As in other populations HLA-DRB1 * 03 is a susceptibility allele in Portuguese SLE patients, while HLA-DRB1 * 09 and DRB1 * 13 alleles may be protective alleles, not only for the disease, but for the development of nephritis.
Overexpression of BAT1 mRNA was associated with carriers of a haplotype containing the LST1 marker transmitted to RA cases in a family study and also DRB1(*)15 associated with susceptibility to nephritis in systemic lupus erythematosus.