Am. J. Respir. Crit. Care Med., Vol 149, No. 3, Mar 1994, 660-666.
Nasal allergen challenge generates 1-0-hexadecyl-2-lyso-sn-glycero-3- phosphocholine
MH Shin, FJ Averill, WC Hubbard, FH Chilton, FM Baroody, MC Liu and RM Naclerio
Department of Medicine, (Division of Allergy and Clinical Immunology and Pulmonary and Critical Care Medicine), Johns Hopkins University School of Medicine, Baltimore, Maryland.
We studied antigen-induced platelet activating factor and the 1-0-
hexadecyl-2-lyso-sn-glycero-3-phosphocholine (lyso-PAF) in nasal lavage
fluids (NLF) by combined gas chromatography/mass spectrometric analysis
(GC/MS). During the early allergic reaction, there was a dramatic increase
in the levels of lyso-PAF that peaked at 15 min (2.6 +/- 5.2 ng/ml, mean
+/- SEM, n = 6). Increasing doses of antigen produced a dose-dependent
increase in the levels of lyso-PAF that peaked at the highest dose. Levels
of lyso-PAF correlated strongly with those of N- alpha-tosyl-L-arginine
methyl ester (TAME)-esterase activity (rs = 0.82, p = 0.0001) and histamine
(rs = 0.57, p = 0.002). There was a no significant increase in the quantity
of lyso-PAF found in NLF from allergic individuals challenged with diluent
or nonallergic individuals challenged with antigen. In subjects showing a
late phase reaction, as indicated by symptoms and histamine release, we
detected lyso-PAF along with TAME-esterase activity and histamine during
the late phase reaction. In contrast to lyso-PAF, PAF levels were near or
below the detection limit of the assay in NLF and remained unchanged after
antigen challenge. We also investigated the potential pathways for lyso-
PAF generation from 2-acetylated phospholipids. We found that the time
required for deacetylation of 50% of [3H]PAF (t1/2) to lyso-PAF was 50 min
in baseline secretions and 10 and 22 min in NLF obtained 10 min and 24 h
after antigen challenge, respectively. These data suggested that catabolic
pathways were present in NLF.(ABSTRACT TRUNCATED AT 250 WORDS)
