Neutrophil and Granulocytic Myeloid-Derived Suppressor Cell-Mediated T Cell Suppression Significantly Contributes to Immune Dysregulation in Common Variable Immunodeficiency Disorders.

Common variable immunodeficiency disorders (CVID) represent a group of primary immunodeficiency diseases characterized by hypogammaglobulinemia and impaired specific Ab response, resulting in recurrent infections due to dysfunctional immune response. The specific mechanisms mediating immune deficiency in CVID remain to be determined. Previous studies indicated that immune dysregulation in CVID patients is associated with chronic microbial translocation, systemic immune activation, and altered homeostasis of lymphocytic and myeloid lineages. A detailed phenotypic, functional characterization of plasma markers and immune cell populations was performed in 46 CVID patients and 44 healthy donors. CVID patients displayed significantly elevated plasma levels of a marker of neutrophil activation neutrophil gelatinase-associated lipocalin. Neutrophils from CVID patients exhibited elevated surface levels of CD11b and PD-L1 and decreased levels of CD62L, CD16, and CD80, consistent with a phenotype of activated neutrophils with suppressive properties. Neutrophils from CVID patients actively suppressed T cell activation and release of IFN-γ via the production of reactive oxygen species. Furthermore, CVID was associated with an increased frequency of low-density neutrophils (LDNs)/granulocytic myeloid-derived suppressor cells. LDN/granulocytic myeloid-derived suppressor cell frequency in CVID patients correlated with reduced T cell responsiveness. Exogenous stimulation of whole blood with bacterial LPS emulated some but not all of the phenotypic changes observed on neutrophils from CVID patients and induced neutrophil population with LDN phenotype. The presented data demonstrate that neutrophils in the blood of CVID patients acquire an activated phenotype and exert potent T cell suppressive activity. Specific targeting of myeloid cell-derived suppressor activity represents a novel potential therapeutic strategy for CVID.

Absence of Surface IgD Does Not Impair Naive B Cell Homeostasis or Memory B Cell Formation in IGHD Haploinsufficient Humans.

Surface IgD is coexpressed with IgM on naive mature B cells. Still, the role of surface IgD remains enigmatic even 50 y after its initial discovery. In this study, we examined the in vivo role of surface IgD in human B cell homeostasis and Ab responses in four individuals with heterozygous nonsense mutations in IGHD All IGHD heterozygous individuals had normal numbers of B cells and serum Igs and did not show signs of immunodeficiency or immune dysregulation. IgD+ and IgD- naive mature B cells were present in equal numbers and showed similar immunophenotypes, except for decreased expression of CD79b in the IgD- subset. Furthermore, both IgD+ and IgD- naive mature B cells had normal replication histories and similar capacities to differentiate into plasma cells upon in vitro stimulation, and Ig class-switched memory B cells showed similar levels of somatic hypermutations. Thus, human B cells lacking IgD expression develop normally and generate immunological memory in vivo, suggesting that surface IgD might function more restrictedly in regulating of B cell activation to specific antigenic structures.

Defects in memory B-cell and plasma cell subsets expressing different immunoglobulin-subclasses in patients with CVID and immunoglobulin subclass deficiencies.

