Rheumatologic and autoimmune manifestations of primary immunodeficiency disorders

Rheumatologic manifestations in children with underlying inborn errors of immunity

BACKGROUND AND OBJECTIVE

In recent years, many studies have been conducted on the possible link between rheumatologic diseases and inborn errors of immunity. Rheumatologic diseases may occur as manifestations of an underlying immunodeficiency disorder, and may appear before the more-common infectious manifestations more typically seen in immunodeficiency disorders. In this study, we have attempted to study such symptoms and uncover their relationship with inborn errors of immunity.

METHODOLOGY

In this retrospective descriptive-analytical study, 381 cases of IEIs in children that were referred to Mofid Children's Hospital clinic between 2015 and 2019 were evaluated for eligibility to be enrolled in the study. Of these patients, 20 that had confirmed rheumatologic diagnoses were entered into the study. Patients' demographic and medical data, including age at disease onset, age at diagnosis and type of diagnosed rheumatologic and immunodeficiency disorders, parental consanguinity rate, and relevant laboratory findings were retrieved for study and analyzed.

RESULTS

Among 20 eligible patients, half of which were female and half were male, the average age at disease onset, average age at diagnosis of the underlying immunodeficiency disease and average age at diagnosis of the rheumatologic disease were 2.98 ± 1.56, 5.26 ± 3.45 and 3.58 ± 2.97, respectively. JIA made up 10 of the observed rheumatic diseases ("the JIA group"); the remaining 10 patients included SLE (3), FMF (2), juvenile dermatomyositis (2), MCTD (1), GPA (1) and reactive arthritis (1) ("the non-JIA group"). As for the underlying immunodeficiency disorders, CID was seen in 8 patients, followed by CVID (5), XLA (4), SIgAD (2) and CGD (1). The average age at onset of the disease and the average age at diagnosis of the rheumatologic disease were significantly lower in the JIA group than in the non-JIA group (p < 0.05).

CONCLUSIONS

A plethora of rheumatologic manifestations may be observed in patients with IEIs; such manifestations should be actively sought out and treated in IEI patients.

CLINICAL TRIAL NUMBER

Not applicable.

International multidisciplinary consensus on the definition and clinical approach for monogenic inflammatory immune dysregulation disorders

OBJECTIVE

To achieve consensus on the definition and clinical approach of Monogenic Inflammatory Immune Dysregulation Disorders (MIIDDs), a collective term for rare conditions marked by inflammation, immune dysregulation, and infection susceptibility. These consensus guidelines specifically apply to pathogenic (or likely pathogenic) gene mutations affecting both innate and adaptive immunity, excluding variants of unknown significance (VUS).

METHODS

A multi-step, evidence-based, multidisciplinary consensus process was employed, consisting of: (1) a systematic literature review across four electronic databases (Cochrane Library, Web of Science, Scopus, and MEDLINE via PubMed), updated through December 31, 2024; (2) a pre-Delphi electronic survey completed by 95 international adult and pediatric immunologists and rheumatologists; and (3) a modified online Delphi process with an international multidisciplinary expert panel, where statements were iteratively analyzed and refined until achieving consensus (≥ 80% agreement among panelists).

RESULTS

Fifteen experts from 12 countries participated in two rounds of the Delphi process, resulting in the development of eight overarching principles and 10 consensus statements. These were categorized into five domains: (1) definitions and conceptual framework, (2) diagnostic and monitoring considerations, (3) treatment and therapeutic strategies, (4) multidisciplinary and collaborative care, and (5) patient education and support.

CONCLUSION

This consensus defines MIIDDs and provides a structured clinical framework to streamline research efforts and improve patient outcomes.

Endocrinopathies in children with inborn errors of immunity: a single-center experience

OBJECTIVES

Inborn errors of immunity (IEI) are a diverse group of genetically inherited disorders. We aimed to summarize and discuss endocrinopathies in children with IEI.

METHODS

This study included 84 IEI patients evaluated between September 2019 and September 2023.

RESULTS

We found that 15.6 % of the 32 patients with 22q11.2 deletion syndrome had permanent hypoparathyroidism. Hypergonadotropic hypogonadism was identified in one of four female patients with ataxia-telangiectasia (AT) and in all four females with severe congenital neutropenia (SCN) due to HAX1 deficiency. Additionally, hypergonadotropic hypogonadism was observed in one of nine males with common variable immunodeficiency (CVID). Among the CVID patients, one presented with autoimmune thyroiditis (AIT), type 1 diabetes mellitus (T1DM), hypoparathyroidism, and primary adrenal insufficiency. Of the 307 patients followed for selective IgA deficiency (sIgAD), 26 also received care in pediatric endocrinology. Among the sIgAD cases, 3.2 % had AIT and 4.5 % had T1DM. A patient with a STAT1 gain-of-function (GOF) variant was diagnosed with T1DM, AIT, and growth hormone deficiency, while a patient with a novel STAT3-GOF variant developed neonatal DM and interstitial lung disease. When the whole group was evaluated, thyroid disease was the most common endocrinopathy affecting 30.9 % of individuals, followed by DM, which was observed in 20.2 % of cases.

CONCLUSIONS

We have determined that AIT and T1DM were the most prevalent endocrine disorders in IEI patients. Pubertal development and gonadal functions should be monitored in the children with IEI. Early diagnosis and individualized treatment of endocrinopathies are crucial for a better quality of life and reduction of IEI-related complications.

Discordant Phenotypes of Nephritis in Patients with X-linked Agammaglobulinemia

PURPOSE

To define the clinical and histological characteristics of nephritis in patients with X-linked agammaglobulinemia (XLA) and their immunological profiles.

METHODS

The clinical, immunological, and histological findings of nine patients with XLA and nephritis were retrospectively analyzed.

