Correlation between HLA and pityriasis rosea susceptibility in Brazilian blacks

The human leucocyte antigen (HLA) has been related to susceptibility factors in several diseases. This study aimed to determine the potential genetic susceptibility of patients with pityriasis rosea (PR) through HLA molecular typing analysis.

The method of choice was polymerase chain reaction with sequence-specific primers (PCR-SSP) using low-resolution typing kits, with determination of the alleles class I (HLA-A, HLA-B and HLA-C) and class II (HLA-DRB1, DRB3, DRB4, DRB5 and DQB1) performed in 30 Afro-Brazilian PR-diagnosed patients and 45 healthy individuals as the control group (PR-C).

Analysis of the HLA typing results showed that the relative risk (RR) of 4.00 [95% confidence interval (95% CI) 1.20-13.28, two-tailed P = 0.018] for allele HLA-DQB1*04 class II, detected in 33.3% of PR patients, was significant. By contrast, in the control group only 11.1% of subjects had that allele. Three out of six B*51 alleles and three out of six B*53 alleles detected in PR patients were found, together with the allele DQB1*04.

We suggest that alleles DQB1*04 may be involved in the genetic susceptibility of PR based on the significant predominance of those alleles observed in the black PR patients. We also recommend that more studies are conducted on populations of other ethnic origins, preferentially with higher resolution techniques of DNA typing.