Barth syndrome: an X-linked cause of fetal cardiomyopathy and stillbirth.

OBJECTIVE: Barth Syndrome (BTHS) is an X-linked multisystem disorder (OMIM 302060) usually diagnosed in infancy and characterized by cardiac problems [dilated cardiomyopathy (DCM) ± endocardial fibroelastosis (EFE) ± left ventricular non-compaction (LVNC)], proximal myopathy, feeding problems, growth retardation, neutropenia, organic aciduria and variable respiratory chain abnormalities. We wished to determine whether BTHS had a significant impact on fetal and perinatal health in a large cohort of family groups originating from a defined region. METHOD: Case note review on 19 families originating from the UK and known to the Barth Syndrome Service of the Bristol Royal Hospital for Children. RESULTS: Details are presented on six kindreds (32%) with genetically and biochemically proven BTHS that demonstrate a wider phenotype including male fetal loss, stillbirth and severe neonatal illness or death. In these families, 9 males were stillborn and 14 died as neonates or infants but there were no losses of females. BTHS was definitively proven in five males with fetal onset of DCM ± hydrops/EFE/LVNC. CONCLUSION: These findings stress the importance of considering BTHS in the differential diagnosis of unexplained male hydrops, DCM, EFE, LVNC or pregnancy loss, as well as in neonates with hypoglycemia, lactic acidosis and idiopathic mitochondrial disease.

Hematopoietic cell transplantation for Chediak-Higashi syndrome.

We reviewed outcomes after allogeneic hematopoietic cell transplantation (HCT) in 35 children with Chediak-Higashi syndrome (CHS). Twenty-two patients had a history of the life-threatening accelerated phase of CHS before HCT and 11 were in accelerated phase at transplantation. Thirteen patients received their allograft from an human leukocyte antigen (HLA)-matched sibling, 10 from an alternative related donor and 12 from an unrelated donor. Eleven recipients of HLA-matched sibling donor, three recipients of alternative related donor and eight recipients of unrelated donor HCT are alive. With a median follow-up of 6.5 years, the 5-year probability of overall survival is 62%. Mortality was highest in those with accelerated phase disease at transplantation and after alternative related donor HCT. Only four of 11 patients with active disease at transplantation are alive. Seven recipients of alternative related donor HCT had active disease at transplantation and this may have influenced the poor outcome in this group. Although numbers are limited, HCT appears to be effective therapy for correcting and preventing hematologic and immunologic complications of CHS, and an unrelated donor may be a suitable alternative for patients without an HLA-matched sibling. Early referral and transplantation in remission after accelerated phase disease may improve disease-free survival.

Unrelated donor bone marrow transplantation for children and adolescents with Philadelphia-positive acute lymphoblastic leukemia.

PURPOSE: Few patients with Philadelphia-positive acute lymphoblastic leukemia (Ph-positive ALL) have been cured by chemotherapy alone. Registry figures show that 38% of patients who have a matched-sibling bone marrow transplant (BMT) are disease-free 2 years after transplant, but the majority of patients lack a sibling donor. Most modern ALL protocols recommend unrelated donor (UD) BMT for patients with Ph-positive ALL in first complete remission (CR1), but the outcome of this is unknown. PATIENTS AND METHODS: We report the results of 15 children and adolescents who had a T-cell depleted UD-BMT for Ph-positive ALL. Thirteen of 15 had been previously treated on United Kingdom ALL protocols. Nine were in CR1 and six had more advanced disease. Eleven donor recipient pairs were matched at HLA-A, HLA-B, HLA-DR, and HLA-DQ, and four were mismatched at one or two HLA loci. RESULTS: The incidence of greater than grade I acute and chronic graft-versus-host disease (GVHD) was low (13% and 8%, respectively). Six patients have relapsed and seven patients survive at a median of 21 months post-BMT; six of seven are disease free. All seven survivors are in full-time education or work. The 2-year overall and disease-free survivals are 44% +/- 13% and 37% +/- 13% (+/- SE). None of four patients who had mismatched donors survived, but seven of 11 matched recipients survive (P < .05). CONCLUSION: UD-BMT can produce prolonged disease-free survival in young patients with Ph-positive ALL who otherwise would have an extremely poor outlook.

