Chemical chaperones reverse early suppression of regulatory circuits during unfolded protein response in B cells from common variable immunodeficiency patients.

B cells orchestrate pro-survival and pro-apoptotic inputs during unfolded protein response (UPR) to translate, fold, sort, secrete and recycle immunoglobulins. In common variable immunodeficiency (CVID) patients, activated B cells are predisposed to an overload of abnormally processed, misfolded immunoglobulins. Using highly accurate transcript measurements, we show that expression of UPR genes and immunoglobulin chains differs qualitatively and quantitatively during the first 4 h of chemically induced UPR in B cells from CVID patients and a healthy subject. We tested thapsigargin or tunicamycin as stressors and 4-phenylbutyrate, dimethyl sulfoxide and tauroursodeoxycholic acid as chemical chaperones. We found an early and robust decrease of the UPR upon endoplasmic reticulum (ER) stress in CVID patient cells compared to the healthy control consistent with the disease phenotype. The chemical chaperones increased the UPR in the CVID patient cells in response to the stressors, suggesting that misfolded immunoglobulins were stabilized. We suggest that the AMP-dependent transcription factor alpha branch of the UPR is disturbed in CVID patients, underlying the observed expression behavior.

Common variable immunodeficiency-associated endotoxemia promotes early commitment to the T follicular lineage.

BACKGROUND: Although chiefly a B-lymphocyte disorder, several research groups have identified common variable immunodeficiency (CVID) subjects with numeric and/or functional TH cell alterations. The causes, interrelationships, and consequences of CVID-associated CD4+ T-cell derangements to hypogammaglobulinemia, autoantibody production, or both remain unclear. OBJECTIVE: We sought to determine how circulating CD4+ T cells are altered in CVID subjects with autoimmune cytopenias (AICs; CVID+AIC) and the causes of these derangements. METHODS: Using hypothesis-generating, high-dimensional single-cell analyses, we created comprehensive phenotypic maps of circulating CD4+ T cells. Differences between subject groups were confirmed in a large and genetically diverse cohort of CVID subjects (n = 69) by using flow cytometry, transcriptional profiling, multiplex cytokine/chemokine detection, and a suite of in vitro functional assays measuring naive T-cell differentiation, B-cell/T-cell cocultures, and regulatory T-cell suppression. RESULTS: Although CD4+ TH cell profiles from healthy donors and CVID subjects without AICs were virtually indistinguishable, T cells from CVID+AIC subjects exhibited follicular features as early as thymic egress. Follicular skewing correlated with IgA deficiency-associated endotoxemia and endotoxin-induced expression of activin A and inducible T-cell costimulator ligand. The resulting enlarged circulating follicular helper T-cell population from CVID+AIC subjects provided efficient help to receptive healthy donor B cells but not unresponsive CVID B cells. Despite this, circulating follicular helper T cells from CVID+AIC subjects exhibited aberrant transcriptional profiles and altered chemokine/cytokine receptor expression patterns that interfered with regulatory T-cell suppression assays and were associated with autoantibody production. CONCLUSIONS: Endotoxemia is associated with early commitment to the follicular T-cell lineage in IgA-deficient CVID subjects, particularly those with AICs.

Renal Evaluation in Common Variable Immunodeficiency.

INTRODUCTION: Common variable immunodeficiency (CVID) comprises a heterogeneous group of disorders characterized by impaired antibody production. Kidney involvement in CVID is described in isolated and sporadic case reports. The objective of this study was to study the renal function pattern in CVID patients through glomerular and tubular function tests. METHODS: Study of 12 patients with CVID diagnosis and 12 healthy control individuals. Glomerular filtration rate (GFR), fractional excretion of sodium (FENa+ ) and potassium (FEK+ ), urinary concentration, and acidification capacity were measured. In addition, microalbuminuria and urinary monocyte chemoattractant protein-1 (MCP-1) were evaluated as markers of selectivity of the glomerular barrier and inflammation, respectively. RESULTS: In relation to glomerular markers, all CVID patients had normal GFR (>90 mL/min/1.73 m2), and microalbuminuria and urinary MCP-1 levels were also similar to those of controls. Interestingly, CVID patients had reduced urinary concentration capacity, as demonstrated by lower U/POsm ratio, when compared to controls. Also, while all control subjects achieved a urinary pH less than 5.3, no CVID patients showed a decrease in urinary pH to such levels in response to acid loading with CaCl2, characterizing impaired urinary acidification capacity. CONCLUSION: Patients showed a trend towards an elevated prevalence of tubular dysfunction, mainly related to urinary acidification and concentration capacities.

