Background: Several types of T cells have been associated with the pathogenesis of unexplained recurrent spontaneous abortion (URSA), including Th1/Th2/Th17/Tregs cell. It has been appreciated that immunotherapy with paternal or third party lymphocytes is an effective method of treatment for URSA patients. The balance of Th1/Th2 cells could be maintained and an increase of Treg cells would be beneficial after immunotherapy; however, the mechanism by which the Th17/Treg balance affects URSA has not yet been fully elucidated.
Methods: Here, we used flow cytometry, liquid chip technology and quantitative real-time PCR (qPCR) methods to characterize Th17/Treg cell populations after immunotherapy. We found that after immunotherapy in URSA patients, the percentage of Th17 cells decreased and the percentage of Treg cells in peripheral blood mononuclear cells (PBMC) increased, as detected by flow cytometry.
Results: Immunotherapy may induce a decrease in the Th17/Treg ratio and the Treg bias, which may be beneficial for the maintenance of pregnancy. The expression level of ROR gamma t, a transcription factor found in Th17 cells, decreased and the expression of the Treg-specific transcription factor Foxp3 increased in peripheral blood as detected by qPCR. Immunotherapy may induce a decrease in the ratio of ROR gamma t to Foxp3 and a Treg cell bias, which would be beneficial for pregnancy maintenance. The secretion of the Treg-associated cytokine TGF-beta, as well as Th2 cytokines, was increased in serum, while the secretion of Th17-associated cytokine IL-17A and Th1 cytokine production was decreased. The Th1/Th2 cytokine ratio significantly decreased. Similarly, the Th17/Treg ratio significantly decreased in the total patient after immunotherapy.
Conclusions: These results indicate that in patients with URSA, immunotherapy with mononuclear cells derived from the baby's father could affect both Th1/Th2 and Th17/Treg balance, and we found that the Th2 and Treg bias would be beneficial for pregnancy, which may lead to a balancing of the Th17/Treg ratio in URSA patients after immunotherapy.