Juvenile rheumatoid arthritis. Monocyte dysfunction in selected patients.

The in vitro parameters of cell-mediated immunity were studied in 20 children with an established diagnosis of Juvenile rheumatoid arthritis (JRA) (age range 4-15 years) and 23 age- and sex-matched healthy children. (No attempt was made to correlate the observed changes with clinical course or treatment). We are not certain, at this time, of clinical relevancy or the generalizability of the findings. The normal level of T-lymphocytes (CD3+) and normal proportions of CD4+ and CD8+ lymphocytes were seen in children with JRA. The in vitro response of lymphocytes to T-cell mitogen phytohemagglutinin (PHA) also was normal. The suppressor activity of JRA monocytes was essentially the same as controls. In contrast, monocytes from patients with JRA showed the following: decreased expression of receptors for Fc part of IgG immunoglobulin (FcR), diminished nitro blue tetrazolium (NBT) reduction activity, and depressed expression of Ia.7 major histocompatibility complex (MHC) class II determinants. This indicates that certain monocyte functions in selected patients with a variety of manifestations of JRA are depressed.