HLA-DR typing of women with recurrent late spontaneous abortion and unsuccessful cervical cerclage.

The release of certain cytokines, e.g. tumour necrosis factor (TNF)-alpha, in the amniotic fluid has been suggested to be a cause of preterm birth. The predisposition to excessive liberation of cytokines from peripheral leukocytes has been shown to depend partly on the individual's HLA-DR genotype. The HLA-DR1 and -DR3 alleles have previously been reported as being associated with a TNF-alpha high responder status and have also been associated with unexplained recurrent spontaneous abortions. In the present study, HLA-DR typing was performed in 10 women who had experienced recurrent very early preterm births resulting in perinatal death, or late spontaneous abortions under a clinical picture resembling that traditionally attributed to cervical incompetence. All patients had had at least one mid-trimester miscarriage in spite of the insertion of a cervical cerclage. Nine out of 10 (90%) patients had the HLA-DR phenotypes DR1 and/or DR3 compared with 37% in the background population (P < 0.005). The results suggest that HLA-DR-associated immunological factors might play a part in recurrent late spontaneous abortions and extremely preterm births under a cervical incompetence-like picture, at least in the subset of cases not treatable by cervical cerclage.