CD40LG and COVID-19: Recovered COVID-19 patients who had a higher titer of IgG and IgM in their isolation period after discharge had a higher risk of RP (OR 1.068, 95% CI: 1.034–1.102, p = 0.000; OR 1.055, 95% CI: 1.006–1.105, p = 0.026, respectively).