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.

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We report long-term (seven yr) immunological tolerance in a 16-yr-old boy, to a liver allograft donated by his father following a bone marrow transplant at age 2.5 yr from the same donor. The bone marrow transplant was complicated by severe GVHD leading to liver failure and the ensuing need for a liver transplant, performed under planned avoidance of immunosuppression. At one wk post-transplant, although a liver biopsy was histologically compatible with acute rejection, favorable clinical and biochemical evolution precluded initiating immunosuppressive therapy, thus highlighting the need for caution when interpreting early histological changes so that administration of unnecessary immunosuppression can be avoided. Induction of tolerance in transplant recipients remains an elusive goal. In those patients who had received conventional bone marrow transplants and had endured the consequences of GVHD, development of macrochimerism may allow immunosuppression-free solid organ transplantation from the same donor.

Severe allergic reaction to food following liver transplantation is a well-known phenomenon. However, the mechanisms underlying this phenomenon are not yet elucidated. This study aimed to reveal the nature of the immune response in post-transplanted allergic patients and compare them to non-allergic transplanted as well as allergic and non-allergic control subjects, with focus on cytokine milieu. Post-liver transplant patients with and without allergic reactions as well as food-allergic but otherwise healthy and healthy non-allergic control patients were recruited. We reviewed patient records and routine laboratory tests and assayed subjects' PBMCs, studying cytokine secretion profile in response to different stimuli. Post-transplant patients with food allergy showed a unique cytokine profile in response to various stimuli, with extremely elevated IL-5, low IL-10 secretion, and somewhat higher IFN-γ. T regulatory cell number was not significantly different among the groups of patients and controls. Immune response of food-allergic post-liver transplant patients is identified by a unique cytokine profile when compared to allergic but otherwise healthy individuals.