CD4 and tuberculosis: 1) A single large study found less pulmonary impairment after TB in patients who were HIV-positive [4], while other studies have not supported this beneficial association between HIV status and spirometric outcomes [5, 10, 11]; 2) furthermore, chest radiography findings in patients with HIV-associated TB and low CD4 counts (CD4 <200 cells·μL−1) are frequently normal or atypical [12]; and 3) HIV co-infection results in lower levels of several of mediators usually implicated in inflammatory lung damage [13].