RESULTS

Based on kidney histological findings, patients with XLA and nephritis could be divided into two groups, viz., chronic glomerulonephritis (CGN) and tubulointerstitial nephritis (TIN). The two groups showed different immunological profiles. Patients in the CGN group exhibited an atypical immunological profile of XLA, with pathogenic leaky B cells producing immunoglobulins that may play a role in forming immune complexes and causing immune-mediated glomerulonephritis. In contrast, patients in the TIN group exhibited a typical immunological profile of XLA, suggesting that antibody-independent/other BTK-dependent mechanisms, or immunoglobulin replacement therapy (IgRT)-related immune/nonimmune-mediated nephrotoxicity causes TIN.

CONCLUSION

Nephritis occurring in patients with XLA could have links between their renal pathology and immunological status. Careful observation is recommended to detect kidney pathology in patients with XLA on IgRT.

Target genes regulated by CLEC16A intronic region associated with common variable immunodeficiency

BACKGROUND

CLEC16A intron 19 has been identified as a candidate locus for common variable immunodeficiency (CVID).

OBJECTIVES

This study sought to elucidate the molecular mechanism by which variants at the CLEC16A intronic locus may contribute to the pathogenesis of CVID.

METHODS

The investigators performed fine-mapping of the CLEC16A locus in a CVID cohort, then deleted the candidate functional SNP in T-cell lines by the CRISPR-Cas9 technique and conducted RNA-sequencing to identify target gene(s). The interactions between the CLEC16A locus and its target genes were identified using circular chromosome conformation capture. The transcription factor complexes mediating the chromatin interactions were determined by proteomic approach. The molecular pathways regulated by the CLEC16A locus were examined by RNA-sequencing and reverse phase protein array.

RESULTS

This study showed that the CLEC16A locus is an enhancer regulating expression of multiple target genes including a distant gene ATF7IP2 through chromatin interactions. Distinct transcription factor complexes mediate the chromatin interactions in an allele-specific manner. Disruption of the CLEC16A locus affects the AKT signaling pathway, as well as the molecular response of CD4+ T cells to immune stimulation.

CONCLUSIONS

Through multiomics and targeted experimental approaches, this study elucidated the underlying target genes and signaling pathways involved in the genetic association of CLEC16A with CVID, and highlighted plausible molecular targets for developing novel therapeutics.

Type 1 diabetes and inborn errors of immunity: Complete strangers or 2 sides of the same coin?

Type 1 diabetes (T1D) is a polygenic disease and does not follow a mendelian pattern. Inborn errors of immunity (IEIs), on the other hand, are caused by damaging germline variants, suggesting that T1D and IEIs have nothing in common. Some IEIs, resulting from mutations in genes regulating regulatory T-cell homeostasis, are associated with elevated incidence of T1D. The genetic spectrum of IEIs is gradually being unraveled; consequently, molecular pathways underlying human monogenic autoimmunity are being identified. There is an appreciable overlap between some of these pathways and the genetic variants that determine T1D susceptibility, suggesting that after all, IEI and T1D are 2 sides of the same coin. The study of monogenic IEIs with a variable incidence of T1D has the potential to provide crucial insights into the mechanisms leading to T1D. These insights contribute to the definition of T1D endotypes and explain disease heterogeneity. In this review, we discuss the interconnected pathogenic pathways of autoimmunity, β-cell function, and primary immunodeficiency. We also examine the role of environmental factors in disease penetrance as well as the circumstantial evidence of IEI drugs in preventing and curing T1D in individuals with IEIs, suggesting the repositioning of these drugs also for T1D therapy.

Inhibitory Effects of Cold Atmospheric Plasma on Inflammation and Tumor-Like Feature of Fibroblast-Like Synoviocytes from Patients with Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic, debilitating systemic disease characterized by chronic inflammation and progressive joint destruction. Fibroblast-like synoviocytes (FLSs) are one of the most important players in the pathophysiology of RA, acting like tumor cells and secreting inflammatory cytokines. Previous research has shown that cold atmospheric plasma (CAP) inhibits cancer cells and may have anti-inflammatory properties. This study examined the effects of argon plasma jet-produced CAP on the suppression of invasion and inflammation caused by cultured RA-FLS. The findings revealed that CAP reduced cell viability and elevated the percentage of apoptotic RA-FLS by producing reactive oxygen species. Carboxyfluorescein diacetate succinimidyl ester (CFSE) staining confirmed that CAP could decrease the proliferation of RA-FLS. Furthermore, CAP effectively reduced the production of inflammatory factors (e.g., NF-κB and IL-6) as well as destructive factors like receptor activator of nuclear factor kappa-B ligand (RANKL) and matrix metalloproteinases-3 (MMP-3). These data suggest that CAP could be a promising treatment for slowing the progression of RA by reducing tumor-like features and inflammation in RA-FLS.

Endocrinopathies in Inborn Errors of Immunity

Inborn errors of immunity (IEI), caused by hereditary or genetic defects, are a group of more than 400 disorders, in which the immune system, including lymphocytes, neutrophils, macrophages, and complements, does not function properly. The endocrine system is frequently affected by IEI as an associated clinical feature and a complex network of glands which regulate many important body functions, including growth, reproduction, homeostasis, and energy regulation. Most endocrine disorders associated with IEI are hypofunction which would be treated with supplementation therapy, and early diagnosis and appropriate management are essential for favorable long-term outcomes in patients with IEI. In this review, we aimed to comprehensively summarize and discuss the current understanding on the clinical features and the pathophysiology of endocrine disorders in IEI. This review is composed with three parts. First, we discuss the two major pathophysiology of endocrinopathy in IEI, autoimmune response and direct effects of the responsible genes. Next, the details of each endocrinopathy, such as growth failure, hypothyroidism, hypoparathyroidism, adrenal insufficiency, diabetes mellitus (DM) are specified. We also illustrated potential endocrinopathy due to hematopoietic stem cell transplantation, including hypogonadism and adrenal insufficiency due to glucocorticoid therapy.

