Significance of hypergammaglobulinemia in patients with chronic myelomonocytic leukemia.

Chronic inflammation is often indicated by a relative increase in the gamma globulin fraction in the serum electrophoresis. In a retrospective study, we analyzed the prevalence of relative hypergammaglobulinemia in 60 patients with chronic myelomonocytic leukemia (CMML), its potential prognostic impact, and potential correlations with laboratory and molecular features. Relative hypergammaglobulinemia (> 20%) was found in 25/60 (42%) patients. The median survival of patients with relative hypergammaglobulinemia was significantly shorter than in patients without hypergammaglobulinemia (10 vs. 24 months, p = 0.018). There was no difference between the groups regarding leukocyte count, hemoglobin value, and platelet count, but a higher prevalence of NRAS mutations and a lower prevalence of ZRSR2 mutations in patients with hypergammaglobulinemia. Our results show that hypergammaglobulinemia is present in a proportion of CMML patients and that this abnormality is associated with poor overall survival. The role of chronic inflammation in the pathophysiology of CMML needs to be further investigated.

Unusual phenotype in patients with a hypomorphic mutation in the DCLRE1C gene: IgG hypergammaglobulinemia with IgA and IgE deficiency.

The nuclease Artemis is a enzyme for V(D)J recombination allowing for the creation of T and B lymphocytes as well as for the repair of radiation-induced DNA double strand breaks encoded by the DCLRE1C gene. Artemis-null mutations are a known cause of severe combined immunodeficiencies (SCIDs) with radiosensitivity. Hypomorphic mutations in Artemis have been reported to cause a "leaky SCID"" phenotype, typically with hypogammaglobulinemia. We present four patients, all harboring the same unique hypomorphic mutation in the DCLRE1C gene, an 8-base pair insertion (c.1299_1306dup, p.Cys436*) presenting with a relatively mild phenotype including pulmonary infectious EBV-related lymphoproliferative diseases, an autoimmune phenomenon. Non-typical findings of IgG hypergammaglobulinemia accompanied by IgA and IgE deficiency were recorded in all patients. The typical viral, fungal, and opportunistic infections were absent, and patients reached a relatively old age.

The Sjögren's syndrome-associated autoantigen Ro52/TRIM21 modulates follicular B cell homeostasis and immunoglobulin production.

Systemic rheumatic diseases are characterized by abnormal B cell activation with autoantibody production and hypergammaglobulinaemia. Ro52/SSA, also denoted tripartite motif (TRIM)21, is a major autoantigen in Sjögren's syndrome and systemic lupus erythematosus. Interestingly, TRIM21-deficient mice develop systemic autoimmunity with B cell-driven manifestations such as autoantibodies, hypergammaglobulinaemia and glomerulonephritis following tissue injury. The mechanisms by which TRIM21-deficiency leads to enhanced B cell activation and antibody production are, however, not well understood, and to further elucidate the role of TRIM21 in systemic autoimmunity, we investigated the B cell phenotype and antibody responses of Trim21-/- mice following immunization with thymus-dependent (TD) and thymus-independent (TI) antigens. We found that TRIM21-deficient mice developed significantly higher specific antibody titres than their wild-type counterparts upon B cell receptor (BCR) engagement by TD and TI type II antigens, and this was accompanied by an altered B cell phenotype. Furthermore, BCR cross-linking, but not anti-CD40 stimulation, in vitro resulted in a significantly higher proliferation of Trim21-/- cells. We also observed that splenic follicular B cells were expanded not only in immunized mice but also already in young, unmanipulated Trim21-/- mice, and transcriptomic analysis of these cells revealed an up-regulation of genes associated with B cell differentiation, indicating a role for TRIM21 in their regulation. In conclusion, in this study we describe a link between the rheumatic autoantigen Ro52/TRIM21 and increased antibody production associated with follicular B cell expansion, implicating a potential role for Ro52/TRIM21 in the pathogenesis of systemic autoimmune diseases.

