CD4+CD25+Foxp3+ T regulatory cells are not involved in oral desensitization.

Oral tolerance has been related to generation of T regulatory cells (Treg) or clonal anergy/deletion, respectively by administering low and high doses of fed antigens. CD4+CD25+ regulatory T cell clones can be induced by the antigen in Peyers patches of animal models. We selected ten subjects (mean age: 89.4 +/- 36.21 months; group A) with severe cows milk allergy. They underwent oral desensitization (OD) according to the current protocols. In six months they reached a tolerance of 50 ml of cows milk. CD4+CD25+Foxp3+ T(reg) blood levels were measured at the beginning of OD (A) and after 6 months (A), but almost the same values were obtained: A = 0.36 +/- 0.11 percent; A prime= 0.59 +/- 0.15 percent. These results were compared with a control group (C) of non-atopic children. Naturally outgrowing cows milk allergy can be related to high blood levels of CD4+CD25+Foxp3+ T(reg), as previously reported in children. On the other hand, a forced oral desensitization through a progressive intake of the antigenic food seems not to be related to an enhancement of CD4+CD25+Foxp3+ T(reg) levels in peripheral blood, making the role of long-lasting systemic immunologic changes unlikely.