Defective Mycobacterium tuberculosis antigen presentation by monocytes from tuberculosis patients

OBJECTIVE: To determine whether there were any defects in the presentation of the Mycobacterium tuberculosis antigen by monocytes from patients with tuberculosis (TB) and the role of vitamin D in the defence against M. tuberculosis. DESIGN: A prospective study aimed at analysing the presentation of the M. tuberculosis antigen by monocytes and the response to vitamin D treatment in three groups of participants: 1) those with active TB, 2) those with healed TB and 3) those with frequent TB contact. RESULTS: The antigen presentation ability of monocytes of persons in the frequent contact group was significantly higher than that of the active TB and healed TB groups. There was no difference between patients with active and healed TB. In addition, 1,25(OH)(2)D-3 increased the presentation of mycobacterial antigens by monocytes from participants with frequent TB contact, but not those with active or healed TB. CONCLUSION: Patients with active and healed TB exhibit defective M. tuberculosis presentation in monocytes. The administration of vitamin D did not correct this defect in monocytes from participants with active or healed TB, but could increase antigen presentation by monocytes in participants with frequent TB contact.