CD4 and COVID-19: In contrast, in convalescent COVID-19 patients, LPS treatment led to a statistically significant increase in the percentage of classical monocytes expressing bright (T-cell intensity) CD4 and CD83, a decrease in the percentage of classical monocytes expressing CD86, and no change in the percentage of classical monocytes expressing CD56 or CD69 from convalescent COVID-19 patients in response to LPS (Figure 4).