Hematopoietic cell transplantation activity in Europe for inherited metabolic diseases: open issues and future directions.

For the past two decades, hematopoietic cell transplantation (HCT) has been used as effective therapy for selected inherited metabolic diseases (IMD). The primary goals of this therapy have been to promote long-term survival with donor-derived engraftment and to optimize quality of life. Careful, multidisciplinary decision-making regarding whether to recommend HCT and how to provide optimal peri- and post-HCT care has proven essential to increase the likelihood of a good outcome. Guidelines for HCT and monitoring have recently been provided in this journal. Here we report data on transplant activity for IMD in Europe and briefly discuss future directions. It is imperative that data collection for these procedures becomes as routine as that for patients undergoing HCT for malignancy and that follow-up is performed in a systematic manner. Large clinical trials have never been performed in this transplant field. Fortunately, accreditation procedures and improvements in information technology can now provide a firm foundation for such trials, which are urgently needed.

Rotavirus as a significant cause of prolonged diarrhoeal illness and morbidity following allogeneic bone marrow transplantation.

Infective diarrhoea is common among allogeneic stem cell transplant (SCT) recipients, frequently caused by viruses and may be difficult to differentiate from acute graft-versus-host disease (GVHD). Viral pathogens may directly or indirectly impact upon transplant-related mortality. Rotavirus is one of the most common causes of diarrhoea worldwide, but one of the least studied causes of diarrhoea post SCT. In this retrospective study we describe 21 cases of confirmed rotavirus infection in allogeneic SCT recipients. Most of these cases may occur in clusters during the winter and spring period. Symptoms of rotaviral infection were diarrhoea (95%), vomiting (62%), abdominal pain (38%), weight loss and loss of appetite in 38 and 29% of the cases, respectively. Possible extraintestinal manifestations of rotavirus infection were observed. The duration of the symptoms in this series ranged from 4 days to 4 months with median of 15 days. Patients with rotavirus infection were invariably lymphopenic and/or on immunosuppression for GVHD. Of the patients diagnosed with rotavirus, 86% required hospitalisation. In 57% of the cases, other viral pathogens were isolated near to the rotavirus infection period. Rotavirus infection is an important cause of prolonged diarrhoea post SCT, causing significant morbidity and frequently requiring hospitalisation.

Early emergence of PNH-like T cells after allogeneic stem cell transplants utilising CAMPATH-1H for T cell depletion.

CAMPATH-1H (C-1H) is widely used in vivo and / or in vitro for T cell depletion in hematopoietic SCT. This humanised monoclonal antibody is specific for CD52, a marker coexpressed on the majority of human lymphocytes with CD48 and other glycosylphosphatidyl-inositol (GPI) anchored proteins. We detected CD52 / CD48 dual expression on >99% of CD3(+) lymphocytes from normal individuals and all 15 post-SCT patients whose transplants did not utilise C-1H. By contrast, 23 / 26 patients with transplants involving C-1H (in vivo, in vitro or both) exhibited populations lacking CD52 expression that accounted for 49.7% (4.2-86.2%) of the CD3+ lymphocytes (median and range) in samples evaluated at a median of 2 months post-SCT. Most CD52- cells also lacked CD48 expression. These GPI- T cells were of either donor or mixed donor / recipient origin. They were predominant in the early months after SCT at times of profound lymphopenia and inversely correlated with the recovery of the absolute lymphocyte count (r= - 0.663, P<0.0001). The presence of CD52- cells has been correlated previously with clinical outcome after CAMPATH therapy for both malignant and nonmalignant diseases.

Third complementarity determining region (CDR III) sequence analysis in childhood B-lineage acute lymphoblastic leukaemia: implications for the design of oligonucleotide probes for use in monitoring minimal residual disease.

