CALCINOSIS AND THE ANTICENTROMERE ANTIBODY: ITS CLINICAL, RADIOLOGICAL AND IMMUNOGENETIC ASPECTS

The relationship between calcinosis and the anticentromere antibody (ACA) was studied from a clinical, radiological and immunogenetic standpoint. Ten ACA-positive scleroderma patients, 34 ACA-negative scleroderma patients, 31 ACA-positive patients without sclerodermatous skin changes and 140 ACA-negative patients with various rheumatic diseases were compared with regard to the incidence of calcinosis as measured by radiographs of hand and/or foot. Calcinosis was found in 10 (100%), 12 (35%), 13 (42%) and eight (6%) patients in each group respectively. Frequent sites for calcinosis in the ACA-positive patients were foot (24%), hand (21%) and leg (19%). The forearm was not usually involved (6%). During the follow-up term (1.0-9.5 years; mean 4.5 years) of 11 ACA-positive patients without calcinosis, four (36%) developed new calcinosis and this incidence was significantly higher (P less than 0.02) than that in the ACA-negative control group (2/42; 4.8%). As a whole, 23 (59%) of 39 patients with ACA showed calcinosis. In the ACA-positive patients with calcinosis, sclerodactyly (P less than 0.005) and CREST syndrome (P less than 0.001) were found more frequently than in ACA-positive patients without calcinosis. HLA-A2 was found more frequently (67%) in the ACA-positive patients with calcinosis when compared to normal subjects (41%) (P less than 0.02). We concluded that calcinosis seems closely related to scleroderma, especially those with ACA, and that the development of calcinosis requires a certain genetic background.