Studies indicate that maternal-fetal incompatibility of HLA-DR and DQ antigens may be associated with a decreased risk of disease activity during pregnancy in women with rheumatoid arthritis. We attempted to replicate these findings in a large cohort of women with inflammatory polyarthritis.
Women with an inflammatory polyarthritis were recruited during the last trimester of pregnancy and were interviewed and examined in their homes by a research nurse. Each woman provided a sample of blood as well as permission for a sample of cord blood to be taken at the time of birth. DNA was extracted from both maternal and cord blood and HLA-DRB1 and DQB1 typing performed. On the basis of known haplotypes found in Caucasian populations, DQA1 type was inferred wherever possible.
Based on 110 or more maternal-fetal pairs, there was no increased occurrence of disease remission associated with maternal-fetal incompatibility of DRB1 alleles (remission ratio 0.7, 95% confidence interval 0.2-2.8), DQB1 alleles (remission ratio 1.2, 0.3-6.5), or DQA1 alleles (remission ratio 0.8,0.3-1.9). Results were similar whether maternal-fetal sharing was defined by broad allelic group or by specific alleles.
Our results do not support the hypothesis that maternal-fetal HLA incompatibility contributes to remission of inflammatory arthritis during pregnancy.