The genetic sequence of the third complementarity determining region (CDR III) of the immunoglobulin heavy chain (IgH) gene was analysed in 55 rearranged alleles from 36 children presenting with B-lineage acute lymphoblastic leukaemia (ALL). This confirmed the unique nature of these rearrangements. However, contrary to the hypothesis that the CDR III is produced by a random process of rearrangement, biased utilisation of diversity (D) segments and of joining (J) regions 4, 5 and 6 was demonstrated. Moreover, preferred sequence boundaries were seen in J regions 1 to 5 and were suggested at the 3'-end of certain D regions, notably D21/9 and DK1. Similar patterns of rearrangement have been noted in normal B-lymphocyte clones. Together with relatively limited N nucleotide addition, these factors may restrict the potential sequence variability at the D-N-J junction. The occurrence of clonal progression by secondary gene rearrangements, such as V-V replacement, favours the use of this site when designing clone-specific oligonucleotide probes for use in monitoring minimal residual disease (MRD). In cases where biased features of D-J rearrangement are shared by both the leukaemic and normal B-lymphocyte clones this could reduce the sensitivity of these probes in detecting low levels of residual disease.

Detection of clonality in childhood B-lineage acute lymphoblastic leukaemia by the polymerase chain reaction.

The polymerase chain reaction (PCR) was used to study clonality in a group of children with B-lineage acute lymphoblastic leukaemia (ALL). Rearrangement of the immunoglobulin heavy chain gene (IgH) results in a hypervariable sequence known as the complementarity determining region III. This can be amplified by the PCR using one pair of consensus primers. The PCR product is highly clone-specific in both size and sequence. Successful amplification was achieved in 50 of 62 cases of B-lineage ALL studied (81%). Both DNA and RNA gave almost identical results. In contrast amplification was only achieved in 2 of 42 control cases (non-B-lineage leukaemias, normal and reactive marrows); these were both cases of T-ALL with IgH rearrangement on Southern blotting. The main advantages of this technique over Southern blot assessment of clonality are the short time to result and requirement for much less DNA allowing study of small samples eg cerebrospinal fluid and testicular biopsies. It is also generally more sensitive for the detection of a malignant clone in a polyclonal marrow cell population and forms the basis of techniques to study minimal residual disease (MRD).

Minimal residual disease (MRD) status prior to allogeneic stem cell transplantation is a powerful predictor for post-transplant outcome in children with ALL.

We have retrospectively investigated the relationship between the level of minimal residual disease (MRD) detected in bone marrow taken prior to conditioning therapy and outcome following stem cell transplantation for high risk childhood ALL. Forty-one patients, in whom both a molecular marker of MRD and sufficient archival material was available, were included in the study. All were in remission at BMT: eight in CR1, 32 in CR2 and five in greater than CR2. MRD was measured by PCR amplification of antigen receptor gene rearrangements and clone-specific oligoprobing, the median sensitivity of detection being one leukaemic cell in 10000 normals. Results were classified as high-level positive (if a clonal band was evident after electrophoresis), low-level positive (if MRD was detected only after oligoprobing) and negative. MRD was detected at high levels in 17 patients, at low levels in 10 patients and 14 patients were MRD negative at the time of transplant. The 5-year event-free survival for these groups was 23%, 48% and 78%, respectively (P = 0.022). Limited multivariate analysis confirmed the significance of MRD (P = 0.0095) vs CR status, donor type, sex, immunophenotype and acute GvHD. This study confirms the strong relationship between MRD level and outcome following allogeneic transplantation. In contrast to a previous study we observed that a minority of children with high-level pre-BMT MRD can enter long lasting remission. The possible role for acute GVHD coupled with a graft-versus-leukaemia effect in the clearance of high level MRD in patients with ALL is discussed.

An optimised biphasic culture system for the generation of functional dendritic cells from patients with acute lymphoblastic leukaemia at presentation and in clinical remission.

