Immunologic characteristics of repeated spontaneous abortions

: In 28 couples with spontaneous abortions, data of immunological investigations revealed an elevated frequency of HLA DR compatibility and immunological characteristics defining distinct patterns of immune responsiveness. In the half of women with recurrent spontaneous abortion (RSA) we observed a failure to develop a recognition response to paternal inherited fetal antigens expressed by the lack of classical evidence of in vivo allo-immunization such as antipaternal antibodies, and the absence of the inhibitors of cell-mediated immunity found in maternal blood during pregnancy. In few cases, the paternal cells are inefficient to elicit in vitro maternal cell-mediated lympholysis. In most women with a normal pregnancy occurring after spontaneous abortions or prior to RSA, an immune recognition response was evidenced by the presence of antipaternal antibodies and/or blocking factor acting on in vitro cell-mediated lympholysis. These observations support the hypothesis that immunological process could be the cause of some fetal losses of unknown etiology, through a defective or unsuitable maternal immune response.