Immunodeficiency最新文献

Multiple intestinal atresias (MIA) is a severe form of intestinal atresias throughout the gastrointestinal tract. In two reports, MIA have been associated with severe immunodeficiency. We report a newborn girl who had profound humoral and B cell immunodeficiency and impaired T cell function. The patient had agammaglobulinemia and decreased blood lymphocytes, with virtually no B cells in the blood or in intestinal lymph nodes. T cells were reduced in number and weakly proliferated to mitogens. These data suggest that a syndrome involving the development of MIA is associated with various forms of severe immunodeficiency, and therefore newborns with MIA should be examined for immunodeficiency.

Carrier detection in X-linked immunodeficiencies (X-SCID, WAS, XLA) relies on the demonstration of non-random X inactivation patterns in blood cell lineages. Only a limited number of cells are available after cell separation methods. PCR-based techniques are therefore necessary to analyze active and inactive X chromosomes. Amplifying a polymorphic CAG repeat in the first exon of the androgen receptor gene after selective digestion of the active X chromosome with a methylation-sensitive restriction enzyme allows to distinguish between the paternal and maternal alleles and to identify their methylation status. DNA from B-, T-lymphocytes and total peripheral leukocytes of normal males, females and obligate carriers of X-linked immunodeficiencies were analyzed. The results of this PCR-based X inactivation assay are concordant with the standard methylation studies at the DXS255 locus using Southern blotting. This PCR assay provides a rapid and informative (heterozygosity > 90%) method in carrier detection of X-linked immunodeficiencies and other X-linked disorders, which show non-random X inactivation in cell lineages from the affected tissues.

We have previously described a new type of selective T-cell deficiency (STD) characterized by persistent infections reminiscent of severe combined immunodeficiency (SCID). We show here that STD patients carry a mutation of zap-70 resulting in a loss of the activity of this kinase. The thymus of zap-70-/- patients shows the presence of CD4CD8 double positive cells in the cortex, however, only CD4 but not CD8 single positive cells are present in the medulla. Peripheral CD4+ T cells from the zap-70-/- exhibit markedly reduced tyrosine phosphorylation, fail to produce IL-2, and do not proliferate in response to TCR stimulation by mitogens or antigens. Thus Zap-70 kinase appears to be indispensable for the development of CD8 single positive T cells as well as for signal transduction and function of single positive CD4 T cells.

Adenosine deaminase (ADA) deficiency is an autosomal recessive disorder resulting in immunodeficiency. Since the cDNA for ADA was cloned approximately 10 years ago, investigators have determined the molecular basis for disease in many patients with ADA deficiency. Mutations that have been identified include point mutations causing amino acid substitutions, premature stop codons, RNA splicing errors, and deletion mutations. Approximately one third of patients are homozygous for their mutation; in some of these cases the parents are known to be related. One mutation, Ala329-Val, is the most common, being present in 8 of the 21 ADA-deficient SCID patients whose mutations have been reported.

Chediak-Higashi syndrome (CHS) is an inherited immunodeficiency disorder characterized by giant lysosomal granules in all granule-containing cells. Prior examination of lysosomal enzyme activities in granulocytes and other cells derived from patients with CHS have revealed multiple abnormalities, with the predominant finding being diminished activity of many of the enzymes tested. Abnormalities in lysosomal enzyme activity are also found in animal models of CHS (cattle, aleutian mink, and beige mice). In this study, we have examined lymphoblastoid cell lines derived from a patient with CHS and from an individual heterozygous for the CHS gene for acid phosphatase, beta-glucuronidase, and alpha-mannosidase activity. These cell lines have recently been shown to be satisfactory in vitro models for the disease. Acid phosphatase activity was increased in the heterozygous-derived cell line when compared to control while other enzyme activities were normal both in the CHS- and heterozygous-derived cell lines. We have reviewed the literature and summarized published abnormalities of lysosomal enzyme activities in humans and animals with CHS.

B and T cell phenotypes in peripheral blood from 71 CVID patients have been measured in a study using directly conjugated monoclonal antibodies and two colour flow cytometry. Data was compared between different patient groups (based on whether their B cells could secrete IgM or IgG in vitro) and normal donors. There was a clear correlation between abnormalities of both B and T cells and the different patient groups. There were reduced absolute numbers of circulating CD4+ T cells, particularly those of the CD4+.CD45RA+ subset, and of CD19+ B cells in those patients whose B cells failed to secrete IgM or IgG in vitro. This demonstrates an association between B cell lymphopenia, failure of B cell immunoglobulin production in vitro and T cell subset lymphopenia in CVID. It supports the view that this group of CVID patients has a disease involving T cell regulation of B cells of varying severity.

Lymphoproliferative disorders and selected carcinomas which occur as complications of primary or secondary immunodeficiencies are frequently fatal. The incidence rates of these cancers vary from 1% to as high as 25% among specific groups of persons with primary (genetically-determined) immunodeficiencies as well as acquired immunodeficiencies, including immunosuppressed organ transplant recipients and individuals infected with HIV. Lymphoproliferative disorders including Epstein Barr virus (EBV) associated B cell lymphoproliferative disease (BLPD) and Hodgkin's disease represent the predominant category of tumors in both primary and acquired immunodeficiencies. EBV is an important cofactor common to many, but not all, B cell "lymphomas." Immunodeficient individuals who are at risk for developing EBV BLPD may demonstrate both inadequate immune responses to the virus as well as generalized immunoregulatory dysfunction reflected as imbalances in cytokine production favoring the proliferation of transformed B lymphocytes. Historically, the success of treatment of lymphoproliferative disorders in immunodeficiencies with conventional multi agent chemotherapies and/or radiation has been limited by unfavorable tumor response rates and high morbidity and mortality related to intercurrent opportunistic infections. With improvements in supportive care and the use of recombinant biologic response modifiers such as alpha interferon and/or other immunotherapies to treat EBV BLPD, survival of immunodeficient hosts following tumor diagnosis may improve. In addition to lymphoproliferative disorders, patients with congenital immunodeficiencies associated with IgA deficiency (including ataxia telangiectasia and Common Variable Immunodeficiency) are at increased risk for gastrointestinal carcinomas. Early detection and surgical excision of such tumors can result in prolonged survival in such patients.