Lymphopenia, Lymphopenia-Induced Proliferation, and Autoimmunity

Immune homeostasis is a tightly regulated system that is critical for defense against invasion by foreign pathogens and protection from self-reactivity for the survival of an individual. How the defects in this system might result in autoimmunity is discussed in this review. Reduced lymphocyte number, termed lymphopenia, can mediate lymphopenia-induced proliferation (LIP) to maintain peripheral lymphocyte numbers. LIP not only occurs in normal physiological conditions but also correlates with autoimmunity. Of note, lymphopenia is also a typical marker of immune aging, consistent with the fact that not only the autoimmunity increases in the elderly, but also autoimmune diseases (ADs) show characteristics of immune aging. Here, we discuss the types and rates of LIP in normal and autoimmune conditions, as well as the coronavirus disease 2019 in the context of LIP. Importantly, although the causative role of LIP has been demonstrated in the development of type 1 diabetes and rheumatoid arthritis, a two-hit model has suggested that the factors other than lymphopenia are required to mediate the loss of control over homeostasis to result in ADs. Interestingly, these factors may be, if not totally, related to the function/number of regulatory T cells which are key modulators to protect from self-reactivity. In this review, we summarize the important roles of lymphopenia/LIP and the Treg cells in various autoimmune conditions, thereby highlighting them as key therapeutic targets for autoimmunity treatments.

Diagnostic and Predictive Contribution of Autoantibodies Screening in a Large Series of Patients With Primary Immunodeficiencies

Objectives

To evaluate the diagnostic and predictive contribution of autoantibodies screening in patients with primary immunodeficiencies (PIDs).

Methods

In the present study, PID patients and healthy controls have been screened for 54 different autoantibodies. The results of autoantibodies screening in PID patients were correlated to the presence of autoimmune diseases.

Results

A total of 299 PID patients were included in this study with a predominance of antibody deficiencies (27.8%) followed by immunodeficiencies affecting cellular and humoral immunity (26.1%) and complement deficiencies (22.7%). Autoimmune manifestations were present in 82 (27.4%) patients. Autoimmune cytopenia (10.4%) was the most common autoimmune disease followed by gastrointestinal disorders (10.0%), rheumatologic diseases (3.7%), and endocrine disorders (3.3%). Autoantibodies were found in 32.4% of PID patients and 15.8% of healthy controls (P < 0.0005). Anti-nuclear antibodies (ANA) (10.0%), transglutaminase antibody (TGA) (8.4%), RBC antibodies (6.7%), anti-smooth muscle antibody (ASMA) (5.4%), and ASCA (5.0%) were the most common autoantibodies in our series. Sixty-seven out of the 82 patients with autoimmune manifestations (81.7%) were positive for one or more autoantibodies. Eleven out of the 14 patients (78.6%) with immune thrombocytopenia had positive platelet-bound IgM. The frequencies of ASCA and ANCA among patients with IBD were 47.4% and 21.0% respectively. All patients with celiac disease had TGA-IgA, while six out of the 11 patients with rheumatologic diseases had ANA (54.5%). Almost one third of patients (30/97) with positive autoantibodies had no autoimmune manifestations. ANA, rheumatoid factor, ASMA, anti-phospholipid antibodies and ANCA were often detected while specific AID was absent. Despite the low positive predictive value of TGA-IgA and ASCA for celiac disease and inflammatory bowel disease respectively, screening for these antibodies identified undiagnosed disease in four patients with positive TGA-IgA and two others with positive ASCA.

Conclusion

The present study provides valuable information about the frequency and the diagnostic/predictive value of a large panel of autoantibodies in PIDs. Given the frequent association of some AIDs with certain PIDs, screening for corresponding autoantibodies would be recommended. However, positivity for autoantibodies should be interpreted with caution in patients with PIDs due to their low positive predictive value.

Risk and clinical outcomes of COVID-19 in patients with rheumatic diseases compared with the general population: a systematic review and meta-analysis

Patients with rheumatic diseases are often more susceptible to different bacteria and viruses because of immune impairment, but it is not clear whether there is a higher risk of infection and a more serious course of disease for novel coronavirus (SARS-CoV-2). We performed this systematic review and meta analysis to assess the risk and clinical outcomes of COVID-19 in patients with rheumatic diseases compared with the general population. We searched PubMed, EMBASE, Scopus and Web of Science databases from January 1, 2020 to October 20, 2020 to determine epidemiological information related to patients with rheumatic diseases and COVID-19, including clear risk estimate or data that could be converted and extracted. We included 26 observational studies, totaling about 2000 patients with rheumatic diseases of whom were infected with COVID-19. Meta-analysis showed that the risk of COVID-19 infection in rheumatic patients was significantly higher than that in the general population (OR = 1.53, 95% CI 1.24–1.88, P = 0.000). In terms of hospitalization and severe clinical outcomes associated with COVID-19, we found that rheumatic patients showed similar results to the reference population (hospitalization OR = 1.36, 95% CI 0.81–2.29, P = 0.247; admitted to ICU OR = 1.94, 95% CI 0.88–4.27, P = 0.098; death OR = 1.29, 95% CI 0.84–1.97, P = 0.248). The presence of comorbidities, hypertension, lung diseases were significantly associated with the increased risk of COVID-19-related hospitalization in rheumatic patients and anti-TNF drugs were associated with lower hospitalization risk. Older age was related to severe COVID-19. Our meta-analysis indicated that rheumatic patients were at a higher risk of COVID-19 infection but might not lead to a more serious disease process.

