Clinical heterogeneity in families with multiple cases of inborn errors of immunity

BACKGROUND

Inborn errors of immunity (IEI) are a diverse range of genetic immune system illnesses affecting the innate and/or adaptive immune systems. Variable expressivity and incomplete penetrance have been reported in IEI patients with similar clinical diagnoses or even the same genetic mutation.

METHODS

Among all recorded patients in the national IEI registry, 193 families with multiple cases have been recognized. Clinical, laboratory and genetic variability were compared between 451 patients with different IEI entities.

RESULTS

The diagnosis of the first children led to the earlier diagnosis, lower diagnostic delay, timely treatment and improved survival in the second children in the majority of IEI. The highest discordance in familial lymphoproliferation, autoimmunity and malignancy were respectively observed in STK4 deficiency, DNMT3B deficiency and ATM deficiency. Regarding immunological heterogeneity within a unique family with multiple cases of IEI, the highest discordance in CD3+, CD4+, CD19+, IgM and IgA levels was observed in syndromic combined immunodeficiencies (CID), while non-syndromic CID particularly severe combined immunodeficiency (SCID) manifested the highest discordance in IgG levels. Identification of the first ATM-deficient patient can lead to improved care and better survival in the next IEI children from the same family.

CONCLUSION

Intrafamilial heterogeneity in immunological and/or clinical features could be observed in families with multiple cases of IEI indicating the indisputable role of appropriate treatment and preventive environmental factors besides specific gene mutations in the variable observed penetrance or expressivity of the disease. This also emphasizes the importance of implementing genetic evaluation in all members of a family with a history of IEI even if there is no suspicion of an underlying IEI as other factors besides the underlying genetic defects might cause a milder phenotype or delay in presentation of clinical features. Thus, affected patients could be timely diagnosed and treated, and their quality of life and survival would improve.

A three-stage developmental pathway for human Vγ9Vδ2 T cells within the postnatal thymus

Vγ9Vδ2 T cells are the largest population of γδ T cells in adults and can play important roles in providing effective immunity against cancer and infection. Many studies have suggested that peripheral Vγ9Vδ2 T cells are derived from the fetal liver and thymus and that the postnatal thymus plays little role in the development of these cells. More recent evidence suggested that these cells may also develop postnatally in the thymus. Here, we used high-dimensional flow cytometry, transcriptomic analysis, functional assays, and precursor-product experiments to define the development pathway of Vγ9Vδ2 T cells in the postnatal thymus. We identify three distinct stages of development for Vγ9Vδ2 T cells in the postnatal thymus that are defined by the progressive acquisition of functional potential and major changes in the expression of transcription factors, chemokines, and other surface markers. Furthermore, our analysis of donor-matched thymus and blood revealed that the molecular requirements for the development of functional Vγ9Vδ2 T cells are delivered predominantly by the postnatal thymus and not in the periphery. Tbet and Eomes, which are required for IFN-γ and TNFα expression, are up-regulated as Vγ9Vδ2 T cells mature in the thymus, and mature thymic Vγ9Vδ2 T cells rapidly express high levels of these cytokines after stimulation. Similarly, the postnatal thymus programs Vγ9Vδ2 T cells to express the cytolytic molecules, perforin, granzyme A, and granzyme K. This study provides a greater understanding of how Vγ9Vδ2 T cells develop in humans and may lead to opportunities to manipulate these cells to treat human diseases.

The contributory role of lymphocyte subsets, pathophysiology of lymphopenia and its implication as prognostic and therapeutic opportunity in COVID-19

The incidence of the novel coronavirus disease (COVID-19) outbreak caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has brought daunting complications for people as well as physicians around the world. An ever-increasing number of studies investigating the characteristics of the disease, day by day, is shedding light on a new feature of the virus with the hope that eventually these efforts lead to the proper treatment. SARS-CoV-2 activates antiviral immune responses, but in addition may overproduce pro-inflammatory cytokines, causing uncontrolled inflammatory responses in patients with severe COVID-19. This condition may lead to lymphopenia and lymphocyte dysfunction, which in turn, predispose patients to further infections, septic shock, and severe multiple organ dysfunction. Therefore, accurate knowledge in this issue is important to guide clinical management of the disease and the development of new therapeutic strategies in patients with COVID-19. In this review, we provide a piece of valuable information about the alteration of each subtype of lymphocytes and important prognostic factors associated with these cells. Moreover, through discussing the lymphopenia pathophysiology and debating some of the most recent lymphocyte- or lymphopenia-related treatment strategies in COVID-19 patients, we tried to brightening the foreseeable future for COVID-19 patients, especially those with severe disease.

