Implementation of an Online Intraoperative Assessment of Technical Performance for Surgical Trainees.

INTRODUCTION: Assessment of surgical resident technical performance is an integral component of any surgical training program. Timely assessment delivered in a structured format is a critical step to enhance technical skills, but residents often report that the quality and quantity of timely feedback received is lacking. Moreover, the absence of written feedback with specificity can allow residents to seemingly progress in their operative milestones as a junior resident, but struggle as they progress into their postgraduate year 3 and above. We therefore designed and implemented a web-based intraoperative assessment tool and corresponding summary "dashboard" to facilitate real-time assessment and documentation of technical performance. MATERIALS AND METHODS: A web form was designed leveraging a cloud computing platform and implementing a modified Ottawa Surgical Competency Operating Room Evaluation instrument; this included additional, procedure-specific criteria for select operations. A link to this was provided to residents via email and to all surgical faculty as a Quick Response code. Residents open and complete a portion of the form on a smartphone, then relinquish the device to an attending surgeon who then completes and submits the assessment. The data are then transferred to a secure web-based reporting interface; each resident (together with a faculty advisor) can then access and review all completed assessments. RESULTS: The Assessment form was activated in June 2021 and formally introduced to all residents in July 2021, with residents required to complete at least one assessment per month. Residents with less predictable access to operative procedures (night float or Intensive Care Unit) were exempted from the requirement on those months. To date a total of 559 assessments have been completed for operations performed by 56 trainees, supervised by 122 surgical faculty and senior trainees. The mean number of procedures assessed per resident was 10.0 and the mean number per assessor was 4.6. Resident initiation of Intraoperative Assessments has increased since the tool was introduced and scores for technical and nontechnical performance reliably differentiate residents by seniority. CONCLUSIONS: This novel system demonstrates that an online, resident-initiated technical assessment tool is feasible to implement and scale. This model's requirement that the attending enter performance ratings into the trainee's electronic device ensures that feedback is delivered directly to the trainee. Whether this aspect of our assessment ensures more direct and specific (and therefore potentially actionable) feedback is a focus for future study. Our use of commercial cloud computing services should permit cost-effective adoption of similar systems at other training programs.

[Neurological complications in haematopoietic stem cell transplant patients]. / Complicaciones neurológicas en pacientes sometidos a trasplante de progenitores hematopoyéticos.

INTRODUCTION: Neurological complications are some of the most important complications that can occur in a patient undergoing haematopoietic stem cell transplantation (HSCT), not only because of the high mortality rate, but also because of the sequelae that appear in survivors. The causes of such complications are manifold and very often coexist in the same patient: toxicity of the conditioning regimen, graft-versus-host disease and its treatment, infections and their treatment, platelets and coagulation disorders, liver failure or arterial hypertension with low platelet count. AIMS: The aim of the present study is to provide a clinical description and to describe the risk factors for complications involving the central nervous system that may occur during the course of HSCT, in order to assist in the early detection of these disorders that may have a negative influence on the morbidity and mortality of these patients. DEVELOPMENT: The following types of neurological complications are described: central nervous system infections, vascular complications, pharmacological toxicity, metabolic complications, immune-mediated disorders and post-HSCT carcinogenesis, and effects of graft-versus-host disease and thrombotic microangiopathy on the nervous system. CONCLUSIONS: The patient undergoing HSCT is at particular risk for the development of neurological complications. Early diagnosis and treatment are needed to try to reduce the high morbidity and mortality in these patients.

