X-linked hyper IgM syndrome: a report of the first case in Thailand with a confirmed mutation of CD40 ligand gene

X-linked hyper IgM (XHIM) syndrome is a rare congenital immunodeficiency disease caused by failure of B cell to isotype switch from IgM to other classes of immunoglobulins in response to infections. Recently, a molecular cloning of the gene responsible for the syndrome, the CD40L gene has been accomplished and the gene was successfully mapped to the long arm of X chromosome at the position Xq26. We, herein, report the first case of molecular proven XHIM in a Thai boy with a classic presentation and with a confirmed mutation of the CD40L gene. Case Report: A.S. was a 1 year 7 month old boy referred from Buriram Provincial Hospital for a work up and treatment for his recurrent infections consisted of chronic respiratory tract infections with otitis media (since 6 months of age), chronic diarrhea (since 9 months of age) and malnutrition (marasmus) secondary to his longstanding illnesses. He was a product of a consanguineous marriage but without history of similar illness observed in his pedigree. Abnormal laboratory works up included IgG of 300 mg/dl, IgA 10 mg/dl, IgM 1,635 mg/dl, positive stool examinations for Cryptosporidium, chronic colitis on radiographic gastrointestinal follow through study, a positive acid fast bacillus (AFB) stain of gastric aspirate and multiple positive bacterial cultures from various body sources. His anti-HIV serology was negative. His hospital course was significant for several bouts of infections of gastrointestinal, respiratory, and genitourinary systems. His treatment consisted of multiple courses of antibiotics, antituberculous drugs and IVIG administrations. His hospital course was complicated with feeding problem from an esophageal stricture requiring several esophageal dilatations. The analysis of CD40L gene revealed a point mutation of exon 5 (A619T) of the CD40L gene resulting in a stop codon confirming that indeed he had XHIM. He died with Pseudomonas septicemia during the waiting period for a bone marrow transplantation from a cord-blood stem cell.     

The polymorphism p.G219R of CD40L does not cause immunological alterations in vivo: conclusions from a X-linked hyper IgM syndrome kindred

Hyper-IgM syndromes (HIGM) are characterized by low levels of IgG, IgA and IgE and normal to high levels of IgM. Patients with these syndromes present recurrent infections due to an impaired immunoglobulin maturation. The most prevalent form of HIGM, X-linked hyper IgM syndrome (XHIM), is caused by mutations in the gene encoding the CD40 ligand (CD40LG). We present two siblings with XHIM caused by a large CD40LG deletion affecting more than half of the gene, and extended from the end of intron 3 to far upstream of the promoter regions. Genetic analysis in the maternal family discovered the CD40L(G219R) polymorphism in several members. Segregation of this polymorphism in the kindred indicated that the deletion of CD40LG was a de novo mutation in the mother. Although half of her CD4+ T cells did not express CD40L and the other half expressed the CD40L(G219R) variant, the mother was healthy. This suggests that this polymorphism is not pathogenic by itself although it has been recently related to X-linked lymphoproliferative syndrome.     

X-linked hyper-IgM syndrome associated with Cryptosporidium parvum and Cryptococcus neoformans infections: the first case with molecular diagnosis in Korea

X-linked hyper-IgM syndrome (XHIM) is a rare primary immunodeficiency disorder, caused by mutations of the gene encoding CD40 ligand (CD40L; CD154). We report the clinical manifestations and mutational analysis of the CD40L gene observed in a male patient from a XHIM family. Having hypogammaglobulinemia and elevated IgM, the 3-yr-old boy exhibited the characteristic clinical features of XHIM. The patient suffered from frequent respiratory infections, and chronic enteritis caused by Cryptosporidium parvum. In addition, a lymph node biopsy and a culture from this sample revealed C. neoformans infection. Activated lymphocytes from the patient failed to express CD40L on their surface as assessed by flow cytometry and a missence mutation (W140R) was found at the XHIM hotspot in his CD40L cDNA to confirm the diagnosis. Genetic analysis of the mother and sister showed a heterozygote pattern, indicating carrier status. To our knowledge, this is the first report on the molecular diagnosis of an XHIM patient in Korea.     

Immunological and genetic analysis of 65 patients with a clinical suspicion of X linked hyper-IgM.