Hypogammaglobulinemia in children: a warning sign to look deeply?

This study investigated phenotypic and functional characteristics of lymphocytes in children with common variable immunodeficiency (CVID) and unclassified hypogammaglobulinemia (UH), as well as B-cell subsets in non-consanguineous parents. Blood samples of 30 children, CVID (n = 9), UH (n = 9), healthy donors HD (n = 12), and 19 adults (parents and controls) were labeled by a combination of surface markers to identify CD4, CD8 T-cell and B-cell subpopulations. T-cell cytokine production in children was analyzed in vitro after stimulation with phytohemagglutinin (PHA) and tetanus toxoid. We observed low percentages of switched memory B cells in children with CVID, increase in total CD4+ T-cell counts, and high percentages of transitional B cells only in UH group. Analysis of T-cell immunity showed that CVID children had decreased percentages of CD8+ IFN-γ-producing cells after stimulation with PHA and tetanus toxoid. Parent of children with CVID had low percentages of naive B cell and increased percentages of memory B cells in comparison with controls. These results suggest that (i) early combined immune defect in children with CVID and (ii) a possible familial B-cell disturbance in pediatric CVID.

Linfadenite recorrente. Caso clínico / Recurrent lymphadenitis. Case report

A imunodeficiência de variável comum é uma imunodeficiência primária de apresentação heterogênea, consistindo em um défice em imunoglobulinas. É caracterizada por infeções de repetição e predisposição para doenças autoimunes, granulomatosas e neoplásicas. Os autores apresentam o caso clínico de um doente com imunodeficiência comum variável manifestada por infeções cutâneas de repetição e linfadenite recorrente. Este caso tem como objetivo alertar para os aspetos clínicos desta imunodeficiência, a fim de permitir seu diagnóstico precoce, evitando-se prognósticos desfavoráveis.(AU)

Common variable immunodeficiency is a primary immunodeficiency with a heterogeneous presentation, characterized by decreased immunoglobulin levels. It is characterized by recurrent infections, predisposition to autoimmune, granulomatous and neoplastic diseases. The authors report a case of a patient with common variable immunodeficiency and history of skin infections and recurrent lymphadenitis. This case report aims to draw the attention to the clinical aspects of this immunodeficiency, in order to promote an early diagnosis, avoiding poor outcomes.(AU)

Common Variable Immunodeficiency and Circulating TFH.

CD4+ T follicular helper cells (TFH) were assessed in adult patients with common variable immune deficiency (CVID) classified according to the presence of granulomatous disease (GD), autoimmunity (AI), or both GD and AI (Group I) or the absence of AI and GD (Group II). TFH lymphocytes were characterized by expression of CXCR5 and PD-1. TFH were higher (in both absolute number and percentage) in Group I than in Group II CVID patients and normal controls (N). Within CXCR5+CD4+ T cells, the percentage of PD-1 (+) was higher and that of CCR7 (+) was lower in Group I than in Group II and N. The percentages of Treg and TFH reg were similar in both CVID groups and in N. TFH responded to stimulation increasing the expression of the costimulatory molecules CD40L and ICOS as did N. After submitogenic PHA+IL-2 stimulation, intracellular expression of TFH cytokines (IL-10, IL-21) was higher than N in Group I, and IL-4 was higher than N in Group II. These results suggest that TFH are functional in CVID and highlight the association of increased circulating TFH with AI and GD manifestations.

Rare variants at 16p11.2 are associated with common variable immunodeficiency.

BACKGROUND: Common variable immunodeficiency (CVID) is characterized clinically by inadequate quantity and quality of serum immunoglobulins with increased susceptibility to infections, resulting in significant morbidity and mortality. Only a few genes have been uncovered, and the genetic background of CVID remains elusive to date for the majority of patients. OBJECTIVE: We sought to seek novel associations of genes and genetic variants with CVID. METHODS: We performed association analyses in a discovery cohort of 164 patients with CVID and 19,542 healthy control subjects genotyped on the Immuno BeadChip from Illumina platform; replication of findings was examined in an independent cohort of 135 patients with CVID and 2,066 healthy control subjects, followed by meta-analysis. RESULTS: We identified 11 single nucleotide polymorphisms (SNPs) at the 16p11.2 locus associated with CVID at a genome-wide significant level in the discovery cohort. The most significant SNP, rs929867 (P = 6.21 × 10(-9)), is in the gene fused-in-sarcoma (FUS), with 4 other SNPs mapping to integrin CD11b (ITGAM). Results were confirmed in our replication cohort. Conditional association analysis suggests a single association signal at the 16p11.2 locus. A strong trend of association was also seen for 38 SNPs (P < 5 × 10(-5)) in the MHC region, supporting that this is a genuine CVID locus. Interestingly, we found that 80% of patients with the rare ITGAM variants have reduced switched memory B-cell counts. CONCLUSION: We report a novel association of CVID with rare variants at the FUS/ITGAM (CD11b) locus on 16p11.2. The association signal is enriched for promoter/enhancer markers in the ITGAM gene. ITGAM encodes the integrin CD11b, a part of complement receptor 3, a novel candidate gene implicated here for the first time in the pathogenesis of CVID.