TITLE: Complicaciones neurológicas en pacientes sometidos a trasplante de progenitores hematopoyéticos.Introducción. Las complicaciones neurológicas son algunas de las más importantes que se pueden presentar en un paciente sometido a un trasplante de progenitores hematopoyéticos (TPH), no sólo porque conllevan una mortalidad elevada, sino también por las secuelas que aparecen en los supervivientes. Las causas de dichas complicaciones son múltiples y, muy frecuentemente, coexisten en el mismo paciente: toxicidad del régimen de acondicionamiento, enfermedad del injerto contra el hospedador y su tratamiento, infecciones y su tratamiento, plaquetopenia y trastornos de la coagulación, fallo hepático o hipertensión arterial con plaquetopenia. Objetivos. El objetivo del presente estudio es el de aportar una descripción clínica y de los factores de riesgo de las complicaciones sobre el sistema nervioso central que pueden presentarse en el curso de un TPH, para ayudar en la detección precoz de estos trastornos que pueden influir negativamente en la morbimortalidad de estos pacientes. Desarrollo. Se describen los siguientes tipos de complicaciones neurológicas: infecciones sobre el sistema nervioso central, complicaciones vasculares, toxicidad farmacológica, complicaciones metabólicas, trastornos inmunomediados y carcinogenia pos-TPH, y efectos de la enfermedad del injerto contra el hospedador y de la microangiopatía trombótica sobre el sistema nervioso. Conclusiones. El paciente sometido a TPH es de especial riesgo para el desarrollo de complicaciones neurológicas. Se precisan un diagnóstico y un tratamiento precoces para intentar disminuir la elevada morbimortalidad de estos pacientes.

Application of a digital PCR method for WT1 to myeloid neoplasms in CR and deep ELN WT1 molecular response (< 10 copies).

Bone marrow WT1 mRNA levels assessed by the ELN method are useful to establish prognostic correlations in myeloid malignancies treated with chemotherapy or hematopoietic stem cell transplantation (HCT). Those patients with WT1 levels below ten copies have a good outcome. However, some of these patients relapse. To further characterize this group of cases, we applied a new and sensitive digital (ddPCR) WT1 method. A consecutive series of 49 patients with treated myeloid malignancies and with an ELN WT1 quantitation of < 10 copies were included in the study. All cases (47 AML and 2 MDS) have received intensive chemotherapy or HCT. One to four micrograms of total RNA were retrotranscribed to obtain ≥ 10,000 ABL1 copies using the ELN protocol. Only those cases with a good quality cDNA were used in the ddPCR WT1 test. The ddPCR Gene Expression WT1 Assay of Bio-Rad© was used to perform the PCR amplification, and the microdroplets were quantified in the Bio-Rad's QX200 droplet reader. Eighteen patients showed a negative WT1 ddPCR assay (0 copies/µl), whereas 31 cases were positive (results ranged from 1 to 15.2 copies/µl). Survival analysis showed statistically significant differences in terms of OS between both groups, 83 ± 8% vs. 46 ± 9% (p = 0.024). A statistically significant correlation was also found between ddPCRWT1 results and CD123+ cell number detected by flow cytometry (p = 0.024). Larger series of patients tested with the current ddPCRWT1 method will solve whether it could be used to stratify patients with myeloid malignancies achieving deep WT1 molecular response (< 10 copies).

[Survival analysis of hematopoietic stem cell transplantation in children with primary immunodeficiency in Spain]. / Análisis de la supervivencia de los niños con inmunodeficiencias primarias que han recibido un trasplante de progenitores hematopoyéticos en España.

INTRODUCTION: Children with primary immunodeficiency have severe life-threatening infections and a higher prevalence of autoimmune problems, allergy and lymphoproliferative disorders. Allogenic hematopoietic stem cell transplantation has been the only potentially curative option. PATIENTS AND METHODS: Patients with primary immunodeficiency underwent allogenic stem cell transplantation in the period 1985-2011, and registered in the Spanish Working Party for Bone Marrow Transplantation in Children. RESULTS: One hundred and fifty nine patients underwent 173 allogenic stem cell transplantations, of whom 97 had severe combined immunodeficiency, 30 with immune dysregulation disorders, 25 Wiskott-Aldrich syndrome, and 21 phagocyte disorders. The median patient age at diagnosis was 6 months (range: 17 days - 168 months) and the median patient age at transplant was 12 months (range: 1 month - 189 months). The donors were 30 (19%) identical siblings, 40 (25%) alternative family donors, and 89 (56%) unrelated donors. The source of stem cells was bone marrow in 68 (43%), cord blood in 52 (33%), and peripheral blood in 39 (24%). Ninety eight (61.6%) are alive, 57 (35.9%) died. Event-free survival at 10 years was 63%, with 90% for children transplanted from identical siblings, 36% for those transplanted from alternative family donors, and 66% for those transplanted from unrelated donors. CONCLUSIONS: The best results have been obtained with identical siblings, but other options may be considered.

