ENDOTOXIN CONTAMINATION CAUSES NEUTROPHILIA FOLLOWING PULMONARY ALLERGEN CHALLENGE

Segmental bronchoprovocation (SBP) with allergen was used in an attemp t to study eoinsophils recruited to the airway 24 h after challenge. U nexpectedly, in the first four patients, neutrophils(rather than eosin ophils) were recruited in the bronchoalveolar lavage (BAL) fluids, and we hypothesized that the allergen extracts were contaminated with end otoxin. The extracts used far challenge in the first four patients tes ted positive for bacterial endotoxin in a limulus amebocyte lysate ass ay. Rechallenge of one patient from the first group with a comparable dose of an endotoxin-free extract and SBP with endotoxin-free extract in five additional patients resulted in preferential recruitment of eo sinophils rather than neutrophils. The number of neutraphils recovered from the challenged segments in the patients challenged with endotoxi n-free extract was significantly less than that observed in the first four patients. Taken together, these observations suggest that neutrop hil recruitment in the 24-h BAL fluids from the first four patients wa s probably due to endotoxin contamination of the allergen extract. We caution investigators that endotoxin contamination of allergen extract may alter the cellular inflammation during the late airway response f ollowing allergen challenge.