[Interstitial lymphoid pneumonia associated with common variable immunodeficiency]. / Neumonía intersticial linfoidea asociada a inmunodeficiencia común variable.

The interstitial lymphoid pneumonia (LIP) is an uncommon disorder, described as non-neoplastic lung lymphoid tissue hyperplasia and classified as an interstitial lung disease. It has been described in association with HIV infection, autoimmune disorders, policlonal hypergammaglobulinemia and less frequently, with hypogammaglobulinemia. We report the case of a 66 year old female patient with a history of diabetes, Sjogren syndrome and hypertension. She was referred to our hospital due to a dry cough and dyspnea (FC II-III). The physical examination showed bilateral dry crackles and splenomegaly. Laboratory studies showed thrombocytopenia (50 000/ mm3) and hypogammaglobulinemia. A computed tomography thoracic scan showed interstitial bilateral basal lung infiltrates with small peribroncovascular nodules. A lung biopsy was made by thoracoscopy and reported LIP. Initial treatment consisted of oral methilprednisone, 40 mg daily, and once a month intravenous gammaglobulin 500 mg/kg, with good clinical and radiological response. A splenectomy was done due to persistent thrombocytopenia associated with hypersplenism, with good response of the platelets counts. No lymphoid clonal or other associated disease was detected.

Neumonía intersticial linfoidea asociada a inmunodeficiencia común variable / Interstitial lymphoid pneumonia associated with common variable immunodeficiency

La neumonía intersticial linfoidea (NIL) es una rara entidad, descripta como hiperplasia no neoplásica del tejido linfoide pulmonar y clasificada dentro de las enfermedades intersticiales idiopáticas. Se la ha descripto asociada a infección por HIV, fenómenos autoinmunes, hipergamaglobulinemia policlonal o menos frecuentemente a hipogammaglobulinemia. Presentamos una paciente de 66 años de edad con diabetes mellitus, síndrome de Sjögren e hipertensión arterial, derivada a nuestro centro por tos seca y disnea clase funcional II-III. En el examen físico presentaba rales tipo “velcro” bibasales y esplenomegalia. Los estudios de laboratorio evidenciaron plaquetopenia (50 000/mm³) e hipogammaglobulinemia; la tomografía axial computarizada (TAC) de tórax mostró compromiso intersticial bibasal, con nódulos peribroncovasculares menores a un centímetro. Se realizó una videotoracoscopia con biopsia pulmonar, la anatomía patológica mostró hallazgos compatibles con neumonía intersticial linfoidea. Se inició tratamiento con metilprednisona 40 mg/día vía oral e infusión endovenosa de gammaglobulina 500 mg/kg, mensual, evolucionando con mejoría clínico-radiológica. Por persistencia de plaquetopenia, asociada a hiperesplenismo, se realizó esplenectomía con buena respuesta. En la anatomía patológica no se observo clonalidad linfoide.

The interstitial lymphoid pneumonia (LIP) is an uncommon disorder, described as non-neoplastic lung lymphoid tissue hyperplasia and classified as an interstitial lung disease. It has been described in association with HIV infection, autoimmune disorders, policlonal hypergammaglobulinemia and less frequently, with hypogammaglobulinemia. We report the case of a 66 year old female patient with a history of diabetes, Sjögren syndrome and hypertension. She was referred to our hospital due to a dry cough and dyspnea (FC II-III). The physical examination showed bilateral dry crackles and splenomegaly. Laboratory studies showed thrombocytopenia (50 000/ mm³) and hypogammaglobulinemia. A computed tomography thoracic scan showed interstitial bilateral basal lung infiltrates with small peribroncovascular nodules. A lung biopsy was made by thoracoscopy and reported LIP. Initial treatment consisted of oral methilprednisone, 40 mg daily, and once a month intravenous gammaglobulin 500 mg/kg, with good clinical and radiological response. A splenectomy was done due to persistent thrombocytopenia associated with hypersplenism, with good response of the platelets counts. No lymphoid clonal or other associated disease was detected.