Mechanisms of severe, immediate reactions to iodinated contrast material.
OBJECTIVE
To measure and elucidate the mechanisms of presumed mediators of unexpected severe, immediate reactions to iodinated contrast materials.


METHODS
In a multicenter study, 20 patients with mild to severe reactions to iodinated contrast material and 20 control subjects without reactions were evaluated. Ionic contrast material was associated with 18 (90%) of 20 reactions. Concentrations of plasma histamine, tryptase, urinary methylhistamine, specific immunoglobulin E (IgE) against ioxitalamate or ioxaglate, and the anaphylatoxins C3a and C4a were measured with radioimmunoassays; complement C3 and C4 levels were measured with nephelometry.


RESULTS
Histamine levels were increased in 14 patients; tryptase levels, in 16; and methylhistamine levels, in six. Histamine and tryptase values correlated with the severity of the reaction (P < .02 and P < .004, respectively). Significantly higher levels of specific IgE against ioxaglate (P < .005) and ioxitalamate (P = .045) were found in patients. No differences were found for complement fractions. Skin test results in two patients with life-threatening reactions were positive for the administered contrast material.


CONCLUSIONS
Histamine release and mast cell triggering are related to severe reactions. An IgE-related mechanism is strongly suspected. Radiologists should be trained to identify and treat anaphylactic shock in patients who react to iodinated contrast material.
Laboratory of Medical Physics, Centre Hospitalier Régional Universitaire, Caen, France.
D
D
Laroche
I
I
Aimone-Gastin
F
F
Dubois
H
H
Huet
P
P
Gérard
M C
MC
Vergnaud
C
C
Mouton-Faivre
J L
JL
Guéant
M C
MC
Laxenaire
H
H
Bricard
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000707:Anaphylaxis / Q000139:chemically induced / Q000276:immunology; D003176:Complement C3 / Q000032:analysis; D003181:Complement C4 / Q000032:analysis; D003287:Contrast Media / Q000008:administration & dosage / Q000009:adverse effects*; D004342:Drug Hypersensitivity / Q000209:etiology* / Q000276:immunology; D005260:Female; D005602:France; D006636:Histamine Release / Q000276:immunology; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000139:chemically induced* / Q000276:immunology; D007073:Immunoglobulin E / Q000097:blood; D008297:Male; D008875:Middle Aged; D012882:Skin Tests; D013997:Time Factors
D003176:Complement C3; D003181:Complement C4; D003287:Contrast Media; D007073:Immunoglobulin E