Kaposi's Sarcoma-Associated Herpesvirus Latency Locus Renders B Cells Hyperresponsive to Secondary Infections.

Kaposi's sarcoma-associated herpesvirus (KSHV) induces B cell hyperplasia and neoplasia, such as multicentric Castleman's disease (MCD) and primary effusion lymphoma (PEL). To explore KSHV-induced B cell reprogramming in vivo, we expressed the KSHV latency locus, inclusive of all viral microRNAs (miRNAs), in B cells of transgenic mice in the absence of the inhibitory FcγRIIB receptor. The BALB/c strain was chosen as this is the preferred model to study B cell differentiation. The mice developed hyperglobulinemia, plasmacytosis, and B lymphoid hyperplasia. This phenotype was ameliorated by everolimus, which is a rapamycin derivative used for the treatment of mantle cell lymphoma. KSHV latency mice exhibited hyperresponsiveness to the T-dependent (TD) antigen mimic anti-CD40 and increased incidence of pristane-induced inflammation. Lastly, the adaptive immunity against a secondary infection with Zika virus (ZIKV) was markedly enhanced. These phenotypes are consistent with KSHV lowering the activation threshold of latently infected B cells, which may be beneficial in areas of endemicity, where KSHV is acquired in childhood and infections are common.IMPORTANCE Kaposi's sarcoma-associated herpesvirus (KSHV) establishes latency in B cells and is stringently linked to primary effusion lymphoma (PEL) and the premalignant B cell hyperplasia multicentric Castleman's disease (MCD). To investigate potential genetic background effects, we expressed the KSHV miRNAs in BALB/c transgenic mice. BALB/c mice are the preferred strain for B cell hybridoma development because of their propensity to develop predictable B cell responses to antigen. The BALB/c latency mice exhibited a higher incidence of B cell hyperplasia as well as sustained hyperglobulinemia. The development of neutralizing antibodies against ZIKV was augmented in BALB/c latency mice. Hyperglobulinemia was dampened by everolimus, a derivative of rapamycin, suggesting a role for mTOR inhibitors in managing immune activation, which is hallmark of KSHV infection as well as HIV infection.

TACI deletion protects against progressive murine lupus nephritis induced by BAFF overexpression.

B cells are known to promote the pathogenesis of systemic lupus erythematosus (SLE) via the production of pathogenic anti-nuclear antibodies. However, the signals required for autoreactive B cell activation and the immune mechanisms whereby B cells impact lupus nephritis pathology remain poorly understood. The B cell survival cytokine B cell activating factor of the TNF Family (BAFF) has been implicated in the pathogenesis of SLE and lupus nephritis in both animal models and human clinical studies. Although the BAFF receptor has been predicted to be the primary BAFF family receptor responsible for BAFF-driven humoral autoimmunity, in the current study we identify a critical role for signals downstream of Transmembrane Activator and CAML Interactor (TACI) in BAFF-dependent lupus nephritis. Whereas transgenic mice overexpressing BAFF develop progressive membranoproliferative glomerulonephritis, albuminuria and renal dysfunction, TACI deletion in BAFF-transgenic mice provided long-term (about 1 year) protection from renal disease. Surprisingly, disease protection in this context was not explained by complete loss of glomerular immune complex deposits. Rather, TACI deletion specifically reduced endocapillary, but not mesangial, immune deposits. Notably, although excess BAFF promoted widespread breaks in B cell tolerance, BAFF-transgenic antibodies were enriched for RNA- relative to DNA-associated autoantigen reactivity. These RNA-associated autoantibody specificities were specifically reduced by TACI or Toll-like receptor 7 deletion. Thus, our study provides important insights into the autoantibody specificities driving proliferative lupus nephritis, and suggests that TACI inhibition may be novel and effective treatment strategy in lupus nephritis.

