The outcome of cow's milk allergy has been a subject of controversy.
We aimed to investigate whether in children with cow's milk allergy of infancy period immunity changes persisted despite the lack of clinical sign of food intolerance.
We studied 20 children with cow's milk allergy (CMA) diagnosed and treated before 2 years of age (group A, age range 6-16 years, mean10.5, 11 girls) and 24 children without any evidences of food allergy (group B, age range 6-17 years, mean 11.6) referred to our department due to recurrent abdominal pain. All the children had recently been on a normal diet. The patients were scheduled for gastroduodenoscopy, skin prick tests, laboratory examination (IgM, IgA, total IgE, IgE specific for cow's milk). Peripheral blood lymphocyte subpopulations (CD19+, CD3+, CD4+, CD8+, CD3 HLADR+, CD16+CD56+) were determined using a cytometric method. In all the children cow's milk-free diet was introduced for 6 weeks, followed by a double blind placebo controlled food challenge (DBPCFC). Further blood samples for immunological analysis were taken after 6 weeks of elimination diet.
In all the patients from both groups the results of skin prick tests, DBPCFC were negative. There were not differences in IgA, IgM and IgE concentrations on normal and on milk free diet. In children with CMA in infancy (group A) elimination of the cow's milk from the diet resulted in an increase of CD8+ cells percentages in peripheral blood and a reduction of CD4+/CD8+ ratio (1.65 ± 0.46 V vs 1.5 ± 0.48, p = 0.0164). Percentages of B cells showed trends to decrease and percentage of NK cells to increase. This was not the case in group B patients.
Our study indicated that despite a lack of clinical sign of food intolerance in children who have outgrown cow's milk allergy, the disturbances in lymphocytes subset in peripheral blood have persisted and can be restored by elimination diet.
This rises the questions if the children really achieved full tolerance.