Uniparental Disomy of Chromosome 4: A Case of Whole Chromosome UPD Presenting with LRBA Deficiency.

PURPOSE: Lipopolysaccharide-responsive beige-like anchor protein (LRBA) encodes a widely expressed cytosolic protein that participates in polarized vesicle trafficking. Homozygous loss-of-function LRBA mutations can lead to immune deficiency due to the lack of immune regulation, classified as a part of Tregopathies. We present a case of a 49-year-old female, with polyarthralgia in metacarpophalangeal and proximal interphalangeal joints bilaterally, and morning stiffness, leading to the diagnosis of rheumatoid arthritis treated with pulse steroid therapy. She had experienced sepsis and in-depth scrutiny revealed panhypogammaglobulinemia. After being referred to the immunology clinic, she was followed under the diagnosis of common variable immunodeficiency (CVID)-like inborn errors of immunity (IEI). METHODS AND RESULTS: Physical examination and diagnostic follow-up revealed massive splenomegaly accompanied by portal hypertension, and ulcerations in the colon. She also presented with periodic hematuria and dysuria. Cystoscopic biopsy revealed mast cell-derived interstitial cystitis which has not been previously reported in LRBA deficiency in the literature to our knowledge. A multi-gene next-generation sequencing panel performed for immune deficiencies (264 genes and 524 amplicons), resulted in the identification of an apparently homozygous LRBA mutation (p.Arg722His) in the Beige and Chediak-Higashi (BEACH) domain. The SNP array showed copy neutral absence of heterozygosity of the entire chromosome 4, which is consistent with uniparental isodisomy of chromosome 4. CONCLUSION: In conclusion, this case study underscores the critical role of LRBA in immune regulation and highlights the clinical heterogeneity associated with LRBA deficiency. The patient's presentation with severe immune dysregulation, including massive splenomegaly, portal hypertension, and the novel finding of mast cell-derived interstitial cystitis, expands the clinical spectrum of LRBA mutations. The identification of an apparently homozygous LRBA mutation via next-generation sequencing further emphasizes the importance of genetic analysis in diagnosing monogenic defects manifested as CVID-like phenotype. This is the first reported case of LRBA deficiency due to whole chromosome UPD to our knowledge. Future research should focus on elucidating the full range of clinical manifestations and developing targeted therapies for patients with LRBA deficiency.

Primary immune regulatory disorders (PIRD): expanding the mutation spectrum in Turkey and identification of sixteen novel variants.

Human Inborn Errors of Immunity (IEIs) encompass a clinically and genetically heterogeneous group of disorders, ranging from mild cases to severe, life-threatening types. Among these, Primary Immune Regulatory Disorders (PIRDs) constitute a subset of IEIs characterized by diverse clinical phenotypes, prominently featuring severe atopy, autoimmunity, lymphoproliferation, hyperinflammation, autoinflammation, and susceptibility to malignancies. According to the latest report from the International Union of Immunological Societies (IUIS), PIRDs arise from mutations in various genes including LYST, RAB27A, AP3B1, AP3D1, PRF1, UNC13D, STX11, STXBP2, FAAP24, SLC7A7, RASGRP1, CD70, CTPS1, RLTPR, ITK, MAGT1, PRKCD, TNFRSF9, SH2DIA, XIAP, CD27 (TNFRSF7), FAS (TNFRSF6), FASLG (TNFSF6), CASP10, CASP8, FADD, LRBA, STAT3, AIRE, ITCH, ZAP70, TPP2, JAK1, PEPD, FOXP3, IL2RA, CTLA4, BACH2, IL2RB, DEF6, FERMT1, IL10, IL10RA, IL10RB, NFAT5, TGFB1, and RIPK1 genes. We designed a targeted next-generation sequencing (TNGS) workflow using the Ion AmpliSeq™ Primary Immune Deficiency Research Panel to sequence 264 genes associated with IEIs on the Ion S5™ Sequencer. In this study, we report the identification of 38 disease-causing variants, including 16 novel ones, detected in 40 patients across 15 distinct PIRD genes. The application of next-generation sequencing enabled rapid and precise diagnosis of patients with PIRDs.

