A model for preservation of thymocyte-depleted thymus

DiGeorge syndrome is a disorder caused by a microdeletion on the long arm of chromosome 22. Approximately 1% of patients diagnosed with DiGeorge syndrome may have an absence of a functional thymus, which characterizes the complete form of the syndrome. These patients require urgent treatment to reconstitute T cell immunity. Thymus transplantation is a promising investigational procedure for reconstitution of thymic function in infants with congenital athymia. Here, we demonstrate a possible optimization of the preparation of thymus slices for transplantation through prior depletion of thymocytes and leukocyte cell lineages followed by cryopreservation with cryoprotective media (5% dextran FP 40, 5% Me2SO, and 5% FBS) while preserving tissue architecture. Thymus fragments were stored in liquid nitrogen at -196°C for 30 days or one year. The tissue architecture of the fragments was preserved, including the distinction between medullary thymic epithelial cells (TECs), cortical TECs, and Hassall bodies. Moreover, depleted thymus fragments cryopreserved for one year were recolonized by intrathymic injections of 3×106 thymocytes per mL, demonstrating the capability of these fragments to support T cell development. Thus, this technique opens up the possibility of freezing and storing large volumes of thymus tissue for immediate transplantation into patients with DiGeorge syndrome or atypical (Omenn-like) phenotype.

Disseminated Langerhans' cell histiocytosis and massive protein-losing enteropathy

Symptomatic involvement of the gastrointestinal (GI) tract as a prominent symptom in Langerhans' cell histiocytosis (LCH) is uncommon, occurring in less than 1 to 5 percent of all cases, even when the disease is in its disseminated form. Up to now, there have been reports of 18 cases of LCH with GI manifestations, including our 2 cases, with diarrhea (77.7 percent), protein-losing enteropathy (33.3 percent) and bloody stool being the most frequent findings. The authors present two patients with severe diarrhea and refractory hypoalbuminemia, and with the protein-losing enteropathy documented by Cr51-labeled albumin studies. A review of the literature indicated that the presence of GI symptoms is often associated with systemic disease as well as with poor prognosis, mainly under 2 years of age. Radioisotopes are useful for documenting protein loss in several diseases with high specificity and sensitivity, and their utilization in the cases reviewed here permitted diagnoses in 6 children, as well as improved therapeutic management

Aplasia medular prolongada como manifestacao pre-leucemica. / Long-term medullary aplasia as pre-leucemic manifestation

Os autores apresentam um caso de aplasia medular prolongada, em crianca de 7 anos e 8 meses de idade, medicado com androgeno por 9 meses sem melhoria do quadro hematologico, ate que foram constatados 32% de celulas leucemicas ao hemograma o que permitiu, entao, o diagnostico de leucemia mielomonocitica, tendo sido possivel obter remissao completa. Os autores comentam a importancia da identificacao de estados pre-leucemicos

Varicela-Zoster em imunodeprimidos. Estudo de 12 casos. / Varicelle-Zoster in immunodeppressive patients. Study of 12 cases

A infeccao por virus Varicela-Zoster e doenca benigna e autolimitada na faixa etaria pediatrica. Ha alguns grupos de alto risco que, ao adquirirem a infeccao, podem evoluir desfavoravelmente, e dentre esses se enquadram pacientes com tumores. O objetivo do trabalho foi o de analisar a evolucao das criancas com tumores acometidas por infeccao Varicela-Zoster. As taxas de mortalidade e complicacao foram respectivamente 16,6% e 25%. Outro dado encontrado foi a ocorrencia de 4 casos de herpes zoster sendo que 3 em criancas com leucemia aguda e 1 em paciente com doenca de Hodgkin, o que contrasta com dados da literatura que demonstram ser a frequencia de herpes zoster maior em pacientes com doenca de Hodgkin do que nos com leucemia aguda