BACKGROUND: Predominantly antibody deficiencies (PADs) are the most prevalent primary immunodeficiencies, but their B-cell defects and underlying genetic alterations remain largely unknown. OBJECTIVE: We investigated patients with PADs for the distribution of 41 blood B-cell and plasma cell (PC) subsets, including subsets defined by expression of distinct immunoglobulin heavy chain subclasses. METHODS: Blood samples from 139 patients with PADs, 61 patients with common variable immunodeficiency (CVID), 68 patients with selective IgA deficiency (IgAdef), 10 patients with IgG subclass deficiency with IgA deficiency, and 223 age-matched control subjects were studied by using flow cytometry with EuroFlow immunoglobulin isotype staining. Patients were classified according to their B-cell and PC immune profile, and the obtained patient clusters were correlated with clinical manifestations of PADs. RESULTS: Decreased counts of blood PCs, memory B cells (MBCs), or both expressing distinct IgA and IgG subclasses were identified in all patients with PADs. In patients with IgAdef, B-cell defects were mainly restricted to surface membrane (sm)IgA+ PCs and MBCs, with 2 clear subgroups showing strongly decreased numbers of smIgA+ PCs with mild versus severe smIgA+ MBC defects and higher frequencies of nonrespiratory tract infections, autoimmunity, and affected family members. Patients with IgG subclass deficiency with IgA deficiency and those with CVID showed defects in both smIgA+ and smIgG+ MBCs and PCs. Reduced numbers of switched PCs were systematically found in patients with CVID (absent in 98%), with 6 different defective MBC (and clinical) profiles: (1) profound decrease in MBC numbers; (2) defective CD27+ MBCs with almost normal IgG3+ MBCs; (3) absence of switched MBCs; and (4) presence of both unswitched and switched MBCs without and; (5) with IgG2+ MBCs; and (6) with IgA1+ MBCs. CONCLUSION: Distinct PAD defective B-cell patterns were identified that are associated with unique clinical profiles.

Immunosenescence - the sunset over the immune system.

Immunosenescence is characterized by remodeling and dysregulation of immune system due to aging process. These changes affect innate as well as adaptive immunity. Due to the complexity of the physiological processes, in which the mechanisms of the immune system interfere, also other systems of the organism are affected by these changes. Thymus involution as well as chronic antigenic stimulation are the main causes of immunosenescence and lead to a proinflammatory setting of the organism. In addition to impaired immune response against infections or reactivation of latent infections, reduced response to vaccination or decreased antitumor immune surveillance, changes of the immune system in elderly are clinically reflected in the development of chronic diseases typical for older age groups, such as neurodegenerative or metabolic diseases. The mechanisms of immunosenescence can be at least partially influenced by an active lifestyle and adequate dietary measures.

Lung diseases and autoimmune hemolytic anemia associted with IgG4 disease.

IgG4 related disease (IgG4-RD) is a rare and relatively new group of systemic inflammatory diseases characterized by inflammatory, fibrotic or sclerotic involvement of one or more organs accompanied by increased IgG4plasma cells tissue infiltration andusually elevated serum IgG4(IgG4 > 1.35g/l, normal range 0.08-1.40 g/l) level. Histopathological findings are crucial for the diagnostics of this disease. The authors present a case report of a patient with IgG4 associated disease manifested by a rare combination of autoimmune hemolytic anemia and pulmonary involvement.

Secondary immunodeficiency as a consequence of chronic diseases.

Secondary immunodeficiencies (SID) represents heterogeneous group of acquired impairment of immune system function with diverse etiology. It is mostly a combined disorder of both humoral and cellular component of the innate and adaptive immune response. SID occurs mainly in adulthood. Among the most important causes of SID development belong diabetes mellitus, impairment of liver and kidney functions, protein-energy malnutrition, splenic defects and immunosenescence. These deficiencies of immunity are clinically manifested by an increased frequency or unusual complications of common infections and occasionally by the occurrence of opportunistic infections. Diagnostic procedure is based on blood count and differential leukocyte count, biochemical examination, including determination of total protein and albumin concentrations, and biochemical urine analysis to eliminate protein losses. If clinically significant secondary defect of the immune system is suspected, immunological examination is indicated. Patients with clinical symptoms of SID can be treated with prophylactic antibiotic therapy, vaccination, substitution immunoglobulin therapy, or by immune system modifiers.

Adverse effects of immunoglobulin therapy.

Immunoglobulin products contain specific antibodies in IgG class which are directed against wide range of pathogens. These products are obtained from plasma of healthy donors. Immunoglobulin derivates can be administrated by intravenous or subcutaneous route in substitution or immunomodulation indications. The administration can be accompanied by a risk of adverse events. The most common are pyretic reactions, chills, headache, nausea, malaise and muscle pain, nevertheless also severe systemic reactions can occur. Almost one third of the reactions appear during the first administration. The number and severity of reactions depends on administered dose, speed and the application way. Pre-existing comorbidities of the patients and presence of acute infection are also an important risk factors for adverse reactions. Therapy of side effects is mostly symptomatic.

