14  Probable histopathological signs of autoimmune reactions in COVID-19
Based upon the possibility to detect autoimmune reactions by morphological methods we analyzed autopsies from 18 deceased patients from COVID-19. The pathological investigation was done by using bright lineage of immunohistochemistry (CD2, 3, 5, 7, 8, 20, 31, 34, 69). Our study allowed us to demonstrate the role of different mechanisms of death [128]. Of special interest was the diffuse infiltration of the lungs, along with focal infiltration of the kidney, liver, intestine, adrenals, pancreas and pericard by lymphocytes, which were seen in different grade in all our cases. In order to understand its nature we were able to prove that the infiltrate was dominated by T lymphocytes (CD3+), and the most numerous of them were CD8+ suppressors, observed in the lungs (Fig. 1a), adrenals (Fig. 1b), liver (Fig. 1c), intestine (Fig. 1d) and other organs partly accompanied by tissue lesions. Taking in to consideration that one of the most important mechanisms of autoimmune reactions is CD8+ T Cell mediated cytotoxicity, we assumed that the findings confirm an autoimmune process. Further complex studies will hopefully allow us to optimize the strategy of treatment as well.
Fig. 1 Infiltration by CD8+ suppressor T-cells of different organs. IHC. Magnification 100. A-Lungs, B -Adrenal gland, C-liver, D- intestine.