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

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

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.

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.

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.

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.