The skewed TCR-BV repertoire displayed at the maternal-fetal interface of women with unexplained pregnancy loss

PROBLEM: The study was undertaken to investigate T-cell receptor (TCR) variable beta (BV)-chain usage at maternal-fetal interface and explore the relationship between the skewed TCR-BV usage and unexplained pregnancy losses. METHOD OF STUDY: A total of 57 patients with unexplained pregnancy loss including 39 cases with unexplained spontaneous abortion and 18 cases with unexplained recurrent spontaneous abortion (RSA) were chosen in Renji Hospital, Shanghai Second Medical University matched with 41 women with normal pregnancies in first trimester between September 2002 and November 2003. A high-resolution spectratyping analysis of complementarity-determining region 3 (CDR3) was used to detect and compare the degree and pattern of TCR-BV repertoire usage at the maternal-fetal interface between patients with pregnancy loss and normal controls. RESULTS: There were two comparisons of TCR usage performed between patients and controls, which included the degree (mean value of every TCR-BVn expression) and the pattern (skewed TCR-BVn frequency). The skewed TCR-BVn is defined as an absolute BVn usage of > 5% calculated from the formula or a double increased BVn usage compared with the mean value of normal BVn. According to the degree of TCR-BV usage, BV2 (P = 0.046), BV10 (P = 0.016), and BV11 (P = 0.030) in spontaneous abortion group and BV19 (P = 0.038) in RSA group showed higher usage, while BV5.2 (P = 0.006 and P = 0.046) in both abortion groups showed significantly lower usage when compared with normal controls. About the pattern of skewed TCR-BV distribution, we found that TCR-BV2, -3, -6, and -7 were the four most common BV families in deciduas of patients with both types of abortion and normal controls. Women with spontaneous abortion demonstrated higher frequency of BV10 (P = 0.035) and lower frequencies of BV4 (P = 0.002) and BV5.2 (P = 0.003) in comparison with controls. In RSA, higher frequencies of BV15 (P = 0.018), BV19 (P = 0.049), and BV20 (P = 0.018), in the mean time, lower frequencies of BV4 (P = 0.026) and BV7 (P = 0.018) distributions were verified. CONCLUSIONS: Our results suggested that a significant skewed TCR-BV repertoire occurred at the maternal-fetal interface with patients undergoing abortion. The specific skewed usages of TCR-BV might be associated with the susceptibility to unexplained pregnancy loss.