Hyper-IgD and periodic fever syndrome (HIDS) due to compound heterozygosity for G336S and V377I in a 44-year-old patient with a 27-year history of fever.

Hereditary autoinflammatory syndromes are a rare, but notable cause of fever of unknown origin. During the last few years, the knowledge of the genetic background has significantly increased. Here, we report a novel pathogenic mutation in the MVK gene as the cause of fever in a 44-year-old male patient with a history of fever over a period of 27 years.

Hyperimmunoglobulinaemia D syndrome: a rare cause of prolonged fever and treatment with anti-interleukin 1 agent.

Hyperimmunoglobulinaemia D syndrome (HIDS) is an autosomal recessive, autoinflammatory disease that is characterised with intermittent febrile episodes, cervical lymphadenopathy, rashes, arthritis and gastrointestinal symptoms associated with synovial or serosal inflammation. HIDS is caused by mutations in the gene encoding mevalonate kinase enzyme. The febrile attacks usually start in early childhood and triggered by stress or vaccinations. We report a case of 16-month-old boy who had episodes of recurrent fever accompanied by maculopapular rash and lymphadenopathy. He was diagnosed as HIDS and he had heterozygote mutation of mevalonate kinase gene.

DNA Microarray Analysis of Submandibular Glands in IgG4-Related Disease Indicates a Role for MARCO and Other Innate Immune-Related Proteins.

IgG4-related disease (IgG4-RD) is a novel systemic disease entity characterized by elevated serum IgG4 and tissue infiltration of IgG4-positive plasma cells accompanied by severe fibrosis. Although recent studies demonstrated that innate immune cells including monocytes and macrophages might promote local fibrosis and IgG4 production, the pathological mechanism remains unclear. In this study, we sought to identify the disease-associated genes, especially innate immune molecules. Gene expression was analyzed by DNA microarray in submandibular glands (SMGs) from patients with IgG4-RD (n = 5), chronic sialoadenitis (CS) (n = 3), and controls (n = 3). Differentially expressed genes (DEGs) were validated by real-time polymerase chain reaction (PCR) and immunohistochemical staining in IgG4-RD (n = 18), CS (n = 4), Sjögren syndrome (n = 11), and controls (n = 10). Gene expression patterns in the 3 groups were quite different from each other by the pvclust method and principal components analysis. In IgG4-RD, 1028 upregulated genes and 692 downregulated genes were identified as DEGs (P < 0.05). Gene Ontology (GO) term analysis indicated that the upregulated DEGs in IgG4-RD encoded proteins involved in T/B cell activation and chemotaxis. PCR validated significantly higher expression of macrophage receptor with collagenous structure (MARCO), a pattern-recognition receptor, in IgG4-RD compared with the other groups (P < 0.01). Immunohistochemical analysis confirmed that the expression pattern of MARCO was similar to that of the M2 macrophage marker CD163. MARCO was identified as a disease-associated molecule in IgG4-RD by DNA microarray. Moreover, M2 macrophages might contribute to the initiation of IgG4-RD via MARCO.

Helios Controls a Limited Subset of Regulatory T Cell Functions.

A subpopulation (60-70%) of Foxp3(+) regulatory T cells (Tregs) in both mouse and man expresses the transcription factor Helios, but its role in Treg function is still unknown. We generated Treg-specific Helios-deficient mice to examine the function of Helios in Tregs. We show that the selective deletion of Helios in Tregs leads to slow, progressive systemic immune activation, hypergammaglobulinemia, and enhanced germinal center formation in the absence of organ-specific autoimmunity. Helios-deficient Treg suppressor function was normal in vitro, as well as in an in vivo inflammatory bowel disease model. However, Helios-deficient Tregs failed to control the expansion of pathogenic T cells derived from scurfy mice, failed to mediate T follicular regulatory cell function, and failed to control both T follicular helper cell and Th1 effector cell responses. In competitive settings, Helios-deficient Tregs, particularly effector Tregs, were at a disadvantage, indicating that Helios regulates effector Treg fitness. Thus, we demonstrate that Helios controls certain aspects of Treg-suppressive function, differentiation, and survival.

