Humoral immune mechanisms involved in protective and pathological immunity during COVID-19 (Publication with Expression of Concern. See vol. 84, pg. 355, 2023)

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causing COVID-19 is associated with excessive inflammation, as a main reason for severe condition and death. Increased inflammatory cytoki-nes and humoral response to SARS-CoV-2 correlate with COVID-19 immunity and pathogenesis. Importantly, the levels of pro-inflammatory cytokines that increase profoundly in systemic circulation appear as part of the clinical pictures of two overlapping conditions, sepsis and the hemophagocytic syn-dromes. Both conditions can develop lethal inflammatory responses that lead to tissue damage, however, in many patients hemophagocytic lymphohistiocytosis (HLH) can be differentiated from sepsis. This is a key issue because the life-saving aggressive immunosuppressive treatment, required in the HLH therapy, is absent in sepsis guidelines. This paper aims to describe the pathophysiology and clinical relevance of these distinct entities in the course of COVID-19 that resemble sepsis and further highlights two effector arms of the humoral immune response (inflammatory cytokine and immunoglobulin production) during COVID-19 infection. (c) 2021 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved.

Automated summary

SARS-CoV-2 associated with COVID-19 causes excessive inflammation, which correlates with severe conditions and death. Increased inflammatory cytokines and humoral response are key factors in COVID-19 immunity and pathogenesis, presenting as part of sepsis and hemophagocytic syndromes. Identifying hemophagocytic lymphohistiocytosis (HLH) from sepsis is crucial for determining appropriate treatment options.