Immunodeficiency in the differential diagnosis of interstitial lung diseases.

Interstitial lung processes (IPP), or diffuse parenchymal lung diseases, are a broad group of diseases characterized by varying degrees of pulmonary fibrosis and inflammation affecting predominantly, but not exclusively, pulmonary interstitium. IPP mostly occur in adulthood with maximum manifestation between 40 and 70 years of age. Although IPP mostly present as a primary diagnosis, they also belong to the portfolio of pulmonary disorders in patients with primary immunodeficiencies. The authors present case reports of patients with interstitial lung involvement and primary immunodeficiencies [particularly those manifesting also in adulthood, such as common variable immunodeficiency (CVID), and cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) deficiency]. In addition, we report the case of silico-sis patient with severe lymphopenia. Therefore, in patients with newly diagnosed interstitial lung disease, congenital immune system disorder should be considered. Basic immunological laboratory examination of humoral and cellular immunity should be an essential part of the differential diagnosis algorithm for interstitial lung disease.

Hyper-IgE in the allergy clinic--when is it primary immunodeficiency?

The 2017 International Union of Immunological Societies (IUIS) classification recognizes 3 hyper-IgE syndromes (HIES), including the prototypic Job's syndrome (autosomal dominant STAT3-loss of function) and autosomal recessive PGM3 and SPINK5 syndromes. Early diagnosis of PID can direct life-saving or transformational interventions; however, it remains challenging owing to the rarity of these conditions. This can result in diagnostic delay and worsen prognosis. Within increasing access to "clinical-exome" testing, clinicians need to be aware of the implication and rationale for genetic testing, including the benefits and limitations of current therapies. Extreme elevation of serum IgE has been associated with a growing number of PID syndromes including the novel CARD11 and ZNF341 deficiencies. Variable elevations in IgE are associated with defects in innate, humoral, cellular and combined immunodeficiency syndromes. Barrier compromise can closely phenocopy these conditions. The aim of this article was to update readers on recent developments at this important interface between allergy and immunodeficiency, highlighting key clinical scenarios which should draw attention to possible immunodeficiency associated with extreme elevation of IgE, and outline initial laboratory assessment and management.

[Remission of the disease associated/related with immunoglobulin IgG4 accompanied by multiple lymphadenopathy after treatment with rituximab and dexamethasone: a case report]. / Remise "the disease associated/related with immunoglobulin IgG4" provázeného mnohocetnou lymfadenopatií po lécbe rituximabem a dexametazonem: kazuistika.

A disease associated with immunoglobulin IgG4 is a rare unit with very variable symptoms. We describe the course and treatment of the disease in a patient who presented with multiple lymphadenopathy and infiltrates in the area of the retroperitoneum and pelvis and signs of chronic sclerosing pancreatitis. The disease was clinically manifested by a significant loss of weight, but also by a loss of perception of taste and smell. The diagnosis was made based on a high amount of IgG4 expressing plasma cells in the sampled tissue and an increased concentration of immunoglobulins of type IgG and mainly subclass IG4. Rituximab in 475 mg/m2 dose was used in the treatment, the initial four doses of rituximab were administered at 14-day intervals, always with a one-off administration of a 40 mg dose of dexamethasone. According to FDG-PET/CT, only partial remission of the disease was reached after 4 applications of rituximab and dexamethasone. The patient recovered its sense of smell and taste. In another 4 cycles ritu-ximab was administered on day 1 of a 28-day cycle. On days 1 and 15 of the cycle dexamethasone at 40 mg and cyclophosphamide at 600 mg were administered by intravenous infusion. After the completion of 8 cycles of treatment based on rituximab and dexamethasone and with cyclophosphamide added in the second half of the treatment, the control FDG-PET/CT examination proved the complete remission. Before the treatment commencement the concentration of the subclass of immunoglobulin IgG4 was equal to 51.0 g/l, after the completion of the aforementioned treatment it dropped to 3.5 g/l. The patient tolerated the treatment without any adverse effects. Ritu-ximab, dexamethasone and cyclophosphamide induced the complete remission of this disease.Key words: IgG4-associated/releated disease - rituximab.

