Association of TMEM173/STING1 Gene Variants with Severe COVID-19 Among Fully Vaccinated vs. Non-Vaccinated Individuals.

Background. The STING protein is activated by the second messenger cGAMP to promote the innate immune response against infections. Beyond this role, a chronically overactive STING signaling has been described in several disorders. Patients with severe COVID-19 exhibit a hyper-inflammatory response (the cytokine storm) that is in part mediated by the cGAS-STING pathway. Several STING inhibitors may protect from severe COVID-19 by down-regulating several inflammatory cytokines. This pathway has been implicated in the establishment of an optimal antiviral vaccine response. STING agonists as adjuvants improved the IgG titers against the SARS-CoV-2 Spike protein vaccines. Methods. We investigated the association between two common functional STING1/TMEM173 polymorphisms (rs78233829 C>G/p.Gly230Ala and rs1131769C>T/p.His232Arg) and severe COVID-19 requiring hospitalization. A total of 801 non-vaccinated and 105 fully vaccinated (mRNA vaccine) patients, as well as 300 population controls, were genotyped. Frequencies between the groups were statistically compared. Results. There were no differences for the STING1 variant frequencies between non-vaccinated patients and controls. Vaccinated patients showed a significantly higher frequency of rs78233829 C (230Gly) compared to non-vaccinated patients (CC vs. CG + GG; p = 0.003; OR = 2.13; 1.29-3.50). The two STING1 variants were in strong linkage disequilibrium, with the rs78233829 C haplotypes being significantly more common in the vaccinated (p = 0.02; OR = 1.66; 95%CI = 1.01-2.55). We also studied the LTZFL1 rs67959919 G/A polymorphism that was significantly associated with severe COVID-19 (p < 0.001; OR = 1.83; 95%CI = 1.28-2.63). However, there were no differences between the non-vaccinated and vaccinated patients for this polymorphism. Conclusions. We report a significant association between common functional STING1 polymorphisms and the risk of developing severe COVID-19 among fully vaccinated patients.