Immunology: Diagnostic relevance of abortion-associated human embryonic antigen expressed on the cell surface of tumour promoter-treated Bloom syndrome cells

We detected stable expression of human embryonic antigen associated with spontaneous abortion (HEAA) on the cell surface of a tumour promoter-treated B lymphoblastoid cell line (BS-SHY) originating from Bloom syndrome. We used indirect immunofluorescence and diluted serum from 44 patients who had recurrent spontaneous abortions. With the use of the panning procedure, we separated characteristic cells expressing strong HEAA. The BS-SHY-HEAA cells separated here would be useful for measuring serum antibody (against HEAA) produced by patients with recurrent abortions. It was also noted that aborters who received husbands' leukocyte immunization have lost this antibody, and have delivered successful pregnancies at term. Using HEAA proteins, we conducted Western blotting analysis for the amino acid sequencing (mol. wt 77 kDa). Amino acid sequencing data indicated that HEAA had 87.5% homology to the immunoglobulin (Ig) VHIII region in the framework. Recently, the protective value of high-dose i.v. administration of immunoglobulin in the treatment of recurrent spontaneous abortions has been reported to be similar to that of leukocyte immunization. Therefore, the BS-SHY-HEAA cells appear to provide a valuable tool for rapid serological diagnosis and for evaluating the efficacy of immunotherapy with husbands' leukocytes in patients with recurrent spontaneous abortions.