Clinical significance of cellular immunity function and inflammatory factors assays in alveolar lavage fluid for severe COVID-19 pneumonia

Abstract

In this study, we aimed to investigate the changes of lymphocyte subsets (CD3⁺ , CD4⁺ , CD8⁺ ) and inflammatory factors (interleukin-6 [IL-6], hypersensitive C-reactive protein [HS-CRP], and procalcitonin [PCT]) of alveolar lavage fluid in patients with severe corona virus-2019 (COVID-19) pneumonia and their clinical impact on the assessment of disease severity and prognosis. Twenty-four patients with severe COVID-19 pneumonia were admitted to the intensive care unit (ICU) of the Ezhou Central Hospital from February 1 to March 22, 2020. According to the 28-day prognosis, they were assigned to a death group and a survival group. On the 3rd day of ICU admission, peripheral blood and alveolar lavage fluid were collected for examination of lymphocyte subsets and inflammatory factors by flow cytometry and immunoturbidimetry, respectively. The CD3⁺ , CD4⁺ , and CD8⁺ cell counts in alveolar lavage fluid and serum were significantly higher in the survival group than those of the death group (p < .05). The levels of IL-6, HS-CRP, and PCT in the alveolar lavage fluid and serum of the death group were statistically higher than those of the survival group (p < .05); The CD3⁺ , CD4⁺ cell count, and IL-6 level were negatively correlated with Sequential Organ Failure Assessment (SOFA) and Acute Physiology and Chronic Health Evaluation II scores, respectively (p < .05). The CD4⁺ cell and SOFA score have a regression relationship for the prognosis of COVID-19 severe patients. The CD3⁺ , CD4⁺ , CD8⁺ cells, and IL-6 levels are valuable in determining the prognosis of severe COVID-19 pneumonia and are strongly correlated with the severity of the disease; the CD4⁺ cell is an independent risk factor affecting the prognosis of COVID-19 pneumonia.

Keywords: COVID-19; alveolar lavage fluid; cellular immunity; inflammatory factors.

Figure 1

Lymphocyte subsets (CD3⁺, CD4⁺, CD8⁺ cells) and inflammatory factors (IL‐6, HS‐CRP, PCT) in alveolar lavage fluid and serum between survival group and death group on COVID‐19 patients. Data are expressed as mean ± SD and were compared with the t test. COVID‐19, coronavirus disease 2019; HS‐CRP, hypersensitive c‐reactive protein; IL‐6, interleukin‐6; PCT, procalcitonin. *p < .05, **p < .01,***p < .001

Figure 2

ROC curve of prognostic factors in patients with severe COVID‐19 pneumonia.COVID‐19, coronavirus disease 2019; ROC, receiver operating curve; SOFA, Sequential Organ Failure Assessment