Determination of N-methylhistamine in urine as an indicator of histamine release in immediate allergic reactions.
The use of the urine histamine metabolite, N-methylhistamine (N-MH), as a parameter of histamine release in immediate allergic reactions was investigated. Baseline levels were determined in 34 normal control subjects and 29 atopic patients. Increases of urine N-MH values were measured during histamine infusions and in venom-allergic patients receiving bee-sting challenges. N-MH was determined by a newly developed radioimmunoassay. Baseline levels in control subjects and atopic patients demonstrated no significant differences. With regard to challenge tests, fluctuation of N-MH levels during a 6-hour period was measured. Random 6-hour increases in healthy and atopic subjects ranged from 5% to 41%. Before infusion of histamine (0.25 micrograms/kg/min for 30 minutes), baseline values were 137 +/- 11.4 micrograms N-MH per gram of creatinine and 9 +/- 1.1 micrograms N-MH per hour (n = 9). Levels peaked 1 hour after infusion at 275 +/- 45 micrograms/gm of creatinine and 44 +/- 5.6 micrograms/hr and decreased to resting levels after 2 hours. Metabolization by N-MH accounted for 9.5% +/- 4.9% (range, 2.4% to 18.4%) of infused histamine in the urine of the nine subjects. Bee-sting challenges were performed in 12 patients and three control subjects. Only in three patients experiencing generalized urticaria, nausea, dyspnea, and hypotension were significant increases of urine N-MH levels (138%, 144%, and 238%) observed. All other patients and three normal control subjects demonstrated normal local reactions without increase of N-MH values.(ABSTRACT TRUNCATED AT 250 WORDS)
University Children's Hospital, Freiburg, West Germany.
V
V
Stephan
A
A
Zimmermann
J
J
Kühr
R
R
Urbanek
D000293:Adolescent; D000328:Adult; D002648:Child; D005260:Female; D006632:Histamine / Q000494:pharmacology; D006636:Histamine Release; D006801:Humans; D006967:Hypersensitivity / Q000378:metabolism / Q000652:urine; D006969:Hypersensitivity, Immediate / Q000378:metabolism* / Q000652:urine; D007299:Insect Bites and Stings / Q000652:urine; D008297:Male; D008761:Methylhistamines / Q000652:urine*; D008875:Middle Aged; D012016:Reference Values; D013997:Time Factors
D008761:Methylhistamines; D006632:Histamine; C048140:N-methylhistamine