Patients with IgE-mediated cow's milk allergy who are nonreactive to baked milk (BM) can be desensitized with BM to promote tolerance to unheated milk (UM).

We sought to test whether patients who are BM reactive can progress in BM oral immunotherapy (OIT) and become desensitized to UM as well.

Fifteen patients (>4 years) who previously failed to complete our milk OIT program were enrolled into the BM OIT protocol. A dose of BM (180°C for 30 minutes) which was less than the eliciting dose was increased 50% monthly while under medical supervision until the primary outcome dose of 1.3 g/d BM protein was achieved. Basophil reactivity and milk protein–specific IgE binding were analyzed at the first round of BM OIT therapy (T₀) and at 12 months of BM treatment.

In terms of the primary outcome, only 3 (21%) of 14 patients tolerated the 1.3 g/d BM dose. Although some patients initially progressed in BM OIT, 8 of 11 failed because of IgE-mediated reactions. Three did not complete the program because of non–IgE-mediated factors. An increase in challenge threshold to UM was noted in patients continuing until 12 months (P = .003), including those among whom reactions precluded continuation in the program. Patients (n = 3) who successfully reached maintenance had decreased milk-specific IgE reactivity. Furthermore, the mean difference at T₀ between induced HM and UM percentages of CD203c expression was significantly lower in patients who successfully completed BM OIT than in those who did not (−11% vs 4.4%, P = .0002), which is consistent with their decreased clinical reactivity to BM.

Although use of hypoallergenic BM in OIT is a promising therapy, care must be taken before its administration in BM-reactive patients because of the risk for anaphylaxis and only limited increase in challenge threshold attained.