Role of adaptive immunity in clinical variability of active tuberculosis patients

<b>Background:</b> Current literature states that patients affected by active tuberculosis (TB) have a lower T-helper CD4+ cells. Information about other subpopulations of lymphocytesis few and contrasting. <b>Aims and objectives:</b> Our aim was to evaluate the immunological status of patients with pulmonary TB and to assess its possible association with radiological pattern (productive or exudative forms), lesion locations (typical or atypical) and ethnicity. <b>Methods:</b> This study included 48 TB patients and 47 control patients affected by other respiratory diseases. Flow cytometry was performed in all the enrolled subjected. TB patients also underwent to computed tomography (CT) scan. <b>Results:</b> TB patients showed a decrease in all the lymphocyte subpopulations compared to controls (p&lt;0.0001). TB patients with exudative/atypical patterns were more immunocompromised than those with typical/productive patterns showing a reduction in CD4+ and CD8+ T-lymphocytes (829.97±281.17 vs 427.68±210.70 and 459.14±273.25 vs 238.04±119.64, respectively; p&lt;0.0001), B-lymphocytes (206.17±132.00 vs 69.22±39.41; p&lt;0.0001) and NK-cells (283.47±189.51 vs 143.82±111.56; p&lt;0.005). Africans, despite younger, showed a significant reduction in CD4+ T-lymphocytes (751.48±336.14 vs 526.31±249.49; p=0-02) and a higher prevalence of atypical/exudative forms compared with Europeans. <b>Conclusions:</b> Adaptive immunity has a key role in determining different manifestations of active TB. The greater CD4+ T-lymphocytes impairment and prevalence of exudative/atypical forms in African TB patients may be linked to genetic or to their hygienic-sanitary indigence. Anyhow, tuberculosis itself may represent an additional factor depressing the immune system.