Correlation of serum interleukin-2 receptor-α levels with clinical manifestations in pulmonary tuberculosis

Setting: The analysis of serum levels of soluble interleukin-2 receptor alpha (sIL-2R-α) is an indirect method of studying the in vivo state of immune activation, particularly in patients with pulmonary tuberculosis (PTB) where the disease is associated with cellular immune reactions. Objective: To quantitate the serum sIL-2R-α in patients and correlate with disease activity. Design: The levels of sIL-2R-α were determined using ELISA in serum samples from untreated patients with PTB ( n = 107), 30 of whom were later tested during treatment, household family contacts ( n = 38), and healthy controls ( n = 22). Results: Concentrations of sIL-2R-α were significantly higher in PTB patients than in controls (2845 ± 187 vs 1217 ± 80 pg/mL, P < 0.0001), and were even more pronounced in the sputum positive (3200 ± 148 pg/mL) and treatment failure (3335 ± 196 pg/mL) groups of patients. However, in household family contacts, the sIL-2R-α levels were found to be similar to those of healthy controls. The sIL-2R-α levels correlated positively with disease activity as assessed by roentgenographic findings. In six of the 16 responder patients, the sIL-2R-α levels fell from 3228 ± 144 pg/mL to 1497 ± 131 pg/mL ( P < 0.0001) after 3 months of successful treatment with anti-tuberculosis drugs. However, no significant change was observed in the treatment failure patients even after one year of chemotherapy with second-line drugs. Conclusion: These studies indicate that determination of serum concentrations of sIL-2R-α is a sensitive and specific method for monitoring disease activity in terms of T cell activation in pulmonary tuberculosis. Cadre: L'analyse des niveaux sériques des récepteurs alpha pour l'interleukine-2 soluble est une méthode indirecte permettant d'étudier l'état d'activation immunitaire in vivo, particulièrement chez les patients atteints de tuberculose pulmonaire, oà la maladie est associée à des réponses immunes de caractère cellulaire. Objectif: Quantifier la sIL-2R-α sérique chez les patients et la corréler avec l'activité de la maladie. Schéma: Les taux de sIL-2R-α ont été déterminés par la méthode ELISA dans des échantillons sériques provenant de patients non encore traités, atteints de tuberculose pulmonaire ( n = 107), dont 30 ont été testés ultérieurement en cours de traitement, de sujets-contact à domicile ( n = 38) et de contrôles sains ( n = 22). Résultats: Les concentrations de sIL-2R-α étaient significativement plus élévees chez les patients at