Lymphocyte sub-populations and NSAIDs. Methodological aspects.

Activated lymphocytes can be enumerated as the less dense lymphocyte population (LDL) on a Ficoll density gradient column. The numbers of LDL are higher in rheumatoid arthritis (RA) but fall with successful second-line therapy; they correlate with active synovitis rather than with extra-articular disease. A cytospin technique has been developed which uses fewer cells than conventional suspension techniques and which allows further characterization of LDL using monoclonal antibodies. This confirms that these cells are relatively T-depleted but enriched in IA bearing cells, which may relate to homing patterns to the RA synovium. Using this technique, RA patients with active synovitis were shown to have more LDL and IA bearing cells, as were the active disease controls, including patients with other autoimmune disease (vasculitis) and with non-immune disease (sepsis). There were no differences between the ratios of T-suppressor to T-helper cells within these patient groups.