The prognostic value of some immunological parameters on the course of subsequent pregnancy in 117 women with recurrent spontaneous abortion of unknown etiology subjected to paternal lymphocytes immunization, were estimated. We conclude that neither antinuclear (ANA) nor low titers of anticardiolipin antibodies (ACA), nor mixed lymphocyte reaction--blocking antibodies (MLR-BAbs) have any significant influence on alloimmunization efficiency. However medium or high ACA titers significantly diminish changes for successful alloimmunization and are connected with most complications of subsequent pregnancy.