Long-term outcome and prognostic factors of unrelated cord blood transplantation in children with haematological malignancies: a retrospective study using the Spanish Working Party for BMT in Children (GETMON) database.

Outcomes of unrelated cord blood transplants (UCBT) were assessed in 172 consecutive children, median age 5 years (range: 0.5-18), with haematological malignancies treated at nine Spanish hospitals between February 1996 and April 2009. Data were collected from the Spanish Working Party for Blood and Marrow Transplantation in Children (GETMON) database. ALL was diagnosed in 125 patients, AML in 43 and myelodysplastic syndrome in 4. Myeloid engraftment (ANC⩾0.5 × 10(9)/L) occurred in 87.2% at a median of 22 days and was associated with the total nucleated cell (TNC) dose infused and use of a TT-containing conditioning regimen. Cumulative incidence of relapse was 20% at 1 year post transplant and 29% at 3 years, being higher in patients with a diagnosis of ALL, very high risk disease and GVHD grades 0-1. Cumulative incidence of non-relapse mortality (NRM) was 19% at 100 days post transplant and 39% at 1 year. BU-FLU-TT-ATG-conditioned patients had lower NRM. Disease-free survival (DFS) was 40% at 2 years post transplant (for patients transplanted since 2006). On multivariate analysis, TNC dose infused, AML and BU-FLU-TT-ATG-conditioning regimen increased the probability of DFS. It is of paramount importance to select cord blood units with the highest cell dose. As the BU-FLU-TT-ATG-conditioning regimen was associated with better DFS owing to lower NRM, further prospective studies testing this regimen are warranted.

A novel monoclonal antibody to CD40 prolongs islet allograft survival.

The importance of CD40/CD154 costimulatory pathway blockade in immunosuppression strategies is well-documented. Efforts are currently focused on monoclonal antibodies specific for CD40 because of thromboembolic complications associated with monoclonal antibodies directed towards CD154. Here we present the rational development and characterization of a novel antagonistic monoclonal antibody to CD40. Rhesus macaques were treated with the recombinant anti-CD40 mAb, 2C10, or vehicle before immunization with keyhole limpet hemocyanin (KLH). Treatment with 2C10 successfully inhibited T cell-dependent antibody responses to KLH without significant peripheral B cell depletion. Subsequently, MHC-mismatched macaques underwent intraportal allogeneic islet transplantation and received basiliximab and sirolimus with or without 2C10. Islet graft survival was significantly prolonged in recipients receiving 2C10 (graft survival time 304, 296, 265, 163 days) compared to recipients receiving basiliximab and sirolimus alone (graft survival time 8, 8, 10 days). The survival advantage conferred by treatment with 2C10 provides further evidence for the importance of blockade of the CD40/CD154 pathway in preventing alloimmune responses. 2C10 is a particularly attractive candidate for translation given its favorable clinical profile.

CTLA4Ig prevents alloantibody formation following nonhuman primate islet transplantation using the CD40-specific antibody 3A8.

