HLA-DR expression on lymphocyte subsets as a marker of disease activity inpatients with systemic lupus erythematosus

A major problem in the management of SLE patients is to predict a flare or to distinguish between active and quiescent disease. Serological markers ar e widely used to assess disease activity, but many patients have close to o r normal values for these parameters while exhibiting obvious disease-relat ed signs and symptoms. This study aimed to determine which serological para meters, among ESR, ANA and anti-dsDNA antibody titres, CH50 and the HLA-DR expression on circulating T-lymphocyte subsets, best reflected the developm ent of SLE flares. Sixty SLE patients were included, 34 with quiescent dise ase throughout the entire follow-up period and 26 who experienced an SLE fl are defined as having active disease. According to univariate analysis, all parameters were significantly higher for patients with active disease, wit h the percentage of CD8(+)DR(+) cells being the most significant parameter (P = 10(-7)). Multivariate logistic regression analysis identified three in dependent variables enabling the identification of a lupus flare: CH50, the CD8(+)DR(+) and CD4(+)DR(+) cell percentages among total lymphocytes. The CD8(+)DR(+) cell percentage is the biological parameter most significantly associated with a flare (P < 0.001), even more powerful than CH50 (P < 0.01 ). HLA-DR expression on CD8(+) lymphocytes clearly coincided with disease e volution in seven patients enrolled as having quiescent disease, but who ex perienced one flare during follow-up that subsequently resolved. The percen tage of circulating CD8(+)DR(+) lymphocytes appears to be a biological mark er which accurately reflects disease activity. A larger prospective study i s needed to demonstrate the real efficacy of this marker in predicting an e xacerbation in SLE patients.