Cytokine profile analysis before and after treatment with abatacept. (A) Cytokine profile component pattern. PC1 denotes principal component 1 score. PC2 denotes principal component 2 score. (B) Cytokine profile of patient plasma before treatment with abatacept and 1 month after receipt of 6 doses of abatacept. Plasma concentrations of IL-1α, IL-21, and TNF-α were measured using multiplex immunoassay at baseline before treatment with abatacept and 1 month after receipt of 6 doses of abatacept.