PROBLEM: The objective was to clarify whether lymphocytes in decidual tissue express only killer inhibitory receptors (KIRs) or both KIRs and killer activatory receptors (KARs).
METHOD OF STUDY: A polymerase chain reaction (PCR)-single strand conformation polymorphism (SSCP) analysis method, using cDNA as a template, was applied to detect as many natural killer receptors (NKRs) expressed on natural killer (NK) cells as possible and to distinguish between KIRs and KARs. Using this method, we analyzed NKRs on lymphocytes in decidual tissue and maternal peripheral blood mononuclear cells (PBMCs) (n = 10) from the same individuals.
RESULTS: More than 20 SSCP bands were detected for NKRs on both the lymphocytes in decidual tissue and the maternal PBMCs. The SSCP band patterns were different for each individual. KARs mRNA was detected in lymphocytes in decidual tissue according to the SSCP analysis results.
CONCLUSION: Lymphocytes in decidual tissue express not only KIRs but also KARs; this finding suggests their roles in placentation and the maintenance of pregnancy.