CD4 and pneumonia: B.1.1.7 variant infection could lead to a more serious inflammatory response, an acute response process, and more severe pneumonia, as indicated by the following results: in the B.1.1.7 variant cases, (i) there were more fevers over 38°C, (ii) CRP, SAA, CK, and DD were significantly higher, (iii) an abnormal proportion of CD4+ T was significantly more common, and (iv) ground-glass opacity in the lung was significantly more common.