The acquisition of tolerance toward cow's milk through probiotic supplementation: A randomized, controlled trial
Background: Cow's milk allergy (CMA) is the most frequently diagnosed food allergy in infancy. In general, patients have a good prognosis because the majority acquire tolerance within the first years. Interventions have been proposed to accelerate tolerance and reduce morbidity. Probiotic supplementation could be effective through modulation of the immune system. Objective: We sought to determine whether supplementation with a combination of probiotics (Lactobacillus casei CRL431 and Bifidobacterium lactis Bb-12) accelerates tolerance to cow's milk (CM) in infants with CMA. Methods: We performed a double-blind, randomized, placebo-controlled trial in 119 infants with CMA. Infants received CRL431 and Bb-12 supplemented to their standard treatment of extensively hydrolyzed formula for 12 months. Primary outcome was clinical tolerance to CM at 6 and 12 months of treatment. Furthermore, we analyzed T- and B-lymphocyte subsets (CD3+, CD3+CD4+, CD3+CD8+, and CD20+) in peripheral blood at randomization and at 12 months with flow cytometry and examined the presence of viable probiotic strains in fecal samples. Results: The cumulative percentage of tolerance to CM at 6 and 12 months was similar in both groups: 56 (77%) in the probiotics group versus 54 (81%) in the placebo group. Infants in the placebo group had higher percentages of CD3+and CD3+CD4+lymphocytes compared with those seen in probiotic-treated infants. Probiotic intake was confirmed because probiotics were isolated from feces more often in treated infants than in the placebo group. Conclusion: Supplementation of CRL431 and Bb-12 to extensively hydrolyzed formula does not accelerate CM tolerance in infants with CMA.