Genotipagem de HLA para avaliação de risco de infeção por SARS-CoV-2

Abstract

Introduction: In December 2019, a new coronavirus was identified in China. It was named SARS-CoV-2 and the associated disease COVID-19. Currently, risk factors for the development of a more severe form of this disease are already recognized. However, the severity is not only associated with the viral infection itself but is also related with the host's immune response to SARS-CoV-2. In this context, the HLA system plays a key role in the immune response’s regulation. Several polymorphisms in HLA genes associated with viral infections, including SARS-CoV-2, have been described. Aims: To characterize a population from Viseu with a previous record of SARS-CoV-2 infection and to genotype its HLA alleles, to eventually identify HLA genetic variants associated with SARS-CoV-2 infection. Materials and Methods: Laboratory research study with questionnaire application and collection of a biological saliva sample. The participants were students and patients from the UCP University Dental Clinic and patients from JS Clínica Médica Lda., in Viseu. The samples were processed to determine viral load and identify changes in HLA genes, to relate these polymorphisms with the COVID-19 severity. Results: The frequencies of the different HLA-A and HLA-B alleles were analyzed and compared between populations. The alleles HLA-A*02, HLA-B*44 and HLA-B*51 are the most frequent in Viseu and in Portugal. The characterization of individuals previously infected with SARS-CoV-2 corroborates the diversity of associated clinical manifestations. Polymorphisms present in HLA-A and HLA-B genes from these individuals were identified. Conclusion: Knowing the wide influence of the HLA system on viral infections, it is imperative to encourage population-level research on HLA susceptibility and protection alleles against SARS-CoV-2 to improve the performance against the spread of this pandemic.

Date of Award	30 Jul 2021
Original language	Portuguese
Awarding Institution	Universidade Católica Portuguesa
Supervisor	Raquel Silva (Supervisor) & Maria José Correia (Co-Supervisor)