Islet transplantation to treat type 1 diabetes has been limited in part by toxicities of current immunosuppression and recipient humoral sensitization. Blockade of the CD28/CD80/86 and CD40/CD154 pathways has shown promise to remedy both these limitations, but translation has been hampered by difficulties in translating CD154-directed therapies. Prior CD40-directed regimens have led to prolonged islet survival, but fail to prevent humoral allosensitization. We therefore evaluated the addition of CTLA4Ig to a CD40 blockade-based regimen in nonhuman primate (NHP) alloislet transplantation. Diabetic rhesus macaques were transplanted allogeneic islets using the CD40-specific antibody 3A8, basiliximab induction, and sirolimus with or without CTLA4Ig maintenance therapy. Allograft survival was determined by fasting blood glucose levels and flow cytometric techniques were used to test for donor-specific antibody (DSA) formation. CTLA4Ig plus 3A8, basiliximab and sirolimus was well tolerated and induced long-term islet allograft survival. The addition of CTLA4Ig prevented DSA formation, but did not facilitate withdrawal of the 3A8-based regimen. Thus, CTLA4Ig combines with a CD40-specific regimen to prevent DSA formation in NHPs, and offers a potentially translatable calcineurin inhibitor-free protocol inclusive of a single investigational agent for use in clinical islet transplantation without relying upon CD154 blockade.

Alternative immunomodulatory strategies for xenotransplantation: CD40/154 pathway-sparing regimens promote xenograft survival.

Immunosuppressive therapies that block the CD40/CD154 costimulatory pathway have proven to be uniquely effective in preclinical xenotransplant models. Given the challenges facing clinical translation of CD40/CD154 pathway blockade, we examined the efficacy and tolerability of CD40/CD154 pathway-sparing immunomodulatory strategies in a pig-to-nonhuman primate islet xenotransplant model. Rhesus macaques were rendered diabetic with streptozocin and given an intraportal infusion of ≈ 50 000 islet equivalents/kg wild-type neonatal porcine islets. Base immunosuppression for all recipients included maintenance therapy with belatacept and mycophenolate mofetil plus induction with basiliximab and LFA-1 blockade. Cohort 1 recipients (n = 3) were treated with the base regimen alone; cohort 2 recipients (n = 5) were additionally treated with tacrolimus induction and cohort 3 recipients (n = 5) were treated with alefacept in place of basiliximab, and more intense LFA-1 blockade. Three of five recipients in both cohorts 2 and 3 achieved sustained insulin-independent normoglycemia (median rejection-free survivals 60 and 111 days, respectively), compared to zero of three recipients in cohort 1. These data show that CD40/CD154 pathway-sparing regimens can promote xenoislet survival. Further optimization of these strategies is warranted to aid the clinical translation of islet xenotransplantation.

Methotrexate consolidation treatment according to pharmacogenetics of MTHFR ameliorates event-free survival in childhood acute lymphoblastic leukaemia.

Recent advances in treatment for childhood acute lymphoblastic leukaemia (ALL) have significantly increased outcome. High-dose methotrexate (MTX) is the most commonly used regimen during the consolidation period, but the optimal dose remains to be defined. We investigated the usefulness of the MTHFR genotype to increase the MTX dosage in the consolidation phase in 141 childhood ALL patients enrolled in the ALL/SHOP-2005 protocol. We also investigated the pharmacogenetic role of polymorphisms in genes involved in MTX metabolism on therapy-related toxicity and survival. Patients with a favourable MTHFR genotype (normal enzymatic activity) treated with MTX doses of 5 g m⁻² had a significantly lower risk of suffering an event than patients with an unfavourable MTHFR genotype (reduced enzymatic activity) that were treated with the classical MTX dose of 3 g m⁻² (P=0.012). Our results indicate that analysis of the MTHFR genotype is a useful tool to optimise MTX therapy in childhood patients with ALL.

Nondepleting anti-CD40-based therapy prolongs allograft survival in nonhuman primates.

