Aims: In patients with active pulmonary tuberculosis (pTB) with negative acid-fast-bacilli
(AFB)-smear results for sputum and bronchial secretions the clinical diagnosis of
tuberculosis is often delayed. In an exploratory study (Jafari et al. AJRCCM 2006)
with 37 patients we found that ELISPOT performed on mononuclear cells from the bronchoalveolar-lavage
(BAL) allows a rapid diagnosis of tuberculosis in these cases. We here present a follow
up of 72 prospectively recruited cases with a presumptive diagnosis of smear-negative
pTB.
Methods: Patients presenting to a tertiary hospital with a medical history and a pulmonary
infiltrate compatible with tuberculosis and 3 negative AFB-smear results from the
sputum were prospectively enrolled in this study. A MTB-specific ELISPOT (T-SPOT.TB) with ESAT-6 and CFP-10 peptides was performed on peripheral blood mononuclear cells
(PBMCs) and mononuclear cells from the BAL (BALMCs).
Results: Among 20 patients with pTB one patient had a negative ELISPOT test result from the
BAL. Among 52 patients with an alternative diagnosis, 4 had a positive ELISPOT test
result from the BAL. Sensitivity and specificity of the MTB-specific ELISPOT performed
on BALMCs was 95 percent and 92.3 percent, respectively.
Conclusions: Smear negative pulmonary tuberculosis can rapidly be diagnosed by identification
of MTB-specific cells in the BAL.