Selective IgM Deficiency: Clinical and Laboratory Features of 17 Patients and a Review of the Literature.

PURPOSE: Primary selective IgM deficiency (sIgMD) is a primary immunodeficiency with unclear pathogenesis and a low number of published cases. METHODS: We reviewed clinical and laboratory manifestations of 17 sIgMD patients. Serum IgM, IgG, and its subclasses, IgA, IgE, antibodies against tetanus toxoid, pneumococcal polysaccharides and Haemophilus influenzae type b, isohemagglutinins, and T and B lymphocyte subsets, expressions of IgM on B cells and B lymphocyte production of IgM were compared with previously reported case reports and a small series of patients, which included 81 subjects in total. RESULTS: We found that some patients in our cohort (OC) and published cases (PC) had increased IgE levels (OC 7/15; PC 21/37), decreased IgG4 levels (OC 5/14), very low titers of isohemagglutinins (OC 8/8; PC 18/21), increased transitional B cell counts (OC 8/9), decreased marginal zone B cell counts (OC 8/9), and increased 21low B cell counts (OC 7/9). Compared with the PC (20/20), only two of five OC patients showed very low or undetectable production of IgM after stimulation. A majority of the patients had normal antibody production to protein and polysaccharide antigens, basic lymphocyte subset counts, and expression of surface IgM molecules on B cells. CONCLUSIONS: Low IgM levels are associated with various immunopathological disorders; however, pathogenic mechanisms leading to decreased IgM serum level in selective IgM deficiency remain unclear. Moreover, it is difficult to elucidate how strong these associations are and if these immunopathological conditions are primary or secondary.

Successful renal transplantation in a patient with a Wiskott-Aldrich syndrome protein (WASP) gene mutation.

Wiskott-Aldrich syndrome (WAS) is a rare primary immunodeficiency disorder caused by mutations in the WAS protein (WASP) gene. Renal disease progressing to renal failure is a well-recognized complication in patients with WAS. Only a few case reports of renal transplantation have been reported to date. Here, we present a patient with a WASP mutation who suffered from severe atopic eczema, mild thrombocytopenia and only a slightly increased frequency of infections, who then developed IgA nephropathy and consequently underwent renal transplantation, which was successful. This study demonstrates that renal transplantation is possible in patients with WAS, regardless of conceivable complications.

Low CD46 expression on activated CD4+ T cells predict improved Th1 cell reactivity to calcitriol in majority of patients with allergic eosinophilic asthma and healthy donors.

Background: Previous research showed that the intracellular complement system, with CD46 as its central molecule, regulates the Th1 response associated with IFN-γ production and transition to a type 1 regulatory response (Tr1) characterized by IL-10 production. This transition can be influenced by a vitamin D (calcitriol), favouring a shift towards Tr1 cells and increased IL-10 production, as described in some autoimmune diseases. Objective: It is unknown whether calcitriol modulates CD46-induced Th1 response towards regulatory type 1 T cells (Tr1) in allergic eosinophilic asthma and its value in relation to reducing inflammatory response. Methods: CD4+ T cells from 58 patients with allergic eosinophilic asthma (AEA) and 49 healthy donors (HDs) were stimulated with αCD3/αCD46/IL-2 or αCD3/αCD46/IL-2/Calcitriol in vitro for 60 h and analyzed by flow cytometry. IFN-γ and IL-10 levels in cell culture supernatants were measured using ELISA. Results: CD4+ T cells from patients with AEA demonstrated elevated CD46 expression in both the non-activated state and under stimulation conditions with αCD3/αCD46/IL-2 or αCD3/αCD46/IL-2/Calcitriol. Moreover, CD46 expression in AEA patients fluctuated with the pollen season, showing a significant increase during period of low pollen exposure. Calcitriol further induced CD4+Tr1 cells from in vitro generated CD4+Th1 cells in both HDs and AEA patients. However, in both cohorts were individuals (HDs: 35/49, AEA: 40/58) who responded to calcitriol with a more pronounced regulatory response. The calcitriol-induced regulatory effect manifested by a stronger surface decrease of CD46 on activated CD4+ T cells (by 40% in HDs and by 26% in AEA), accompanied by a significant inhibition of IFN-γ and increased IL-10 production (by 31% in HDs and by 85% in AEA). These individuals were termed as the CD46D group. Contrary to this, calcitriol induced an increase in CD46 expression at the CD4+ T cell surface in a minor group of HDs (14/49), and AEA patients (18/58), who were termed as the CD46I group. In CD46I group, CD4+ T cells produced less IFN-γ in comparison with CD46D group (by 33% in HDs and by 43% in AEA) and were unable to upregulate IL-10 production following stimulation with αCD3/αCD46/IL-2/Calcitriol. Conclusion: Our results suggest the potential existence of a key for stratifying individuals suitable for calcitriol treatment in the context of low serum vitamin D levels. After validation in clinical studies, this key could be used as an adjunctive therapy not only for patients with allergic eosinophilic asthma, but also for other diseases.

