TCR gamma delta+ T lymphocytes in unexplained recurrent spontaneous abortions

PROBLEM: It is generally accepted that the immune system and cellular immun ity in particular are involved in the mechanisms affecting the outcome of g estation. In order to evaluate a putative role of lymphocytes in the immuno logical mechanisms of unexplained recurrent spontaneous abortions (URSA), w e studied peripheral blood lymphocyte subpopulations in 244 women with URSA and 44 controls. METHOD OF STUDY: Direct immunofluorescence in whole blood with the appropri ate combinations of monoclonal antibodies and flow cytometry was used. RESULTS: The study showed: a) a statistically significant increase of the m ean CD4/CD8 ratio (2.12 +/- 0.84 vs 1.85 +/- 0.63, P = 0,039); b) a statist ically significant decrease of the mean value of the percentage of CD5 + CD 19 + lymphocytes (0.4 +/- 0.6 vs 1.4 +/- 0.78, P < 0.0001); and c) a statis tically significant increase of the percentage of T lymphocytes expressing TCR<gamma>delta (4.68 +/- 3.19 vs 2.61 +/- 1.14, P < 0.0001). It should be noted that a statistically significant high number of women with URSA (72/1 95, 36.9%) showed an increased percentage of TCR<gamma>delta T cells (great er than or equal to 5%, where 5 equals the mean value + 2 standard deviatio ns (SD) of the mean value of controls), whereas such a high percentage was not found in any control subject. CONCLUSIONS: It seems that women who experienced URSA comprise a heterogene ous population, as far as immunological parameters are concerned. At least in a subgroup of them, TCR gamma delta + T cells could be considered to pla y a role in the immune pathogenesis of fetal loss.