We have tested the hypothesis that functional dendritic cells (DC) may be generated from patients with acute lymphoblastic leukaemia (ALL). We evaluated the production of DC from blast cells taken at presentation from nine children with ALL. Blast cells were expanded in serum-free medium supplemented with Flt3L, G-CSF, GM-CSF, IL-3, IL-6 and SCF for 7 days and subsequently stimulated with Flt3L, GM-CSF and TGF-beta for a further 14 days, with the addition of TNF-alpha for the final 48 h of culture. Cultured cells had the morphological appearance of DC and expressed the DC-associated antigens CD1A (range 2-87%) and CD83 (15-44%). Expression of the co-stimulatory molecules CD80 and CD86 was increased and the majority of these cells retained their expression of CD34 (73+/-4%) and HLA-DR (79+/-5%). Seven of the nine ALL had a leukaemia-specific abnormality and DC generated from five of these seven cases were derived from the leukaemic clone. Leukaemic DC derived from four HLA-A*02-positive ALL pulsed with CMV-associated peptides could induce significant proliferation of peptide-specific CD8+ T cells. This specificity was verified using tetrameric complexes of HLA class l/antigenic peptide. DC could also be generated from cells taken at times of complete remission of ALL and from normal controls using these culture conditions. These findings show that functional DC can be generated both from ALL blasts and from patients in remission; these might be utilised in future for immunotherapeutic strategies in the treatment of ALL.

Correlation between microsatellite discrepancy scores and transplant outcome after haemopoietic SCT for pediatric ALL.

Microsatellite analyses show that self-reported ethnicity often correlates poorly with true genetic ancestry. As unknown ancestral differences could potentially have an impact on transplant outcome, we developed an average allele length discrepancy (AALD) score to assess allele length discrepancy between donor/recipient (D/R) using microsatellites analysed routinely in post-transplant chimeric assessment. This was then compared with outcome in a homogeneously treated cohort of pediatric patients undergoing high-resolution sibling or matched unrelated donor transplantation for acute lymphoblastic leukemia (ALL). AALD scores formed a numeric continuum ranging from 0 to 1.4 (median 0.76) for sibling pairs and 0.8-2.17 (median 1.6) for high-resolution matched unrelated donor (HR-MUD) pairs. There was a trend for worse OS with increasing AALD score, which reached statistical significance above a threshold of 1.7 for OS. Patients whose transplants had an AALD score of ⩾1.8 had a risk of non-relapse mortality 4.9 times greater (P=0.025) and relapse risk three times greater (P=0.058) than those scoring <1.8. This approach will now be explored in a Centre International for Blood and Marrow Transplantation Research (CIBMTR) study of 750 D/R pairs across all disease groups; if confirmed, it has the potential to improve donor selection for patients with multiple prospective donors.

Study of the nonresorptive phenotype of osteoclast-like cells from patients with malignant osteopetrosis: a new approach to investigating pathogenesis.

Osteopetrosis manifests as failure of osteoclastic bone resorption. The cause of the disease lies either in the hematopoietic lineage or in the bone marrow stromal microenvironment. It has not been possible to define the cell type involved in the various forms of the human disease because of the inability to form human osteoclasts in vitro. Using the recently described method for generating human osteoclasts from peripheral blood in coculture with rat osteoblastic UMR 106 cells, we demonstrate that a defect lies in the mature osteoclast-like cells in four cases of this disease. Control and osteopetrotic cocultures generated large numbers of osteoclast-like cells (calcitonin and vitronectin receptor positive, and F-actin ring-positive cells) with similar morphology. Bone resorption did not occur in three of the four osteopetrotic cultures. In case 1, in which bone resorption was identified, the area of resorption was negligible compared with the number of osteoclast-like cells in the culture and was detected only by scanning electron microscopy. In contrast, up to 20% of the bone surface in controls was resorbed. The normal and osteopetrotic osteoclast-like cells had a similar phenotype except that two of the osteopetrotic cases did not express CD44 and two expressed CD44 weakly, whereas CD44 was strongly expressed in the controls. This study shows that it is possible to reproduce in vitro the pathological features of human osteopetrosis, and the assay provides a means of acquiring a greater understanding of the pathogenesis of human osteopetrosis.

