Different Susceptibility to SARS CoV-2 Infection Among Health Care Workers Highly Exposed to COVID-19.

"ACE2 and CD26 receptor study: After genomic DNA extraction and quantification using a NanoDrop-1000, 14 ACE2 SNPs (rs1978124, rs2048683, rs2074192, rs2106809, rs2285666, rs233575, rs4240157, rs4646142, rs4646155, rs4646156, rs4646188, rs4830542, rs6632677, and rs879922) will be studied. In addition, one CD26 (DPP4) SNP (rs7608798) will be analysed (qualitative measure).~SARS-CoV-2 CD4/CD8 T cell response: SARS-CoV-2 peptides (Prot-S, Pros-N and Port-M) will be used to activate CD4 and CD8 T cells. Cytokines released, such as IFNg, TNFa, IL4, IL17A, and IL2, from each cell subset will be measured by flow cytometry (quantitative measure).~KIR characterization: Characterization of the presence of 14 genes plus 2 pseudogenes of KIR gene family (qualitative genotyping) by PCR, mRNA expression profiling (quantitative measures) by RT-PCR, and phenotyping of human NK cells analyzing different KIR receptors (quantitative measure) by flow cytometry, will be analyzed."