BACKGROUND: X linked hyper-IgM (XHIM) is a primary immunodeficiency caused by mutations in the tumour necrosis factor superfamily 5 gene, TNFSF5, also known as the CD40 ligand (CD40L) gene. Patients often present with recurrent infections, and confirmation of a diagnosis of XHIM enables appropriate therapeutic interventions, including replacement immunoglobulin, antibiotics, and bone marrow transplantation. AIM: To review and optimise the institution's diagnostic strategy for XHIM. METHOD: Samples from 65 boys were referred to this centre for further investigation of suspected XHIM. The results, which included a flow cytometric whole blood assay for CD40L expression followed by mutation analysis in selected patients, were reviewed. RESULTS: Twenty one patients failed to express CD40L and TNFSF5 mutations were found in 20 of these patients. In contrast, no TNFSF5 mutations were found in 16 patients with weak expression of CD40L. Interestingly, one quarter of patients with confirmed XHIM who had TNFSF5 mutations had low concentrations of IgG, IgA, and IgM. Most of the remaining patients with XHIM had the classic pattern of normal or raised IgM with low concentrations of IgA and IgG. CONCLUSIONS: This study demonstrates the usefulness of the whole blood staining method as a rapid screen to select patients for subsequent TNFSF5 mutation analysis, and shows the benefits of a unified protein/genetic diagnostic strategy.     

Hyper-IgM1 syndrome with interstitial pneumonia and diarrhea caused by coxsackievirus B4 in a 3-month-old infant.

BACKGROUND: Hyper-IgM1 syndrome is a rare genetic primary immunodeficiency disease caused by mutations of the CD40 ligand gene. It is characterized by normal or elevated levels of IgM and markedly decreased serum IgG, IgA, and IgE levels. Patients with this syndrome often easily develop infections. During the past decade, it has become clear that enteroviral infections may also occur as a manifestation of hyper-IgM1 syndrome. OBJECTIVE: To report a case of hyper-IgM1 syndrome in a 3-month-old boy who had interstitial pneumonia and intractable diarrhea. METHODS: Chest radiography, bronchoscopy, immune studies, and open lung biopsy were performed. RESULTS: Chest radiography revealed diffuse bilateral infiltrates. Immune studies revealed the following proportions of lymphocyte markers: CD3, 5,976/microL; CD4, 5,015/microL; CD8, 866/microL; CD19, 1,325/microL; CD16 + 56, 935/microL; and active T cells, 225/microL. The IgG level was 190 mg/dL; IgA, 2 mg/dL; IgM, 34 mg/dL; IgE, 1 IU/dL; and CH50, 23.8/mL. CD40L expression was less than 1%, and a Tyr 169 Asn (t526a) mutation in the exon 5 tumor necrosis factor domain of the CD40L gene was found. The patient was treated with intravenous immunoglobulin and had a dramatic improvement in symptoms. Open lung biopsy failed to demonstrate pneumocystis, and there was no evidence of cryptosporidium in the stool. However, coxsackievirus B4 was isolated by viral throat culture. CONCLUSION: Interstitial pneumonia and diarrhea caused by coxsackievirus B4 may be a complication of hyper-IgM1 syndrome.     

Immunologic reconstitution following bone marrow transplantation for X-linked hyper IgM syndrome

X-linked hyper IgM syndrome (XHIM), caused by mutations of the CD40 ligand (CD40L) gene, is characterized by recurrent bacterial and opportunistic infections, an increased incidence of autoimmunity and malignancies, and immunodeficiency due to abnormal T/B cell interaction. Because of poor long-term prognosis, bone marrow transplantation (BMT) has been proposed as an alternative treatment. An 8-month-old boy with XHIM and a splice site mutation of CD40L underwent BMT using a fully matched sibling donor. Markers of engraftment and immunologic reconstitution were measured serially. After BMT, activated T cells expressed functional CD40L, and genomic DNA obtained from circulating white cells contained predominantly wild-type CD40L sequences. Serum immunoglobulin levels including IgE and antibody responses to recall antigens normalized, and immunization with the T-cell-dependent neoantigen, bacteriophage φX174, demonstrated amplification of the response and isotope switching. BMT provides a permanent cure for XHIM if a fully matched sibling donor is available and the procedure is performed before complications have occurred.     

Disseminated Bacille Calmette-Guérin disease as the initial presentation of X-linked severe combined immunodeficiency--a case report

