[Articular chondrocalcinosis. Association with B15 antigen]

Antigens of HLA loci A, B and DR were determined in 35 elderly patients with primary articular chondrocalcinosis and compared with a control population. The B15 antigen was present in 13 out of 35 patients, i.e. 37.1% as against 13% of controls (chi 2 = 13.4; pc = 0.05) and the BW21 antigen in 8 out of 35 patients, i.e. 22.8% as against 6.6% of controls (chi 2 = 10.25; pc less than 0.005). These results confirm those of a previous study carried out in the same unit, which showed a 41% incidence of HLA B15 antigen in patients with chondrocalcinosis. The HLA B15 antigen seems to be a marker of imbalanced binding with a susceptibility antigen. Calculation of the relative risk shows that an elderly subject with HLA B15 antigen if about 4 times more liable to articular chondrocalcinosis than a subject without this antigen.