Objectives: BAL, an important tool in assessing
occupational lung diseases, is unsuitable for screening programs,
exposure evaluation, or monitoring hazardous dust because it is an
invasive technique. The results of induced sputum (IS) analysis were
compared with BAL and evaluated as a possible alternative.
Methods: We compared BAL with IS analysis of 5 workers
exposed to asbestos and 14 exposed to silica and hard metals. Pulmonary
function tests and BAL were performed by conventional methods. IS
induction was performed after a 20-min inhalation of 3.5% saline
solution with an ultrasonic nebulizer. Giemsa-stained cytopreparations
were differentially counted. T-lymphocyte subsets were analyzed by
flow-activated cell sorter, and messenger RNA (mRNA) was transcribed by
reverse transcriptase-polymerase chain reaction. Mineralogic particles
were analyzed by scanning electron microscopy and polarizing light
microscopy and quantified by an analyzer.
Results: The percentage of neutrophils was
significantly lower in BAL fluid than in IS specimens, whereas
no differences were found in the percentage of lymphocytes and subsets
profile. Asbestos fibers were found in BAL but not in IS samples from
workers exposed to asbestos. Polarizing particles were found in
both samples. Similar mineral elements were found in qualitative
analysis by scanning electron microscopy. Quantitative studies showed
similar size distribution with a small shift toward larger particles in
sputum; mRNA showed the same cytokine profile.
Conclusions: A comparison of BAL and IS specimens in the
evaluation of the study population yielded similar quantitative and
qualitative results. Further research is needed to evaluate the
hypothesis that IS, being a noninvasive technique, may be useful in
monitoring exposed workers.