Enhancement of the expression of progesterone receptor on progesterone-treated lymphocytes after immunotherapy in unexplained recurrent spontaneous abortion. 
The immunological mechanism of an effective immunotherapy with paternal lymphocytes for unexplained recurrent spontaneous abortion (RSA) is not yet clear.  Previous studies revealed that progesterone plays an important role in maintaining normal pregnancy and lower expression of progesterone receptor (PGR) on lymphocytes was found in RSA.  Therefore, it was of interest to investigate whether immunotherapy for RSA would be able to enhance the expression of PGR on lymphocytes of RSA.  PGR expression on lymphocytes was analyzed with indirect immunofluorescence using flow cytometry.  There was no change of PGR expression on PBL of RSA between pre- and post-immunotherapy (P > 0.05), while in the presence of 10.0 micrograms/ml progesterone for 24 h, PGR expressed on PBL on post-immunotherapy was increased significantly as compared with that of pre-immunotherapy in successful cases (P < 0.05) and decreased in abortive cases (P < 0.05).  Most PGR was expressed on both CD4+ and CD8+ lymphocyte subsets.  In successful cases, CD8+PGR+ subset of post-immunotherapy was found to be increased significantly (P < 0.05) in comparison with that of pre-immunotherapy.  The data in the present study suggest that immunotherapy for RSA induced a higher expression of PGR on progesterone-treated lymphocytes, which may be involved in successful pregnancy.