[Comparative study of soluble interleukin 2 receptor and adenosine deaminase levels in tuberculous and other etiologies pleural fluids]. / Estudio comparativo de los niveles de receptor soluble de interleucina 2 y adenosín-desaminasa en líquidos pleurales tuberculosos y de otras etiologías.

In order to better understand the immunological mechanisms involved in host protection against Mycobacterium tuberculosis infection, we studied soluble interleukin 2 receptor (sIL-2R) concentration in tuberculous pleural exudates as well as in pleural fluids of non-mycobacterial etiology. We collected pleural fluid from 40 patients: 10 with tuberculous bacterial pneumonia and 10 with trasudate. Soluble IL-2R was measured in the stored specimens using a standard ELISA technique. In patients with tuberculosis, sIL-2R in pleural fluid was 14,666 +/- 5,634 U/ml, significantly higher than was detected in any other group, being 4,341 +/- 2,655 U/ml in pneumonic exudates, 5,542 +/- 3,682 U/ml in neoplastic exudates and 1,377 +/- 125 in trasudates (p < 0.001). Also, an excellent correlation was demonstrated between adenosine-desaminase (ADA) and sIL-2R in tuberculous pleural fluids, with p < 0.001 and r = 0.805. In pleuropulmonary tuberculosis, compartmentalization of the immune response in the pleural space is responsible for the significantly higher levels of sIL-2R that were found in tuberculous pleural liquids compared with the ones detected in other diseases. This observation, as well as the demonstration of a good correlation between sIL-2R and ADA, suggest the possible usefulness of this molecule as an additional marker in the differential diagnosis of pleural effusions, though in the present study it appears to be less reliable than ADA.

Serum soluble interleukin-2 receptor: a useful indicator of the clinical course in pulmonary tuberculosis.

SETTING: In tuberculosis both host protection and most pathogenic mechanisms depend on T lymphocytes. After activation by mycobacterial antigens, T cells both secrete interleukin-2 (IL-2) and express a high affinity receptor for this molecule (IL-2R) on their own surface. A soluble fraction of IL-2 receptor (sIL-2R), released from cell membrane, is detectable in serum and its concentration is known to be elevated in tuberculosis. OBJECTIVE: To ascertain the role of sIL-2R as an indicator of clinical evolution and response to antituberculosis treatment. DESIGN: A prospective study, in which we have measured serum sIL-2R in 52 patients (42 with active and 10 with inactive pulmonary tuberculosis) and in 36 healthy controls. In 20 patients, serum sIL-2R levels were measured serially throughout the treatment. Levels of sIL-2R were correlated to clinical and radiological parameters. RESULTS: Serum sIL-2R was significantly increased in patients with tuberculosis as compared to healthy subjects. Both the radiological findings and the clinical state of patients showed a good correlation with sIL-2R. All patients with normal values of sIL-2R 6 months after starting therapy had a favourable clinical evolution. CONCLUSION: Serum sIL-2R is a useful marker of the clinical state and evolution of patients with pulmonary tuberculosis. The detection of permanently high values beyond 3-6 months of treatment suggests that additional drugs or prolonged administration would be advisable in order to ensure full recovery.