IGHV3-associated restriction fragment length polymorphisms confer susceptibility to bullous pemphigoid

To determine whether the immunoglobulin heavy chain genes contribute to the occurrence of bullous pemphigoid (BP), polymorphisms of both the immunoglobulin constant IGHC and variable IGHV groups were studied in 100 Caucasian BP patients and 143 ethnically matched healthy individuals.

To analyze the restriction fragment length polymorphism (RFLP) of the IGHG constant locus, a genomic immunoglobulin gamma 3 probe which detects polymorphisms in the gamma constant genes was hybridized to BstEII- or BamHI/SacI-digested germline DNA, while IGHV3 subgroup polymorphism was analyzed by hybridizing a cloned VH3 probe to EcoRI-digested DNA.

No difference in the frequencies of the genotypes defined by the constant probe was observed between patients and controls. Analysis of the RFLP obtained with the VH3 probe showed that within the range of 4.5 and 1.5 kb, the observed band pattern was composed of 8 monomorphic and 7 polymorphic bands. Among the latter, 4 allowed to define 10 different restriction patterns. One pattern was shown to be significantly less frequent in patients than in controls.

IGHV3 polymorphism might be a factor conferring susceptibility to BP.