title: CD4-reactive antibodies in systemic lupus erythematosus.
abstract: An important place in the immune network is reserved for specific interactions between regulatory antibodies (Ab) and their ligands on T and B lymphocytes. Several lines of evidence indicate that the CD4 glycoprotein may be recognized by such Ab. High levels of CD4-reactive Ab occur in approximately 10-20% of HIV-infected patients. Moreover, between 20 and 30% SLE patients have Ab preferentially reactive with the CD4+ T cells. In relation to this, we have done studies aimed at demonstrating the existence and characteristics of Ab directly targeting CD4 in patients with SLE in comparison with rheumatoid arthritis and normal controls. Assessment of the CD4-reactive Ab by different approaches revealed a several-fold increase in serum concentration of anti-CD4 Ab restricted to a subset of SLE patients (n = 15/87, 17.2%). Enhanced binding was shown to occur specifically both on native CD4 (by immunofluorescence) and on recombinant CD4 (by ELISA and Western blot). Anti-CD4 Ab belonged to IgM and/or IgG isotypes. The overall binding of immunoglobulins to the CD4 molecule was not significantly contributed by DNA/anti-DNA and other circulating immune complexes, and there was no restriction in the usage of kappa and lambda light chains. Clinically, high CD4 reactivity occurred in SLE patients with active disease, as measured by the SLEDAI, and was associated with particular clinical manifestations, including neuropsychiatric disease and lymphopenia.
authors.affiliation: Louis-Charles Simard Research Center, Notre-Dame Hospital, University of Montréal, Québec, Canada.
authors.forename: P
authors.initials: P
authors.lastname: Lenert
authors.forename: G
authors.initials: G
authors.lastname: Lenert
authors.forename: J L
authors.initials: JL
authors.lastname: Senécal
mesh_terms: D000328:Adult; D000918:Antibody Specificity; D001323:Autoantibodies / Q000032:analysis* / Q000378:metabolism; D001666:Binding Sites, Antibody; D015153:Blotting, Western; D015704:CD4 Antigens / Q000276:immunology* / Q000378:metabolism; D003430:Cross-Sectional Studies; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007106:Immune Sera / Q000737:chemistry; D008180:Lupus Erythematosus, Systemic / Q000276:immunology*; D008297:Male; D011485:Protein Binding / Q000276:immunology; D012044:Regression Analysis
chemical_list: D001323:Autoantibodies; D015704:CD4 Antigens; D007106:Immune Sera