Costimulation blockade of the CD40/CD154 pathway has been effective at preventing allograft rejection in numerous transplantation models. This strategy has largely depended on mAbs directed against CD154, limiting the potential for translation due to its association with thromboembolic events. Though targeting CD40 as an alternative to CD154 has been successful at preventing allograft rejection in preclinical models, there have been no reports on the effects of CD40-specific agents in human transplant recipients. This delay in clinical translation may in part be explained by the presence of cellular depletion with many CD40-specific mAbs. As such, the optimal biologic properties of CD40-directed immunotherapy remain to be determined. In this report, we have characterized 3A8, a human CD40-specific mAb and evaluated its efficacy in a rhesus macaque model of islet cell transplantation. Despite partially agonistic properties and the inability to block CD40 binding of soluble CD154 (sCD154) in vitro, 3A8-based therapy markedly prolonged islet allograft survival without depleting B cells. Our results indicate that the allograft-protective effects of CD40-directed costimulation blockade do not require sCD154 blockade, complete antagonism or cellular depletion, and serve to support and guide the continued development of CD40-specific agents for clinical translation.

Islet xenotransplantation using gal-deficient neonatal donors improves engraftment and function.

Significant deficiencies in understanding of xenospecific immunity have impeded the success of preclinical trials in xenoislet transplantation. Although galactose-α1,3-galactose, the gal epitope, has emerged as the principal target of rejection in pig-to-primate models of solid organ transplant, the importance of gal-specific immunity in islet xenotransplant models has yet to be clearly demonstrated. Here, we directly compare the immunogenicity, survival and function of neonatal porcine islets (NPIs) from gal-expressing wild-type (WT) or gal-deficient galactosyl transferase knockout (GTKO) donors. Paired diabetic rhesus macaques were transplanted with either WT (n = 5) or GTKO (n = 5) NPIs. Recipient blood glucose, transaminase and serum xenoantibody levels were used to monitor response to transplant. Four of five GTKO versus one of five WT recipients achieved insulin-independent normoglycemia; transplantation of WT islets resulted in significantly greater transaminitis. The WT NPIs were more susceptible to antibody and complement binding and destruction in vitro. Our results confirm that gal is an important variable in xenoislet transplantation. The GTKO NPI recipients have improved rates of normoglycemia, likely due to decreased susceptibility of xenografts to innate immunity mediated by complement and preformed xenoantibody. Therefore, the use of GTKO donors is an important step toward improved consistency and interpretability of results in future xenoislet studies.

CD40-specific costimulation blockade enhances neonatal porcine islet survival in nonhuman primates.

The widespread clinical implementation of alloislet transplantation as therapy for type 1 diabetes has been hindered by the lack of suitable islet donors. Pig-to-human islet xenotransplantation is one strategy with potential to alleviate this shortage. Long-term survival of porcine islets has been achieved using CD154-specific antibodies to interrupt the CD40/CD154 costimulation pathway; however, CD154-specific antibodies seem unlikely candidates for clinical translation. An alternative strategy for CD40/CD154 pathway interruption is use of CD40-specific antibodies. Herein, we evaluate the ability of a chimeric CD40-specific monoclonal antibody (Chi220) to protect islet xenografts. Neonatal porcine islets (~50,000 IEQ/kg) were transplanted intraportally into pancreatectomized diabetic macaques. Immunosuppression consisted of induction therapy with Chi220 and the IL-2 receptor-specific antibody basiliximab, and maintenance therapy with sirolimus and the B7-specific fusion protein belatacept. Chi220 effectively promoted xenoislet engraftment and survival, with five of six treated recipients achieving insulin-independent normoglycemia (median rejection-free survival 59 days; mean 90.8 days, maximum 203 days). No thromboembolic phenomena were observed. CD40 represents a promising alternative to CD154 as a therapeutic target, and the efficacy of CD40-specific antibodies in islet xenotransplantation warrants further investigation.

Observational prospective study of viral infections in children undergoing allogeneic hematopoietic cell transplantation: a 3-year GETMON experience.

