All iodinated contrast media (CM) are known to cause both immediate (≤1 h) and nonimmediate (>1 h) hypersensitivity reactions. Although for most immediate reactions an allergic hypersensitivity cannot be demonstrated, recent studies indicate that the severe immediate reactions may be IgE‐mediated, while most of the nonimmediate exanthematous skin reactions, appear to be T‐cell mediated. Patients who experience such hypersensitivity reactions are therefore advised to undergo an allergologic evaluation. Several investigators have found skin testing to be useful in confirming a CM allergy, especially in patients with nonimmediate skin eruptions. If a patient with confirmed allergy to a CM needs a new CM exposure, a skin test negative CM should be chosen and premedication may be tried. However, none of these precautional measures is a guarantee against a repeat reaction. More research focusing on pathomechanisms, diagnostic testing and premedication is therefore clearly needed in order to prevent CM‐induced hypersensitivity reactions in the future.

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.

No abstract

Allergic reactions to peanut oil are very much debated, even if the responsibility of peanut oil has been evoked in several cases of adverse reactions, including death related to severe asthma. The aim of the present study was to investigate the presence of allergenic proteins in peanut oil. Proteins were extracted from commercial refined peanut oil, with a relative content in the order of 0.1-0.2 microg per g of oil, and molecular sizes ranging from 14 up to 76kDa in SDS-PAGE. Eight protein bands were systematically observed in crude, neutralized and refined oils, with a molecular mass ranging from approximately 14 to 76 kDa, including one at 18 kDa which was identified by Western blot performed with serum from two allergic patients. The protein extract gave positive IgE-RIA with patient sera, positive in vitro leucocyte histamine release tests and positive skin-prick tests in allergic patients. The allergenic protein was purified by HPLC and [125I] iodide-labelled. It had an isoelectric point at 4.5 in isoelectrofocusing. In conclusion, we have demonstrated the presence of allergenic proteins in crude and refined peanut oil. These proteins are the same size as two allergens previously described in peanut protein extracts.

The cobalamin status of 27 patients suffering from alcoholic cirrhosisand 20 control subjects was analyzed. Plasma cobalamin (p < 0.005), total corrinoids (p < 0.005) and their analogs (p < 0.05) were all significantly elevated in the cirrhosis patients. These differences were due to increased haptocorrin (HC)-bound corrinoid (p < 0.02), which could be explained by a deficient hepatic clearance of cobalamin bound to HC. The increase in the concentration of true cobalamin was greater than that of its analogs. There were positive correlations between cholestasis (serum alkaline phosphatase) and plasma analog concentrations (p < 0.05), HC-bound cobalamin (p < 0.005) and total corrinoids bound to HC (p < 0.005). The plasma concentrations of the indicators of cobalamin deficiency, homocysteine (p < 0.05) and methylmalonic acid (p < 0.001), were increased, which could indicate poor cellular penetration of vitamin B₁₂ or a defect in the activation of the two vitamin-B₁₂-dependent enzymes.