Bacille Calmette-Guerin (BCG) vaccination is used to prevent severe M. tuberculosis infection. It has been used in many countries for a long time. However, complications do occur, including localized abscesses, regional lymphadenitis and disseminated disease. The latter is often associated with underlying immunodeficiency. We report an 8-month-old male infant presenting with cough and fever who had had a generalized pigmented skin rash for one month. Skin biopsy revealed mycobacterial infection, but his response to treatment was poor and he had a persistent mild fever. Immunological studies revealed an IgG of 49 mg/dl, IgA 4 mg/dl, IgM 28 mg/dl, IgE < 1 mg/dl, CD3 1.1%, CD4 0.6%, CD8 0.6%, CD19 93.9%, CD57 1.1%, activated T cells 0.9%, and CH50 < 6.3%. These findings are compatible with the diagnosis of T(-)B(+)NK- severe combined immunodeficiency. Sequence analysis was performed and showed the presence of missense mutation in IL2Rgamma gene. An X-linked recessive inheritance pattern was proved by sequence analysis of his mother and grandmother. In order to identify the strain of the microorganism, we reviewed pathology of the skin biopsy which consisted of diffuse histiocytic infiltrate with poorly formed granulomas and no necrosis and used polymerase chain reaction (PCR) with the stain-positive clinical specimen and verify the organism found in the child's biopsy as M. bovis BCG strain. The diagnosis of disseminated BCG disease must be considered in any infant with cutaneous mycobacterial lesions, especially with atypical histologic findings. Such a patient's immunologic status should be evaluated and further family study is suggested. A high index of suspicion is needed to make a timely diagnosis, as early intervention with intensive treatment and bone marrow transplantation may be life-saving.     

Wiskott-Aldrich syndrome complicated by an atypical lymphoproliferative disorder: a case report.

Wiskott-Aldrich syndrome (WAS) is an X-linked syndrome consisting of eczema, recurrent pyogenic infection, and thrombocytopenia with decreased platelet volume. Immunologic studies reveal normal immunoglobulin G (IgG), decreased IgM, elevated IgA and IgE levels, and decreased T-cell function. Patients with WAS often have increased susceptibility to lymphoproliferative disorders (LPDs). We report a 3-year-old boy who had persistent thrombocytopenia with bleeding, recurrent infections, and chronic eczema with frequent skin infections since birth. A blood smear revealed small platelets (50% of normal size). Immunologic studies showed normal IgG (1880 mg/dL), decreased IgM (76 mg/dL) and increased IgA (228 mg/dL) and IgE (14,282 IU/mL) levels. The relative proportions of immune cells were CD2 52.2%, CD3 41.1%, CD4 23.4%, CD8 16.8%, CD19 8.0%, CD57 7.7% and active T cells 14.6%. T-cell dysfunction was detected on the multitest for cell-mediated immunity. The WAS diagnosis was confirmed by mutation analysis which demonstrated a 4-base pair deletion in WAS protein gene exon 1. His thrombocytopenia was uncontrolled despite intravenous immunoglobulin infusions, so splenectomy was performed. The platelet count then rose to about 60,000 to 80,000/microL. However, about 2 weeks after splenectomy, he developed generalized lymphadenopathy and lymphoma was misdiagnosed based on lymph node biopsy at another hospital where he was admitted for urgent care. However, our analysis of his lymph node pathology led to the diagnosis of atypical LPD (ALPD). The lymphadenopathy regressed spontaneously 1 month later without chemotherapy. Early and correct diagnosis of WAS complicated with ALPD is important to avoid unnecessary chemotherapy.     

Critical function of the CD40 pathway in parvovirus B19 infection revealed by a hypomorphic CD40 ligand mutation

Parvovirus B19-induced chronic anemia has been associated with failure to mount an effective neutralizing antibody response. We describe an adolescent male with a 13-year history of parvovirus B19-induced anemia as the primary manifestation of X-linked hyper IgM immunodeficiency (XHIM). This patient, whose serum IgG concentration was at the low end of the normal range and who mounted IgG antibody responses to T cell-dependent antigens, suffered from a nonsense mutation (R11 --> X) in the CD40 ligand (CD40L) gene. This resulted in low-level expression of a mutant CD40L predicted to lack the cytoplasmic domain. Intravenous immunoglobulin therapy alone or in combination with interferon gamma, given in the context of impaired Th1 cytokine production, suppressed but did not eradicate the infection. These results highlight the critical function of the CD40/CD40L pathway in parvovirus B19 infection and suggest that subtle defects in this pathway may underlie cases of chronic parvovirus B19 infection atypical of XHIM.     

