Recommendations on hematopoietic stem cell transplantation for inherited bone marrow failure syndromes.

Allogeneic hematopoietic stem cell transplantation (HSCT) offers the potential to cure patients with an inherited bone marrow failure syndrome (IBMFS). However, the procedure involves the risk of treatment-related mortality and may be associated with significant early and late morbidity. For these reasons, the benefits should be carefully weighed against the risks. IBMFS are rare, whereas case reports and small series in the literature illustrate highly heterogeneous practices in terms of indications for HSCT, timing, stem cell source and conditioning regimens. A consensus meeting was therefore held in Vienna in September 2012 on behalf of the European Group for Blood and Marrow Transplantation to discuss HSCT in the setting of IBMFS. This report summarizes the recommendations from this expert panel, including indications for HSCT, timing, stem cell source and conditioning regimen.

Consensus of German transplant centers on hematopoietic stem cell transplantation in Fanconi anemia.

Allogeneic hematopoietic stem cell transplantation (HSCT) is currently the only curative therapy for the severe hematopoietic complications associated with Fanconi anemia (FA). In Germany, it is estimated that 10-15 transplants are performed annually for FA. However, because FA is a DNA repair disorder, standard conditioning regimens confer a high risk of excessive regimen-related toxicities and mortality, and reduced intensity regimens are linked with graft failure in some FA patients. Moreover, development of graft-versus-host disease is a major contributing factor for secondary solid tumors. The relative rarity of the disorder limits HSCT experience at any single center. Consensus meetings were convened to develop a national approach for HSCT in FA. This manuscript outlines current experience and knowledge about HSCT in FA and, based on this analysis, general recommendations reached at these meetings.

X-linked inhibitor of apoptosis (XIAP) deficiency: the spectrum of presenting manifestations beyond hemophagocytic lymphohistiocytosis.

X-linked inhibitor of apoptosis (XIAP) deficiency caused by mutations in BIRC4 was initially described in patients with X-linked lymphoproliferative syndrome (XLP) who had no mutations in SH2D1A. In the initial reports, EBV-associated hemophagocytic lymphohistiocytosis (HLH) was the predominant clinical phenotype. Among 25 symptomatic patients diagnosed with XIAP deficiency, we identified 17 patients who initially presented with manifestations other than HLH. These included Crohn-like bowel disease (n=6), severe infectious mononucleosis (n=4), isolated splenomegaly (n=3), uveitis (n=1), periodic fever (n=1), fistulating skin abscesses (n=1) and severe Giardia enteritis (n=1). Subsequent manifestations included celiac-like disease, antibody deficiency, splenomegaly and partial HLH. Screening by flow cytometry identified 14 of 17 patients in our cohort. However, neither genotype nor protein expression nor results from cell death studies were clearly associated with the clinical phenotype. Only mutation analysis can reliably identify affected patients. XIAP deficiency must be considered in a wide range of clinical presentations.

Allo-SCT using BU, CY and melphalan for children with AML in second CR.

Based on the results from the AML-BFM 98 trial, hematopoietic SCT (HSCT) is recommended for children with AML in second CR only. Here, we retrospectively analyze interphase data of children who underwent HSCT after myeloablative conditioning with BU, CY, and melphalan (BuCyMel) for AML in second remission (CR2) between 1998 and 2009. Out of 152 children, transplant data were available on 109 individuals. Sixty out of 109 children (55%) received BuCyMel. Median age at HSCT was 12.2 years (range 3.0; 18.3). GVHD prophylaxis mostly consisted of CsA and short term MTX with or without antithymocyte globulin. Matched-sibling donors were used for 6/60 analyzed recipients, the remainder either received grafts from matched unrelated (30/60) or mismatched donors. OS after 5 years was 62% (s.e. 6%), relapse incidence 35% (18/60 children) and treatment-related mortality accounted for 12% (7/60) of fatal events. In conclusion, even taking into account possible selection bias in this retrospective analysis, HSCT in CR2 using BuCyMel resulted in a respectable OS. Based on this data the prospective, controlled and centrally monitored AML SCT-BFM 2007 trial has started to recruit patients in January 2010 aiming to generate valid outcome data for further strategy decisions.

