Circulating haematopoietic stem cells and long‐term outcomes of COVID‐19

Abstract

AbstractBackground and AimsAn acute depletion of circulating haematopoietic stem/progenitor cells (HSPCs) occurs during COVID‐19, especially among patients with a poorer disease course. We herein examined whether HSPCs levels at hospital admission for COVID‐19 predict 1‐year mortality and the long‐COVID syndrome.Materials and MethodsPatients hospitalized for COVID‐19 in an infectious disease ward were consecutively enrolled. Circulating HSPC levels were assessed by flow cytometry as cells expressing CD34 and/or CD133. Follow‐up was performed for 12 months after hospitalization through the review of electronic medical records and demographic local registers.ResultsThe study included 100 patients, 36 of whom reported symptoms of long‐COVID and 20 died during follow‐up. The reduction of 1‐SD of HSPCs was associated with a 3‐ to 5‐fold increase in the risk of 1‐year mortality. Age, admission hyperglycaemia, C‐reactive protein peak, liver enzymes, the need of high‐flow oxygen and/or invasive ventilation were predictors of mortality at univariate analysis. Among pre‐existing comorbidities, coronary heart disease and chronic kidney disease, but not diabetes, were associated with 1‐year mortality. In multivariate analyses, HSPCs remained significantly associated with 1‐year mortality independently of confounders. The development of pneumonia an in‐hospital treatment with glucocorticoids and convalescent plasma were associated with long‐COVID symptoms at follow‐up. HSPCs, diabetes and other comorbidities were not predictors of long‐COVID.ConclusionsIn a cohort of patients hospitalized for COVID‐19, lower HSPC levels at the time of admission were independent predictors of 1‐year mortality. However, COVID‐19 severity, but not HSPC level, was significantly associated with the development of long‐COVID symptoms.