Macrophage colony-stimulating factor and receptor activator NF-kappaB ligand fail to rescue osteoclast-poor human malignant infantile osteopetrosis in vitro.

Malignant infantile osteopetrosis (MIOP) is a disease characterized by failure in bone resorption, leading to dense fragile bones with a severely reduced bone marrow cavity. Normal or increased numbers of osteoclasts are present in the common variant of this disease; in such cases, the defect is likely to be inherent to the mature osteoclast and can be cured by bone marrow transplantation. However, MIOP also results from failure of osteoclast formation (osteoclast-poor MIOP). We report on two infants diagnosed with osteoclast-poor MIOP and utilize modern cell culture techniques to investigate the pathogenesis of disease. Peripheral blood mononuclear cells (PBMNCs) from these children were cultured in the presence of recombinant macrophage colony-stimulating factor and receptor activator NF-kappaB ligand for up to 3 weeks. Control cultures included PBMNCs from age-matched children, one of whom had an osteoclast-rich form of MIOP. Formation of osteoclasts (cells coexpressing vitronectin receptor and F-actin rings) occurred in all the control cultures. Significant bone resorption occurred in cultures from PBMNCs of the healthy individuals, whereas almost no bone resorption occurred in the osteoclast-rich MIOP cultures. In contrast, PBMNC cultures from the osteoclast-poor MIOP child formed only very occasional small F-actin ring-positive osteoclasts, which coexpressed vitronectin receptor and cathepsin K, and extremely rare foci of resorption. Because neither macrophage colony-stimulating factor nor receptor activator NF-kappaB ligand rescued the defect in osteoclast differentiation in the two cases of osteoclast-poor MIOP in vitro, there would be little benefit in treating these children with either of these recombinant proteins. Finally, these results demonstrate that this experimental culture model replicates the human osteopetrosis phenotype observed in vivo and should prove useful in analyzing the pathogenesis of the various forms of MIOP.

The use of Teflon cell culture bags to expand functionally active CD8+ cytotoxic T lymphocytes.

We have investigated the ability of Teflon cell culture (TCC) bags, compared to conventional tissue culture flasks and plates, to support the expansion of human CD8+ T cells in response to an allogeneic stimulus. TCC bags, which are compatible with good manufacturing practice (GMP), facilitated CD8+ T cell growth as well as conventional culture vessels and resulted in cytotoxic T cells which were able to kill allogeneic targets. Growth characteristics were compared by investigating the number, immunophenotype and cell cycle properties of the cells generated. The kinetics of cell growth were not significantly different over the first 14 days of culture in each vessel type, with the cell counts being highest at day 10 in all cases. However, the TCC bags resulted in a significantly higher proportion of cells with the morphology of typical lymphocytes than tissue culture flasks after 14 and 18 days in culture. There were no significant differences in the percentage of typical lymphocytes expanded in TCC bags compared to those expanded in plates. Expanded CD8+ cells maintained their initial level of expression of CD3, CD11a, CD18 and T cell receptor (alphabeta heterodimer, TCR (alphabeta)) but increased expression of CD45RO, CD95 and of activation markers HLA-DR and CD25 in each culture vessel. Studies of cell cycle parameters showed that each vessel supported CD8+ T cell stimulation, as demonstrated by significantly higher levels of S phase than fresh PBMN cells. The cells generated in TCC bags were able to kill allogeneic targets and also possessed natural killer (NK) cell activity. Thus, TCC bags are able to support the expansion of CD8+ T lymphocytes as well as flasks or tissue culture plates and are applicable to lymphocyte expansion for use in immunotherapy.

Hematopoietic cell transplantation for inherited metabolic diseases: an overview of outcomes and practice guidelines.

