• Lower levels of CD3+ T cells, CD4+ T cells, CD8+ T, NK cells as well as B cells were found in COVID-19 patients. Treated patients who exhibited clearance of virus showed restoration in levels of CD3+ T cells, CD4+ T cells, CD8+ T cells, whereas NK cell count was inconsistent.• Lymphocytopenia was considered as predicative biomarker for the disease. The gene discussed is CD8A; the disease is COVID-19.