Intermediate Monocytes with PD-L1 and CD62L Expression as a Possible Player in Active SARS-CoV-2 Infection

Abstract

Monocytes play a role in viral biology, but little is known about the monocyte subpopulation in the course of COVID-19 disease. The aim of the study was the analysis of classical, intermediate and non-classical monocytes with expression of PD-L1 and CD62L, TIM-3 and CD86 molecules in peripheral blood (PB) to distinguish patients with SARS-CoV-2 infection from convalescent patients. The study group consisted of 55 patients with SARS-CoV-2 infection and 51 convalescent patients. The cells were analyzed by flow cytometry. The number and proportion of monocytes were lower in patients with COVID-19 than convalescent patients. We observed a lower proportion of non-classical monocytes in COVID-19 patients than convalescent ones. There was a higher proportion of PDL-1-positive intermediate monocytes in COVID-19 patients than convalescent ones. We noticed a higher geometric mean fluorescence intensity (GeoMean) of PD-L1 on intermediate monocytes in COVID-19 patients than convalescent patients, and a higher proportion of CD62L-positive monocytes in COVID-19 patients in comparison with convalescent ones. We found a higher GeoMean of CD62L on monocytes in COVID-19 patients than convalescent ones. Assessment of PD-L1- and CD62L-positive monocyte subsets may identify patients with a possible predisposition for rapid recovery. The monitoring of monocyte subsets in PB might be a useful test in COVID-19 patients.

Mild/asymptomatic COVID-19 in unvaccinated pregnant mothers impairs neonatal immune responses

“…Our results show that maternal SARS-CoV-2 infection was associated with the development of “regulatory” monocytes as described for adults with COVID-19 ( 62 – 64 ). Alterations in monocyte activation state may contribute to dysregulated antimicrobial responses.…”

Immune cell pair ratio captured by imaging mass cytometry has superior predictive value for prognosis of non‐small cell lung cancer than cell fraction and density

“…Additionally, higher ratios of infiltrating non-classical monocytes, intermediate monocytes, CD163 + macrophages, and other T cells to B cells, CD8 + T cells, or CD4 + T cells, were linked to poorer OS (Supplementary Figure S3). These results highlight the pivotal prognostic role of the ratio of non-classical or intermediate monocytes to CD4 + or CD8 + T cells in LUAD, consistent with previous studies showing that non-classical or intermediate monocytes suppressed the proliferation and immune responses of CD8 + or CD4 + T cells [9,10].…”

Major alterations to monocyte and dendritic cell subsets lasting more than 6 months after hospitalization for COVID-19

“…For pDC and cDC subsets this aligns with gene and protein expression levels in hospitalized patients during acute disease ( 32 , 73 , 74 ). In contrast, an increase in PD-L1 expression has been seen in other studies on bulk monocytes ( 67 , 75 ), and circulating DC subsets ( 66 , 67 ). In our data this reduced expression of PD-L1 persisted for the entire duration of the study, as was seen also in a previous study at 7 months post-COVID-19 ( 32 ).…”