Pathological anatomy of the lungs in patients with humoral immunity to the SARS-CoV-2 virus

Since the COVID-19 pandemic, numerous articles have appeared on clinical changes in organs and systems in individuals with humoral immunity to the SARS-CoV-2 virus. However, there is a lack of data on a comprehensive clinical and morphological study of a group of patients with acquired immunity. OBJECTIVE: To compare lung pathology with humoral immunity data to the SARS-CoV-2 virus in patients who died from a new coronavirus infection with elevated serum Ig class G and M levels and negative PCR. MATERIAL AND METHODS: An analysis of clinical, laboratory, and pathomorphological changes was conducted in 33 autopsy observations of patients who died during the first half of 2021 in the specialized non-infectious departments of the City Clinical Hospital No. 31 named after Academician G.M. Savelyeva with an elevated content of serum Ig class G and M in the blood. RESULTS: Despite the negative PCR, elevated concentrations of Ig to SARS-CoV-2 proteins were detected in the blood of patients: IgG 0.31 - 532.56 OCE (Me 109.33 OCE), IgM 0.14 - 16.8 U / ml (Me 0.62 IU / ml). At an IgG concentration of 0.31-109.33 OCE in the lungs, an exudative phase of diffuse alveolar damage (DAD) was described, in the IgG range of 122.57-158.72 OCE, exudative-proliferative DAD was described, at IgG values 207.2-532.56 OCE, the proliferative phase of DAD occurred. CONCLUSION: The study revealed a sequence of pathological changes in the lungs, depending on the serum IgG concentration, characteristic of DAP. The findings confirm the multifaceted nature of the novel coronavirus infection.