CD4 and non-small cell lung carcinoma: In NSCLC patients, the percentage of CD3+PD-L1+, CD3+PD-L2+, CD3+CD4+PD-L1+ and CD3+CD4+PD-L2+ cells negatively correlated with the levels of IL-2 (P=0.019, P=0.044, P=0.009 and P=0.036; respectively).