Phenotypes of lung mononuclear phagocytes in HIV seronegative tuberculosis patients: evidence for new recruitment and cell activation

Abstract

tuberculosis negative patients who had BAL samples taken during this time (n = 9) or normal healthy volunteers (n = 3) served as control group. Compared to the control group, the tuberculosis group had significantly higher proportion of cells expressing markers of young monocytes (UCHM1) and RFD7, a marker for phagocytic cells, and increased expression of HLA-DR, a marker of cell activation. In addition, tuberculosis group had significantly higher proportion of cells expressing dendritic cell marker (RFD1) and epithelioid cell marker (RFD9). These data suggest that despite recruitment of monocytes probably from the peripheral blood and local cell activation, host defense of the resident lung cells is insufficient to control M. tuberculosis.

Infection of Monocytes From Tuberculosis Patients With Two Virulent Clinical Isolates of Mycobacterium tuberculosis Induces Alterations in Myeloid Effector Functions

“…Another alteration observed in monocytes of our patients with TB was the negative regulation of genes encoding MHC II molecules such as CD74, HLA-DPA1, HLA-DRB3, and HLA-DRB4, which were grouped in the functional category "Antigen processing and presentation" (Figure 1A). The reduced expression of HLA-DR on monocytes has been associated with the severity of infectious diseases since HLA-DR directly influences cell activation and increases the efficiency of antigen presentation to T lymphocytes (Lapa e Silva et al, 1996;Ditschkowski et al, 1999). Our group had previously reported that patients with TB have a higher proportion of inflammatory circulating monocytes (Castaño et al, 2011b), and they express lower amounts of surface HLA-DR (Sanchez et al, 2006).…”