Compared with normal individuals, patients with primary open-angle glaucoma have increased prevalences of HLA-B12 and B7 antigens and are more responsive to glucocorticoids. Lymphocytes from both ocular normotensive and glaucomatous individuals with the HLA-B12 antigen require significantly (P less than .02) lower concentrations of prednisolone to inhibit phytohemagglutinin-induced transformation.