INCREASED RATE OF APOPTOSIS AND DECREASED EXPRESSION OF BCL-2 PROTEININ PERIPHERAL-BLOOD LYMPHOCYTES FROM PATIENTS WITH ACTIVE SYSTEMIC LUPUS-ERYTHEMATOSUS

Defective regulation of apoptosis may play a role in the development o f autoimmune diseases, and the proto-oncogene bcl-2 is known to inhibi t cells from undergoing apoptosis. We studied the rate of apoptosis an d the expression of bcl-2 in peripheral blood lymphocytes of patients with systemic lupus erythematosus(SLE). A lower proportion of lymphocy tes were bcl-2(+) in SLE patients with active disease (median 84.9%) t han in patients with inactive disease or normal (medians 95.3% and 97. 1% respectively, p<0.05). The rate of apoptosis of freshly isolated PB L was significantly higher in SLE patients than in normal (medians 1.2 % vs 0.5%, p<0.05). After 48-hour culture the apoptotic rate was furth er increased in SLE patients, particularly those with active disease ( SLE overall 34.2%, active 62%, inactive 27.5%, normal 11.5%). These fi ndings support the theory that in SLE patients increased apoptosis may provide a source of extracellular nuclear antigens which stimulate th e autoimmune response and form immune complexes with autoantibodies.