The results showed that the elevation in levels of serum IL-10 and TLR-4 could be a potential diagnostic marker for lymphopenia in COVID-19 patients with (AUC = 0.66 ± 0.08; P value = 0.05) for IL-10 and (AUC = 0.73 ± 0.07; P value = 0.006) for TLR-4 (Fig. 4a and 4b). Here, TLR4 is linked to lymphopenia.