Spectrum of Hepatic Manifestations of Common Variable Immunodeficiency.

Common variable immunodeficiency (CVID) has a heterogenous clinical presentation and can be challenging to diagnose. Distinct histologic changes have been linked with CVID in several organ systems, which can help identify the correct diagnosis. In this study we review a cohort of hepatic CVID biopsies, to better define the spectrum of histologic and biochemical alterations. We reviewed 26 liver biopsies from 24 patients with CVID, obtained at 4 institutions between 2010 and 2019. Histologic slides were examined, and pathologic, biochemical, and clinical features were recorded. A control cohort of 21 patients with nodular regenerative hyperplasia (NRH) but lacking CVID was also examined. Liver function tests were frequently abnormal, especially alkaline phosphatase (median: 193 IU/L) and aspartate transaminase (median: 56 U/L), elevated in 23 and 17 of 25 biopsies, respectively. Fifteen patients had CVID involvement of other organs. Histologic features of primary biliary cholangitis were present in 2 patients, with florid duct lesions and prominent bile duct injury, in association with positive antimitochondrial antibodies. Among the other 24 biopsies, mild to moderate portal and lobular inflammation were present in 18 and 17 of 24 biopsies, respectively. Overall, 22 of 24 biopsies showed NRH-like changes. Plasma cell were absent. A distinct pattern of pericellular fibrosis was present in 23 of 26 biopsies overall. Involvement ranged from focal centrizonal fibrosis to bridging fibrosis and was accompanied by increased intrasinusoidal lymphocytes in 13 of 24 biopsies. Pericellular fibrosis was identified in 1 of 21 biopsies in the control cohort. Additional findings included granulomatous inflammation or nonhepatocellular foreign body-type multinucleate giant cells, identified in 4 biopsies. Three of 6 examined biopsies also demonstrated focal hepatocellular copper deposition. Hepatic disease in CVID is often associated with elevated alkaline phosphatase and aspartate transaminase and is characterized histologically by the mild nonspecific portal and lobular hepatitis, absence of plasma cells, NRH-like changes, and less commonly, typical histologic features of primary biliary cholangitis. We have also identified a distinctive pattern of delicate pericellular fibrosis that is a helpful clue to the diagnosis of hepatic disease in CVID, especially when accompanied by NRH-like changes.

Gastrointestinal findings in 26 adults with common variable immunodeficiency: The fickle nature of the disease manifests in gastrointestinal biopsies.

BACKGROUND/AIMS: The aim of the present study was to demonstrate the histopathological findings in gastrointestinal (GI) biopsies in adults with common variable immunodeficiency (CVID). MATERIALS AND METHODS: A total of 172 GI biopsies of 26 patients with CVID obtained over a 16-year period were reevaluated. Findings were analyzed using descriptive analyzes and χ2 test. RESULTS: Female-to-male ratio was 1.36. The median age at diagnosis was 36±13.94 (16-72) years. Chronic esophagitis was noted in 3 patients. The absence of plasma cells in the stomach, duodenum, and colon was observed in 16, 14, and 9 patients, respectively. Divergent results for the presence of plasma cells in concurrent stomach and duodenum samples were found in 11 (44%) patients. Nodular lymphoid hyperplasia (NLH) was notable in the duodenum (56%). The mean number of eosinophils in one high-power field was significantly higher in duodenal biopsies with NLH (27.21 vs. 14.37, p=0.002). Active inflammation was more prominent in the colon (91%) than in the stomach (65%) and duodenum (60%). Helicobacter pylori infection was found in 57.6%, including a case with persistent infection by the coccoid form. Celiac-like villous blunting and increased intraepithelial lymphocytes were seen in 40% and 24%, respectively. In addition, 23% had giardiasis associated with acute duodenitis and duodenal NLH (p<0.05). CONCLUSION: CVID gastroenteropathy is a challenging entity, and due to the heterogeneity in the presence and distribution of plasma cells throughout the GI tract and diverse disease course, multiple concurrent biopsies may be needed for tissue diagnosis. Duodenal CVID may present with villous alterations and giardiasis, and NLH appears to be an important clue in the duodenum. The association between duodenal NLH and eosinophil infiltration deserves further investigation.

