PROBLEM: The questions of whether production of mixed lymphocyte reaction-blocking factors (MLR-BFs) after immunotherapy with lymphocytes for recurrent spontaneous abortion (RSA) has prognostic value and whether cytotoxic antibodies are also involved were tested.
METHOD OF STUDY: A prospective study with 33 patients who had a history of two or more abortions, lacking MLR-BFs, was carried out. The patients received immunizations with lymphocytes and 6 weeks or later were tested for seroconversion of MLR-BFs. Seventeen of these thirty-three patients were evaluated for antipaternal cytotoxic antibodies. The results were correlated with the outcome of the next pregnancy after treatment. RESULTS: Eighty percent of the 33 patients had a live child. Of those patients having success, only 50% produced MLR-BFs. Of those patients having a new loss, five did and two did not produce MLR-BF (P > 0.05). Regarding the 17 patients tested for cytotoxic antibodies, 4 of the 5 patients who tested positive had a new abortion, whereas only 1 of 12 whose tests remained negative did not have gestational success (P < 0.01). CONCLUSION: The presence of MLR-BFs is not a prognostic criterium for the outcome of pregnancy after alloimmunotherapy, and, consequently, it is not a good diagnostic tool for RSA of alloimmune cause.