Evaluation of Known Defective Signaling-Associated Molecules in Patients Who Primarily Diagnosed as Common Variable Immunodeficiency

Host JAK-STAT activity is a target of parasitoid wasp virulence strategies

Innate immune responses that allow hosts to survive infection depend on the action of multiple conserved signaling pathways. Pathogens and parasites in turn have evolved virulence factors to target these immune signaling pathways in an attempt to overcome host immunity. Consequently, the interactions between host immune molecules and pathogen virulence factors play an important role in determining the outcome of an infection. The immune responses of Drosophila melanogaster provide a valuable model to understand immune signaling and host-pathogen interactions. Flies are commonly infected by parasitoid wasps and mount a coordinated cellular immune response following infection. This response is characterized by the production of specialized blood cells called lamellocytes that form a tight capsule around wasp eggs in the host hemocoel. The conserved JAK-STAT signaling pathway has been implicated in lamellocyte proliferation and is required for successful encapsulation of wasp eggs. Here we show that activity of Stat92E, the D. melanogaster STAT ortholog, is induced in immune tissues following parasitoid infection. Virulent wasp species are able to suppress Stat92E activity during infection, suggesting they target JAK-STAT pathway activation as a virulence strategy. Furthermore, two wasp species (Leptopilina guineaensis and Ganaspis xanthopoda) suppress phenotypes associated with a gain-of-function mutation in hopscotch, the D. melanogaster JAK ortholog, indicating that they inhibit the activity of the core signaling components of the JAK-STAT pathway. Our data suggest that parasitoid wasp virulence factors block JAK-STAT signaling to overcome fly immune defenses.

Cytokine dysregulation despite immunoglobulin replacement therapy in common variable immunodeficiency (CVID)

Introduction

Common variable immunodeficiency (CVID) is the most prevalent symptomatic primary immunodeficiency. CVID is a heterogeneous disorder with a presumed multifactorial etiology. Intravenous or subcutaneous immunoglobulin replacement therapy (IgRT) can prevent severe infections but not underlying immune dysregulation.

Methods

In this study, we evaluated the serum concentrations of proinflammatory (TNF-α, IL-1β, IL-6) and immunoregulatory cytokines (IL-10), as well as lipopolysaccharide (LPS) and soluble CD14 (sCD14) in CVID individuals with infectious only (INF-CVID), and those with additional systemic autoimmune and inflammatory disorders (NIC-CVID), and healthy donors (HD).

Results

Our results showed increased serum concentrations of TNF-α, IL-1β, IL-6, and IL-10 in both INF-CVID and NIC-CVID subjects compared to HD. However, elevations of TNF-α, IL-1β, IL-6, and IL-10 were significantly more marked in NIC-CVID than INF-CVID. Additionally, LPS concentrations were increased only in NIC-CVID but not in INF-CVID compared to HD. Circulating levels of sCD14 were significantly increased in NIC-CVID compared to both INF-CVID and HD.

Discussion

These findings indicate persistent cytokine dysregulation despite IgRT in individuals with CVID. Moreover, the circulating cytokine profile reveals the heterogeneity of immune dysregulation in different subgroups of CVID subjects.

Autoimmune haemolytic anaemia due to immunodeficiency

Autoimmune disorders are common presenting manifestations of immunodeficiency syndromes. We present a case of a woman in her late teens, with a history of frequent sinopulmonary tract infections during her childhood, who presented to our hospital with anaemia, jaundice and fatigue. She also had significant physical growth retardation for her age and sex. With this case report, we intend to present the diagnostic and therapeutic challenges faced by the patient and our healthcare system and propose a few feasible solutions to tackle these challenges.

Atypical patterns of STAT3 phosphorylation in subpopulations B cells in patients with common variable immunodeficiency

BACKGROUND

Common Variable Immunodeficiency (CVID) is a heterogeneous disorder characterized by defective B cell differentiation and antibody production. Interleukin (IL)-21 activates STAT3, a potent regulator of B cell differentiation into plasma cells. We have studied the phosphorylation of STAT3 in CVID patients and its contribution to B cells subsets.

