Neppert J, Mueller-Eckhardt G, Neumeyer H, Malchus R, Kiefel V, Gerhard I, Kuhn U, Westphal E, Harpprecht J
Institute of Clinical Immunology and Blood Transfusion, Justus Liebig University, Giessen, F.R.G.
J Reprod Immunol. 1989 May;15(2):159-67. doi: 10.1016/0165-0378(89)90035-1.
To analyse the nature of antibodies which are purported to be essential for the maintenance of normal human pregnancy, six centers participated in a workshop of "blind" tests on 19 allosera. Fc-receptor dependent assays detected antibodies with specificity only for HLA. In addition to cytotoxic antibodies, the Fc-receptor dependent immune phagocytosis inhibition test revealed two non-cytotoxic alloantibodies with HLA specificity. These antibodies had high titers and may, therefore, be essentially non-cytotoxic. Murine monoclonal antibodies to HLA-A, B, C or DR (W6/32 and 2MC3) were used to evaluate the methods. These antibodies inhibited immune rosette formation as well as immune phagocytosis. Diluted to concentrations below the threshold of complement-dependent cytotoxicity, the monoclonal antibodies still inhibited the mixed lymphocyte reaction and the immune phagocytosis. A human monoclonal immunoglobulin M with specificity for monomorphic non-HLA lymphocyte antigens inhibited the mixed lymphocyte reaction. The immune rosette inhibition test exhibited several false positive reactions, e.g. three out of four with a serum that did not contain alloantibodies to blood cells. Non-cytotoxic antibodies were therefore rare in the selected sera of the workshop and they exhibited HLA specificity only. No participant was able to identify pregnancy-maintaining non-HLA-antibodies.
