Volume 7 Supplement 1
Quantifying the contribution of the second HLA-DRB1 susceptibility allele to the risk of rheumatoid arthritis: a meta-analysis
© BioMed Central Ltd 2005
Received: 11 January 2005
Published: 17 February 2005
HLA-DRB1 alleles encoding the shared epitope (SE) susceptibility sequence predispose to rheumatoid arthritis (RA). Having two copies results in even higher risk. This study analyzes whether the contribution of the second SE allele to RA risk is identical to that of the first SE allele.
In a meta-analysis of 44 datasets of case–control studies meeting pre-defined criteria, the odds ratios OR1/0 and OR2/1 are calculated, as an estimate of the relative risk for RA for individuals having one compared with zero, or two compared with one SE allele; from these, the ratio OR2/1:OR1/0 is calculated.
The contribution of the second SE allele to RA risk does not differ significantly from that of the first SE allele. This result will help to pool immunogenetic data across populations, resulting in a detailed description of the contribution of immunogenetic factors to RA risk.
In addition this finding implies that pathogenetic models for RA that incorporate the role of HLA should explain the fact that the first and the second SE alleles increase RA risk equally. Such effects might, for example, be described for models incorporating presentation of pathogenic antigenic peptides.