Hematopoietic stem cell transplantation for advanced myelodysplastic syndrome in children: results of the EWOG-MDS 98 study.

We report on the outcome of children with advanced primary myelodysplastic syndrome (MDS) transplanted from an HLA-matched sibling (MSD) or an unrelated donor (UD) following a preparative regimen with busulfan, cyclophosphamide and melphalan. Ninety-seven patients with refractory anemia with excess blasts (RAEB, n=53), RAEB in transformation (RAEB-T, n=29) and myelodysplasia-related acute myeloid leukemia (MDR-AML, n=15) enrolled in the European Working Group of MDS in Childhood (EWOG-MDS) 98 study and given hematopoietic stem cell transplantation (HSCT) were analyzed. Median age at HSCT was 11.1 years (range 1.4-19.0). Thirty-nine children were transplanted from an MSD, whereas 58 were given the allograft from a UD (n=57) or alternative family donor (n=1). Stem cell source was bone marrow (n=69) or peripheral blood (n=28). With a median follow-up of 3.9 years (range 0.1-10.9), the 5-year probability of overall survival is 63%, while the 5-year cumulative incidence of transplantation-related mortality (TRM) and relapse is 21% each. Age at HSCT greater than 12 years, interval between diagnosis and HSCT longer than 4 months, and occurrence of acute or extensive chronic graft-versus-host disease were associated with increased TRM. The risk of relapse increased with more advanced disease. This study indicates that HSCT following a myeloablative preparative regimen offers a high probability of survival for children with advanced MDS.

Reduced intensity conditioning in unrelated donor transplantation for refractory cytopenia in childhood.

Myelodysplastic syndromes (MDS) are a heterogenous group of acquired hematopoietic stem cell disorders. Refractory cytopenia (RC) is the most common subtype of childhood MDS and hematopoietic stem cell transplantation (HSCT) is the only curative treatment. HSCT following a myeloablative preparative regimen is associated with a low probability of relapse and considerable transplant-related mortality. In the present European Working Groups of MDS pilot study, we investigated whether a reduced intensity conditioning regimen (RIC) is able to offer reduced toxicity without increased rates of graft failure or relapse. Nineteen children with RC were transplanted from an unrelated donor following RIC consisting of fludarabine, thiotepa and anti-thymocyte globulin. Three patients experienced graft failure. Neutrophil and platelet engraftment occurred at a median time of 23 and 30 days, respectively. Cumulative incidence of grade II-IV and grade III and IV acute graft-versus-host disease (GVHD) was 0.48 and 0.13, respectively; three patients developed extensive chronic GVHD. Although infections were the predominant complications, only one patient with extensive chronic GVHD died from infectious complications. Overall and event-free survival at 3 years were 0.84 and 0.74, respectively. In conclusion, our results were comparable to those of patients treated with myeloablative HSCT. Long-term follow-up is needed to demonstrate the expected reduction in long-term sequelae.

Defibrotide in the treatment of children with veno-occlusive disease (VOD): a retrospective multicentre study demonstrates therapeutic efficacy upon early intervention.

Veno-occlusive disease (VOD) of the liver is a complication observed particularly in patients undergoing hematopoietic stem cell transplantation (HSCT). Defibrotide (DF) is a polydeoxyribonucleotide with aptameric activity on endothelium. We evaluated in a retrospective analysis the efficacy of DF in pediatric patients developing hepatic VOD after HSCT.A total of 45 patients between 0.2 and 20 years (median age: 8.2 years) with hepatic VOD were treated with DF: 22 patients (49%) met risk criteria for severe or progressive disease and 23 (51%) for moderately severe and mild disease. The median duration of DF treatment was 17 days. In all, 34 patients (76%) achieved complete response (CR) with a survival rate of 64% at day 100. CR rate in patients with severe disease was 50% with long-term survival of 36%. The average DF dose in the CR group was 45 mg/kg/day and in the no responder (NR) group 27 mg/kg/day. The use of additional drugs besides DF to treat VOD made no difference in the outcome compared to DF alone. The average interval from diagnosis to start of DF was 1 day in the CR and 5.5 days in NR group. In multivariate analysis, early intervention remained the only significant factor for a CR.

