NEW YORK (Reuters Health) - Oral immunotherapy for cow’s milk allergy appears to effectively desensitize allergic children, a new study indicates, although further work is needed to determine the best dosing, duration of therapy, and whether permanent tolerance can be achieved, the study team emphasizes.
Twenty children, 6 to 17 years of age, with a known history of milk allergy were randomly assigned to placebo or to milk in a three-phase dosing schedule. On the first day, a dose of 0.4 mg milk protein was administered, and escalated about every 30 minutes to a maximum first-day dose of 50 mg.
Home dosing was then initiated at the highest tolerated dosage, followed by 8 weekly in-office dose increases to a maximum of 500 mg. Once a dose of 500 mg (equivalent to 15 mL of milk) was achieved, participants remained on this daily maintenance dose for 13 weeks.
Twelve children in the active group and seven in the placebo group completed the study, Dr. Robert A. Wood from the Johns Hopkins Hospital, Baltimore, and colleagues report in the Journal of Allergy and Clinical Immunology.
One child dropped out due to persistent eczema during dose escalation. “Adverse reactions were common, but the risk of a severe reaction fell within the range that we would consider acceptable. Despite the relatively high frequency of reactions of any type (45 percent of active doses), nearly 90 percent were transient reactions that required no treatment.”
The researchers found that milk oral immunotherapy was effective in increasing the threshold for reactions to milk in all treated children. Before treatment, nearly all of the children had symptoms after exposure to an average of 40 mg of milk. Following milk oral immunotherapy, the children had an allergic reaction only after exposure to an average of 5140 mg milk. There were changes in the placebo group.
After milk immunotherapy, the lowest milk dose to cause a reaction was 1340 mg, “which is still likely to be protective against the overwhelming majority of accidental exposures,” the investigators note.
However, despite an increased reaction threshold after completion of the oral milk immunotherapy regimen, post-treatment food challenge still elicited reactions in 14 of 18 children, Wood and colleagues point out.
Even in those who did not react to the post-treatment food challenge, “it is not clear whether they are fully tolerant or rather transiently desensitized and thus still at risk of future reactions,” the researchers added.
SOURCE: Journal of Allergy and Clinical Immunology, December 2008.