IL1R1 and rheumatoid arthritis: Thus, it was found that B cells and monocytes showed oppositely directed changes in percentage of IL-1R1-positive cells and the number of receptors on these cells in RA patients compared with normal controls, but the change in IL-1R1 on B cells in RA patients correlated with the change on monocytes (as confirmed by its positive correlation with r = 0.66, p < 0.05, for both indicators during the acute phase of the disease and r = 0.71 and r = 0.48 for the percentage of positive cells, resp., in patients who had responded to treatment) but in an opposite direction.