A case of Good syndrome accompanied by myasthenia gravis: immunological evaluations]

Good syndrome, characterized by both thymoma and hypogammaglobulinemia, is a rare immunodeficient disorder. We experienced a case of Good syndrome accompanied by myasthenia gravis (MG). A 58-year-old man was admitted to our hospital because of muscle weakness and fatigability. Based on the presence of anti-acetylcholine receptor (AChR) antibody and thymoma, he was diagnosed as having MG. Peripheral blood lymphocyte count was normal, but gammaglobulin levels were markedly decreased (IgG 283 mg/dl, IgA 17 mg/dl, IgM 1 mg/dl). Clinical remission of MG was achieved by thymectomy followed by high-dose corticosteroids. Despite monthly intravenous immunoglobulin supplementation, he suffered from repeated respiratory tract infections and candidiasis. Body CT revealed adrenal tumor and pancreatic cancer with liver metastasis, and he died of bacterial pneumonia. Immunological evaluations showed complete lack of CD19+ B cell in the peripheral blood and responses of peripheral blood mononuclear cells to mitogens. Peripheral blood T cells responded to a suboptimal concentration of a recombinant AChR fragment: this pattern of AChR-induced T cell response was typical of MG patients. We failed to detect IgG autoantibodies reactive with B cells in his serum. Patients with Good syndrome represent imbalance of immune responses, leading to both immunodeficiency and autoimmunity.     

Severe congenital neutropenia or hyper-IgM syndrome? A novel mutation of CD40 ligand in a patient with severe neutropenia

Severe congenital neutropenia (SCN) and CD40 ligand deficiency (CD40LD) are two primary immunodeficiency diseases caused by different underlying genetic defects. In this report, we present a case who clinically presented as a SCN patient, but subsequent mutation analysis of this patient was compatible with CD40LD. The patient is a 3-year-old boy, who was referred to our center because of pneumonia, oral and anal ulcers, and periodontitis. As severe consistent neutropenia and maturation arrest in the myeloid series were observed in the bone marrow, a diagnosis of SCN was made. However, no mutations were found in the ELA2 and HAX1 genes. As functional T cell defects were observed, we suspected CD40LD. DNA sequencing showed a 17-base pair deletion in the CD40L gene. Although the patient did not have a decreased serum level of IgA, and his serum IgM level was within the normal range, the diagnosis of CD40LD was confirmed, suggesting that CD40LD should be suspected in any male patient with recurrent infections and neutropenia.     

Leukocyte Transfusion-Associated Granulocyte Responses in a Patient with X-Linked Hyper-IgM Syndrome

X-linked hyper-IgM syndrome (XHIM) is a severe congenital immunodeficiency caused by mutations in CD154 (CD40 ligand, gp39), the T cell ligand for CD40 on B cells. Chronic or cyclic neutropenia is a frequent complicating feature that heightens susceptibility to severe infections. We describe a patient with a variant of XHIM who produced elevated levels of serum IgA as well as IgM and suffered from chronic severe neutropenia. Eight of ten leukocyte transfusions with cells from a maternal aunt, performed because of mucosal infections, resulted in similar episodes of endogenous granulocyte production. Transfection studies with the mutant CD154 protein indicate that the protein is expressed at the cell surface and forms an aberrant trimer that does not interact with CD40. The data suggest that allogeneic cells from the patient's aunt, probably activated T cells bearing functional CD154, may interact with CD40⁺ recipient cells to produce maturation of myeloid precursors in the bone marrow.     

A novel disease-causing CD40L mutation reduces expression of CD40 ligand,but preserves CD40 binding capacity

Mutations in CD40 ligand (CD40L) that permit residual CD40L expression typically impair binding of CD40. We report a male patient who presented with recurrent bacterial respiratory tract infections, normal IgM, decreased IgG, absent IgA levels, and CD40L expression at ~ 50% of the level observed in the normal control. He subsequently developed autoimmunity, inflammatory bowel disease, severe opportunistic infections suggestive of a combined immunodeficiency, and a cervical spine schwannoma. Whole exome sequencing of the patient's genomic DNA revealed a novel missense mutation (p.H47Y) in CD40L. Although this mutation was predicted to be benign in silico, flow cytometry at 13 years of age demonstrated markedly decreased CD40L expression (~ 32% of normal control) that retained the capacity to bind soluble CD40-Ig, suggesting that the mutation impairs CD40L surface expression without affecting its affinity for CD40. This case highlights the variability in the clinical evolution and phenotype of CD40L deficiency.     

Cellular and Molecular Characterisation of the Hyper Immunoglobulin M Syndrome Associated with Congenital Rubella Infection

Introduction  The hyper-immunoglobulin M syndrome (HIM) is a rare group of immune deficiency disorders characterised by normal or increased serum IgM with normal or reduced IgG, IgA and IgE. Materials and Methods  We have undertaken detailed cellular and molecular studies in a 53-year-old man with HIM as a result of congenital rubella. Results  No mutations were detected in the CD40 ligand, activation-induced cytidine deaminase and uracil DNA glycosylase. His T-cell responses to lectins and antigens were normal. Flow cytometry confirmed the presence of CD40 ligand on activated T cells. Most CD40-dependent functions that were tested, including B-cell proliferation, isotype switching and production of memory B cells, were normal. CD40/IL4 dependent rescue from anti-IgM-induced apoptosis was impaired. Conclusion  The detection of cell-surface IgG but lack of serum IgG indicated that he may have an antibody secretion defect.     

