Patient demographics and disease variables correlate with distinct cytokine patterns in mitogen-stimulated peripheral blood mononuclear cells from rheumatoid arthritis patients

There is paucity of literature on the association of peripheral blood cytokine patterns with patient demographics and disease variables in rheumatoid arthritis (RA). We test the hypothesis that there may be differences in peripheral blood levels of inflammatory cytokines in RA subjects according to various disease variables. In this case, we could identify peripheral blood cytokine markers that correlate with different disease variables. Forty-two seropositive RA patients were characterized according to the age at onset, gender, disease duration, severity, activity and ACR functional class. The production levels in mitogen-stimulated PBMCs of five pro-inflammatory cytokines (IFN gamma, TNF alpha, TNF beta, IL-8, IL-18) and three anti-inflammatory cytokines (IL-4, IL-10, IL-13) were evaluated in these patients and in healthy controls. Several new findings emerge: (1) higher levels of IL-4 correlate with female gender, milder disease, non-erosive disease, and earlier age at onset; (2) higher levels of IL-10 correlate with the requirement of <= 2 DMARDs; (3) higher levels of IL-18 correlate with non-erosive disease and younger age at onset; (4) higher TNF beta levels correlate with older present age of patients; and (5) higher IL-8 levels correlate with established/late disease. There are several interesting differences in cytokine patterns with respect to age at onset, current age, disease severity, and the number of DMARDs the patients require.