FURTHER EVIDENCE OF THE ROLE OF HLA-DR4 IN THE GENETIC SUSCEPTIBILITYTO ACTINIC PRURIGO

Background: Actinic prurigo (AP) is triggered by sun exposure. Its pre valence in Mexicans seems to be particularly high, which suggests a ge netic susceptibility. Objective: Our purpose was to determine the role of major histocompatibility complex (MHC) genes in the genetic suscep tibility to AP. Methods: Fifty-six Mexican Mestizo patients with AP un derwent serologic typing for HLA class I and class II antigens. Class II MHC: genes were also studied by DNA analysis. Findings in patients were compared with 100 ethnically matched healthy controls. Results: W e found that 92.8% of patients with AP were HLA-DR4 positive (correcte d p = 0.002; odds ratio [OR] = 10.1). The class I antigens HLA-A28 and KLA-B39 (B16) were also significantly increased (p less than or equal to 0.000001, OR = 20.9 and p = 0.0001, OR = 6.7, respectively) compar ed with normal controls. Allele-specific oligonucleotide DR4 subtyping showed that 80.7% of HLA-DR4(+) patients with AP were also positive f or the DRB10407 allele. Conclusion: These results confirm the role of HLA-DR4 (DRB10407) in the genetic susceptibility to AP and raise the possibility of a role for class I MHC antigens HLA-A28 and B16 in Mex ican patients.