Correlation of clonal T cell expansion with disease activity in systemic lupus erythematosus

It has been proposed that T cell activation may play an important role inthe pathogenesis of systemic lupus erythematosus (SLE). In order to examinethis hypothesis, we assessed the whole degree of clonal accumulation of Tcells using RT-PCR and subsequent single-strand conformation polymorphism(SSCP) analysis. The analysis of the beta chain of the TCR revealed littleclonotypic T cell expansion in the peripheral blood of lupus patients inremission, whereas in patients with active disease many dominant T cellclonal expansions without any distinct V beta bias were observed. Thealteration in the number of T cell clones correlated well with diseaseactivities, since these T cell expansions decreased as patients hadimproved. Furthermore, similar but more intense accumulations of T cellclones were found in pleural and pericardial effusions of patients withlupus serositis. Some of these identical expanded clonotypes were observedirrespective of the lesions and the times of sampling, and some of themwere identical to those observed in the peripheral blood. These resultssuggest that the T cell clonal expansions correlate with the diseaseactivities and that the expansion might contribute to the pathogenic lesionformation in SLE.