Trasplante de células progenitoras hematopoyéticas en pediatría: Una alternativa de tratamiento en inmunodeficiencias primarias / Hematopoietic stem cell transplant in combined immunodeficiency syndromes of childhood: An optimal treatment for primary immunodeficiency

The congenital immunodeficiency disorders in which the defect has been clearly traced to the stem cell can be cured with allogeneic stem-cell transplantation (SCT) from an unaffected donor. Widespread application of this treatment modality has been tempered by the fact that risk-benefit considerations do not always favor a procedure that carries a significant risk for morbidity and mortality. Some malignant disorders of childhood eventually have to be treated by an autologous or allogeneic SCT, however nonmalignant disorders can also be treated with this approach. This article reviews the current status of SCT for nonmalignant inherited immunodeficiency disorders.

Tradicionalmente el trasplante de células progenituras hematopoyéticas (TCPH) se ha utilizado en pacientes pediátricos para el tratamiento de padecimientos malignos. Sin embargo, también existen indicaciones y experiencia para padecimientos benignos dentro de los cuales se encuentran los síndromes de inmunodeficiencia combinada primaria. Estos síndromes de la infancia constituyen una serie de padecimientos que aun cuando son infrecuentes en la patología infantil constituyen un grupo de alteraciones que hasta hace más de tres décadas eran irremediablemente fatales. Con el advenimiento del TCPH el pronóstico de estos síndromes ha mejorado sustancialmente, por lo que es importante conocer sus resultados, así como su morbimortalidad asociada.

Can thymic tissue induce tolerance to kidney allografts?

The aim of this study was to investigate the beneficial effect of donor thymic tissue to induce tolerance in thymokidney allografts, transplanted to thymectomized cross-bred canines. Seven pairs of transplant donors and recipients were selected from 3- to 4-month-old cross-bred canines with major histocompatibility complex [MHC] mismatches. Recipients underwent partial thymectomy 4 weeks before transplantation and received an autologous thymic graft under the renal capsule, which had been engrafted in the donors 3 months before transplantation [thymokidney]. Successful engraftment with evidence of thymocyte development in the donors was determined by gross and histologic examination at the time of transplantation. Biopsy specimens were obtained at the transplant day and 3 months after transplantation and were studied histologically for evidence of hyperacute or acute rejection. At 90 days after the operation, all 7 juvenile thymic grafts had developed with normal thymic structure under the renal capsule. Hyperacute rejection was not observed in allografts, and all of them were functioning until the end of follow-up; however, all of the allografts showed acute cell-mediated rejection 3 months after transplantation. No tolerance was induced by vascularized donor thymokidneys in MHCmismatched canines. The advantages of tolerance over chronic immunosuppression are so great that a potentially tolerogenic approach such as thymic transplantation would seem worthy of further investigations on large animal models. To evaluate the beneficial effects of thymic tissue in tolerance induction, utilizing a short course, lowdose adjuvant immunosuppressant to this regimen and/or application of in-bred MHCmatched canines is suggested