Evaluation of respiratory allergies burden and management in primary care and comparative analysis of health care data from Romania, Poland, Czech Republic and Bulgaria - preliminary study.

BACKGROUND: Respiratory allergies mostly allergic rhinitis and asthma represent an important and increasing public health problem and one of the priorities for the European health systems. There is an increasing public concern regarding the persistence and severity of allergic diseases and many difficulties of health systems in providing prompt specialized medical assistance. Our study aims to highlight the main results of the Alliance 4Life project focused on the evaluation of the burden and management of respiratory allergies in primary care from Romania and comparative health-related data from four Central and Eastern European countries. METHOD: We developed a questionnaire focused on patients with allergic rhinitis and asthma directly addressed to general practitioner (GP) specialists from Romania who attended the annual national conference in Bucharest. RESULTS: The main results showed that patients with respiratory allergies are frequently encountered in primary care practice, only a few patients are evaluated by allergists and there is a clear need for education in this field. CONCLUSIONS: This preliminary study confirms that respiratory allergies represent a considerable burden in primary care and the questionnaire may be a useful tool in further studies considering the experience of other healthcare systems. More advanced studies integrating epidemiology with data on air pollution and environmental conditions should be envisaged.

Phenotype and oxidative burst of low-density neutrophil subpopulations are altered in common variable immunodeficiency patients.

Common variable immunodeficiency disorder (CVID) is the most common form of primary antibody immunodeficiency. Due to low antibody levels, CVID patients receive intravenous or subcutaneous immunoglobulin replacement therapy as treatment. CVID is associated with the chronic activation of granulocytes, including an increased percentage of low-density neutrophils (LDNs). In this study, we examined changes in the percentage of LDNs and the expression of their surface markers in 25 patients with CVID and 27 healthy donors (HD) after in vitro stimulation of whole blood using IVIg. An oxidative burst assay was used to assess the functionality of LDNs. CVID patients had increased both relative and absolute LDN counts with a higher proportion of mLDNs compared to iLDNs, distinguished based on the expression of CD10 and CD16. Immature LDNs in the CVID and HD groups had significantly reduced oxidative burst capacity compared to mature LDNs. Interestingly we observed reduced oxidative burst capacity, reduced expression of CD10 after stimulation of WB, and higher expression of PD-L1 in mature LDNs in CVID patients compared to HD cells. Our data indicate that that the functional characteristics of LDNs are closely linked to their developmental stage. The observed reduction in oxidative burst capacity in mLDNs in CVID patients could contribute to an increased susceptibility to recurrent bacterial infections among CVID patients.

Risk Factors for Severe COVID-19 and Hospital Admission in Patients With Inborn Errors of Immunity - Results From a Multicenter Nationwide Study.

