Placental antibody transfer: influence of maternal HIV infection and placental malaria. (1/363)

AIM: To determine the influence of placental malaria, maternal HIV infection, and maternal hypergammaglobulinaemia on transplacental IgG antibody transfer. METHODS: One hundred and eighty materno-neonatal pairs from a Malawian population were assessed. Cord and maternal serum samples were tested for total serum IgG antibody titres using nephelometry, and for specific IgG antibody titres to Streptococcus pneumoniae, measles, and tetanus toxoid antibodies using an enzyme linked immunosorbent assay (ELISA). RESULTS: Multiple regression analyses showed that placental malaria was associated with a decrease in placental IgG antibody transfer to S pneumoniae and measles to 82% and 81%, respectively. Maternal HIV infection was associated with a reduction in IgG antibody transfer to S pneumoniae to 79%; raised maternal total serum IgG titres were correlated with S pneumoniae and measles IgG antibody transfer reduction to 86% and 87%, respectively. No effect was seen with tetanus toxoid antibody transfer. CONCLUSION: The combined influence of placental malaria, maternal HIV infection, and maternal hypergammaglobulinaemia seems to be linked to the low transplacental antibody transfer observed in the Malawian population.  (+info)

CD40 ligand mutants responsible for X-linked hyper-IgM syndrome associate with wild type CD40 ligand. (2/363)

CD40 ligand (CD40L) is a 33-kDa type II membrane glycoprotein mainly expressed on activated CD4(+) T cells in trimeric form. When it is mutated, the clinical consequences are X-linked hyper-IgM syndrome (XHIM), a primary immunodeficiency disorder characterized by low levels of IgG, IgA, and elevated or normal levels of IgM. Mutated CD40L can no longer bind CD40 nor provide signals for B cells to proliferate and to switch from IgM to other immunoglobulin isotypes. When considering gene therapy for XHIM, it is important to address the possibility that the mutated CD40L associates with transduced wild type CD40L, and as a consequence, immune reconstitution is not attained. In this study, we demonstrate that the various mutated CD40L species we have identified in patients with XHIM, including both full-length and truncated mutants, associate with wild type CD40L on the cell surface of co-transfected COS cells. The association between wild type and mutated CD40L was also observed in CD4(+) T cell lines established from XHIM patients with leaky splice site mutations. The clinical phenotype of these patients suggests that this association between wild type and mutated CD40L species may result in less efficient cross-linking of CD40.  (+info)

Defects of T-cell effector function and post-thymic maturation in X-linked hyper-IgM syndrome. (3/363)

X-linked hyper-IgM syndrome (XHIM) results from mutations in the gene encoding for CD40 ligand (CD154). Patients with the syndrome suffer from infections with opportunistic pathogens such as Cryptosporidium and Pneumocystis carinii. In this study, we demonstrate that activated T cells from patients with XHIM produce markedly reduced levels of IFN-gamma, fail to induce antigen-presenting cells to synthesize IL-12, and induce greatly reduced levels of TNF-alpha. In addition, we show that the patients' circulating T lymphocytes of both the CD4(+) and CD8(+) subsets contain a markedly reduced antigen-primed population, as determined by CD45RO expression. Finally, we demonstrate that the defects in antigen priming are likely due to the lack of CD154 expression and insufficient costimulation of T cells by CD80/CD86 interactions. Taken together, this study offers a basis for the increased susceptibility of patients with XHIM to certain opportunistic infections.  (+info)

Defective self-reactive antibody repertoire of serum IgM in patients with hyper-IgM syndrome. (4/363)

We have analyzed the self-reactive repertoires of IgM and IgG Abs in the serum of 19 patients with hyper-IgM syndrome (HIM) by means of a quantitative immunoblotting technique that allows for a quantitative comparison of Ab repertoires in health and disease by multiparametric statistical analysis. Normal tissue extracts of liver, lung, stomach, and kidney were used as sources of self Ags. Extracts of Pseudomonas aeruginosa and Staphylococcus epidermidis were used as sources of nonself Ags. We demonstrate a significant bias in repertoires of reactivities of IgM of patients with HIM with self Ags. Ab repertoires of IgM toward nonself Ags did not differ, however, between patients and controls. No difference was found between IgM repertoires of untreated patients and those of patients receiving substitutive treatment with i.v. IgG. IgG in the serum of HIM patients lacked reactivity with self Ags, although it exhibited a pattern of reactivity with nonself Ags that was similar to that of IgG of healthy controls. The data demonstrate that functional CD40-CD40 ligand interactions are essential for the selection of natural self-reactive B cell repertoires.  (+info)