Lupus-like autoimmunity and increased interferon response in patients with STAT3-deficient hyper-IgE syndrome

We report on patients with STAT3 loss-of-function (LOF) mutations who developed lupus-like autoimmunity. Immune dysregulation seen in STAT3 LOF patients suggests a susceptibility to systemic autoimmunity with important implications in monitoring and management of these patients.

Autoimmune and inflammatory manifestations in pediatric patients with primary immunodeficiencies and their importance as a warning sign

INTRODUCTION AND OBJECTIVES

As well as increased susceptibility to infections, autoimmune and inflammatory manifestations also eventuate due to dysregulation of immune system in a substantial proportion of patients with primary immunodeficiency (PID). Autoimmune and inflammatory manifestations can occur prior or after diagnosis of PID. This study aimed to evaluate autoimmune and inflammatory complications among all types of PID patients in childhood and to emphasize the importance of these findings as a warning sign to diagnose PIDs.

METHODS

Medical records of 1036 patients with PID, followed up between 2003 and 2019, were retrospectively screened for occurrence of autoimmunity and inflammation. During this time, demographic features, autoimmune/inflammatory findings and initial time, genetic mutations, laboratory and clinical follow up findings, treatment regimens and outcomes were recorded.

RESULTS

Autoimmune and inflammatory manifestations were observed in 83 patients (10.1%). The median age of autoimmunity initial time was 61.3±53 months. Sixty-seven (80.7%) patients presented with autoimmune and inflammatory manifestations, and these findings had occurred during 16 patients' (19.3%) follow-up. The most common autoimmune manifestations were autoimmune hematologic (51.8%) and endocrine diseases (26.5%). Fifty patients (60.2%) had a single autoimmune/inflammatory manifestation, however 23 patients (27.7%) had two, eight patients (9.6%) had three and two patients (2.4%) had four different types of autoimmune/inflammatory manifestations. The frequency of autoimmune and inflammatory manifestations in phagocyte defects (56%), combined immune deficiencies (53%) and immune dysregulation diseases (52%) were observed higher than other forms of PIDs. During follow-up 13 (15.7%) patients died.

CONCLUSION

Autoimmune/inflammatory manifestations are associated with high morbidity in patients with PIDs and may precede the diagnosis of PID in childhood. Therefore, physicians must be aware of underlying possible immune deficiency and patients with known PIDs should be evaluated for autoimmune and inflammatory complications.

COVID-19 in patients with rheumatic disease in Hubei province, China: a multicentre retrospective observational study

BACKGROUND

In the ongoing COVID-19 pandemic, the susceptibility of patients with rheumatic diseases to COVID-19 remains unclear. We aimed to investigate susceptibility to COVID-19 in patients with autoimmune rheumatic diseases during the ongoing COVID-19 pandemic.

METHODS

We did a multicentre retrospective study of patients with autoimmune rheumatic diseases in Hubei province, the epicentre of the COVID-19 outbreak in China. Patients with rheumatic diseases were contacted through an automated telephone-based survey to investigate their susceptibility to COVID-19. Data about COVID-19 exposure or diagnosis were collected. Families with a documented history of COVID-19 exposure, as defined by having at least one family member diagnosed with COVID-19, were followed up by medical professionals to obtain detailed information, including sex, age, smoking history, past medical history, use of medications, and information related to COVID-19.

FINDINGS

Between March 20 and March 30, 2020, 6228 patients with autoimmune rheumatic diseases were included in the study. The overall rate of COVID-19 in patients with an autoimmune rheumatic disease in our study population was 0·43% (27 of 6228 patients). We identified 42 families in which COVID-19 was diagnosed between Dec 20, 2019, and March 20, 2020, in either patients with a rheumatic disease or in a family member residing at the same physical address during the outbreak. Within these 42 families, COVID-19 was diagnosed in 27 (63%) of 43 patients with a rheumatic disease and in 28 (34%) of 83 of their family members with no rheumatic disease (adjusted odds ratio [OR] 2·68 [95% CI 1·14-6·27]; p=0·023). Patients with rheumatic disease who were taking hydroxychloroquine had a lower risk of COVID-19 infection than patients taking other disease-modifying anti-rheumatic drugs (OR 0·09 [95% CI 0·01-0·94]; p=0·044). Additionally, the risk of COVID-19 was increased with age (adjusted OR 1·04 [95%CI 1·01-1·06]; p=0·0081).

INTERPRETATION

Patients with autoimmune rheumatic disease might be more susceptible to COVID-19 infection than the general population.

FUNDING

National Natural Science Foundation of China and the Tongji Hospital Clinical Research Flagship Program.

Frequency and Manifestations of Autoimmunity Among Children Registered in the Kuwait National Primary Immunodeficiency Registry

Objectives: To present a prospective report on the characteristics of autoimmune manifestations in patients with primary immunodeficient children registered in the Kuwait National PIDs Registry (KNPIDR).

Methods: The data were obtained from the Kuwait National Primary Immunodeficiency Disorders Registry during the period of January 2004 to December 2019.

Results: A total of 286 PID children were registered in KNPIDR during the study period with a predominance of immunodeficiencies affecting cellular and humoral immunity followed by combined immunodeficiencies with associated syndromic features and diseases of immune dysregulation. Fifty-seven (19.9%) patients presented with a total of 107 autoimmune manifestations. There was no significant statistical association between autoimmune manifestations and gender. Patients with autoimmune manifestations were older at onset of PID symptoms compared to those with no such manifestations, but this did not reach level of significance. The diagnosis delay was longer in patients with autoimmune manifestations compared to those with no such manifestations (p = 0.038). Forty-seven percent of these manifestations were among the presenting symptoms while 53% were documented later during the course of the disease. Fifty-seven percent of the patients developed 1 autoimmune manifestation, 30% developed 2 such manifestations, and 16% had ≥3 autoimmune manifestations. The most common autoimmune manifestation was cytopenia, followed by gastrointestinal manifestations and manifestations of the skin, hair, and nails. Autoimmune cytopenia were more common in patients with immune dysregulation syndromes, while gastrointestinal and skin manifestations predominate in patients with immunodeficiencies affecting cellular and humoral immunity and endocrine manifestations were more common in immune dysregulation syndromes. There were significant statistical associations between developing autoimmune manifestations and death as well as PID categories, being more common in patients with immune dysregulation. The frequency of autoimmunity was high among patients with RAG, WAS, STAT5b, NF-κB2, Fas, FasL, LRBA, APECED, IL-10, and C4 deficiencies.

