker for neonatal screening of primary immunodeficiency diseases.

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