We studied surveillance, incidence and outcome of viral infections in children undergoing allogeneic hematopoietic cell transplantation (HCT) in the main pediatric transplant units in Spain. We prospectively collected data from first year post-HCT in every consecutive allogeneic HCT performed during 3 years (N = 215): first HCT = 188 and second HCT = 27; median age = 6.6 years (0.1-20.7). Most patients had acute leukemia (N = 137) and 135 recipients (63%) were CMV seropositive. A total of 46 patients underwent cord blood transplant, 133 patients underwent HCT from alternative donors (62%) and 101 patients received anti-thymocyte globulin. Observational time was completed in 137 patients, whereas the remaining 78 died after a median survival time of 99 days (3-352). CMV was monitored in all patients; adenovirus (ADV) and human herpesvirus 6 (HHV-6) were monitored in 101 and 33 patients, respectively. We found 145 viral infections in 103 patients: CMV (n = 42), ADV (n = 32), HHV-6 (n = 7), polyomavirus (n = 20), EBV (n = 6), VZV (n=17) and others (n = 8). CMV infection was significantly higher in seropositive patients (25 vs 7%) (P = 0.02). Extensive chronic GVHD (cGVHD) was significantly associated with an increased rate of viral infections (12 of 16 patients with cGVHD had infections vs 91 of 199 without GVHD) (P = 0.035). In total, 10 patients (4.6%) died of viral infections (CMV = 5, ADV = 3, respiratory = 2). We found a high incidence of viral infection, but mortality was low.

Cytokines following SCT: indications and controversies.

The use of G-CSF and GM-CSF has been shown to benefit patients undergoing autologous hematopoietic SCT (HSCT), mainly after autologous bone marrow transplantation. Their benefit in allogeneic transplant is not as pronounced and the use of growth factors in this patient group remains controversial due to conflicting reports of whether the use of growth factors increases the incidence of acute and chronic GvHD. The efficacy of EPO in HSCT patients is not well studied, but a reduction in the number of RBC transfusions has been shown in patients undergoing allogeneic transplant. Also the efficacy of thrombopoietic agents to date has not been demonstrated. One promising new approach to reduce the degree of mucositis is the use of recombinant keratinocyte growth factor.

Allogeneic hemopoietic stem cell transplantation for childhood acute lymphoblastic leukemia in second complete remission-similar outcomes after matched related and unrelated donor transplant: a study of the Spanish Working Party for Blood and Marrow Transplantation in Children (Getmon).

The authors report the results of 58 children with ALL in 2CR after related (n = 31) or unrelated (n = 27) AHSCT. Characteristics at diagnosis and initial and after relapse antileukemic treatment were similar in the related donor (RD) and the unrelated donor (UD) groups. Conditioning consisted of TBI/CY +/- VP-16 for patients > or = 3 years old (n = 43) and Bu/CY for the rest. Median recipient age was 8 years (range 1-17) in the RD and 9 years (range 3-14) in the UD group. Median follow-up was 54 months (range 24-80) and 52 months (range 22-85) in the RD and the UD groups repectively. The 5-year EFS probability was 43 +/- 9% for the RD group and 36 +/- 9% in the UD group (p = .25). The transplant-related mortality was 16% in the RD and 37% in the UD group (p = .016). In the RD group 36.7% of patients relapsed versus 18.6% in the UD group (p = .05). GvHD associated with organ failure or infection caused most of the transplant-related deaths in both groups. Survivor quality of life for both groups was good (Lansky score < or = 90).

Unrelated cord blood transplantation for severe combined immunodeficiency and other primary immunodeficiencies.