ß2-Microglobulin deficiency causes a complex immunodeficiency of the innate and adaptive immune system.

BACKGROUND: Most patients with MHC class I (MHC-I) deficiency carry genetic defects in transporter associated with antigen processing 1 (TAP1) or TAP2. The clinical presentation can vary, and about half of the patients have severe skin disease. Previously, one report described ß2-microglobulin (ß2m) deficiency as another monogenetic cause of MHC-I deficiency, but no further immunologic evaluation was performed. OBJECTIVE: We sought to describe the molecular and immunologic features of ß2m deficiency in 2 Turkish siblings with new diagnoses. METHODS: Based on clinical and serologic findings, the genetic defect was detected by means of candidate gene analysis. The immunologic characterization comprises flow cytometry, ELISA, functional assays, and immunohistochemistry. RESULTS: Here we provide the first extensive clinical and immunologic description of ß2m deficiency in 2 siblings. The sister had recurrent respiratory tract infections and severe skin disease, whereas the brother was fairly asymptomatic but had bronchiectasis. Not only polymorphic MHC-I but also the related CD1a, CD1b, CD1c, and neonatal Fc receptor molecules were absent from the surfaces of ß2m-deficient cells. Absent neonatal Fc receptor surface expression led to low serum IgG and albumin levels in both siblings, whereas the heterozygous parents had normal results for all tested parameters except ß2m mRNA (B2M) expression. Similar to TAP deficiency in the absence of a regular CD8 T-cell compartment, CD8(+) γδ T cells were strongly expanded. Natural killer cells were normal in number but not "licensed to kill." CONCLUSION: The clinical presentation of patients with ß2m deficiency resembles that of patients with other forms of MHC-I deficiency, but because of the missing stabilizing effect of ß2m on other members of the MHC-I family, the immunologic defect is more extensive than in patients with TAP deficiency.

Multicenter experience in hematopoietic stem cell transplantation for serious complications of common variable immunodeficiency.

BACKGROUND: Common variable immunodeficiency (CVID) is usually well controlled with immunoglobulin substitution and immunomodulatory drugs. A subgroup of patients has a complicated disease course with high mortality. For these patients, investigation of more invasive, potentially curative treatments, such as allogeneic hematopoietic stem cell transplantation (HSCT), is warranted. OBJECTIVE: We sought to define the outcomes of HSCT for patients with CVID. METHODS: Retrospective data were collected from 14 centers worldwide on patients with CVID receiving HSCT between 1993 and 2012. RESULTS: Twenty-five patients with CVID, which was defined according to international criteria, aged 8 to 50 years at the time of transplantation were included in the study. The indication for HSCT was immunologic dysregulation in the majority of patients. The overall survival rate was 48%, and the survival rate for patients undergoing transplantation for lymphoma was 83%. The major causes of death were treatment-refractory graft-versus-host disease accompanied by poor immune reconstitution and infectious complications. Immunoglobulin substitution was stopped in 50% of surviving patients. In 92% of surviving patients, the condition constituting the indication for HSCT resolved. CONCLUSION: This multicenter study demonstrated that HSCT in patients with CVID was beneficial in most surviving patients; however, there was a high mortality associated with the procedure. Therefore this therapeutic approach should only be considered in carefully selected patients in whom there has been extensive characterization of the immunologic and/or genetic defect underlying the CVID diagnosis. Criteria for patient selection, refinement of the transplantation protocol, and timing are needed for an improved outcome.

Granulomatous disease in common variable immunodeficiency.

