Giuseppe Morreale

Genotype-Phenotype Relationship in Human ATP6i-Dependent Autosomal Recessive Osteopetrosis

Autosomal-recessive osteopetrosis is a severe genetic disease caused by osteoclast failure. Approximately 50% of the patients harbor mutations of the ATP6i gene, encoding for the osteoclast-specific a3 subunit of V-ATPase. We found inactivating ATP6i mutations in four patients, and three of these were novel. Patients shared macrocephaly, growth retardation and optic nerve alteration, osteosclerotic and endobone patterns, and high alkaline phosphatase and parathyroid hormone levels. Bone biopsies revealed primary spongiosa lined with active osteoblasts and high numbers of tartrate-resistant acid phosphatase (TRAP)-positive, a3 subunit-negative, morphologically unremarkable osteoclasts, some of which located in shallow Howship lacunae. Scarce hematopoietic cells and abundant fibrous tissue containing TRAP-positive putative osteoclast precursors were noted. In vitro osteoclasts were a3-negative, morphologically normal, with prominent clear zones and actin rings, and TRAP activity more elevated than in control patients. Podosomes, alphaVbeta3 receptor, c-Src, and PYK2 were unremarkable. Consistent with the finding in the bone biopsies, these cells excavated pits faintly stained with toluidine blue, indicating inefficient bone resorption. Bone marrow transplantation was successful in all patients, and posttransplant osteoclasts showed rescue of a3 subunit immunoreactivity.

Risk factors and severe outcome in thrombotic microangiopathy after allogeneic hematopoietic stem cell transplantation

Background. Thrombotic microangiopathy (TMA) has been described as severe complication after hematopoietic stem cell transplantation (HSCT). The principal aim of this study was to focus the incidence and the outcome of TMA in the era of more complex HSCTs. Methods. We analyzed the role of some predicting factors for the incidence and the outcome of TMA after HSCT. We enrolled 539 consecutive patients (307 males, median age 31 years) undergoing HSCT from match or mismatch human leukocyte antigen family donor (314) or match/mismatch unrelated (195) and haploidentical donor (30) for malignant or nonmalignant diseases. TMA diagnosis was performed by homogeneous clinical and laboratory criteria. Results. Sixty-four of 539 patients presented TMA (11,87%) and the five-year cumulative incidence of TMA was 14% (HR=0.13). Fifty nine of 64 patients were affected by malignant and 5/64 by non-malignant diseases. On multivariate analysis, TMA occurrence was influenced by graft versus host disease >grade II (P=0.0001), donor type (P=0.029), gender (P=0.0233), total body irradiation based conditioning regimen (P=0.0041). Three factors for TMA outcome proved to be statistically significant by multivariate analysis: age (P=0.009), donor type (P=0.0187) and TMA index (P=0.029). The TMA mortality rate was 50%. The outcome was influenced by defibrotide (P=0.02 in univariate analysis). Conclusions. The study underlines the possibility of finding out which patients are more prone to developing post-HSCT TMA, and identifies which risk factors are more frequently associated with a dismal outcome after TMA.

Severe neurologic complications after hematopoietic stem cell transplantation in children

Objective: To describe and evaluate the incidence and risk factors of severe neurologic events (SNE) in pediatric recipients of allogeneic or autologous hematopoietic stem cell transplantation (HSCT) for hematologic or nonhematologic diseases. Methods: Retrospective analysis of 272 consecutive children admitted to the G. Gaslini Children’s Research Institute and given HSCT (70 from unrelated donors, 115 from related donors, and 87 autologous) between June 1985 and January 2001. Results: Thirty-seven children (13.6%) developed SNE after a median of 90 days (range, 5 days to 8.8 years) after HSCT. Cyclosporine A (CSA) neurotoxicity was the most frequent SNE (n = 21), followed by irradiation or chemotherapy injury (n = 7), CNS infections (n = 7), cerebrovascular events (n = 3), and immune-mediated etiology SNE (n = 2). Eleven patients (30%) died because of the neurologic complications. Type of HSCT, treatment with total body irradiation (TBI), acute graft-vs-host disease (GvHD), GvHD >grade 2, and treatment with CSA were associated with a significant increased risk of SNE. Conclusions: Severe neurologic complications are frequent (14%) among children receiving HSCT, causing 8.5% of deaths after transplant. Transplant from allogeneic donor, especially if unrelated, the development of severe acute GvHD grade >2, and the use of TBI in the preparative regimen are the main risk factors for such complications.