HCT is currently the treatment of choice for children with severe primary immunodeficiencies (PIDs). Frequently, these patients lack an HLA-identical sibling donor, and umbilical cord blood (UCB) transplantation may be an option; however, experience in this field remains scant. Fifteen children with PID (SCID 11, X-linked lymphoproliferative syndrome 2, Omenn's syndrome 1, Wiskott-Aldrich syndrome 1) received a UCB transplant. The donor was unrelated in 14 cases and related in 1. Median age at transplant was 11.6 months (range, 2.9-68.0) and median weight 7 kg (range, 4-21). Thirteen patients were conditioned with busulphan and cyclophosphamide and 2 with fludarabine and melphalan. Nine patients received antithymocyte globulin. Median NC x 10(7)/kg infused was 7.9 (range, 2.9-25.0) and median CD34 x 10(5)/kg 2.9 (range, 1.0-7.9). All patients engrafted. Median days to >0.5 x 10(9)/l neutrophils was 31. Eight patients developed acute graft-versus-host disease (GvHD) grades II-IV and one chronic GvHD. Viral and fungal infections were frequent. Four patients died: three from GvHD grade IV complicated by infection and one from progressive interstitial lung disease. Five-year survival was 0.73+/-0.12. All surviving patients presented complete immunologic reconstitution. No patient is intravenous immunoglobulin (IVIg) replacement therapy-dependent. UCB transplantation is a valid option for children with PID who lack an HLA-identical sibling donor.

NF-kappaB p50 and p52 regulate receptor activator of NF-kappaB ligand (RANKL) and tumor necrosis factor-induced osteoclast precursor differentiation by activating c-Fos and NFATc1.

Postmenopausal osteoporosis and rheumatoid joint destruction result from increased osteoclast formation and bone resorption induced by receptor activator of NF-kappaB ligand (RANKL) and tumor necrosis factor (TNF). Osteoclast formation induced by these cytokines requires NF-kappaB p50 and p52, c-Fos, and NFATc1 expression in osteoclast precursors. c-Fos induces NFATc1, but the relationship between NF-kappaB and these other transcription factors in osteoclastogenesis remains poorly understood. We report that RANKL and TNF can induce osteoclast formation directly from NF-kappaB p50/p52 double knockout (dKO) osteoclast precursors when either c-Fos or NFATc1 is expressed. RANKL- or TNF-induced c-Fos up-regulation and activation are abolished in dKO cells and in wild-type cells treated with an NF-kappaB inhibitor. c-Fos expression requires concomitant RANKL or TNF treatment to induce NFATc1 activation in the dKO cells. Furthermore, c-Fos expression increases the number and resorptive capacity of wild-type osteoclasts induced by TNF in vitro. We conclude that NF-kappaB controls early osteoclast differentiation from precursors induced directly by RANKL and TNF, leading to activation of c-Fos followed by NFATc1. Inhibition of NF-kappaB should prevent RANKL- and TNF-induced bone resorption.

A simplified approach to improve the efficiency and safety of ex vivo hematopoietic gene therapy in fanconi anemia patients.

Fanconi anemia (FA) is an inherited DNA repair disorder characterized by genetic instability of cells lacking a functional FA/BRCA pathway. Previous studies have shown that in vitro stimulation of bone marrow cells (BMCs) from FA mice promotes apoptosis, reduces the reconstitution ability of the stem cells, and induces myelodysplasia and myeloid leukemia upon reinfusion of the cells. This suggests the convenience of adapting standard protocols of gene therapy to FA. Here we show that the reserve of BM progenitors in FA patients is generally below 20% of normal values. Because this reduced reserve could activate the cycling of BM progenitors, we developed a simplified protocol to transduce BMCs from FA patients with gammaretroviral vectors. We demonstrate that a short in vitro manipulation (12-24 hr) of fresh mononuclear BMCs is sufficient to transduce 42% of hematopoietic progenitors from FA-A patients, in the absence of in vitro prestimulation. When FANCA-expressing vectors were used, this simple procedure reversed the phenotype of the BM progenitors from these patients. We propose that our approach will be more efficient and safer compared with standard gene therapy protocols for FA.