Cytokines affecting megakaryocytopoiesis in rheumatoid arthritis with thrombocytosis

Particular interleukins, namely interleukin (IL)-6, IL-4 and IL-1, with pro-inflammatory mediator activities have also been shown to be involved in the regulation of megakaryocytopoiesis. As rheumatoid arthritis (RA) is not uncommonly associated with reactive thrombocytosis, we investigated serum IL-1 alpha, IL-1 beta, IL-4 and IL-6 concentrations in RA patients with marked thrombocytosis, and compared them to the levels in RA patients with normal platelet counts and healthy volunteers. IL-1 beta, IL-4 and IL-6 concentrations were found to be correlated with the disease activity in both groups of RA patients, with higher serum levels of each cytokine in the thrombocythaemic group. Significant positive correlations of IL-1 beta and IL-4 with the platelet counts were documented only in patients with thrombocytosis. According to our results, IL-6 and IL-1 beta were found to be good indicators of disease activity in RA, while IL-1 beta and IL-4 seemed to be related more with the process of reactive thrombocytosis secondary to rheumatoid inflammation.