METHODS

We studied 23 CVID patients and 14 healthy donors (HD), determining pSTAT3 in naïve and memory B cells, stimulated with IL-21 at 15 and 60 min.

RESULTS

pSTAT3 was increased in total (p = 0.044), naïve (p = 0.023), and memory (p = 0.001) B cells at 60 min in CVID patients compared with HD. We classified patients by the percentage of isotype-switched memory B cells. We observed an increase in pSTAT3 at 60 min in memory B cells in both CVID groups of patients (p = 0.026, p = 0.007, respectively). Interestingly, the analysis of each group individually; demonstrated that patients with decreased memory B cells exhibited an increase in pSTAT3 at 60 min (p = 0.023), while HD had an expected decrease in pSTAT3 (p = 0.045).

CONCLUSION

CVID patients showed an increased atypical of pSTAT3, which could affect the differentiation of B cells. Further studies in the IL-21 pathway are necessary to understand how this alteration could promote differentiation defects in patient B cells.

Comprehensive Assessment of Skin Disorders in Patients with Common Variable Immunodeficiency (CVID)

BACKGROUND

Common variable immunodeficiency (CVID) is an inborn error of immunity (IEI) characterized by various clinical manifestations such as hypogammaglobulinemia, recurrent infections, and autoimmune diseases. Among different clinical manifestations, skin manifestations have been less reported in these patients.

METHODS

In this study, we investigated the prevalence of dermatologic features in 387 CVID patients. Demographic information, clinical manifestations, laboratory data, and genetic findings were collected from medical records. All data were analyzed based on the presence or absence of skin disorders in CVID patients.

RESULTS

We observed at least one skin manifestation in about 40% of these patients. Among these complications, skin infection (n = 64, 42.1%) was the most frequent presentation, followed by non-infectious skin lesions (n = 54, 35.6%). Among skin infections, abscesses (n = 34, 22.4%) were the most common complication. Skin infections such as cellulitis, impetigo, measles, and warts were also documented. Eczema (n = 34, 22.4%) was the most common complication in atopic lesions, and vitiligo (n = 13, 8.5%) was prevalent in autoimmune/pigmentation disorders. Among all the patients with genetic mutations, one-quarter had a deleterious mutation in the LRBA gene, relating to the autoimmune and atopic skin lesions.

CONCLUSION

This rate of skin disorders in our cohort demonstrating these manifestations could be significant in CVID patients, and they are not rare. Low data of skin complications in CVID patients could be attributed to insufficient attention of physicians and also might alert dermatologists to perform immunological investigations in children with certain skin manifestations.

Lymphocytes subsets in correlation with clinical profile in CVID patients without monogenic defects

Objectives: Common variable immunodeficiency (CVID) patients experience clinical manifestations rather than recurrent respiratory infections including autoimmunity, enteropathy, and lymphoproliferation. We evaluated the correlation of lymphocyte subpopulations with such manifestations.Methods: Twenty-six genetically unsolved CVID patients were subdivided into four phenotypes: infection only (IO), autoimmunity (AI), chronic enteropathy (CE), and lymphoproliferative disorders (LP) and examined for lymphocyte subsets by flow cytometry and TCD4⁺ proliferation by Carboxyfluorescein succinimidyl ester (CFSE) test.Results: We detected reduced memory B and increased total, effector memory (EM), cytotoxic, and activated TCD8⁺ in IO, AI and CE, decreased plasmablasts, total and naive TCD4⁺, Regulatory TCD4⁺ (Treg) and naive TCD8⁺ in IO and CE, elevated CD21^low B and terminally differentiated effector memory (T_EMRA) TCD8⁺ in IO and AI, increased helper T (Th2) and Th17 in IO, decreased Th1 in AI and defective total and naive B and central memory (CM) TCD4⁺ in CE. IO showed reduced TCD4⁺ proliferation response.Conclusions: In genetically unsolved CVID patients, increased Th2 and Th17 and reduced Treg is associated with IO, increased CD21^low B and T_EMRA TCD8⁺ and reduced Th1 is contributed to AI and reduced total and naive B, CM TCD4⁺ and naive TCD8⁺ and expanded total TCD8⁺ is correlated with CE.

