title: Defective inducer T-cell function before the onset of insulin-dependent diabetes mellitus.
abstract: To investigate the possible role of CD4+ T lymphocyte immunoregulatory abnormalities in the pathogenesis of human insulin-dependent diabetes mellitus (IDD), we studied the in vitro function of CD4+ helper/inducer and suppressor/inducer T-cell subpopulations in 25 high risk non-diabetic individuals who tested positive for islet-cell antibodies (ICA). Helper-inducer T-cell function, as measured in the pokeweed mitogen T-B co-culture system, was decreased in the ICA+ subjects in comparison to controls. This abnormality in helper/inducer T-cell function was present for both IgG (P = 0.0001) and IgM (P = 0.004) secretion by B cells. Diminished helper/inducer function correlated with ICA titer (Pearson correlation coefficient -0.44) with subjects having an ICA titer greater than or equal to 40 JDF units demonstrating the most significant disturbances in function (P = 0.01). The helper/inducer T-cell subset percentage was also decreased in ICA+ subjects when compared to matched controls (30 +/- 3% vs 39 +/- 2%; P = 0.02). The abnormality in helper/inducer function was intrinsic to the CD4+ CD45RA+ subset and was not simply due to diminished numbers of helper/inducer T-cells added in the co-culture experiments, since the defect persisted when CD4+ CD45RA+ helper/inducer T-cells were purified and added to B cells as the only source of T-cell help. Our results indicate that ICA+ subjects have functional defects in the helper/inducer subpopulation of CD4+ T-cells. This abnormality may contribute to the pathogenesis of IDD and may provide a novel marker for identifying persons at risk for developing IDD.
authors.affiliation: Department of Pediatrics, University of Florida College of Medicine, Gainesville 32610.
authors.forename: D A
authors.initials: DA
authors.lastname: Schatz
authors.forename: W J
authors.initials: WJ
authors.lastname: Riley
authors.forename: N K
authors.initials: NK
authors.lastname: Maclaren
authors.forename: D J
authors.initials: DJ
authors.lastname: Barrett
mesh_terms: D000293:Adolescent; D000328:Adult; D000943:Antigens, Differentiation; D001323:Autoantibodies; D001402:B-Lymphocytes / Q000276:immunology; D015704:CD4 Antigens; D002648:Child; D003922:Diabetes Mellitus, Type 1 / Q000209:etiology* / Q000276:immunology; D005260:Female; D006649:Histocompatibility Antigens; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism; D066298:In Vitro Techniques; D017493:Leukocyte Common Antigens; D008297:Male; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D016176:T-Lymphocyte Subsets / Q000276:immunology; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology
chemical_list: D000943:Antigens, Differentiation; D001323:Autoantibodies; D015704:CD4 Antigens; D006649:Histocompatibility Antigens; D007074:Immunoglobulin G; C024211:islet cell antibody; D017493:Leukocyte Common Antigens; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1