Inhalation challenge testing of latex-sensitive health care workers and the effectiveness of laminar flow HEPA-filtered helmets in reducing rhinoconjunctival and asthmatic reactions
N. Laoprasert et al., Inhalation challenge testing of latex-sensitive health care workers and the effectiveness of laminar flow HEPA-filtered helmets in reducing rhinoconjunctival and asthmatic reactions, J ALLERG CL, 102(6), 1998, pp. 998-1004
Background: There are few data relating latex aeroallergen concentrations t
o biologic responses in latex-sensitized persons.
Objectives: We sought to investigate acceptable latex aeroallergen concentr
ations below which latex-sensitive health care workers do not experience sy
mptoms and to study the effect of high-efficiency particle arrest (HEPA)-fi
ltered laminar flow helmets in preventing latex-induced symptoms.
Methods: Under challenge chamber conditions, latex-sensitive health care wo
rkers underwent 7 sequential inhalation challenge tests by donning and disc
arding either vinyl gloves (challenge 1), low latex-allergen powder-free gl
oves (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 chal
lenges; HEPA biters in the helmet were in place only during challenges 3 an
d 4. Flow-volume loops, symptom scores, and latex aeroallergen concentratio
ns were measured before and during each test.
Results: At 60 minutes, latex aeroallergen concentrations during challenges
3 to 7 (mean, 7600 ng/m(3); range, 93 to 54,000 ng/m3) were significantly
higher than during challenges 1 or 2 (mean, 65 ng/m(3); range, nondetectabl
e to 100 ng/m(3)) (P < .001). During challenges 5 and 6, mean maximum perce
nt falls in FEV1 (-16% and -11%, respectively) were significantly greater c
ompared with those measured during challenges 3 and 4 (-3% and -1%, respect
ively) (P = .03). Mean maximum change from baseline symptom scores during c
hallenges 5 and 6 was significantly higher than that during challenges 3 an
d 4 (P = .006), During challenges with high latex-allergen gloves, 4 volunt
eers had reproducible FEV1 falls of 20% or greater at cumulative inhaled la
tex aeroallergen doses ranging from less than 100 ng to 1500 ng.
Conclusion: The laminar flow helmets were effective in reducing latex-induc
ed symptoms. Only 1 volunteer exhibited a fall in FEV1 of 20% or greater af
ter a cumulative inhaled latex aeroallergen dose of less than 100 ng, and n
o volunteer showed a decline in FEV1 after exposure to powder-free low alle
rgen gloves.