Flow cytometry and cytoadherence studies of sera from children with juvenile rheumatoid arthritis and normal controls

Recently, antibodies reactive with T cell subpopulations have been reported to exist in children with active juvenile arthritis (JRA). In an attempt to verify and extend these observations, we have studied children with JRA for the presence of anti-T cell antibodies by flow cytometry and cytoadherence rosette techniques. T cells were isolated from peripheral blood mononuclear cells (PBL) by two methods: 1) Differential sedimentation of PBL rosetted with neuraminidase-treated sheep erythrocytes, and 2) removal of immunoglobulin positive PBL by rosetting with rabbit anti-human F(ab')2 coated bovine erythrocytes and differential sedimentation. Utilizing these methods to detect lymphoreactivity of JRA sera to either population of T cell isolates, we observed the binding of ultracentrifuged normal human sera (NHS) to be comparable to JRA sera (active and quiescent). NHS reacted with 15-25% of T cells. Further studies demonstrate that monomeric IgG was chiefly responsible for lymphoreactivity. The results of these studies are discussed in the context of previous observations.