Abstract
IgM memory B cells, are a peculiar subset of memory B cells, which probably originates in the spleen and outside germinal centers and provide a rapid line of defence against mucosal infections. Their role in counteracting COVID-19 is still elusive but, recent evidence, mainly boosted by studies on spleen function/involvement in COVID-19, seems to support the notion that this subset of memory B cells could exert a protective role against this virus, along with other coronaviruses, particularly in the acute setting of the infection, as outlined by worst clinical outcomes observed in unvaccinated patients with impaired IgM B memory response and spleen function. Herein we critically summarise the current landscape of studies on IgM memory B cells, focusing on the clinical impact of their depletion, by comparing the COVID-19-related splenic dysfunction with other hypo- and asplenic conditions and by adding recent data on follow-up studies and postulate a mechanistic explanation for their reduced numbers. The early detection of an impaired IgM memory B cell response in patients with COVID-19 may contribute to their improved care through different strategies, such as through tailored vaccine strategies, prompt hospital admission and/or administration of anti-infective treatments, thus resulting in an better prognosis, although at present management algorithms are still unavailable. Moreover, further studies with longer follow-up are needed to assess the evolution of COVID-19-associated/exacerbated immune deficit.
Keywords: B cell; IgM memory B cell; SARS-CoV-2; hyposplenism; plasma cells.
【저자키워드】 SARS-CoV-2, B cell, Plasma cells., IgM memory B cell, hyposplenism, 【초록키워드】 COVID-19, Evolution, IgM, Vaccine, Prognosis, Infection, memory B cells, virus, immune, Clinical outcome, infections, management, Algorithm, Patient, clinical impact, Germinal center, Hospital admission, Follow-up, Care, spleen, memory B cell, Plasma cells, memory response, Evidence, mucosal, administration, follow-up study, Support, dysfunction, other coronaviruses, protective role, Cell, memory B, resulting, reduced, condition, contribute, subset, outlined, patients with COVID-19, 【제목키워드】 COVID-19, IgM, function, role,