The corticosteroid-induced inhibitory effect on NK cell function reflects down-regulation and/or dysfunction of triggering receptors involved in natural cytotoxicity.

Corticosteroids are known to inhibit NK cell functions. However no information is available on whether such inhibition may affect the expression and/or the function of receptors involved in NK cell activation. In an attempt to analyze this point, we studied peripheral blood NK cells isolated from pediatric patients undergoing allogeneic BM transplantation. NK cells were analyzed before, during and after methylprednisolone administration to treat acute graft‐versus‐host disease. In NK cells freshly isolated from peripheral blood during methylprednisolone treatment, the surface expression of activating receptors, particularly NKp46 and NKp30, was consistently reduced. Such impaired expression could also be detected after 5 days of culture in IL‐2. Such cultured NK cells also failed to express the IL‐2‐inducible NKp44 receptor. Accordingly, cytotoxicity against different tumor target cell lines was sharply reduced. The effect on NK cells isolated from healthy individuals and cultured in the presence of methylprednisolone was also analyzed. A similar inhibitory effect occurred in the expression of activating NK receptors. In addition, a sharp impairment of NK cytotoxicity against different tumor target cell lines or immature DC was detected.

Analysis of the activating receptors and cytolytic function of human natural killer cells undergoing in vivo differentiation after allogeneic bone marrow transplantation

Patients undergoing allogeneic bone marrow transplantation offer a unique system to analyze NK cell development in vivo. We analyzed NK cells from 23 such patients to assess the acquisition of activating receptors. Four patients displayed an immature NK cell surface phenotype at engraftment, as their cells were CD16–KIR– and NKG2D– but expressed low levels of NKp46, NKp30, 2B4 and NKG2A. These NK cells had particularly low cytolytic activity against the HLA‐class‐I– melanoma F01 cell line and the 721‐221 EBV‐infected B cell line. Moreover, cytoxicity was inhibited upon mAb‐mediated crosslinking of 2B4. Analysis of NK cells at day 30 after bone marrow transplantation revealed the occurrence of both phenotypic and functional maturation. These data are in agreement with a previous in vitro study showing that immature NK cell precursors express CD16, NKG2D and KIR only at a late stage of differentiation and also express inhibitory 2B4. Our present study allows a better understanding of the NK cell differentiation in vivo.

The outcome of children with Fanconi anemia given hematopoietic stem cell transplantation and the influence of fludarabine in the conditioning regimen: a report from the Italian pediatric group

Background and Objectives Hematopoietic stem cell transplantation (HSCT) still represents the only treatment potentially able to prevent/rescue the development of marrow failure and myeloid malignancies in patients with Fanconi anemia (FA). While in the past HSCT from an HLA-identical sibling was proven to cure many patients, a higher incidence of treatment failure has been reported in recipients of an unrelated donor (UD) or HLA-partially matched related allograft. Design and Methods We analyzed the outcome of 64 FA patients (age range, 2–20 years) who underwent HSCT between January 1989 and December 2005. Patients were transplanted from either an HLA-identical sibling (n=31), an UD (n=26), or an HLA-partially matched relative (n=7). T-cell depletion of the graft was performed in patients transplanted from an HLA-disparate relative. Results The 8-year estimate of overall survival (OS) for the whole cohort was 67%; it was 87%, 40% and 69% when the donor was an HLA-identical sibling, an UD and a mismatched relative, respectively (p<0.01). The outcome of recipients of grafts from an UD improved over time, the probability of survival being 10% and 72% for patients transplanted before and after 1998, respectively (p<0.05). The OS probability of children who did or did not receive fludarabine in preparation for the allograft was 86% and 59%, respectively (p<0.05). Interpretation and Conclusions These data, useful for counselling, provide support to the concept that a relevant proportion of FA patients undergoing HSCT can now be successfully cured, even in the absence of an HLA-identical sibling, especially if the conditioning regimen includes fludarabine.

Incidence of bacteremias and invasive mycoses in children undergoing allogeneic hematopoietic stem cell transplantation: a single center experience.

