- Paper Report
- Open Access
T cell microchimerism associated with HLA-DQA1*0501
- Gerry Wilson1
© Current Science Ltd 2000
- Published: 15 September 2000
- systemic sclerosis
SSc is an autoimmune disease that is more common in women than men and shows strong association with MHC class II alleles (DR and DQ). The disease has been noted to have similarities with graft-versus-host disease which is caused by chimerism. A possible explanation for the higher female incidence of SSc is that fetal cells may transfer to the maternal circulation during pregnancy and that their persistence in the circulation may precipitate disease. This group has previously demonstrated that fetal cells can be detected in both healthy women and SSc patients decades after childbirth and that the levels of these cells tends to be higher in patients compared with healthy controls (see Additional information). This study aimed to determine if maternal or fetal MHC class II genotypes are associated with persistent fetal microchimerism.
Microchimerism was detected in nine controls (47%) and five SSc patients (42%). Carriage of DQA1*0501 by either the mother or son was found to be associated with T cell microchimerism. The association appeared strongest with carriage of this allele by the son; indeed every women with microchimerism had a DQA1*0501-positive son whilst non-carriage of this allele by a son was associated with absence of microchimerism. Two mothers negative for microchimerism had DQA1*0501-positive sons suggesting that other factors are also involved. There was no association with the carriage of DRB1*11 or *03, alleles both of which are in strong linkage disequilibrium with DQA1*0501.
Two main groups were studied: 19 healthy controls and 12 with SSc, all of whom had given birth to at least one son, while three healthy nulligravid and three women with daughters only were used as controls. Nested PCR was used to amplify Y chromosome specific sequences using DNA extracted from peripheral blood CD3+ cells as a template. A sensitivity of 1 male cell in 50,000 female cells was achieved.
Nelson JL, Furst DE, Maloney S, Gooley T, Evans PC, Smith A, Bean MA, Ober C, Bianchi DW: Microchimerism and HLA-compatible relationships of pregnancy in scleroderma. Lancet 1998, 351:559-562 (PubMed abstract).