Tumor necrosis factor genomic polymorphism in Spanish IGA deficiency patients

Selective IgA deficiency (IgAD) is the most common form of primary immunode ficiency. Tts association with genes within the major histocompatibility co mplex (MHC) has been repeatedly reported. Recently the susceptibility gene has been located in the class In region, around the tumor necrosis factor ( TNF) cluster. In this study we have examined IgAD association with TNF-alph a gene promoter polymorphisms and TNFa and b microsatellites. No significan t association was found with the former polymorphisms and the observed asso ciations with TNFa2 allele and haplotypes TNFa2b1 and TNFa2b3 were proven t o be secondary to their occurrence on the B14-DR1 and B8-DR3 haplotypes, pr eviously reported to be associated with susceptibility to IgAD. However, a primary negative (protective) association was found between the TNFa10 alle le and IgAD.