We performed a retrospective single center study to define the epidemiology of bacteremias or invasive mycoses in pediatric allogeneic hematopoietic SCT (HSCT) from matched related donors (MRD) or alternative donors (AD). During 119 213 days of follow-up, 156 infections were observed: 130 bacteremias (27 in MRD-HSCT and 103 in AD-HSCT recipients) and 26 invasive mycoses (8 in MRD-HSCT and 18 in AD-HSCT recipients). Overall, the risk of bacteremia was fivefold that of invasive mycosis (P<0.001). AD-HSCT recipients had a higher percentage of infections (89 vs 27%; P<0.001), a higher rate/100 days of immunosuppression (infection rate (IR): 0.21 vs 0.06; P<0.001) and a higher proportion of repeated infections (44 vs 9%; P=0.001). In AD-HSCT, the relative risk of bacteremia was 2.87 in the pre-engraftment period, 5.84 in the early post-engraftment period and 6.46 in the late post-engraftment period (P<0.001) compared to MRD-HSCT. Only after 1 year did the epidemiology become similar. The epidemiology of invasive mycoses did not differ significantly between the two types of transplant.

Four year follow-up of a case of fucosidosis treated with unrelated donor bone marrow transplantation

Fucosidosis is a rare autosomal recessive lysosomal disorder caused by α-fucosidase deficiency. We report a child with fucosidosis, second daughter of non-consanguineous parents, for whom biochemical diagnosis followed clinical evidence of the disease in her older sister. Based on previous experiences, the indication to transplant was considered. Since she lacked a matched sibling, an unrelated marrow donor was found. At pre-hematopoietic stem cell transplantation evaluation, first signs of neurological involvement were clinically detectable. MRI showed diffuse hypomyelination and auditory brainstem responses and somatic-sensorial evoked potentials were altered. Visual evoked potentials were normal, tortuosity in the retinal veins and peripapillary hemorrhages were detected. Bone marrow transplantation conditioning was with a regimen of busulphan, thiotepa and cyclophosphamide; in vivo Campath 1G, cyclosporin A and short course methotrexate were given to prevent graft-versus-host disease. The patient engrafted rapidly and her post-transplant course was complicated by moderate graft-versus-host disease, transient episodes of idiopathic thrombocytopenic purpura, repeated septic complications and recurrent episodes of Sweets syndrome. Sequential short tandem repeat polymorphisms on peripheral blood and bone marrow cells documented the persistence of donor engraftment. Follow-up showed a progressive rise of enzymatic levels. Psychomotor development improved, as confirmed by evaluation of evoked potentials and by MRI scanning. Bone Marrow Transplantation (2001) 27, 747–751.

Invasive mycoses in children receiving hemopoietic SCT

Invasive mycoses represent a rare but severe complication following hemopoietic SCT (HSCT) in children. Their incidence is related to the type of donor, being higher after allogeneic transplant, especially from alternative donors. Moreover, the incidence of invasive mycoses varies in the different post transplant phases. Neutropenia, lymphopenia, GvHD, high-dose steroids or other immunosuppressive drugs represent well-known risk factors. The clinical features of invasive mycoses after HSCT in children are similar to those observed in adults, and the diagnostic tools, including Aspergillus galactomannan antigen detection, are feasible also in pediatrics. Mortality due to invasive mycoses after HSCT in children is high.

Bloodstream infections can develop late (after day 100) and/or in the absence of neutropenia in children receiving allogeneic bone marrow transplantation.

We retrospectively evaluated the incidence and time from transplantation of bloodstream infections occurring in children receiving bone marrow transplant (BMT) at G Gaslini Children’s Hospital between September 1984 and December 1997. During this period the incidence was 35% after allogeneic and 26% after autologous BMT (P = 0.08). Among these episodes, 38% after allogeneic BMT and 90% after autologous BMT were detected in the presence of neutropenia within the first 30 days from reinfusion (P < 0.001). incidence of catheter-related bloodstream infections was 40% after allogeneic and 8% after autologous bmt (P < 0.001). bloodstream infections in the absence of neutropenia were 55% after allogeneic bmt vs 10% after autologous BMT (P < 0.001) and occurred later after reinfusion (mean 199 vs 41 days, P <0.001). among the episodes occurring after allogeneic bmt and in the absence of neutropenia, 61% were related to the presence of a central venous catheter, 15% were related to the presence of gvhd, but 23% were not associated with any of major risk factors for infection. finally, 38% of episodes following allogeneic bmt were detected after day 100 vs 1% after autologous BMT. We concluded that patients receiving allogeneic BMT experience a high incidence of bloodstream infections in the absence of neutropenia and that a significant proportion of these episodes is not clearly associated with well known risk factors such as GVHD or central venous catheters. Moreover, many episodes develop a long time after the transplantation procedure. Therefore, any febrile episode following allogeneic BMT even late and/or in the absence of neutropenia should be intensively managed.