The profile of IL-4, IL-5, IL-10 and GATA3 in patients with LRBA deficiency and CVID with no known monogenic disease: Association with disease severity

BACKGROUND

Common variable immunodeficiency (CVID) is the most common symptomatic form of primary immunodeficiency (PID). LPS-responsive beige-like anchor protein (LRBA) deficiency is an autosomal recessive disease characterized by a CVID-like phenotype. T cell abnormality was reported in patients with CVID and LRBA deficiency. The study's aim was to evaluate IL-4, IL-5, IL-10 and GATA3 expression in patients with LRBA deficiency and CVID with no known monogenic disease, and further evaluate its relevance with immunological futures and clinical complications of patients.

METHODS

The study population comprised patients with CVID, LRBA deficiency and age-sex matched healthy controls. Mutation analysis was done by whole exome sequencing in CVID patients to rule out monogenic PIDs. After CD4+ T cell stimulation with anti-CD3 and anti-CD28 monoclonal antibodies, gene expression of IL-4, IL-5, IL-10 and transcription factor GATA3 was evaluated by real-time polymerase chain reaction. The protein of mentioned cytokines was assessed by enzyme-linked immunosorbent assay.

RESULTS

The main clinical presentations of CVID patients were infections only and lymphoproliferations phenotypes, but in LRBA patients were autoimmune and enteropathy phenotype. The frequencies of CD4⁺ T cells were significantly reduced in LRBA and CVID patients. There were no statistically significant differences among GATA3, IL4, and IL5 gene expressions by CD4⁺ T cells of patients and controls, however, the IL10 expressions in CVID patients was significantly lower than in LRBA patients and HCs. As compared with HCs, CVID patients showed a prominent decrease in IL-4 and IL-10 production by CD4⁺ T cells.

CONCLUSIONS

Our findings demonstrated that patients with CVID and LRBA deficiency (even with severe infectious and inflammatory complications) have not imbalance in Th2 response, which is in parallel with lower frequency of allergy and asthma in these patients.

G2-lymphocyte chromosomal radiosensitivity in patients with LPS responsive beige-like anchor protein (LRBA) deficiency

Lipopolysaccharide-responsive, beige-like anchor protein (LRBA) deficiency is an autosomal recessive primary immunodeficiency disease characterized by a CVID-like phenotype, particularly severe autoimmunity and inflammatory bowel disease. This study was undertaken to evaluate radiation sensitivity in 11 LRBA-deficient patients. Therefore, stimulated lymphocytes of the studied subjects were exposed to a low dose γ-radiation (100 cGy) in the G₂ phase of the cell cycle and chromosomal aberrations were scored. Lymphocytes of age-sex matched healthy individuals used in the same way as controls. Based on the G₂-assay, six (54.5%) of the patients had higher radiosensitivity score comparing to the healthy control group, forming the radiosensitive LRBA-deficient patients. This chromosomal radiosensitivity showed that these patients are predisposed to autoimmunity and/or malignancy, and should be protected from unnecessary diagnostic and therapeutic procedures using ionizing radiation and exposure to other DNA damaging agents.