Granulomatous disease occurs in 8-22% of patients with common variable immunodeficiency (CVID). We examined the clinical and immunologic information of all 37 of 455 (8.1%) CVID subjects with this complication. The median age at diagnosis of CVID was 26 (2-59). 14 had granulomas 1-18 years before diagnosis of CVID. In 6 detection of granulomas coincided with this diagnosis; for 17, granulomas were documented later. 54% had lung granulomas, 43% in lymph nodes and 32% in liver. 54% of the group had had autoimmune diseases, mostly immune thrombocytopenia and hemolytic anemia. 24% had had a splenectomy. Nineteen (51.3%) required steroid treatment for granulomas; other immune suppressants were used in some. Over 25 years 28.5% died (median age 37.5), but not significantly more when compared to our CVID patients without granulomas (19.8%). Those with lung granulomas had similar mortality to those with granulomas in other tissues.

Vitamin D deficiency in the absence of enteropathy in three cases with common variable immunodeficiency.

BACKGROUND: Common variable immunodeficiency (CVID) is characterized by hypogammaglobulinemia and a defect in antibody production. Herein we describe 3 patients diagnosed with CVID in whom vitamin D deficiency was detected in the absence of enteropathy. METHODS: Biochemical and immunological analysis, serum osteocalcin, parathyroid hormone, 25-OH vitamin D, 1,25(OH)(2) vitamin D, vitamin A, vitamin E, urinary calcium, and deoxypyridinoline measurements were carried out. Vitamin D receptor (VDR) expression was examined in the peripheral blood mononuclear cells and hair follicles by reverse transcriptase polymerase chain reaction. VDR gene polymorphism was evaluated by high-performance liquid chromatography. RESULTS: None of the patients presented nutrient deficiencies other than vitamin D. Two of them were free of osteomalacia-related symptoms. VDR expression was found to be lower in the peripheral blood mononuclear cells and hair follicles when compared to the control group. CONCLUSIONS: Patients with CVID may present asymptomatic vitamin D deficiency. Vitamin D and VDRs play an important role in the innate immune system and modulate Toll-like receptor-related responses. Delay in diagnosis may predispose these patients not only to irreparable bone loss but also to infections, and autoimmune and malignant disorders, thus emphasizing the importance of prompt intervention.

Common variable immunodeficiency (CVID) presenting with malabsorption due to giardiasis.

Common variable immunodeficiency is characterized with B-cell and T-cell dysfunction and hypogammaglobulinemia. Recurrent bacterial infections, such as otitis media, chronic sinusitis and recurrent pneumonia due to diminished immunoglobulin (Ig) levels and impaired antibody production are frequently observed in common variable immunodeficiency. Almost half of the patients with common variable immunodeficiency have problems related to the gastrointestinal system. A 39-year-old woman was referred to our department with the complaint of chronic diarrhea. She had experienced diarrhea without mucus or blood in the last year and had lost 30 kg. In her medical history, she had suffered from recurrent upper and lower respiratory infections like sinusitis, otitis media and pneumonia since childhood. Serum immunoglobulin levels were low. There were no parasites or ova in her stool examinations. Esophagogastroduodenoscopy detected widespread macroscopic nodular appearance on duodenum, and biopsies from the duodenum revealed giardiasis invading the tissue. She was diagnosed as common variable immunodeficiency. After metronidazole therapy and intravenous immunoglobulin infusion was started, her diarrhea attacks ceased and she regained her normal weight. Common gastrointestinal system problems in patients with common variable immunodeficiency are lactose intolerance, lymphoid hyperplasia/diffuse lymphoid infiltration, loss of villi and infection, especially with Giardia lamblia. Giardiasis may lead to severe mucosal flattening and sometimes to lymphoid hyperplasia at the lamina propria of the duodenum. Medical history should be evaluated carefully regarding recurrent respiratory infections. In such cases with chronic diarrhea, common variable immunodeficiency should be kept in mind as a possible cause.