Examination included 51 patients with essential hypertension (EH) of an uncomplicated course, labile (IB-IIA stage, according to A. L. Myasnikov's classification) and stable (IIB stage) hypertension. Clinical characteristics were given to the stages and duration of EH, body weight of the patients, arterial hypertension (AH) heredity and the AP level. Immunological examination included determination of the concentration of the basic classes of immunoglobulins IgG, IgA, IgM, circulating immune complexes (CIC), concentration of IgE and beta 2-microglobulins. It was revealed that EH development is attended by an increased concentration of immunoglobulins, primarily of IgA (23 per cent), IgE (31 per cent) and CIC (21 per cent), which is associated, to a certain degree, with a factor of AH hereditary aggravation.