Investigation of plasma cytokine levels and endometrial tissue leukocytes in recurrent pregnancy loss

Immigrant and resident leukocytes are the main immune components of endometrial and decidual tissue. Altered immune responses have been suspected to be involved in idiopathic recurrent pregnancy loss (RPL) pathogenesis. We aimed to investigate the plasma cytokine levels and endometrial leukocyte subpopulations of RPL cases. This study was conducted with 60 idiopathic RPL (28 primary and 32 secondary) cases. Peripheral venous blood samples were drawn and hysteroscopic investigation of uterine cavity with endometrial samplings were performed during mid-follicular phase. IL-17, IFN-gamma, TNF-alpha, TGF-beta, IL-6, IL-4, IL-10, SOCS3 and IL-35 plasma levels were assayed by enzyme linked immunosorbent assay. CD4, CD8, CD56 and CD163 staining of endometrial tissue was performed with immunohistochemistry method. The comparison of plasma IFN-ɣ, IL-35, IL-17, SOCS-3, TGFβ, IL-6, TNF-α, IL-10 and IL-4 levels between primary and secondary RPL cases revealed no significant difference. The major staining of endometrial tissue was composed of CD8 antigen. The second dominancy was observed with CD56 antigen. CD163 antigen staining was lower than CD8 and CD56 staining. CD4 positive cells were occasionally found. CD8 and CD56 positivity of secondary RPL cases were significantly higher than those of primary RPL cases. There were interaction between IL-10 levels and CD163 staining and TNF-α levels and CD56 staining. In conclusion; natural killer cells, macrophages and T supressor cells came into prominence on endometrial samplings of our RPL cases. And it is not possible yet to make definite consequences on RPL immunology with our results.