Association of the HLA-DR2/DR4 phenotype with skin test responses to bovine dermal collagen: a potential interaction of two MHC alleles in regulating an immune response.

We examined the HLA-DR characteristics of a population of 30 healthy collagen responders. Each had previously exhibited a localized hypersensitivity response to an intradermal challenge with a bovine collagen implant. A one-tailed binomial test revealed a significant increase in the alloantigen DR2 (p less than 0.007) and an increase in DR4 which bordered on significance (p less than 0.06). These data are consistent with murine studies that demonstrate that the immune response to bovine collagen is under H-2 linked genetic control. Furthermore, the increased frequencies of DR2 and DR4 in these collagen responders were attributable to a statistically significant disruption in Hardy-Weinberg equilibrium in favor of the heterozygote DR2/DR4 (p less than 0.0001). This finding supports a model in which at least two interacting HLA-linked alleles may influence the immune response to bovine collagen.