The SARS-CoV-2 disease presents different phenotypes of severity. Comorbidities, age, and
being overweight are well established risk factors for severe disease. However, innate immunity plays
a key role in the early control of viral infections and may condition the gravity of COVID-19. Natural
Killer (NK) cells are part of innate immunity and are important in the control of virus infection by
killing infected cells and participating in the development of adaptive immunity. Therefore, we
studied the short tandem repeat (STR) transmembrane polymorphisms of the major histocompatibility
complex class I chain-related A (MICA), an NKG2D ligand that induces activation of NK cells, among
other cells. We compared the alleles and genotypes of MICA in COVID-19 patients versus healthy
controls and analyzed their relation to disease severity. Our results indicate that the MICA*A9 allele
is related to infection as well as to symptomatic disease but not to severe disease. The MICA*A9
allele may be a risk factor for SARS-CoV-2 infection and symptomatic disease.Instituto de Salud Carlos III - FEDER funds (European Union) PI 16/00752
B-CTS-410-UGR-20Junta de Andalucia CTS-143
C-0013-201