Expression of CD154 mRNA in T lymphocytes according to CD154 genotype. T lymphocytes from patients with rheumatoid arthritis (RA; 24CAs group, n = 9; non-24CAs group, n = 11) and controls (24CAs group, n = 3; non-24CAs group, n = 3), obtained after in vitro expansion of peripheral blood mononuclear cells, were stimulated for 6 or 24 hours with anti-CD3 plus anti-CD28; after this, mRNA decay assays were performed as indicated in the Materials and methods section. (a) mRNA half-life, t1/2, in T lymphocytes. (b) mRNA molecules per μg of total RNA in CD4+ T lymphocytes. *P < 0.05, **P < 0.005, comparing the 24CAs group with the non-24CAs group.