title: Inhalation challenge testing of latex-sensitive health care workers and the effectiveness of laminar flow HEPA-filtered helmets in reducing rhinoconjunctival and asthmatic reactions.
abstract: BACKGROUND
  There are few data relating latex aeroallergen concentrations to biologic responses in latex-sensitized persons.
  
  
  OBJECTIVE
  We sought to investigate acceptable latex aeroallergen concentrations below which latex-sensitive health care workers do not experience symptoms and to study the effect of high-efficiency particle arrest (HEPA)-filtered laminar flow helmets in preventing latex-induced symptoms.
  
  
  METHODS
  Under challenge chamber conditions, latex-sensitive health care workers underwent 7 sequential inhalation challenge tests by donning and discarding either vinyl gloves (challenge 1), low latex-allergen powder-free gloves (challenge 2), or high latex-allergen powdered gloves (challenges 3 to 7) for up to 1 hour. Volunteers wore a laminar flow helmet during all challenges; HEPA filters in the helmet were in place only during challenges 3 and 4. Flow-volume loops, symptom scores, and latex aeroallergen concentrations were measured before and during each test.
  
  
  RESULTS
  At 60 minutes, latex aeroallergen concentrations during challenges 3 to 7 (mean, 7600 ng/m3; range, 93 to 54,000 ng/m3 ) were significantly higher than during challenges 1 or 2 (mean, 65 ng/m3; range, nondetectable to 100 ng/m3 ) (P <.001). During challenges 5 and 6, mean maximum percent falls in FEV1 (-16% and -11%, respectively) were significantly greater compared with those measured during challenges 3 and 4 (-3% and -1%, respectively) (P =.03). Mean maximum change from baseline symptom scores during challenges 5 and 6 was significantly higher than that during challenges 3 and 4 (P =.006). During challenges with high latex-allergen gloves, 4 volunteers had reproducible FEV1 falls of 20% or greater at cumulative inhaled latex aeroallergen doses ranging from less than 100 ng to 1500 ng.
  
  
  CONCLUSIONS
  The laminar flow helmets were effective in reducing latex-induced symptoms. Only 1 volunteer exhibited a fall in FEV1 of 20% or greater after a cumulative inhaled latex aeroallergen dose of less than 100 ng, and no volunteer showed a decline in FEV1 after exposure to powder-free low allergen gloves.
authors.affiliation: Mayo Graduate School of Medicine, Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: N
authors.initials: N
authors.lastname: Laoprasert
authors.forename: M C
authors.initials: MC
authors.lastname: Swanson
authors.forename: R T
authors.initials: RT
authors.lastname: Jones
authors.forename: D R
authors.initials: DR
authors.lastname: Schroeder
authors.forename: J W
authors.initials: JW
authors.lastname: Yunginger
mesh_terms: D000328:Adult; D000395:Air Pollutants, Occupational / Q000009:adverse effects; D000485:Allergens / Q000009:adverse effects; D001985:Bronchial Provocation Tests / Q000009:adverse effects / Q000379:methods*; D004731:Endotoxins / Q000378:metabolism; D004780:Environment, Controlled; D005260:Female; D005374:Filtration / Q000295:instrumentation; D006260:Head Protective Devices; D006282:Health Personnel; D006801:Humans; D020315:Latex Hypersensitivity / Q000175:diagnosis* / Q000517:prevention & control*; D008875:Middle Aged; D010865:Pilot Projects; D011446:Prospective Studies; D016037:Single-Blind Method
chemical_list: D000395:Air Pollutants, Occupational; D000485:Allergens; D004731:Endotoxins