Elevated plasma levels of beta-thromboglobulin and platelet factor 4 in patients with rheumatic disorders and cutaneous vasculitis.

The efficacy of plasma levels of beta-thromboglobulin (beta-TG) and platelet factor 4 (PF4) as markers of the presence and activity of vasculiditic processes in rheumatic diseases were evaluated, first by serial measurement of their levels in a patient with rheumatoid arthritis and a chronic leg ulcer in the course of treatment, and second in 11 patients with rheumatoid arthritis without cutaneous vasculitis, and in nine patients with a variety of rheumatic diseases with cutaneous vasculitis. In the former, plasma levels of beta-TG and PF4 were elevated and slowly reduced in parallel with healing, raised again after relapse, and normalized after disappearance of the leg ulcer. In the latter, both plasma levels were elevated in all of the nine patients with cutaneous vascular lesions and in one of the 11 patients rheumatoid arthritis without skin lesions. Levels of beta-TG and PF4 may be useful to estimate the presence of vascular lesions in rheumatic disorders.