Tacrolimus immunosuppression - an association with asymptomatic eosinophilia and elevated total and specific IgE levels.

De novo development of food allergy is an infrequent but potentially serious complication of transplantation. An increased prevalence of food allergy noted specifically in children receiving tacrolimus immunosuppression supports the hypothesis that selective suppression of Th1 lymphocytes by the IL-2 inhibitor immunosuppressants CsA, and the more potent drug, tacrolimus , promotes Th2 lymphocytes and an allergic immune response. This study was undertaken to characterize the IgE-mediated immune response, in CsA and tacrolimus-treated, post-OLT children. Thirty children and adolescents aged 1.9-21 yr, mean: 10.6 yr, (6.4 yr post-tx.) were studied. Immunosuppression-CsA: 10 patients, tacrolimus; 20 patients. Blood eosinophils, total IgE levels and specific IgE antibodies (Immulite 2000 Allergy; Diagnostic Products Corp., Los Angeles, CA, USA) to a panel of food and inhaled allergens were measured and correlated with clinical symptoms of allergy. Eosinophilia (>500/mm(3)) range: 599-3125, mean: 1294, was present in 10/20 of patients treated with tacrolimus and 1/10 treated with CsA. IgE levels were elevated in eight of these 10 tacrolimus-treated patients and in two CsA patients ; five were <3 yr of age and IgE levels ranged from 54 to 111 IU/mL (mean: 83), normal for age <45 IU/mL and five were > or =9 yr and IgE levels ranged from 134 to 1606 IU/mL (mean: 557), normal for age <87 IU/mL. Specific IgE levels to a wide panel of food allergens were positive in five tacrolimus-treated patients and to both food and inhaled allergens in three patients (two tacrolimus-treated, one CsA). Four children (tacrolimus-treated) had symptoms of food allergy . None had a family history of allergy. Eosinophilia is present in up to 50% of children and adolescents receiving tacrolimus immunosuppression. The majority of these patients also have elevated levels of total and specific (mainly to food allergens) IgE antibodies. Most patients are asymptomatic and do not manifest food allergy or asthma.