Blood transfusions generate/increase previously absent/weak blocking antibody in women with habitual abortion * †

Women who suffered recurrent spontaneous abortions of unknown cause were studied for cellular reactivity and blocking antibody in a one-way mixed lymphocyte culture. A defined group of 20 women whose serum displayed no blocking capacity was given three transfusions of leukocyte-rich erythrocyte concentrates. Serum from all women displayed significant blocking capacity 2 months after the third transfusion. Because blocking antibody seems to be one of the necessary prerequisites for successful pregnancy, leukocyte transfusions from third-party donors ought to be an effective cure for habitual abortion in selected cases.