An association between immune status and chest CT scores in COVID-19 patients

Abstract

Background: The characteristic features of the immune responses of COVID-19 patients and how they reflect lung involvement have not been clearly elucidated.

Aim: The aim of this study was to examine the immune status and the correlations thereof with chest CT scores and lung involvement of patients with COVID-19.

Methods: In this retrospective and single-center study, 72 patients with laboratory-confirmed COVID-19 were recruited. The counts of peripheral lymphocyte subsets (CD3⁺ T cells, CD4⁺ T cells, CD8⁺ T cells, CD19⁺ B cells and CD16⁺ 56⁺ NK cells) and those of serum immunoglobulins (IgA, IgG, IgM) were measured and their associations with chest CT scores analysed.

Results: The proportions of lymphopenia in patients with extensive lung involvement were twice that in the general study population. In the severe disease group, the levels of total lymphocytes, T cells, B cells, NK cells; and serum IgA levels, were significantly lower than in the mild disease group (all P < .05). We found that the numbers of lymphocyte subsets and the IgA level negatively correlated with the chest CT scores. On multivariate regression analysis, pretreatment decreases in total lymphocytes, CD3⁺ T cells, CD4⁺ T cells, and CD19⁺ B cells, and serum IgA levels, were independent predictors of severe lung involvement.

Conclusions: The cell numbers of peripheral lymphocyte subsets and the serum IgA level were negatively correlated with the chest CT scores in COVID-19 patients. These parameters tended to independently predict severe lung involvement in such patients.