For the past two decades, hematopoietic cell transplantation (HCT) has been used as effective therapy for selected inherited metabolic diseases (IMD) including Hurler (MPS IH) and Maroteaux-Lamy (MPS VI) syndromes, childhood-onset cerebral X-linked adrenoleukodystrophy (X-ALD), globoid-cell leukodystrophy (GLD), metachromatic leukodystrophy (MLD), alpha-mannosidosis, osteopetrosis, and others. Careful pre-HCT evaluation is critical and coordinated, multidisciplinary follow-up is essential in this field of transplantation. The primary goals of HCT for these disorders have been to promote long-term survival with donor-derived engraftment and to optimize the quality of life. Guidelines for HCT and monitoring are provided; a brief overview of long-term results is also presented.

A laboratory comparison of T cell depletion by CD34+ cell immunoaffinity selection and in vitro Campath-1M treatment: clinical implications for bone marrow transplantation and donor leukocyte therapy.

Donor leukocyte infusions (DLI) have been used effectively to induce remission in patients who relapse after BMT. Using CD34+ cell immunoaffinity enrichment, donor T cells may be captured in the unadsorbed (residual) fraction and we assessed this as a potential source of functional T cells for post-BMT immunotherapy. We extended our study to compare CD34+ cell selection and antibody-mediated cell lysis using Campath-1M and measured T cell-depletion, CD34+ cell recovery and relative progenitor proliferative potential. The recovery of CD3+ cells (responsive to IL-2 or PHA) in the unadsorbed fraction was 84+/-12% (mean+/-s.d.) using a laboratory scale CD34+ cell selection process (CEPRATE LC). The immunoselected (CD34+ cell enriched) product contained 55+/-12% of the starting CD34+ cells (purity, 75+/-6%) with recoveries of 44+/-12% and 42+/-13% for CFU-GM and BFU-E respectively. T cell depletion was 99.8+/-0.2% (FACS) and the frequency of clonable T cells estimated at 1:640 (limiting dilution assay). In comparison, Campath-1M-treated marrow samples gave recoveries of CD34+ cells, CFU-GM and BFU-E of 50+/-7%, 78+/-20% and 79+/-18%, respectively. The frequency of clonable T cells was 1:2700 despite an estimated T cell depletion of 98.4+/-1.9%. Data obtained from four BM harvests processed on the clinical grade CEPRATE SC system was comparable in every respect to the laboratory scale system. The yield of 1259 +/- 222 x 10(6) CD3+ cells in the unadsorbed fraction would allow for multiple graded incremental T cell aliquots for DLI for patients with acute leukaemia.

Second allogeneic bone marrow transplants from unrelated donors for graft failure following initial unrelated donor bone marrow transplantation.

Graft failure is a common and severe complication of unrelated donor bone marrow transplantation (UD-BMT). However, there are few reports of a second UD-BMT in this setting. We describe 12 patients with graft failure (five primary, seven secondary) who had a second transplant, five from their original donor and seven from a different donor. Their median age was 9 years. Two patients died before day 10 of regimen-related toxicity. Nine of 10 evaluable patients engrafted in a median of 17 days. Secondary graft failure was seen in one patient. Transplant-related morbidity was significant. Six of nine developed acute GHVD, there were five severe infections and five patients developed Bearman grade 3 or 4 extramedullary toxicity. Overall, five patients survive at a median of 38 months after the second BMT and two are in continuous complete remission. Second transplants from unrelated donors for graft failure can result in prolonged survival.

Double T cell depletion of bone marrow using sequential positive and negative cell immunoaffinity or CD34+ cell selection followed by Campath-1M; effect on CD34+ cells and progenitor cell recoveries.

