Mean hematological test results on the day of COVID-19 diagnosis were: white blood cell count, 4.8×109/L (IQR, 4.0–6.0×g/L); neutrophil count, 2.9×109/L (2.0–3.9×109/L); hemoglobin, 137×g/L (126–147×g/L); lymphocyte count, 1.5×109/L (1.1–1.9×109/L); platelet count, 182×109/L (141–213×109/L); C-reactive protein, 6.6×mg/L (2.8–14.7×mg/L); erythrocyte sedimentation rate, 24 mm/h (11–47 mm/h); D-dimer, 0.20×mg/ml (0.12–1.78×mg/ml); creatine kinase, 60.1×U/L (44.8–101.0×U/L); CD4+ T-cell count, 447×cells/μl (342–648×cells/μl); and CD8+ T-cell count, 336×cells/μl (254–465×cells/μl). Here, CD4 is linked to COVID-19.