Plasma platelet-activating factor acetylhydrolase deficiency in Japanese patients with asthma.
Platelet-activating factor (PAF), a phospholipid with a wide range of proinflammatory actions, is immediately degraded and inactivated in vivo by PAF acetylhydrolase (PAF-AH). Surprisingly, 4% of the Japanese population lacks the extracellular isoform of this enzyme, plasma PAF-AH, due to a genetic missense (V279F) mutation. We studied the association of this mutation with asthma prevalence and phenotypes in the Japanese adult population. The allele frequency of V279F mutation was 18.6% in 279 patients with asthma (28.7% heterozygotes and 4.3% homozygotes) and 21.7% in 217 healthy subjects (32.3% heterozygotes and 5.5% homozygotes). V279F mutant allele prevalence was consistent regardless of asthma type (16.3% in atopic [n = 156] and 21.6% in nonatopic [n = 123]), or the severity of disease (21.7% in patients with mild [n = 97], 17.5% in those with moderate [n = 131], and 15.8% in those with severe [n = 51] asthma). Plasma PAF-AH activity was inversely proportional to the number of mutant alleles, and did not correlate with asthma prevalence, type, or severity. We concluded that plasma PAF-AH deficiency due to V279F mutation is not essential to the pathophysiology of asthma in the Japanese adult population.
Cardiopulmonary Division, Department of Medicine, Keio University School of Medicine, Tokyo, Japan.
N
N
Satoh
K
K
Asano
K
K
Naoki
K
K
Fukunaga
M
M
Iwata
M
M
Kanazawa
K
K
Yamaguchi
D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000483:Alleles; D001249:Asthma / Q000201:enzymology / Q000235:genetics*; D005260:Female; D005838:Genotype; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D020125:Mutation, Missense; D010641:Phenotype; D010741:Phospholipases A / Q000097:blood / Q000172:deficiency* / Q000235:genetics; D010972:Platelet Activating Factor / Q000378:metabolism
D010972:Platelet Activating Factor; D010741:Phospholipases A; D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase