HLA-typing was performed in 149 patients with essential hypertension, 86 males and 63 females. In 66 patients with significantly elevated serum levels of immunoglobulins, HLA-B27 was increased to 18%, from 8% in the controls (P less than 0.007). This was not significant when correcting the P-value for the number of antigens analyzed, but confirms reports of an association of this antigen with serum levels of immunoglobulins. HLA-Bw15 was found to be increased two-fold in patients with a family history of hypertension (P corrected less than 0.05) and in patients with autoantibodies (not significant). This is discussed in relation to the increase of Bw15 in juvenile diabetes and in Systemic Lupus Erythematosus, diseases in which vascular damage also occurs.