An advantage of CD34+ cell selection over antibody purging is that a component allograft is produced comprising a stem cell enriched and an unadsorbed fraction, the latter containing T cells which may be used for post-transplant immunotherapy. Initial reports with PBSC allografts suggested that T cell depletion (TCD) by CD34+ cell selection and post-graft cyclosporin A +/- methotrexate was insufficient prophylaxis against acute GVHD. We compared sequential TCD (of a CD34+ cell-selected fraction) using a second (CD2) immunoaffinity step or Campath-1M monoclonal antibody and complement. Since a high stem cell 'dose' enhances engraftment across HLA barriers and improves overall post-transplant outcome, the recovery of CD34+ cells and progenitors were assessed. Sequential positive (CD34+) and negative (CD2+) immunoaffinity selection resulted in a 3.4 log depletion of T cells as compared to a 4.05 log depletion when CD34+ cell selection was followed by Campath-1M treatment. Recoveries of CD34+ cells, CFU-GM and BFU-E following double depletion using CD34+ cell selection plus CD2+ cell depletion were 28, 25 and 17% as compared to 20, 18 and 16% when CD34+ cells were treated with Campath-1M. The unadsorbed fraction contained 85% of the original T cells, from which donor leukocyte infusions in the range of 10(5) to 10(7) CD3+ cells per kg body weight of the recipient were harvested. Despite the advantages of component allografts, the loss of stem/progenitor cells may restrict sequential TCD steps unless single BM harvests are supplemented and/or replaced with mobilised PBSCs.

Outcome and clinical course of 100 patients with adenovirus infection following bone marrow transplantation.

We conducted a retrospective review of the clinical features and outcome of adenovirus infection in 572 consecutive patients transplanted in a single centre over a 10 year period. One hundred patients (17%) had a total of 105 episodes of adenovirus infection diagnosed at a median of 18 days post transplant (range 2-150 days). The incidence was higher in children than adults (21% vs 9%, P < 0.001) and in unrelated donor vs matched sibling donor transplants (26% vs 9%, P < 0.001). Diarrhoea and fever were the most common presenting features. Reflecting these symptoms, the most common site of isolation was the stool. Serotypes 1, 2 and 7 were the most frequently seen (total of 41/68 or 60% of evaluable cases). In six patients (6%) adenovirus infection was the direct cause of death occurring at a median of 72 days post transplant (range 18-365 days). Five of these six patients had pulmonary involvement and four had associated graft-versus-host disease (GVHD). Three further patients were considered to have severe adenoviral disease (total incidence 9%). Isolation of virus from multiple sites correlated with a poor outcome (P < 0.001). Comorbid viral infection was common in this group with 50% of all patients having other viruses isolated (predominantly polyoma virus and cytomegalovirus). We conclude that adenovirus is commonly isolated after bone marrow transplant and is a cause of significant morbidity but was a rare cause of mortality (6/572 = 1%) in our patient group as a whole. The relative infrequency of severe infection will make it difficult for the transplant physician to decide which patients should receive experimental antiviral drugs such as ribavirin and cidofovir or immunomodulatory therapy with donor white cell infusions.

Long-term outcome of haematopoietic stem cell transplantation in autosomal recessive osteopetrosis: an EBMT report.

A retrospective analysis was made of 122 children who had received an allogeneic haematopoietic stem cell transplantation (HSCT) for autosomal recessive osteopetrosis between 1980 and 2001. The actuarial probabilities of 5 years disease free survival were 73% for recipients of a genotype HLA-identical HSCT (n=40), 43% for recipients of a phenotype HLA-identical or one HLA-antigen mismatch graft from a related donor (n=21), 40% for recipients of a graft from a matched unrelated donor (n=20) and 24% for patients who received a graft from an HLA-haplotype-mismatch related donor (n=41). In the latter group, a trend towards improvement was achieved at the end of the study period (17% before 1994, 45% after 1994, P=0.11). Causes of death after HSCT were graft failure and early transplant-related complications. Severe visual impairment was present in 42% of the children before HSCT. Conservation of vision was better in children transplanted before the age of 3 months. Final height was related to height at the time of HSCT and better preserved in children transplanted early. Most children attended regular school or education for the visually handicapped. At present, HSCT is the only curative treatment for autosomal recessive osteopetrosis and should be offered as early as possible.