Hyperimmunoglobulin syndrome due to CD40 deficiency: possibly the first case from India.

Hyperimmunoglobulin M (HIGM) type 3 due to CD40 deficiency is a very rare syndrome. Only 16 cases have been reported thus far. The clinical presentation is very variable. We present the first case of this rare disorder from India. The case is of a two-and-a-half-year-old female, with a history of repeated episodes of skin infections and diarrhea since birth. Laboratory evaluation revealed elevated absolute lymphocyte count and an absolute neutrophil count (ANC) of 1026/mm3. The lymphocyte subset analysis showed normal absolute counts of Natural Killer (NK) cells and elevated absolute counts of T-cells (CD4 and CD8) and B-cells. The serum immunoglobulin estimation showed low levels of IgG, IgA, IgE and an elevated level of IgM. The CD154 analysis was normal and expression of CD40 was absent on the B-cells. Molecular analysis showed a novel mutation, with deletion of 3bp (AAG) [p.Glu107GlyfsX84] in the homozygous state, in the CD40 gene. Thus the patient was diagnosed as HIGM type 3. The parents were screened and counseled regarding prenatal diagnosis at the time of next pregnancy.

Cryptococcal meningoencephalitis in a patient with hyper immunoglobulin M (IgM) syndrome: a case report.

BACKGROUND: Cryptococcal meningoencephalitis is an opportunistic infection that predominantly affects immunocompromised patients. Hyper immunoglobulin M syndrome is a primary immunodeficiency syndrome that increases susceptibility to several opportunistic infections. Here, we report a case of cryptococcal meningoencephalitis in the context of hyper immunoglobulin M syndrome, a situation that has been reported very few times and whose management is not clearly defined. We describe our management of this case and the outcome of the patient to help in future similar situations. CASE PRESENTATION: The patient is a 19-year-old Caucasian male student diagnosed with X-linked hyper immunoglobulin M syndrome and treated chronically with weekly intravenous immunoglobulin and daily sulfamethoxazole-trimethoprim. He was admitted to the infectious diseases ward because of headache, diplopia and a cerebral-spinal fluid analysis revealing cryptococcal meningoencephalitis. The patient was treated with liposomal amphotericin and flucytosine with a favorable outcome. Maintenance therapy with fluconazole has continued and will be sustained for 6 months following his upcoming bone marrow transplantation. CONCLUSION: Monitoring for cryptococcal meningoencephalitis should be considered in patients with primary immunodeficiencies, as clinical manifestations may go unnoticed. In these patients, it is expected that chronic treatment with fluconazole will be the only treatment that will prevent reinfection or reactivation, and therefore should be kept at least until bone marrow transplant, the only curative treatment, is performed. It may, however, lead to intolerable side effects and hepatic toxicity.

A Novel CD40 Ligand Mutation in a Patient With Pneumonia, Neutropenia, and Hyperimmunoglobulin M Phenotype

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Cooperative immunoregulatory function of the transmembrane adaptor proteins SIT and LAX.

Lymphocyte activation is crucial for the generation of immune responses. In vitro studies have demonstrated that TRAPs are critical regulators of lymphocyte activation. However, more recent in vivo studies have demonstrated that with the exception of LAT, TRAPs, such as SIT, NTAL, and LAX, only minimally affect immune cell functions. Additional studies have suggested that the mild or the apparent lack of a phenotype displayed by most TRAP KO mice may be explained by functional redundancy among this family of adaptors. In fact, it has been shown that the phenotype of NTAL/LAT or SIT/TRIM double-deficient mice is more severe than that of the single KOs. Here, we have evaluated whether SIT and the related transmembrane adaptor LAX have overlapping functions by generating SIT/LAX DKO mice. We show that DKO, in contrast to single KO mice, accumulate large numbers of activated CD4(+) T cells in the spleen. Moreover, conventional B cells from DKO mice are hyperproliferative upon CD40 stimulation. Additionally, we found that DKO mice displayed an expansion of the B1 cell pool in the peritoneal cavity, hypergammaglobulinaemia, and an enhanced immune response to the T1-independent antigen, TNP-LPS. Finally, we demonstrate that SIT/LAX double deficiency resulted in a more pronounced breakdown of peripheral tolerance and the development of autoimmunity characterized by ANAs and renal disease (glomerulonephritis and proteinuria). Collectively, our data indicate that SIT and LAX are important negative regulators of immune responses that functionally cooperate.

