Prolactin and proinflammatory cytokine expression at the fetomaternal interface in first trimester miscarriage

Objective: To investigate the expression of prolactin (PRL), PRL-receptor (PRL-R), and the TH1 cytokines interleukin-2 (IL-2), tumor necrosis factor-α (TNF-α), and interferon-γ (IFN-γ) at the maternofetal interface.

Design: Case-control study.

Setting: University hospital unit of gynecology and obstetrics and research laboratories.

Patient(s): Women undergoing suction curettage for spontaneous miscarriage (study group) and voluntary termination of pregnancy (control group) in the first trimester.

Intervention(s): Samples of decidua and villi collected and histologically examined at the time of suction curettage.

Main outcome measure(s): Evaluation of all villous samples for karyotype with only euploid cases included; detection of transcripts of PRL, PRL-R, TNF-α, IFN-γ, and IL-2 by qualitative reverse-transcriptase-polymerase chain reaction (RT-PCR); investigation of pattern and site of expression by immunohistochemistry.

Result(s): In both groups, PRL-R and IFN-γ were broadly expressed. The expression of PRL was impaired or absent in the villi of the study group compared with controls. Expression of TNF-α was reduced, although not statistically significantly, in both decidual and villous samples of the study group. Immunohistochemical analysis showed the lack of IL-2 expression in decidual specimens of the control group versus the full expression shown in the study group.

Conclusion(s): Our results highlight the correspondence between PRL expression and vital pregnancy and the involvement of the TH1 cytokines with different specific roles at the implantation site. Prolactin and IL-2 may reciprocally influence expression.