Conclusions: Autoimmunity is frequent in patients with PIDs in Kuwait. This should prompt the suspicion of a PID in patients who present initially with autoimmunity, especially autoimmune cytopenia. Such patients should be managed with extra care since they are at a higher risk of death.

The Plasticity of Newly Formed B Cells

Newly formed B cells (NF-B cells) that emerge from the bone marrow to the periphery have often been referred to as immature or transitional B cells. However, NF-B cells have several striking characteristics, including a distinct BCR repertoire, high expression of AID, high sensitivity to PAMPs, and the ability to produce cytokines. A number of findings do not support their designation as immature because NF-B cells have the potential to become Ab-producing cells and to undergo class-switch recombination. In this review, we provide a fresh perspective on NF-B cell functions and describe some of the signals driving their activation. We summarize growing evidence supporting a role for NF-B cells in protection against infections and as a potential source of autoantibody-producing cells in autoimmune diseases such as systemic lupus erythematosus.

Base Excision Repair in the Immune System: Small DNA Lesions With Big Consequences

The integrity of the genome is under constant threat of environmental and endogenous agents that cause DNA damage. Endogenous damage is particularly pervasive, occurring at an estimated rate of 10,000–30,000 per cell/per day, and mostly involves chemical DNA base lesions caused by oxidation, depurination, alkylation, and deamination. The base excision repair (BER) pathway is primary responsible for removing and repairing these small base lesions that would otherwise lead to mutations or DNA breaks during replication. Next to preventing DNA mutations and damage, the BER pathway is also involved in mutagenic processes in B cells during immunoglobulin (Ig) class switch recombination (CSR) and somatic hypermutation (SHM), which are instigated by uracil (U) lesions derived from activation-induced cytidine deaminase (AID) activity. BER is required for the processing of AID-induced lesions into DNA double strand breaks (DSB) that are required for CSR, and is of pivotal importance for determining the mutagenic outcome of uracil lesions during SHM. Although uracils are generally efficiently repaired by error-free BER, this process is surprisingly error-prone at the Ig loci in proliferating B cells. Breakdown of this high-fidelity process outside of the Ig loci has been linked to mutations observed in B-cell tumors and DNA breaks and chromosomal translocations in activated B cells. Next to its role in preventing cancer, BER has also been implicated in immune tolerance. Several defects in BER components have been associated with autoimmune diseases, and animal models have shown that BER defects can cause autoimmunity in a B-cell intrinsic and extrinsic fashion. In this review we discuss the contribution of BER to genomic integrity in the context of immune receptor diversification, cancer and autoimmune diseases.

Determination of antibodies in everyday rheumatological practice

Antibody determination is routinely used in everyday rheumatological practice. Its result repeatedly determines the diagnosis or exclusion of a particular disease. Antibodies are immunoglobulins, i.e. some of the most important proteins in the immune system, and have specific properties that we should know. In addition, there are a number of factors that can affect their concentration, including drugs commonly used in the treatment of rheumatic diseases. There are definite indications, when the total concentrations of individual classes of immunoglobulins should be initially determined and it should be evaluated whether the patient produces them at all or their production is impaired. In some cases, we should evaluate the levels of specific antibodies along with the total protein concentration and the γ-globulin fraction, in which the antibodies are contained. The article presents information on the most common mistakes made when performing these tests.

Autoimmune and Inflammatory Manifestations in 247 Patients with Primary Immunodeficiency-a Report from the Slovenian National Registry

An abnormal regulation of immune responses leads to autoimmune and inflammatory manifestations in patients with primary immunodeficiencies (PIDs). The objective of our study was to evaluate the frequency of non-infectious and non-malignant manifestations in a large cohort of patients included in the Slovenian national PID registry and to assess the time of manifestation onset with respect to the time of PID diagnosis. Medical records of registered patients were reviewed. Data on autoimmunity, lymphoproliferation, autoinflammation, allergies, PID diagnosis, and underlying genetic defects were collected and analyzed. The time of each manifestation onset was determined and compared with the time of PID diagnosis. As of May 2015, 247 patients with 50 different PIDs were registered in the Slovenian national PID registry (147 males, 100 females; mean age 20 years). Mean disease duration was 14 years; 78 % of patients were younger than 18 years; and 22 % of patients were adults. Diagnosis of PID was genetically confirmed in 51 % of patients. Non-infectious and non-malignant manifestations were present in 69/235 (29 %) patients, including autoimmune manifestations in 52/235 (22 %), lymphoproliferative/granulomatous in 28/235 (12 %), autoinflammatory in 12/247 (5 %), and allergic manifestations in 10/235 (4 %) of all registered patients. Autoimmune manifestations were present in all patients whose PIDs were classified as diseases of immune dysregulation, 47 % of patients with chronic granulomatous disease, and 38 % of patients with predominantly antibody immune deficiencies. A high prevalence of non-infectious and non-malignant manifestations among patients in the Slovenian national PID registry suggests common genetic factors of autoimmunity, inflammation, and immunodeficiency. Patients with PID should be routinely screened for autoimmune and inflammatory manifestations at the time of PID diagnosis and during the long-term follow up.