Tuberculosis comorbidity with rheumatoid arthritis: Gene signatures, associated biomarkers, and screening

Rheumatoid arthritis (RA) is known to be related to an elevated risk of infections because of its pathobiology and the use of immunosuppressive therapies. Reactivation of latent tuberculosis (TB) infection is a serious issue in patients with RA, especially after receiving anti-TNFs therapy. TNF blocking reinforces the TB granuloma formation and maintenance and the growth of Mycobacterium tuberculosis (Mtb). After intercurrent of TB infection, the standard recommendation is that the treatment with TNF inhibitors to be withheld despite its impressive effect on suppression of inflammation until the infection has resolved. Knowing pathways and mechanisms that are common between two diseases might help to find the mechanistic basis of this comorbidity, as well as provide us a new approach to apply them as therapeutic targets or diagnostic biomarkers. Also, screening for latent TB before initiation of an anti-TNF therapy can minimize complications. This review summarizes the shared gene signature between TB and RA and discusses the biomarkers for early detection of this infection, and screening procedures as well.

Role of exosome in autoimmunity, with a particular emphasis on rheumatoid arthritis

Cell-derived exosomes are identified as carriers of lipids, proteins, and genetic materials that participate in cell-cell signal communication, biological process, and cell signaling. Also, their involvement has been reported in a vast array of disorders and inflammatory conditions such as autoimmune diseases. Rheumatoid arthritis (RA), a common cause of joint disorder, is an inflammation-based disease in which the precise understanding of its pathogenesis needs to be further investigated. Also, there is only a palliative care approach for the alleviation of RA symptoms. This paper discusses the recent advances in the biology of exosomes in autoimmune disorders especially in RA, and also provides a new line of research for arthritis therapy using exosomes.

Comparison of Bone Mineral Density in Common Variable Immunodeficiency and X-Linked Agammaglobulinaemia Patients

BACKGROUND

Primary antibody deficiency (PAD) is the most common group of primary immunodeficiency disorders, resulting from different defects in the development and function of B cell lineage. Common variable immunodeficiency (CVID) and X-linked agammaglobulinemia (XLA) are two of the major types of PADs. Optimal growth and subsequently bone health could potentially compromise due to the interference of several factors in PAD with childhood onset. In the present study, our aim was to evaluate bone mineral density (BMD) of patients with CVID and XLA.

METHODS

BMD of 37 CVID and 19 XLA patients was examined. Total BMD was determined by dual-energy X-ray absorptiometry and the calculated scores were compared internally and externally with age-sex matched and ethnic-specific reference. Related factors associated with bone density including immune-related complications, serum calcium, phosphate, total alkaline phosphatase, 25(OH) vitamin D and parathyroid hormone levels were recorded.

RESULTS

The median age at the time of study was 20 years among all patients and was not statistically different between CVID and XLA groups and the mean of body mass index (BMI) was 19.4±4.6 kg/cm². Thirty-eight (67.9%) of total patients had normal BMD and 18 (32.1%) patients had a low BMD. BMI was positively correlated with BMD at lumbar spine and femoral neck. The number of low BMD patients in CVID (40.5%) group was more than the XLA (15.8%).

CONCLUSION

Beside nutritional, gastrointestinal and infectious complications which are shared in both groups of patients, CVID patients are more prone to alteration of BMD due to association with lymphoproliferative and endocrine diseases. Therefore routine evaluation of bone density and treatment adjustment should be considered in all PAD patients particularly in CVID patients.

