title: Frequencies of immune hypersensitivity reaction-associated HLA class I alleles in healthy South African Indian and mixed ancestry populations determined by a novel real-time PCR assay.
abstract: We have determined the frequencies of human leucocyte antigen (HLA)-B*57:01, HLA-B*35:05, HLA-C*04 and HLA-C*08 in healthy individuals of South African Indian (SAI) ethnicity (n = 50) and South African mixed (SAM) ancestry (n = 50) using real-time allele-specific polymerase chain reaction (AS-PCR) assay. HLA-B*57:01 associates with immune hypersensitivity reaction (IHR) in individuals exposed to abacavir (ABC), while nevirapine (NVP) IHR associates with HLA-B*35:05, HLA-C*04 and HLA-C*08. Real-time AS-PCR assays typically use less DNA, are more cost-effective and rapid compared with conventional genotyping methods, such as sequence-based typing (SBT). The assay was developed using samples of known HLA class I genotype and subsequently applied to the SAI and SAM samples. HLA-B*57:01 was detected in SAM and SAI populations at frequencies of 8.0% and 12.0%, respectively, while HLA-B*35:05 was not found in SAI individuals, but was present in 6.0% of SAM individuals. HLA-C*04 was detected in 22.0% and 24.0% of SAM and SAI individuals, respectively, while 10.0% and 8.0% of SAM and SAI individuals, respectively, were HLA-C*08 positive. This study reports the development of a novel real-time AS-PCR assay to identify HLA class I alleles associated with ABC and NVP IHR and has established the frequencies of these alleles present in healthy SAI and SAM populations. Using South African demographic data, our hypothetical analysis suggests that a substantial number of individuals would benefit from the assay.
authors.affiliation: Centre for HIV and STIs, National Institute for Communicable Diseases, the National Health Laboratory Service and Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
authors.forename: S
authors.initials: S
authors.lastname: Loubser
authors.forename: M
authors.initials: M
authors.lastname: Paximadis
authors.forename: N
authors.initials: N
authors.lastname: Gentle
authors.forename: A
authors.initials: A
authors.lastname: Puren
authors.forename: C M
authors.initials: CM
authors.lastname: Gray
authors.forename: C T
authors.initials: CT
authors.lastname: Tiemessen
mesh_terms: D000483:Alleles; D015331:Cohort Studies; D005260:Female; D005787:Gene Frequency; D015395:Histocompatibility Antigens Class I / Q000235:genetics*; D006801:Humans; D006967:Hypersensitivity / Q000208:ethnology* / Q000235:genetics*; D008297:Male; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*; D013019:South Africa / Q000208:ethnology
chemical_list: D015395:Histocompatibility Antigens Class I
keywords: abacavir; human leucocyte antigen; immune hypersensitivity reaction; nevirapine; real-time polymerase chain reaction