Cytoskeletal Regulation of Inflammation and Its Impact on Skin Blistering Disease Epidermolysis Bullosa Acquisita

Actin remodelling proteins regulate cytoskeletal cell responses and are important in both innate and adaptive immunity. These responses play a major role in providing a fine balance in a cascade of biological events that results in either protective acute inflammation or chronic inflammation that leads to a host of diseases including autoimmune inflammation mediated epidermolysis bullosa acquisita (EBA). This review describes the role of the actin cytoskeleton and in particular the actin remodelling protein called Flightless I (Flii) in regulating cellular inflammatory responses and its subsequent effect on the autoimmune skin blistering disease EBA. It also outlines the potential of an antibody based therapy for decreasing Flii expression in vivo to ameliorate the symptoms associated with EBA.

Rheumatologic manifestations of primary immunodeficiency diseases

In the last 5 years, several hundred articles have been published concerning the link between primary immunodeficiency disease (PID) and rheumatologic diseases. Although rheumatologic complications were originally thought to be at the opposite ends of the spectrum of immunopathologic manifestations, they are now all being considered secondary manifestations of a causative primary "immune derangement." For the rheumatologist, it is important to be able to identify patients who may present with typical rheumatologic findings but who have an underlying PID. In a systematic manner, this overview addresses both the systemic and organ-based rheumatologic diseases which have known associations with primary immunodeficiencies, and explores how immunodeficiency may actually cause these clinical manifestations.

Immunodeficiencies with hypergammaglobulinemia: a review

Primary immunodeficiencies (PID) can present with recurrent infections, autoimmunity, inflammation, or malignancy and each of these conditions can be associated with elevated immunoglobulin. A high level of immunoglobulin G (IgG) is an uncommon finding, especially in pediatrics, and does not rule out primary immunodeficiency. Deficiencies in varied aspects of immune response have been described with high IgG. Reported PID conditions with elevated IgG include defects in humoral, cellular, and innate immunity. Some of these immunodeficiencies can have fatal outcomes, some require hematopoetic stem cell transplantation, and some require systemic medications. The mechanisms driving elevated IgG are not well understood, but in some cases abnormal cytokine production has been proposed. The evaluation of a patient with high IgG is guided by the patient's history and a physical examination, with special attention to autoimmunity in pediatrics and malignancy and liver disease in adults. In the setting of autoimmunity, chronic gastrointestinal disease, or chronic infections, the measurement of specific antibodies to evaluate the function of the IgG should be considered. An increased appreciation of elevation in IgG reflecting immune dysregulation may lead to earlier PID diagnoses.

Linear growth and endocrine function in children with ataxia telangiectasia

INTRODUCTION

Ataxia telangiectasia (AT) is a rare, genetic, primary immune deficiency disease characterized by immunodeficiency and neurological manifestations, with an increased tendency to infection, malignancy, and autoimmune diseases. Both growth delay and endocrine abnormalities are occasionally reported in these patients.

PATIENTS AND METHODS

We studied growth parameters height (Ht), weight, body mass index (BMI) and calculated the Ht standard deviation scores (HtSDS) of 13 patients (age 7.7 ± 3.5 years-age range: 3-14.5 years) with AT in relation to their mid-parental Ht SDS (MPHtSDS). We measured their serum calcium (Ca), phosphorus (PO4), alkaline phosphatase, alanine transferase (ALT), serum ferritin, creatinine and albumin concentrations. Endocrine investigations included the assessment of serum free thyroxine (FT4), thyrotropin (TSH), insulin-like growth factor-I (IGF-I) and morning cortisol. Complete blood count and serum immunoglobulins (IgG, IgM and IgA antibodies) were also measured. Growth data were correlated to hormonal and immune data.

RESULTS

About 31% of patients with AT had short stature (HtSDS <-2). However, their MPHtSDS denoted that their short stature was familial because four out of 13 had MPHtSDS <-2. They had low BMI, and two of them had low serum albumin and IGF-I, denoting malnutrition or disturbed growth hormone secretion. Elevated serum ALT and ferritin in some patients suggest immune-related inflammation in the liver. 30% of patients had high TSH, two of them had low FT4 diagnosing overt (15%) and sub-clinical (15%) hypothyroidism. Anti-thyroid peroxidase antibodies were high in two out of 13 patients denoting immune-related thyroid aggression. Eight out of 13 patients had Vitamin D deficiency (<20 ng/ml) however, their serum Ca and PO4 levels were in the normal range. One adolescent girl (14.5 years) had hyper-gonadotropic hypogonadism (low estradiol and high follicle stimulating hormone). All patients had normal 8 AM cortisol and renal function. None of the growth parameters were correlated with the IgG, IgM or IgA levels.

IN SUMMARY

Patients with AT had a high prevalence of growth retardation and endocrine dysfunction in the form of low IGF-I, overt and subclinical hypothyroidism and hypogonadism. Physicians should be aware of these possible endocrinopathies for an early diagnosis and proper treatment.

