Cytokine promoter gene polymorphisms and idiopathic recurrent pregnancy loss.

Approximately one in 300 women experience recurrent pregnancy loss (RPL), the aetiology of which is unknown in at least 40% of cases. Previously, some studies have shown increased production of pro-inflammatory cytokines (tumour necrosis factor-alpha and interferon-gamma) and reduced production of anti-inflammatory cytokines (interleukin-10) by circulating blood lymphocytes isolated from these patients when compared with controls. The reasons for this are unclear. The production of these cytokines are partly under genetic control. This study investigated whether polymorphisms in these three cytokine genes known to be associated with either high or low production, are associated with idiopathic RPL. No association was found. It may be that genetic factors are not a major determinant of cytokine production during pregnancy, or alternatively it may be that the observed differences in cytokine production by peripheral lymphocytes do not accurately indicate what is occurring at the local maternofoetal interface during successful and abortive pregnancies.