Association of HLA-DRB1* and keloid disease in an Afro-Caribbean population

Summary Background. Keloid disease (KD) is a fibroproliferative dermal tumour of unknown aetiology. The high incidence of familial clustering in KD, its prevalence in certain races and its concordance in identical twins suggest a strong genetic predisposition to keloid formation. The highest incidence of keloids is found in black populations, where the incidence has been estimated to be up to 16%. The most polymorphic genetic system in vertebrates is the major histocompatibility complex (MHC) also known as the human leucocyte antigen (HLA) system. The MHC has been shown to be strongly associated with numerous conditions. Of particular relevance is the association of DR2 with dermal fibrotic diseases including sarcoidosis and systemic sclerosis. Aims. To investigate the aetiology of KD and the potential involvement of the MHC.Methods. We compared the HLA-DRB1 phenotype frequencies of Afro-Caribbeanpatients of Jamaican origin with keloid scars against those seen in a controlpopulation of the same ethnicity (n = 121; mean age 34.8 years, range 14-88). In total, 180 keloid cases of Afro-Caribbean origin, recruited from Kingston,Jamaica, were evaluated in the study (mean age 29.7 years, range 2-90 years).HLA-DRB1 alleles were determined in all participants using a semiautomated typingsystem of reverse hybridization PCR with sequence-specific oligonucleotide probes. HLA-DRB1* phenotype frequencies were established in the Jamaican Afro-Caribbean population and comparisons made between cases and controls. Furthermore, the influence of multiple vs. single lesions, patient gender and family history were also investigated. Results. Differences were observed between the disease and control cohorts although none was significant. Conclusions. This study does not support an association between HLA-DRB1* alleles and susceptibility to keloid in people of Afro-Caribbean origin.