Successful anti-TNF-α treatment in a girl with LAD-1 disease and autoimmune manifestations

Leukocyte adhesion deficiency type 1 (LAD-1) is an autosomal recessive disorder, caused by the absence or reduced expression of the beta-2 integrins on granulocytes, and characterized by the inability of these cells to emigrate from the bloodstream towards the sites of tissue inflammation. A twelve-year-old girl with a diagnosis of LAD-1 syndrome and recurrent skin and mucosal infections since birth, presented with a two week history of fever, abdominal pain, vomiting, weight loss and polyarthralgia. She underwent an exploratory laparotomy with the finding of inflamed terminal ileum and colon and a normal appendix. Colonoscopy and videocapsule endoscopy showed multiple ileal and colonic mucosal ulcerations, which were compatible with inflammatory bowel disease, confirmed on histological examination. Given the lack of response to conventional therapy (prednisone and mesalamine), a monoclonal anti-TNF-α antibody was started at a dosage of 5 mg/kg at weeks 0,2,4,6 and then every 8 weeks. We observed a significant improvement of all clinical and laboratory parameters after the first weeks of therapy. Five months later, we anticipated the drug's administration every 5 weeks because of a precocious recurrence of symptoms. After 30 months of treatment no relapse nor any relevant side effects have been observed, and corticosteroids were withdrawn. Interestingly, our patient presented a small subset of CD18+ T cells, similarly to previously reported LAD-1 patients with mild phenotype, inflammatory bowel disease and CD18+ somatic revertant T cells. To the best of our knowledge, this is the first LAD-1 pediatric patient with inflammatory autoimmune complications who experienced a positive response to anti-TNF-α treatment.

Membranoproliferative glomerulonephritis and x-linked agammaglobulinemia: an uncommon association

Introduction. X-linked agammaglobulinemia (XLA) is a primary immunodeficiency characterized by agammaglobulinemia requiring replacement treatment with immunoglobulin. The association of XLA and membranoproliferative glomerulonephritis (MPGN) is unexpected and, to our knowledge, only one case was previously published. Case Report. The authors report the case of a 10-year-old boy with family history and prenatal diagnosis of XLA, treated from birth with intravenous immunoglobulin replacement therapy. He presented with pneumonia, macroscopic hematuria, nephrotic proteinuria, hypoalbuminemia, and hypercholesterolemia with normal renal function and serum complement levels. Renal histology showed immune complex mediated MPGN. He was started on high dose prednisolone and ramipril and switched to weekly subcutaneous immunoglobulin. After a 4-month treatment, hematuria and proteinuria significantly improved and prednisolone was gradually tapered without relapse. Conclusion. The pathogenic process underlying MPGN development in this patient is unknown but residual humoral immunity might play an important role. Thus, this case highlights the risk of autoimmune disorders among patients with XLA.

Immunoglobulin class switch recombination deficiency type 1 or CD40 ligand deficiency: from bedside to bench and back again

The immunoglobulin class switch recombination deficiency or hyper-IgM syndrome is characterized by normal or elevated serum IgM and low serum levels of other immunoglobulins. Since the first reported patient with hyper-IgM, more than 200 patients with this phenotype resulted from CD40 ligand deficiency have been reported. However, in addition to this common finding, they presented with different manifestations like opportunistic infections, autoimmunity and malignancies each of them are worth a detailed look. In this review, we will focus on different underlying mechanisms of these presentations to review what we have learned from our patients. In the end, we will discuss different treatment options available for these patients using this knowledge.

Autoimmunity in immunodeficiency

Primary immunodeficiencies (PID) comprise a diverse group of clinical disorders with varied genetic defects. Paradoxically, a substantial proportion of PID patients develop autoimmune phenomena in addition to having increased susceptibility to infections from their impaired immunity. Although much of our understanding comes from data gathered through experimental models, there are several well-characterized PID that have improved our knowledge of the pathways that drive autoimmunity. The goals of this review will be to discuss these immunodeficiencies and to review the literature with respect to the proposed mechanisms for autoimmunity within each put forth to date.

Primary immunodeficiency diseases in children: 15 year experience in a tertiary care medical center in Qatar

BACKGROUND

Primary immunodeficiency diseases (PID) are a group of heterogeneous, rare, genetic, mainly childhood disorders that affect specific components of immune system leading to serious complications.

OBJECTIVES

This study is aimed at describing the prevalence and the categories of PID, the ages of onset and the diagnosis, the clinical presentations, the treatment modalities and the overall outcome of affected patients.

MATERIALS AND METHODS

A retrospective study was conducted on 131 pediatric patients (aged 0-14 years) diagnosed with PID at Hamad General Hospital during a 15-year period (1998-2012).

RESULTS

Data of 131 patients (75 males & 56 females) was analyzed with an estimated prevalence of 4.7 PID patients per 100,000 children younger than 14 years of age. The most common type of PID was predominantly antibody deficiency (23.7 %), followed by other well-defined immunodeficiency syndromes (22.9 %), 19.1 % combined T and B cell immunodeficiency, but rare CVID, and no cases of complement deficiency. The mean onset age was 24.01 months and diagnosis age was 42.2 months. Recurrent infections, particularly pneumonia (48.9 %), failure to thrive (34.4 %), otitis media (26 %), sepsis (23.7 %), and chronic diarrhoea (21.4 %) were commonest presenting conditions. P. aeruginosa (15.7 %), Salmonella species (13.2 %), and Non-TB mycobacteria (13.2 %) were the most common bacterial isolates. The overall mortality rate was 21.4 % with combined immunodeficiency's accounting for 53.4 % of deaths.

CONCLUSIONS

This study reveals that PIDs are not rare in children in Qatar; and like other studies predominantly antibody deficiencies are the most common. Strategies that reinforce awareness and education of practicing physicians, bone marrow transplantation, and establishing PID national registry should be adopted to reduce mortality and morbidity of PID patients in Qatar.