Decreased anion gap associated with monoclonal and pseudomonoclonal gammopathy. (5/363)

Nine patients with monoclonal and one with pseudomonoclonal gammopathy were found to have a decreased anion gap. Eight of the patients had multiple myeloma, one has plasma cell leukemia and one had chronic active hepatitis. In all of the the decreased anion gap was associated with an increased concentration of IgG greater than 5 g/dl.  (+info)

CD40-CD40 ligand interaction is central to cell-mediated immunity against Toxoplasma gondii: patients with hyper IgM syndrome have a defective type 1 immune response that can be restored by soluble CD40 ligand trimer. (6/363)

Cell-mediated immunity that results in IL-12/IFN-gamma production is essential to control infections by intracellular organisms. Studies in animal models revealed contrasting results in regard to the importance of CD40-CD40 ligand (CD40L) signaling for induction of a type 1 cytokine response against these pathogens. We demonstrate that CD40-CD40L interaction in humans is critical for generation of the IL-12/IFN-gamma immune response against Toxoplasma gondii. Infection of monocytes with T. gondii resulted in up-regulation of CD40. CD40-CD40L signaling was required for optimal T cell production of IFN-gamma in response to T. gondii. Moreover, patients with hyper IgM (HIGM) syndrome exhibited a defect in IFN-gamma secretion in response to the parasite and evidence compatible with impaired in vivo T cell priming after T. gondii infection. Not only was IL-12 production in response to T. gondii dependent on CD40-CD40L signaling, but also, patients with HIGM syndrome exhibited deficient in vitro secretion of this cytokine in response to the parasite. Finally, in vitro incubation with agonistic soluble CD40L trimer enhanced T. gondii-triggered production of IFN-gamma and, through induction of IL-12 secretion, corrected the defect in IFN-gamma production observed in HIGM patients. Our results are likely to explain the susceptibility of patients with HIGM syndrome to infections by opportunistic pathogens.  (+info)

An aggressive form of polyarticular arthritis in a man with CD154 mutation (X-linked hyper-IgM syndrome). (7/363)

Hyper-IgM syndrome (HIM) is a rare immunodeficiency disorder that has been associated with the development of symptoms and clinical features characteristic of rheumatoid arthritis (RA). We describe a patient with HIM and severe erosive arthritis with prominent nodules in the absence of detectable serum rheumatoid factor. Because HIM results from defects in either T cell CD154 (CD40 ligand) expression or abnormal CD40 signaling, the molecular basis of the patient's disease was analyzed. Activated CD4+ T cells failed to express surface CD154 protein, and molecular analysis of CD154 complementary DNA revealed a nucleotide transversion resulting in the nonconservative amino acid substitution G-D at amino acid 257. This case indicates that defective CD154-dependent CD40 signaling can be associated with susceptibility to a severe inflammatory arthritis that has both similarities to and differences from idiopathic RA.  (+info)

Successful bone marrow transplantation in a child with X-linked hyper-IgM syndrome. (8/363)

We report a case of an 11-year-old boy who underwent successful bone marrow transplantation for X-linked hyper-IgM syndrome (XHIM). The donor was an HLA-matched brother. The patient was conditioned with busulfan, cyclophosphamide and anti-thymocyte globulin. He received 4.7 x 10(8) marrow cells per kg from the donor. Prophylaxis against graft-versus-host disease consisted of cyclosporine and short-term methotrexate. The clinical course after the bone marrow transplantation was uneventful, and 12 months after transplantation the patient was doing well with no need for therapy. We examined expression of the CD40 ligand (CD40L) on the patient's activated T lymphocytes and in vitro production of immunoglobulins by his lymphocytes. Although expression of CD40L was totally absent before the bone marrow transplant, subnormal expression appeared after the transplantation. In vitro production of IgG and IgA also was improved by the transplant. Based on our experience bone marrow transplantation appears to be a reasonable therapeutic option for patients with XHIM if HLA-matched family donors are available.  (+info)