[Characteristics of subpopulations of lymphocytes and cells of the liver mononuclear phagocyte system in the acute period and in the long term after COVID-19 disease].

Abstract

Objective: Comparative analysis of liver subpopulations of lymphocytes and cells of the system of mononuclear phagocytes on the material of autopsies in deaths from acute period of COVID-19, without its previous diseases and bacterial/mycotic superinfection, as well as from noninfection diseases in the distant future after the new coronavirus infection.

Material and methods: Study of morphological changes of the liver in 47 deaths from COVID-19, confirmed by a PCR test, and noninfection diseases within 40 to 300 days after a new coronavirus infection. The study did not include those who died with previous liver diseases and comorbid diseases accompanied by liver damage, and in the first two groups of observations - also with bacterial/mycotic superinfection, and after hepatotoxic therapy. 1 group consisted of 10 observations (average age - 75.2 years) with the exudative phase of diffuse alveolar damage (DAD), 2^nd group - 27 observations (average age - 71.7 years) with the proliferative or exudative-proliferative phases of DAD, 3d group - 10 observations (average age - 84.7 years), died from cardiovascular diseases in the period from 40 to 300 days after the transfer COVID-19. Imunohistochemical (IHC) reactions with antibodies to CD3, CD4, CD8, CD20, CD56 and CD68 were used with statistical analysis.

Results: In portal tracts and perisinusoid spaces, the total number of CD3+, CD4+, CD8+, CD56+ and CD20+ lymphocytes and CD68+ cells are not higher in the acute period COVID-19, and in perisinusoid spaces are even less than in observations after a new coronavirus infection in patients died from cardiovascular diseases. The number of intraepithelial CD3+, CD4+, CD8+, CD56+ lymphocytes of the bile ducts of portal tracts was increased, which also infiltrate the walls of small vessels. Number of CD4+ lymphocytes in the stroma and liver parenchyma, ratio CD4+/CD8+ lymphocytes and proliferation of Kupfer cells are most increased in the exudative phase of DAD in COVID-19.

Conclusion: The study confirms that the morphological substrate COVID-19-associated liver damage may be ischemic hepatitis and COVID-19-associated cholangiopathy and microangiopathy give it a certain specificity. The revealed changes do not allow to exclude that the pathogenesis of liver damage can be also associated, including with other factors the direct action of SARS-CoV2 or immune disorders associated with COVID-19.