Gammopathy and B lymphocyte clonality in patients with Gaucher type I disease.

INTRODUCTION: We evaluated a novel approach for investigation of lymphocyte dysregulation in Gaucher patients by including determination of IgH and TCR gene rearrangements together with levels of immunoglobulins, natural autoantibodies as well as presence of monoclonal protein. MATERIALS AND METHODS: Measurement of serum immunoglobulins, monoclonal immunoglobulins, selected autoantibodies, as well as analysis of immunoglobulin heavy chain and T cell receptor gene rearrangements. RESULTS: Immunoglobulin disorder was detected in 29.6% patients, 40.7% demonstrated presence of B cell clonality and 44.4% demonstrated presence of autoantibodies. In five patients in our series, the presence of IgH gene rearrangement was the only detectable indicator of B cell dysfunction. TCR gene rearrangements were not found in any of the patients. CONCLUSION: Based on our results, we propose IgH gene rearrangements as a new biomarker for investigation of B cell dysfunction occurring as a complication of Gaucher disease.

Granulomatous skin lesions, severe scrotal and lower limb edema due to mycobacterial infections in a child with complete IFN-γ receptor-1 deficiency.

Interferon-γ receptor-1 (IFNγR1) deficiency is caused by mutations in the IFNγR1 gene and is characterized mainly by susceptibility to mycobacterial disease. Herein, we report an 8-month-old boy with complete recessive IFNγR1 deficiency, afflicted by recurrent mycobacterial diseases with Mycobacterium bovis, Mycobacterium tuberculosis, Mycobacterium avium intracellulare and Mycobacterium fortuitum. Genetic analysis showed a homozygous mutation (106insT) in the IFNγR1 gene leading to complete IFNγR1 deficiency. In addition, he had atypical mycobacterial skin lesions caused by M. avium intracellulare and developed scrotal and lower limb lymphedema secondary to compression of large and fixed inguinal lymphadenopathies. Hematopoietic stem cell transplantation was performed from a matched unrelated donor at 5 years of age; however, he died at 9 months post-transplant. To our knowledge, the patient is the first case with IL-12/IFN-γ pathway defect and severe lymphedema. We have also reviewed and summarized the literature related with IFNγR1 deficiency.

Phenotypic heterogeneity in a family with a CD40 ligand intracellular domain mutation.

We describe a family with the rare mutation R11X that leads to a truncated CD40 ligand (CD40L) missing the intracellular domain. The index case had detectable CD40L expression and presented at the age of 41 years with cerebral toxoplasmosis. A brother and two nephews were also identified as having the same mutation but exhibited milder and variable phenotypes. The older affected nephew had a moderately depressed immunoglobulin G level and a history of pneumonia at 4 months of age. The younger nephew suffered from sinusitis with normal immunoglobulin levels. Both nephews had absent antibody responses to a protein antigen with conserved responses to polysaccharide antigens. The two sisters of the index case are carriers who had elevated levels of IgM but remain well. This mutation may affect CD40 ligand function by reducing cell surface levels, diminishing CD40 interaction or disrupting CD40L intracellular signalling in T cells. The variable phenotype in members of this family offers an opportunity to further understand the CD40-CD40L signalling pathway in human immune responses.