Despite the progress in the understanding how COVID-19 infection may impact immunocompromised patients, the data on inborn errors of immunity (IEI) remain limited and ambiguous. Therefore, we examined the risk of severe infection course and hospital admission in a large cohort of patients with IEI. In this multicenter nationwide retrospective survey-based trial, the demographic, clinical, and laboratory data were collected by investigating physicians from 8 national referral centers for the diagnosis and treatment of IEI using a COVID-19-IEI clinical questionnaire. In total, 81 patients with IEI (including 16 with hereditary angioedema, HAE) and confirmed SARS-CoV-2 infection were enrolled, and were found to have a 2.3-times increased (95%CI: 1.44-3.53) risk ratio for hospital admission and a higher mortality ratio (2.4% vs. 1.7% in the general population). COVID-19 severity was associated with the presence of clinically relevant comorbidities, lymphopenia, and hypogammaglobulinemia, but not with age or BMI. No individuals with HAE developed severe disease, despite a hypothesized increased risk due to perturbed bradykinin metabolism. We also demonstrated a high seroconversion rate in antibody-deficient patients and the safety of anti-spike SARS CoV-2 monoclonal antibodies and convalescent plasma. Thus, IEI except for HAE, represent significant risk factors for a severe COVID-19. Therefore, apart from general risk factors, immune system dysregulation may also be involved in the poor outcomes of COVID-19. Despite the study limitations, our results support the findings from previously published trials.

Common variable immunodeficiency patients display elevated plasma levels of granulocyte activation markers elastase and myeloperoxidase.

Common variable immunodeficiency disorders (CVIDs) represent a group of primary immunodeficiency diseases characterized by hypogammaglobulinemia and dysfunctional immune response to invading pathogens. Previous studies have indicated that CVID is associated with microbial translocation and systemic myeloid cell activation. The goal of this study was to determine whether patients with CVID display elevated systemic levels of markers of granulocyte activation and whether the levels are further influenced by intravenous immunoglobulin (IVIg) infusions. The plasma levels of granulocyte activation markers elastase and myeloperoxidase were determined using enzyme-linked immunosorbent assay (ELISA) in 46 CVID patients and 44 healthy controls. All CVID patients were in a stable state with no apparent acute infection. In addition, granulocyte activation markers' plasma levels in 24 CVID patients were determined prior to and 1 h following IVIg administration. Neutrophil elastase and myeloperoxidase plasma levels were significantly higher in CVID patients than in healthy controls. Systemic elastase levels were further increased following IVIg administration. In vitro stimulation of 13 CVID patients' whole blood using IVIg in a therapeutically relevant dose for 2 h resulted in a significant increase in plasma elastase levels compared to unstimulated blood. The data presented here indicate that CVID is associated with chronic granulocytic activation which is further exacerbated by administering IVIg. Increased myeloperoxidase and elastase levels may contribute to associated comorbidities in CVID patients.

Antibody forming cells and plasmablasts in peripheral blood in CVID patients after vaccination.

Common variable immunodeficiency (CVID), the most frequent primary antibody disorder, is characterized by hypogammaglobulinaemia and impaired antibody production. Poor vaccination response is essential for the diagnosis of CVID. Their under laying defects remain to be elucidated. Routine determination of antibody production in serum from CVID patients after vaccination and investigation of B cell function in vivo is complicated due to substitution therapy. Therefore we investigated antibody production on the B-cell level by ELISPOT and characterized changes in B-cell subpopulations in CVID patients, including plasmablasts, in peripheral blood by flow cytometry after vaccination for specification of the diagnosis. Thirty-seven CVID patients and eighty healthy volunteers were immunized with tetanus toxoid and pneumococcal polysaccharide vaccines. Specific antibody levels and B cell subpopulations were measured before vaccination and on day 7 after vaccination by ELISPOT assay and flow cytometry respectively. Of the thirty-seven well defined CVID patients studied, thirty lacked detectable spot forming cells producing specific IgG, IgA or IgM antibodies against employed vaccines and seven had only weak responses compared to controls. In the control group, an increase in circulating plasmablasts on day 7 post immunization corresponded with the appearance of antibody forming cells. In contrast, CVID patients failed to increase plasmablasts significantly in peripheral blood after antigen challenge. Our findings indicate that CVID patients have a block in terminal B-cell differentiation and that flow based assessment of plasmablasts in peripheral blood after vaccination serves as a surrogate diagnostic marker for assessing in vivo antibody responses in patients suspected to have CVID.