Characteristics, management, and outcome of pediatric patients with post-transplant lymphoproliferative disease-A 20 years' experience from Austria.

BACKGROUND: Management of pediatric post-transplantation lymphoproliferative disorder (PTLD) after hematopoietic stem cell (HSCT) and solid organ transplantation (SOT) is challenging. AIM: This study of 34 PTLD patients up to 19-years old diagnosed in Austria from 2000 to 2018 aimed at assessing initial characteristics, therapy, response, and outcome as well as prognostic markers of this rare pediatric disease. METHODS AND RESULTS: A retrospective data analysis was performed. Types of allografts were kidney (n = 12), liver (n = 7), heart (n = 5), hematopoietic stem cells (n = 4), lungs (n = 2), multi-visceral (n = 2), small intestine (n = 1), and vessels (n = 1). Eighteen/34 were classified as monomorphic PTLD, with DLBCL accounting for 15 cases. Polymorphic disease occurred in nine, and non-destructive lesions in six cases. One patient had a non-classifiable PTLD. Thirteen/34 patients are surviving event-free in first remission (non-destructive, n = 4/6; polymorphic, n = 4/9; monomorphic, n = 6/18). Fourteen/34 patients lacked complete response to first-line therapy, of whom seven died. Four/34 patients relapsed, of whom two died. In 3/34 patients, death occurred as a first event. The 5-year overall and event-free survival rates were 64% ± 9% and 35% ± 9% for the whole cohort. Among all parameters analyzed, only malignant disease as the indication for transplantation had a significantly poor influence on survival. CONCLUSIONS: This study shows PTLD still to be a major cause of mortality following SOT or HSCT in children. A continued understanding of the molecular biology of the disease shall allow to decrease treatment intensity for lower risk patients and to identify patients who may benefit from newer therapy approaches to improve outcome and decrease morbidity.

Inverted formin 2-related Charcot-Marie-Tooth disease: extension of the mutational spectrum and pathological findings in Schwann cells and axons.

Mutations in the gene encoding inverted formin FH2 and WH2 domain-containing protein (INF2), a Cdc42 effector involved in the regulation of actin dynamics, cause focal segmental glomerulosclerosis (FSGS) and intermediate Charcot-Marie-Tooth neuropathy combined with FSGS (FSGS-CMT). Here, we report on six patients from four families with sensorimotor polyneuropathy and FSGS. Nerve conduction velocities were moderately slowed, and amplitudes of sensory and motor potentials were decreased. One patient had internal hydrocephalus and was intellectually disabled. Molecular genetic testing revealed two known and two novel missense mutations in the second and fourth exons of the INF2 gene. Investigations of one nerve biopsy confirmed the diagnosis of intermediate-type CMT and revealed occasional abnormal in- and outfoldings of myelin sheaths and expansions of the endoplasmic reticulum in axons and Schwann cells. While earlier reports suggested that mutations causing FSGS-CMT are restricted to exons 2 and 3 of the INF2 gene, we found one CMT-FSGS causing mutation (p.Glu184Lys) in exon 4 extending the critical region of INF2 for rapid CMT-FSGS molecular genetic diagnosis. Study of a nerve biopsy showed abnormalities that might be related to the known role of the INF2-binding partner CDC42 in myelination.