Skin manifestations in primary immunodeficient children

Skin manifestations are prevalent in primary immunodeficiency disorders (PID). In a large proportion of patients, they manifest as presenting signs and serve as important factors for the early diagnosis of PID. Only a few studies describing the spectrum of skin disorders in PID are available. The objective of the current study was to determine the prevalence and characteristics of skin manifestations in children with PID. Participants were 128 pediatric patients with PID (aged <16 years) registered prospectively over 6 years. Skin manifestations were observed in 61 patients (48%), and those manifestations were the presenting features in 50 (39% of total PID and 82% of those with skin lesions). Skin infections were the most prevalent manifestations, seen in 39 patients (30%), followed by eczemas in 24 (19%). Skin infections were significantly more prevalent in those with congenital defects in phagocyte number, function, or both, as well as in those with well-defined immunodeficiencies. Although widely present in all participants with PID, eczema was a consistent feature (100%) in patients with hyper IgE syndrome and Wiskott-Aldrich syndrome (WAS). Erythroderma of infancy with diffuse alopecia was seen exclusively in patients with severe combined immunodeficiency disorders, telangiectasia in patients with ataxia telangiectasia, and partial albinism with silvery gray hair in those with Chediak-Higashi syndrome. Autoimmune skin manifestations were observed in 6% of reported cases of PID. This study highlights the importance of awareness of skin manifestations of PID to assist in the early diagnosis and management of these disorders.

Autoimmune thrombocytopenic purpura in partial DiGeorge syndrome: case presentation

The absence of an appropriate central tolerance in primary immunodeficiencies favors proliferation of autoreactive lymphocyte clones, causing a greater incidence of autoimmunity. Del 22q11.2 syndrome presents an increased incidence of allergic and autoimmune diseases. One of the most relevant and frequent immune manifestations is autoimmune thrombocytopenia. We present the case of a pediatric patient with autoimmune thrombocytopenia due to the immunological dysregulation observed in partial DiGeorge syndrome.

Membranous glomerulopathy in an adult patient with X-linked agammaglobulinemia receiving intravenous gammaglobulin

BACKGROUND

Immune complex deposition in the subepithelial zone of glomerular capillaries can lead to membranous glomerulopathy.

OBJECTIVE

To present the case of a 23-year-old man with X-linked agammaglobulinemia (XLA) who developed idiopathic membranous glomerulopathy while receiving intravenous immunoglobulin (IVIG).

METHODS

We performed an immunological workup, genetic testing, and a renal biopsy.

RESULTS

XLA was confirmed with less than 0.02% CD19+ cells in the blood after sequence analysis revealed a nonfunctional BTK gene. The patient presented with microhematuria, which persisted for 3 years and spanned treatment with 5 different preparations of intravenous gammaglobulin. Immunohistochemistry revealed membranous glomerulopathy.

CONCLUSION

Although endogenous serum immunoglobulin (Ig) production is severely impaired in XLA, rare B lymphocytes that have managed to mature can produce functional IgG antibodies. The pathogenic immune complexes could reflect IVIG reacting with polymorphic autoantigens, an endogenous IgG-producing clone reacting with a common idiotype present in the IVIG, or both.

Immune pathology associated with altered actin cytoskeleton regulation

The actin cytoskeleton plays a crucial role in a variety of important cellular processes required for normal immune function, including locomotion, intercellular interactions, endocytosis, cytokinesis, signal transduction, and maintenance of cell morphology. Recent studies have uncovered not only many of the components and mechanisms that regulate the cortical actin cytoskeleton but have also revealed significant immunopathological consequences associated with genetic alteration of actin cytoskeletal regulatory genes. These advances have provided new insights into the role of cortical actin cytoskeletal regulation in a number of immune cell functions and have identified cytoskeletal regulatory proteins critical for normal immune system activity and susceptibility to autoimmunity.

Mast cell and T cell communication; amplification and control of adaptive immunity

Recent advances in understanding the physiological role of mast cells (MCs) point to an important regulatory role for these cells in adaptive immunity. MCs express a diverse array of molecules that can promote their interaction with T cells as well as with other immune cells. New evidence demonstrates that mast cells can directly and indirectly communicate with T cells. They can control both effector and regulatory T cell responses and their activity can in turn be modulated by these interactions. Here we briefly summarize these advances and discuss some of the major challenges in understanding the communication of MCs and T cells.

Lymphocyte proliferation in immune-mediated diseases

Defects in T cell homeostatic mechanisms can result in T cell lymphopenia, defined as decreased numbers of lymphocytes. Lymphopenia results in homeostatic proliferation in order to maintain T cell homeostasis. It has been proposed that homeostatic proliferation can expand the pool of autoreactive T cells that promote autoimmunity, and indeed recent studies have further substantiated this observation in both animal models and humans. Conversely, homeostatic proliferation can promote tumor immunity by allowing tumor-specific T cells to accumulate. In this review, we discuss how the outcome of homeostatic proliferation can function both in a deleterious manner in autoimmunity and a beneficial way in tumor immunity. We also discuss the roles of various cytokines and T regulatory cells that control homeostatic proliferation.

Primary immunodeficiencies (PIDs) presenting with cytopenias

Autoimmune manifestations are increasingly being recognized as a component of several forms of primary immunodeficiencies (PID). Defects in purging of self-reactive T and B cells, impaired Fas-mediated apoptosis, abnormalities in development and/or function of regulatory T cells, and persistence of immune activation as a result of inability to clear infections have been shown to account for this association. Among autoimmune manifestations in patients with PID, cytopenias are particularly common. Up to 80% of patients with autoimmune lymphoproliferative syndrome (ALPS) have autoantibodies, and autoimmune hemolytic anemia and immune thrombocytopenia have been reported in 23% and 51% of ALPS patients, and may even mark the onset of the disease. ALPS-associated cytopenias are often refractory to conventional treatment and represent a therapeutic challenge. Autoimmune manifestations occur in 22% to 48% of patients with common variable immunodeficiencies (CVIDs), and are more frequent among CVID patients with splenomegaly and granulomatous disease. Finally, autoimmune cytopenias have been reported also in patients with combined immunodeficiency. In particular, autoimmune hemolytic anemia is very common among infants with nucleoside phosphorylase deficiency. While immune suppression may be beneficial in these cases, full resolution of the autoimmune manifestations ultimately depends on immune reconstitution, which is typically provided by hematopoietic cell transplantation.