Hyper-immunoglobulin M syndrome type 3 with normal CD40 cell surface expression

Mutations of the CD40 gene have been found in patients with autosomal recessive hyper-immunoglobulin M (HIGM) syndrome type 3. Five patients from four unrelated families with CD40 mutation have been reported so far. Clinical manifestations include recurrent sinopulmonary infections, Pneumocystis carinii pneumonia and Cryptosporidium parvum infection. Affected patients typically have very low levels of IgG and IgA and normal or high levels of IgM. Flow cytometry analysis of these five patients demonstrated that peripheral blood B lymphocytes lacked expression of surface CD40. Herein, we present two siblings from second-degree consanguineous Turkish parents with homozygous CD40 deletion of four nucleotides including the stop codon resulting presumably to a longer protein. Clinical and immunological profile of these patients is similar to the already reported HIGM3 patients except normal CD40 expression on B lymphocytes. This observation emphasizes the requirement of CD40 mutation analysis for definite diagnosis of HIGM3 despite normal flow cytometric expression of CD40, particularly if the immunological and clinical profile is suggestive for HIGM3.     

Clinical and Molecular Characterization of X‐linked Hyper‐IgM Syndrome Patients in China

X‐linked Hyper‐IgM syndrome (XHIM) is caused by mutations of CD154 gene also known as CD40 ligand (CD40L). CD40L is expressed in activated T cells and interacts with CD40 receptor expressed on B lymphocytes and dendritic cells. Affected patients present cellular and humoral immune defects, with infections by intracellular, opportunistic and extracellular pathogens. In the present study, we investigate molecular defects involved in the XHIM in five patients and identified five distinct CD40L mutations, three of which had not been previously described. P1 harboured a novel p.L193P mutation, which abolished the expression of CD40L. P2 had a frameshift deletion in exon 3 (p.E108fsX19), which also decreased the protein expression. P3 demonstrated p.E54X change in exon 2. P4 harboured the p.Q186X change in the exon 5. P5 demonstrated p. E142X change in exon 5. Mutations in P3, P4 and P5 all led to the production of premature CD40L protein. Two of the five genetically defined patients received umbilical cord blood stem cell transplantation from unrelated donor and achieved clinical remission, and the expression of CD40L on the peripheral blood mononuclear cells restored. These mutations reflect the heterogeneity of CD40L gene, indicating the need for accurate and reliable molecular testing in patients suspected of XHIM.     

CD40 ligand and its role in X-linked hyper-IgM syndrome

CD40 ligand (CD40L) on activated T cells binding to CD40 on B cells is of critical importance for Ig heavy-chain switching and rescue of B cells from apoptosis after somatic mutation in the germinal centre. Mutations in the CD40L gene are now known to cause X-linked hyper-IgM syndrome (HIGM1), an immunodeficiency characterized by the absence of serum IgG, IgA and IgE. In this review, we discuss how basic and clinical immunology have combined to provide major insights into the function of CD40 in T-B cell collaboration.     

Inhibitory receptors CD85j, LAIR-1, and CD152 down-regulate immunoglobulin and cytokine production by human B lymphocytes

Class switching consists in the substitution of the heavy-chain constant region of immunoglobulin M (IgM) with that of IgG, IgA, or IgE. This enables antibodies to acquire new effector functions that are crucial to combat invading pathogens. Class switching usually requires engagement of CD40 on B cells by CD40 ligand (CD40L) on antigen-activated CD4(+) T cells and the production of cytokines. The process must be regulated tightly because abnormal IgG and IgA production favors the onset of autoimmunity, whereas increased switching to IgE leads to atopy. These inflammatory disorders can be triggered or exacerbated by costimulatory signals. Although thoroughly investigated on T cells, the roles of the inhibitory receptors CD85j, LAIR-1, and CD152 on B-cell functions have not been fully elucidated. In this study we show that cross-linking of the B-cell inhibitory receptors by specific monoclonal antibodies inhibits IgG and IgE production, reduces the percentage of IgG- and IgE-expressing B cells, and down-regulates interleukin 8 (IL-8), IL-10, and tumor necrosis factor alpha production. These effects were demonstrated using different B-cell stimulatory pathways (recall antigens, CD40L-transfected cells plus IL-4, and lipopolysaccharide plus IL-4). It thus appears that CD85j, LAIR-1, and CD152 play a central role for the control of IL-4-driven isotype switching.