Frequency of Human Leukocyte Antigen-B*57:01 Allele Carriers in People Living with HIV/AIDS in Türkiye.

Introduction: Abacavir is among the first-line initial antiretroviral regimens for most patients living with HIV/AIDS (PLWHA). Although well tolerated, it is associated with hypersensitivity reaction (HSR), which is treatment-limiting and potentially life-threatening. HSR was shown to be associated with the class I MHC allele, HLA-B*57:01. In this study, we aimed to evaluate the prevalence of HLA-B*57:01 in PLWHA in Istanbul, Türkiye.

Material and methods: Five HIV treatment centers in Istanbul included all sequential treatmentnaïve, ≥ 18 years adult PLWHA, between December 2017- December 2021. Demographic, clinical, and laboratory data were collected at baseline and during treatment. HLA-B* 57:01 genotyping was determined with PCR-SSP.

Results: Eight hundred sixty-seven PLWHA were included (male:91%, mean age 39.6±11.1 years). 1.6% of patients were found to be HLA-B*57:01 positive. Among HLA-B*57:01 positive patients, 4 were initially given abacavir-containing treatment; they were switched to non-abacavir treatment upon the allele found to be positive.

Conclusion: Although previous studies reported the HLA-B*57:01 prevalence of PLWHA in Türkiye as 3-3.6%, we have found the prevalence to be 1.6%. The current study includes higher numbers of patients than the previous studies. Furthermore, patients from all over the country apply to the centers in Istanbul; compared to the other studies, which involve patients limited to the relevant regions. It can be assumed that the number in our cohort is more representative of the country. In conclusion, the prevalence of the HLA-B*57:01 allele in PLWHA in this study is relatively low. With evident benefit in preventing abacavir HSR, HLA-B*57:01 should be screened in planning antiretroviral therapy.