Pleural Effusions from tuberculosis patients (TB-CFPE) induces Apoptosis of a subset of Natural Killer Cells (NK).

SCHIERLOH P; YOKOBORI N; ALEMÁN M; MUSELLA R; BEIGIER-BOMPADRE M; ABBATE E; DE LA BARRERA S; SASIAIN MC

Córdoba. Argentina.

Congreso; VII Latin American Congress of Immunology; 2005

Asociación Latinoamericana de Inmunología (ALAI)

We have previously demonstrated a notable reduction of CD56dimCD16+ NK subset in tuberculous pleural effusions (PE). The aim of the present study was to determine whether Mycobacterium tuberculosis (Mtb) or cell free pleural effusions (CFPE) were capable to induce apoptosis of NK cells. A total of 10 PE from patients with tuberculosis pleurisy (TB-CDPE) and 5 from non tuberculosis etiology (Non-Tb CFPE) (2 parapneumonia and 3 cancer) were studied. Peripheral mononuclear cells were incubated with Mtb and/or CFPE for 24-48 h and apoptosis was evaluated by determining Annexin V+ (AV+) on CD3-CD56+ cells. Apoptosis of NK cells was not induced by Mtb. TB-CFPE per se induced apoptosis with higher rates on CD56dimCD16+ cells (% AV+: Medium=9±2, TB-CFPE=46±11, p<0.005; non-Tb CFPE= 11±3, p>0.05). The apoptotic effect of TB-CFPE was dose dependent. Heated TB- CFPE (60oC, 30 min) reduced but not abolished the proapoptotic effect (Medium= 8±2, TB-CFPE=44±11, Heated TB- CFPE= 27±10, p<0,05). These results suggest that the enrichment of CD56bright cells is due to a selective apoptosis of CD56dimCD16+cells mediated by heat stable soluble factors present in tuberculous but not in non-TB effusions.