HLA-G/A HAPLOTYPES IN PRE-ECLAMPSIA AND RECURRENT SPONTANEOUS ABORTIONS.
M Carreiras, V Visconti, Z Layrisse Laboratorio de Fisiopatologia, Instituto Venezolano de Investigaciones Cientificas.
The peculiar HLA-G antigen expression at the materno-fetal interface and its potentially protective effect upon decidual NK cytolitic activity has raised interest in the study of HLA-G polymorphism among women with pregnancy problems. Our laboratory has defined HLA-G and HLA-A alleles by intermediate resolution PCR-SSOP in 26 women with pre-eclampsia, 24 with recurrent spontaneous abortions (RSA) and a control group of 55 women of similar mixed ethnic origin and normal history of pregnancies. HLA-G testing was done using 4 primers to amplify exons 2 and 3 and the 10 probes described by Morales et al, 1997, while typing for HLA-A was carried out using primers and probes from BSHI (Kennedy et al, 1997) modified by D Middleton for the VII Latin American Histocompatibility Workshop. Six HLA-G alleles and 15 HLA-A allelic groups were identified. The highest frequencies observed in the 3 groups of women were 0.346, 0.354, 0.427 respectively for HLA-G*01011; 0.250, 0.167 and 0.164 for G*0104 and 0.187, 0.250 and 0.164 for HLA-G*01012, with no statistically significant difference between them. A similarly high frequency of HLA-G*0104 has been reported previously among Thais and Japanese. Of interest if the relatively high frequency of HLA-G*0105 (0.109 and 0.111) found in this study among controls and women with RSA, not reported so far in any population and present only in 1 of the 26 pregnants with pre-eclampsia (RR=0.14, p=0.03). The observed linkage between HLA-G*01011 and A*02; G*01012 with A*26, *01, *23, *68 and G*0104 with A*23 or *24 is in agreement with previous population studies. Our results confirm that HLA-G polymorphism alone does not seem to have a direct influence in pregnancy outcome. More elaborate studies considering other parameters as well are needed to clarify the involvement of HLA-G in fetal tolerance.