Evaluation of the TLR negative regulatory network in CVID patients

Common variable immunodeficiency (CVID), a clinically symptomatic primary immunodeficiency disease (PID), is characterized by hypogammaglobulinemia leading to recurrent infections and various complications. Recently, some defects in the signaling of TLRs have been identified in CVID patients which led us to investigate the expression of TLR4 and 9 negative regulatory molecules and their upregulation status following their activation. Using TaqMan real-time PCR, SOCS1, TNFAIP3, RFN216, and IRAK-M transcripts among peripheral blood mononuclear cells (PBMCs) were measured with/without TLR4 and 9 activations. TLR4 and 9 were activated by lipopolysaccharide (LPS) and unmethylated CpG-oligodeoxynucleotide (CpG-ODN), respectively. Production of IFN-α and TNF-α cytokines, as a part of the functional response of mentioned TLRs, was also measured using ELISA. Deficient transcripts of IRAK-M and TNFAIP3 in unstimulated PBMCs and lower production of TNF-α and IFN-α after treatments were observed. Upregulation of RFN216 and TNFAIP3 after TLR9 activation was abnormal compared to healthy individuals. Significant correlations were found between abnormal IRAK-M and TNFAIP3 transcripts, and lymphadenopathy and inflammatory scenarios in patients, respectively. It seems that the transcriptional status of some negative regulatory molecules is disturbed in CVID patients, and this could be caused by the underlying pathogenesis of CVID and could involve complications like autoimmunity and inflammatory responses.

A Comparison of Clinical and Immunologic Phenotypes in Familial and Sporadic Forms of Common Variable Immunodeficiency

Common variable immunodeficiency (CVID) is the most frequent symptomatic primary immunodeficiency disease, and its prevalence varies significantly among different population. Minority of CVID patients present a familial aggregation suggesting a higher probability of heritable genetic defects. A total of 235 registered CVID patients were evaluated in this cohort study. Familial and sporadic patients were stratified, and demographic information, clinical records, laboratory and molecular data were compared among these two groups of patients. Multiple cases were identified in 12 families (30 patients) and sporadic presentation in 120 cases. The rate of parental consanguinity (83.3%) and clinical presentation of lymphoid malignancy (20.7%) were predominant in familial CVID patients, whereas significantly increased recurrent upper respiratory infections were recorded in sporadic patients (0.3 infections per year). Probands of familial group were presented with a higher severity score resulting in a profound mortality rate (41.7% after 30-year follow-up) comparing to the non-proband CVID patients in the same families with a lowered diagnostic delay. Familial CVID patients had a specific signature in clinical presentation and immunologic profile, and a high consanguinity in this group of patients suggests a Mendelian trait with an autosomal recessive inheritance pattern. Diagnosis of an index patient within a multiple case families significantly improves the diagnostic process and outcomes of the yet asymptomatic patients.

Defective IL-4 signaling in T cells defines severe common variable immunodeficiency

Common variable immunodeficiency (CVID) is defined by hypogammaglobulinemia and B-cell dysfunction, with significant clinical and immunological heterogeneity. Severe non-infectious complications, such as autoimmunity, granulomatous disease and splenomegaly, constitute a major cause of morbidity in CVID patients. T cells are generally regarded important for development of these clinical features. However, while T-cell abnormalities have been found in CVID patients, functional characteristics of T cells corresponding to well-defined clinical subtypes have not been identified. As common γ-chain cytokines play important roles in survival and differentiation of T cells, characterization of their signaling pathways could reveal functional differences of clinical relevance. We characterized CVID T cells functionally by studies of cytokine-induced signaling, and correlated the findings to defined clinical subtypes. Peripheral blood T cells from 29 CVID patients and 19 healthy donors were analyzed for i) phenotype, ii) cytokine-induced (interleukin (IL)-2, IL-4, IL-7 and IL-21) phosphorylation of signal transducer and activator of transcription (STAT) 3, STAT5 and STAT6, and iii) T-helper (Th)1/Th2 polarization. Expression of IL-4 receptor and downstream signaling molecules was measured. A subgroup of CVID patients (n = 7) was identified by impaired IL-4-induced p-STAT6 in naive and memory CD4 and CD8 T cells. This corresponded to patients with the largest accumulation of severe (non-infectious) complications. The signaling defect persisted over years and was not due to constitutively activated p-STAT6. The CD4 T cells were strongly Th1-skewed, but IL-4 signaling was impaired independently of Th status. However, IL-4Rα and Janus kinase (JAK) 1 mRNA levels were significantly lower than in normal donors, providing a likely mechanism for the defective IL-4-induced p-STAT6 and Th1-bias. In conclusion, we identified a subgroup of CVID patients with defective IL-4 signaling in T cells, with severe clinical features of inflammation and autoimmunity.