A Review on Defects of Dendritic Cells in Common Variable Immunodeficiency

BACKGROUND AND OBJECTIVES

Common variable immunodeficiency (CVID) is the most important primary disorder that is associated with clinical complications including recurrent infections, malignancy and autoimmune diseases. The genetic cause of CVID is mostly unknown and only a few genetic causes are identified. The various options are proposed for determining the etiology of CVID patients, such as T- and B-cell defects, Toll-like receptors (TLRs) impairments, altered cytokine production as well as blemished dendritic cells (DCs). The patients with CVID show a reduction in number and frequency of DCs in blood, an altered expression of cell surface molecules, and defective activation through toll-like receptors (TLRs). Also loss of IFNα has a critical role in B-cell impairments of CVID patients. The aim of this review is to collect under one umbrella, all the recent knowledge about DCs defects of CVID patients.

METHODS

This review covers basic information about physiology of DCs followed by reports of DCs situation in CVID.

CONCLUSION

According to the results of researches assessing DCs frequency and function in CVID, the roll of DCs in the pathogenesis of CVID cannot be ruled out. The article is expected to encourage the researchers to do comprehensive researches about complex connections between DCs and other immune cells in CVID.

The Profile of Toll-like Receptor 2 (TLR2), TLR4 and Their Cytosolic Downstream Signaling Pathway in Common Variable Immunodeficiency (CVID) Patients

Common variable immunodeficiency (CVID) is the most common clinical primary antibody deficiency, characterized by increased susceptibility to recurrent bacterial infections. Since Toll-like receptors (TLRs) play an important role in the maturation and differentiation of B-cells, TLRs' defect can be involved in the pathogenesis of CVID. Therefore, we evaluated the expression of TLR2 and TLR4 and their signaling pathway; also their association with autoimmunity, B-cell subtypes and response to pneumovax-23 were assessed in CVID patients. Sixteen CVID patients were enrolled in the study. Flow cytometry was used for assessing the protein expression of TLR2 and TLR4, and real-time PCR was used for gene expression of myeloid differentiation primary response 88 (MyD88) and toll interacting protein (Tollip). We found a higher protein expression of TLR2 in CVID patients which was associated with lower number of end stage B-cells and hyporesponse to pneumovax-23 vaccination. We showed a lower mRNA expression of MyD88 and an almost equal Tollip mRNA expression in CVID patients compared with controls. There was a profound association between MyD88 gene expression and autoimmunity in CVID patients. According to the presence of the lower number of end stage B-cells and poor vaccine response in CVID patients and their correlation with the higher expression of TLR2, we hypothesized that there is a functional defect in this receptor and/or its downstream in the peripheral blood mononuclear cells (PBMCs) of CVID patients.

Autoimmunity and its association with regulatory T cells and B cell subsets in patients with common variable immunodeficiency

BACKGROUND

Common variable immunodeficiency (CVID) is one of the most prevalent symptomatic primary immunodeficiencies (PIDs), which manifests a wide clinical variability such as autoimmunity, as well as T cell and B cell abnormalities.

METHODS

A total of 72 patients with CVID were enrolled in this study. Patients were evaluated for clinical manifestations and classified according to the presence or absence of autoimmune disease. We measured regulatory T cells (Tregs) and B-cell subsets using flow cytometry, as well as specific antibody response (SAR) to pneumococcal vaccine, autoantibodies and anti-IgA in patients.

RESULTS

Twenty-nine patients (40.3%) have shown at least one autoimmune manifestation. Autoimmune cytopenias and autoimmune gastrointestinal diseases were the most common. A significant association was detected between autoimmunity and presence of hepatomegaly and splenomegaly. Among CVID patients, 38.5% and 79.3% presented a defect in Tregs and switched memory B-cells, respectively, whereas 69.0% presented CD21^low B cell expansion. Among patients with a defect in Treg, switched memory and CD21^low B cell, the frequency of autoimmunity was 80.0%, 52.2% and 55.0%, respectively. A negative correlation was observed between the frequency of Tregs and CD21^low B cell population. 82.2% of patients had a defective SAR which was associated with the lack of autoantibodies.

CONCLUSIONS

Autoimmunity may be the first clinical manifestation of CVID, thus routine screening of immunoglobulins is suggested for patients with autoimmunity. Lack of SAR in CVID is associated with the lack of specific autoantibodies in patients with autoimmunity. It is suggested that physicians use alternative diagnostic procedures.