Recurrent B-cell non-Hodgkin's lymphoma in two brothers with X-linked lymphoproliferative disease without evidence for Epstein-Barr virus infection.

We present two male siblings suffering from recurrent manifestations of B-cell non-Hodgkin's lymphoma (NHL) and recurrent infections of the lower respiratory tract associated with bronchiectasis. Immunodeficiency could not be demonstrated by any laboratory investigation. In both patients, lymphomas developed without evidence for Epstein-Barr virus (EBV) infection, i.e. no antibody response to EBV-specific antigens, negative EBV-PCR (polymerase chain reaction) in peripheral blood cells, and absence of latent membrane protein (LMP) and EBV-encoded RNA (EBER) in lymphoma cells. Molecular analysis of the SH2D1A, the gene for X-linked lymphoproliferative disease (XLP) led to the identification of a deletion in the first exon in both patients. Therefore, we postulate that the genetic defect and the following dysregulation of the B-/T-cell interaction rendered these patients susceptible to the early onset of B-cell NHL and that EBV infection is not an obligate prerequisite.

Epstein-Barr virus-negative boys with non-Hodgkin lymphoma are mutated in the SH2D1A gene, as are patients with X-linked lymphoproliferative disease (XLP).

X-linked lymphoproliferative disease (XLP) is a primary immunodeficiency, which most often manifests itself after Epstein-Barr virus (EBV) infection. The main clinical phenotypes include fulminant or fatal infectious mononucleosis, dysgammaglobulinaemia and malignant lymphoma. We have recently cloned the SH2D1A gene, which has been shown to be mutated in approximately 70% of XLP patients. Now we report five novel SH2D1A mutations in patients from five unrelated XLP families. No mutations were found in another three XLP families. In three boys with early onset non-Hodgkin lymphoma (NHL) from two unrelated families a deletion of SH2D1A exon 1 and a splice site mutation were found, respectively. These patients did not show any laboratory or clinical signs of a previous EBV infection. A fourth EBV-uninfected and unrelated boy with a stop mutation in the SH2D1A gene shows only signs of dysgammaglobulinaemia. Development of dysgamma-globulinaemia and lymphoma without evidence of prior EBV infection in four of our patients suggests that EBV is unrelated to these phenotypes, in contrast to fulminant or fatal infectious mononucleosis. The role of SH2D1A as a putative tumour suppressor gene remains to be investigated.

Lack of large, homozygous deletions of the nephronophthisis 1 region in Joubert syndrome type B. APN Study Group. Arbeitsgemeinschaft für Pädiatrische Nephrologie.

Joubert syndrome type B (JSB) is a developmental disorder of the nephronophthisis (NPH) complex with multiple organ involvement, including NPH, coloboma of the eye, aplasia of the cerebellar vermis, and the facultative symptoms of psychomotor retardation, polydactyly, and neonatal tachypnea. In isolated autosomal recessive NPH type 1 (NPH1), homozygous deletions have been described as causative in more than 80% of patients. Since different combinations of the extrarenal symptoms with NPH occur in JSB, a contiguous gene deletion syndrome in the NPH1 genetic region would seem a highly likely cause for JSB. We therefore examined 11 families with JSB for the presence of extended deletions at the NPH1 locus. Genomic DNA was examined using four consecutive polymerase chain reaction (PCR) markers that are deleted in NPH1 and three PCR makers flanking the NPH1 deletion. In all seven markers examined, there was no homozygous deletion detected in any of the 11 JSB families studied. Since these markers saturate the NPH1 deletion region at high density, this finding excludes the presence of large homozygous deletions of the NPH1 region in these JSB families, making it unlikely that deletions of the NPH1 region are a primary cause for JSB.

Two novel mutations of the gene for Kir 1.1 (ROMK) in neonatal Bartter syndrome.

