PULMONARY RESPONSES AFTER WOOD CHIP MULCH EXPOSURE

Organic Dust Toxic Syndrome (ODTS) is a flu-like syndrome that can occ ur after inhalation of cotton, grain, wood chip dusts, or other organi c dusts or aerosols. We investigated whether inflammatory pulmonary re sponses occur, even after relatively brief, low-level wood chip mulch exposure. Six volunteers were exposed to wood chip mulch dust. Total d ust and/or endotoxin levels were measured in five subjects. Pulmonary function and peripheral blood counts were measured before and after ex posure in each subject. Bronchoalveolar lavage (BAL) was performed in each subject after exposure, and cell, cytokine, and protein concentra tions were measured. Control BAL without previous exposure was also pe rformed on three of the subjects. Three of six subjects had symptoms c onsistent with ODTS. No clinically relevant or statistically significa nt changes in pulmonary function tests after exposure were found. Thre e subjects manifested a marked elevation in neutrophil percentage in t heir BAL (range, 10 to 57%). When these three subjects underwent contr ol BAL, the postexposure comparison demonstrated an increase in neutro phil levels of 154 +/- 89 x 10(3)/mL (mean +/- standard err or; P = 0. 22). The mean increase in BAL interleukin-8 levels after exposure, com pared with paired control values, was 11.2 +/- SE 2.5 pg/mL (P = 0.047 ). There was also an increase in BAL interleukin-G levels that reached borderline significance (6.4 +/- SE 2.0 pg/mL; P = 0.08). Tumor necro sis factor levels were increased in all three subjects' BAL as well (0 .4 +/- SE 0.2 pg/mL), but this change was not statistically significan t (P = 0.2). Our findings of increased BAL proinflammatory cytokine an d neutrophil levels are consistent with the theory that cytokine netwo rking in the lung may mediate ODTS.