COVID-19 in the context of inborn errors of immunity, autoimmune diseases, and immune suppression

The COVID-19 pandemic reached five waves in three years, with over 6.5 million deaths across the globe. Knowing the differential susceptibility to the novel betacoronavirus has allowed us to better understand the pathophysiology and inflammatory complications and dissect the response against the virus. As in other viral infections, CD8+ T lymphocytes and NK cells stand out as key players, together with viral sensors, type 1 interferons, an exaggerated inflammatory response by NLRP3, and a storm that includes cytokines IL-6 and IL-8. Whole-exome sequencing has identified several genes with pathogenic germline variants in patients with severe COVID-19; said genes would account for around 5% of all severe cases. In addition, up to 20% of hospitalized adults harbor autoantibodies against type-I and III interferons. These findings translate into novel genetic etiologies, whereas autoantibodies explain the worse prognosis of the elderly, linked to the inflammaging phenomenon. In general, patients with known primary immune deficiencies who acquired COVID-19 fared well, with global survival rates over 80% and a predominance of mild courses. The exceptions were patients with severe-combined immune deficiency, and with the autoimmune polyglandular syndrome 1, the latter because they develop autoantibodies against interferon. Neither have there been reports of greater severity in patients with autoimmune or autoinflammatory disorders. However, those receiving immunosuppressant treatments usually have a more protracted course. Patients with NLRP3 or STAT1 gain of function might be especially susceptible to systemic inflammatory complications. In this review, we summarize the global experience in the caretaking of patients with immune alterations who were infected by SARS-CoV-2.