Aziz Rodan Sarohan
Although more than a year has passed since the COVID-19 outbreak, the pathogenesis of the disease has not yet been clearly explained. The way to develop effective vaccines and drugs against the disease depends on a clear elucidation of the pathogenesis. Therefore, the underlying mechanism of COVID-19 pathogenesis has been one of the most curious and studied topics since the beginning of the pandemic. Systemic organ involvement in COVID-19 cannot be explained by viral tropism mediated by ACE2 and TMPRSS2. Many chronic, inflammatory, and autoimmune diseases such as autism, dementia, and memory problems that emerged late after COVID-19 have made the pathogenesis of COVID-19 even more mysterious. Our studies and current literature show that the main problem in the pathogenesis of COVID-19 is retinol depletion and retinoid signal impairment. It is understood that many chronic diseases, serious clinical pictures, and residual diseases, which are called multisystem involvement in COVID-19, occur as a result of retinoid signal disorders. Due to the widespread distribution and intense activity of retinoid activity in the body, COVID-19 manifests itself with a very common and systemic involvement and a wide variety of symptoms and disease tables. Interestingly, organ involvement and disease severity of COVID-19 also parallels the intensity of retinoid activity in organs. Clarifying the pathogenesis of COVID-19 will enable us to develop effective strategies that will yield results regarding disease treatment, prophylaxis, and vaccination programs.