COMPLEMENT C4B NULL ALLELE STATUS CONFERS RISK FOR SYSTEMIC LUPUS-ERYTHEMATOSUS IN A SPANISH POPULATION

Genetic susceptibility to systemic lupus erythematosus (SLE) may vary amongst different populations. In UK patients, genes encoded in the HL A class ZI (DQA0501/DRB1*0301) and class III [C4A*Q0 and tumour necro sis factor (TNF) polymorphisms] subregions appear to contribute to dis ease susceptibility. We have examined HLA-DRB1, C4 and TNF microsatell ites in 50 Spanish SLE patients and 48 matched controls. HLA-DRB10301 was increased in patients but did not achieve statistical significanc e (41% vs. 25.5%). C4AQ0 was not increased in patients, but C4B*Q0 al lele frequency was significantly increased compared with the controls (29% vs. 6%; OR: 6.0). TNF c2 microsatellite allele frequency was also increased in SLE patients. The C4B null allele (C4BQ0) appears to pl ay an important role in SLE susceptibility in the Spanish population.