In the joint detection of SARS-CoV-2 IgM and IgG, there was only one negative patient (male, 77 years old) who had respiratory failure, chronic obstructive pulmonary disease, coronary atherosclerosis, acute myocardial infarction, and heart failure with SARS-CoV-2 infection. The gene discussed is CD40LG; the disease is chronic obstructive pulmonary disease.