Evaluation of infectious and non-infectious complications in patients with primary immunodeficiency

INTRODUCTION

Primary immunodeficiency diseases (PIDs) are a heterogeneous group of genetic immune disorders. PID patients suffer from a variety of complications. The aim of this study was to determine the infectious and non-infectious complications among PID patients.

MATERIAL AND METHODS

This retrospective cohort study was performed on recorded data of 202 PID patients who were diagnosed with eight major categories: common variable immunodeficiency (CVID), X-linked agammaglobulinemia, hyper-IgM syndrome, hyper IgE syndrome, chronic granulomatous disease (CGD), ataxia telangiectasia, hereditary angioedema and leukocyte adhesion deficiency. For all patients, infectious and non-infectious manifestations and laboratory data were collected in a comprehensive questionnaire.

RESULTS

Infectious complications were more frequent than non-infectious complications. Pneumonia and otitis media were the main infectious problems in PID patients, especially in patients with antibody deficiencies. Among the non-infectious complications, splenomegaly and hepatomegaly were the most common complications in PID patients, and were more commonly seen in CGD patients than others. Splenomegaly, hepatomegaly and autoimmunity were the most common findings in CVID patients. A significant correlation was observed between diagnostic delay and bronchiectasis in CVID patients (p = 0.042).

CONCLUSIONS

PID patients are at risk of multiple infectious and non-infectious problems. Timely diagnosis of PIDs not only improves their outcome and quality of life, but also helps prevent these troubling complications.

Ral signaling pathway in health and cancer

The Ral (Ras‐Like) signaling pathway plays an important role in the biology of cells. A plethora of effects is regulated by this signaling pathway and its prooncogenic effectors. Our team has demonstrated the overactivation of the RalA signaling pathway in a number of human malignancies including cancers of the liver, ovary, lung, brain, and malignant peripheral nerve sheath tumors. Additionally, we have shown that the activation of RalA in cancer stem cells is higher in comparison with differentiated cancer cells. In this article, we review the role of Ral signaling in health and disease with a focus on the role of this multifunctional protein in the generation of therapies for cancer. An improved understanding of this pathway can lead to development of a novel class of anticancer therapies that functions on the basis of intervention with RalA or its downstream effectors.

Evaluation of pulmonary complications in patients with primary immunodeficiency disorders

Background. Primary immunodeficiencies (PIDs) are inherited disorders in which one or several components of immune system are defected. Moreover, affected patients are at high risk for developing recurrent infections, particularly pulmonary infections. The spectrum of pulmonary manifestations in PIDs is broad, and includes acute and chronic infection, structural abnormalities (eg, bronchiectasis), malignancy and dysregulated inflammation resulting in tissue damage. In this study, our aims are to evaluate pulmonary complications in PID patients. Patients and Methods. We studied 204 cases with confirmed PID. To evaluate pulmonary complications in these patients, we used pulmonary function test (PFT), high resolution computed tomography (HRCT) scan and bronchoalveolar lavage (BAL). Results. Our results showed that pneumonia was the most frequent clinical manifestations in all PID patients. There were significantly greater numbers of episodes of pneumonia in HIgM, XLA and CVID patients with delayed diagnoses < 6 years. Moreover, of 57.4% CVID patients, 55% XLA patients and 33.3% HIgM patients had abnormal PFT results, and bronchiectasis was showed in 9 (42.9%) of XLA, 6 (11.8%) of HIES, 3 (21.4%) of HIgM and 38 (62.3%) of CVID patients. Conclusion. Pulmonary complications should be considered in cases with PIDs especially in CVID cases.

T-Cell Abnormalities in Common Variable Immunodeficiency

Common variable immunodeficiency (CVID) is the most common clinical primary immunodeficiency. It is characterized by a defect in B-cell differentiation to plasma and memory B cells. Moreover, numerous T-cell abnormalities have been reported and include decreased T-cell count and proliferative response, increased T-cell activation and apoptosis, and abnormalities in cytokine production. The aims of this review are to describe phenotypic and functional defects in T cells in CVID patients and to review the literature with respect to the effects of immunoglobulin replacement on the T-cell component in CVID patients.