Bartter syndrome, an autosomal recessive renal tubular disorder, is associated with hypokalemic metabolic alkalosis with high renin and aldosterone plasma concentrations with low or normal blood pressure and renal salt loss. Two genes, the gene encoding the furosemide-sensitive apical Na-K-2Cl cotransporter (NKCC2) and the gene encoding the luminal inwardly-rectifying potassium channel Kir 1.1 (ROMK), have been reported to cause the neonatal subtype of Bartter syndrome. In a patient with neonatal Bartter syndrome, we report two novel mutations resulting in amino acid exchanges Ala156Val and Leu220Phe in the gene for Kir 1.1 that have been identified by single-strand conformation polymorphism analysis and subsequent direct sequencing. Both mutations occur in functional relevant domains of the channel protein and are therefore highly suggestive of altering channel properties.

Late occurrence of cysts in autosomal dominant medullary cystic kidney disease.

Medullary cystic kidney disease (MCD) is characterized by multiple renal cysts at the corticomedullary boundary area, by autosomal dominant inheritance, and by onset of chronic renal failure in the third decade of life. We report on a family with three affected individuals of both sexes in two generations presenting with end-stage renal failure at age 22-31 years. Primarily diagnoses considered included unclassified hereditary nephropathy and autosomal dominant polycystic kidney disease. Careful evaluation of all findings, initiated after investigation of renal morphology with CT, revealed features characteristic for MCD and led to the final diagnosis of MCD. We conclude that MCD is an important differential diagnosis for polycystic kidney disease in young adults with end-stage renal failure. Establishing the correct diagnosis has considerable impact for genetic counselling.

Molecular cloning of the interleukin-1 gene cluster: construction of an integrated YAC/PAC contig and a partial transcriptional map in the region of chromosome 2q13.

Genes of the interleukin-1 (IL-1) gene cluster localized on chromosome 2q13 are implicated in many physiological and pathophysiological processes. We present here a high-resolution physical map of this region between markers D2S2008 and D2S4/PAX8. An integrated YAC/PAC contig and a partial transcriptional map were constructed by STS-constent mapping using the CEPH YAC library and three PAC libraries. A total of 3 YACs, 34 PACs, and 56 STSs were integrated: 33 newly generated probes to PAC end sequences, 9 polymorphic and 4 nonpolymorphic markers, 5 known genes, 4 expressed sequence tags, and 1 pseudogene. Within the map, a complete PAC contig of > 1 Mb encompasses the IL-1 gene cluster and PAX8, a paired-box-containing gene. This allowed us to define the transcriptional orientation of GLVR1, IL1B, and IL1RN and to show that PAX8 is localized outside the IL-1 gene cluster. FISH analysis localized PAC clones containing the IL-1 gene cluster to 2q12-q13. The data provide the basis for further characterization of the IL-1 gene cluster and for the construction of a sequence-ready PAC contig of this region.

Molecular genetic identification of families with juvenile nephronophthisis type 1: rate of progression to renal failure. APN Study Group. Arbeitsgemeinschaft für Pädiatrische Nephrologie.

Familial juvenile nephronophthisis (NPH), an autosomal recessive cystic disease of the kidney, is the most common genetic cause of end-stage renal disease (ESRD) in the first two decades of life. A gene locus for nephronophthisis type 1 (NPH1) has been mapped by linkage analysis to chromosome 2q13. We performed a haplotype analysis in 16 NPH families with at least two affected patients with the typical history, clinical signs and histology of NPH using microsatellite markers of the NPH1 genetic region. By demonstration of a recombinant event marker D2S1893 was identified as a novel centromeric flanking marker to the NPH1 critical genetic region. Absence of linkage to the NPH1 locus in six NPH families confirmed the existence of at least one additional gene locus for NPH. Linkage to the NPH1 locus was demonstrated in 10 families. In 8 of these families a homozygous deletion was identified. These data permit for the first time the study of the development of renal failure in a subset of NPH1 families, which is most likely homogeneous with regard to the responsible gene locus. We present a statistical description of serial serum creatinine measurements in NPH1. Analysis of renal death revealed a median of 13.1 years. Age-dependent quartiles were generated for serum creatinine. In summary, the new marker provides a diagnostic tool to aid in the diagnosis of NPH, while the progression charts offer a standard for an assessment of the rate of progression to ESRD for patients with NPH1 to be used in future therapeutic trials and for a prediction of the individual course of the disease.