Approach to the Management of Autoimmunity in Primary Immunodeficiency

Primary immunodeficiency diseases (PIDs) consist of a genetically heterogeneous group of immune disorders that affect distinct elements of the immune system. PID patients are more prone to infections and non-infectious complications, particularly autoimmunity. The concomitance of immunodeficiency and autoimmunity appears to be paradoxical and leads to difficulty in the management of autoimmune complications in PID patients. Therefore, management of autoimmunity in patients with PID requires special considerations because dysregulations and dysfunctions of the immune system along with persistent inflammation impair the process of diagnosis and treatment.

Comparison of various classifications for patients with common variable immunodeficiency (CVID) using measurement of B-cell subsets

BACKGROUND

Common variable immunodeficiency (CVID) is a heterogeneous disease, characterised by hypogammaglobulinaemia leading to recurrent infections and various complications. The aim of this study was to classify CVID patients based on four known classifications (Paris, Freiburg, EUROclass, and B-cell patterns) by measurement of B-cell subsets and to assess the relation of each classification with clinical manifestations.

METHODS

We measured all B-cell subsets as both absolute count and percentage in 30 CVID patients and 30 healthy individuals using four-colour flow cytometry. Moreover, we evaluated antibody responses to pneumococcal vaccine in patients.

RESULTS

A significant reduction in percentage of terminal B-cell subsets (total, marginal zone-like, switched memory, IgM-only memory, total memory B-cells and plasmablast) and absolute count of all B-cell subsets along with a strong increase in CD21^low B-cells has been observed in patients. Patients with splenomegaly and hepatomegaly clustered in group Ia, smB+21^low and group 1 based on known classifications, and significantly tended to have a decreased transitional and marginal zone-like B-cells count, as well as an increase in CD21^low B-cell counts. Patients with lymphadenopathy, bronchiectasis and allergy had a significant decrease in absolute count of total memory, switched memory and total B-cells, respectively.

CONCLUSION

Classification of patients could provide useful information to guide clinicians in long-term follow-up of CVID patients. Our data demonstrate that it may be more accurate to use absolute counts of B-cell subpopulations in CVID patients because absolute counts of B-cell subsets are more associated with clinical manifestations compared with their percentage and also four known classifications.

Patterns of constitutively phosphorylated kinases in B cells are associated with disease severity in common variable immunodeficiency

Patients with common variable immunodeficiency (CVID) constitute a clinically and immunologically heterogeneous group characterized by B-cell dysfunction with hypogammaglobulinemia and defective immunoglobulin class switch of unknown etiology. Current classification systems are insufficient to achieve precise disease management. Characterization of signaling pathways essential for B-cell differentiation and class switch could provide new means to stratify patients. We evaluated constitutive and induced signaling by phospho-specific flow cytometry in 26 CVID patients and 18 healthy blood donors. Strong responses were induced both in CVID and healthy donor B cells upon activation. In contrast, constitutive phosphorylation levels of STAT3,-5,-6, Erk, PLC-γ and Syk were significantly increased in CVID B cells only. Hierarchical clustering revealed a subgroup of CVID patients with elevated constitutive phosphorylation of Syk and PLC-γ. All these patients had non-infectious complications, indicating that a distinct phosphorylation pattern of kinases in B cells identifies a clinically important subgroup of CVID patients.