Changes of hematological and immunological parameters in COVID-19 patients

The aim of this study was to identify the changes of hematologic and immunological parameters in COVID-19 patients. We collected and analyzed the data of 117 patients who were laboratory confirmed as SARS-CoV-2 infection. The cases were divided into regular group, severe group and critically ill group according to the sixth edition scheme for COVID-19 diagnosis and treatment of China. The laboratory tests included blood routine, cellular and humoral immunity indices, biochemical detections and inflammatory biomarker. Compared with regular patients, severe and critically ill patients had significantly lower lymphocyte count (p < 0.01), decreased red blood cell and hemoglobin (p < 0.01), low levels of immunoglobulin G (p < 0.05) and significantly higher in D-dimer (p < 0.0001), fibrinogen (p < 0.01), white blood cell count (p < 0.01), neutrophil count (p < 0.0001), interleukin-6 (p < 0.05), C-reactive protein (p < 0.01), procalcitonin (p < 0.01), erythrocyte sedimentation rate (p < 0.05), ferritin (p < 0.01) and lactate dehydrogenase (p < 0.0001). The specific immunoglobulin G antibodies to the SARS-CoV-2 in severe and critically ill patients were significantly lower than that in regular patients (p < 0.05). Our findings suggest that the lymphocyte counts, red blood cell counts and the immunoglobulin G antibodies of COVID-19 patients were impaired to varying degrees and the blood was in a state of hypercoagulation, which were more obvious in critically ill patients.