Although several mechanisms such as HAART, repeated lung infections, chronic pulmonary inflammation and/or immunosuppression have been reported to promote the development of lung cancer9,10, in this study, we found that most patients did not have a low CD4+ cell count, with a median CD4+ count at lung cancer diagnosis of 281/ml; there were 14 patients with CD4+ count <200/mL and 41 patients with CD4+ count >200/mL. Here, CD4 is linked to lung carcinoma.