title: Characterization of in vivo mutated T cell clones from patients with systemic lupus erythematosus.
abstract: Patients with systemic lupus erythematosus (SLE) have increased percentages of activated T cells and increased numbers of cells with mutations in their hypoxanthineguanine phosphoribosyltransferase (hprt) gene, as judged by growth in the presence of 6-thioguanine. To study the relevance of these mutant T cells to disease pathogenesis, we have assessed the phenotype and functional capabilities of such cells from 21 patients with SLE who never had received cytotoxic drugs. The frequency of T cells with mutations in hprt in the blood of these patients ranged from normal to 25 times normal (mean +/- SEM [21.1 +/- 6.1] x 10(-6) versus [4.8 +/- 0.8] x 10(-6), in 15 age-matched normal individuals, P < 0.001) and correlated significantly with disease duration. CD4+ and CD8+ phenotypes were comparable among mutated and nonmutated clones from both patients and normals. Although the frequency of CD3+CD4-CD8- cells was low, it was increased among SLE-derived T cells (mutated and wild-type) compared with clones derived from normals (5% for SLE vs 1% for normals). A substantial percentage of all clones were able to help autologous B cells to produce anti-ssDNA, 11 of 68 (16%) selected clones and 3 of 28 (11%) nonselected clones. Help for autoantibody production was confined to CD4+ SLE-derived T cell clones. It could be blocked using an anti-HLA-DR mAb, suggesting that classical cognate help was operative. This represents the first estimate of the frequency of T cells able to drive autoantibody production in SLE.
authors: Department of Clinical Investigation, Walter Reed Army Medical Center, Washington, DC 20307.
authors: S
authors: S
authors: Theocharis
authors: P P
authors: PP
authors: Sfikakis
authors: R N
authors: RN
authors: Lipnick
authors: G L
authors: GL
authors: Klipple
authors: A D
authors: AD
authors: Steinberg
authors: G C
authors: GC
authors: Tsokos
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000974:Antibodies, Antinuclear / Q000096:biosynthesis; D000938:Antigen-Presenting Cells / Q000276:immunology; D001324:Autoantigens / Q000276:immunology; D002999:Clone Cells; D004277:DNA, Single-Stranded / Q000276:immunology; D005260:Female; D006801:Humans; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics; D008180:Lupus Erythematosus, Systemic / Q000235:genetics* / Q000276:immunology*; D008213:Lymphocyte Activation; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000974:Antibodies, Antinuclear; D001324:Autoantigens; D004277:DNA, Single-Stranded; D007041:Hypoxanthine Phosphoribosyltransferase