PtdIns(3)P regulates the neutrophil oxidase complex by binding to the PX domain of p40(phox).

The production of reactive oxygen species (ROS) by neutrophils has a vital role in defence against a range of infectious agents, and is driven by the assembly of a multi-protein complex containing a minimal core of five proteins: the two membrane-bound subunits of cytochrome b(558) (gp91(phox) and p22(phox)) and three soluble factors (GTP-Rac, p47(phox) and p67(phox) (refs 1, 2). This minimal complex can reconstitute ROS formation in vitro in the presence of non-physiological amphiphiles such as SDS. p40(phox) has subsequently been discovered as a binding partner for p67(phox) (ref. 3), but its role in ROS formation is unclear. Phosphoinositide-3-OH kinases (PI(3)Ks) have been implicated in the intracellular signalling pathways coordinating ROS formation but through an unknown mechanism. We show that the addition of p40(phox) to the minimal core complex allows a lipid product of PI(3)Ks, phosphatidylinositol 3-phosphate (PtdIns(3)P), to stimulate specifically the formation of ROS. This effect was mediated by binding of PtdIns(3)P to the PX domain of p40(phox). These results offer new insights into the roles for PI(3)Ks and p40(phox) in ROS formation and define a cellular ligand for the orphan PX domain.

Fever as a predictor of adverse outcomes in COVID-19.

BACKGROUND/INTRODUCTION: There are little data on outcomes of COVID-19 patients with the presence of fever compared to the presence of symptoms. AIM: We examined the associations between symptomology, presence of fever and outcomes of a COVID-19 cohort. DESIGN AND METHODS: Between 23 January and 30 April 2020, 554 COVID-19 patients were admitted to a tertiary hospital in Singapore. They were allocated into four groups based on symptomology and fever-Group 1: asymptomatic and afebrile, Group 2: symptomatic but afebrile, Group 3: febrile but asymptomatic and Group 4: symptomatic and febrile. The primary outcomes were intensive care unit (ICU) admissions and mortality. The composite end-point included ICU admissions, mortality or any COVID-19 related end-organ involvement. RESULTS: There were differences in ferritin (P=0.003), C-reactive protein (CRP) levels (P<0.001) and lymphopenia (P=0.033) across all groups, with the most favourable biochemical profile in Group 1, and the least in Group 4. Symptomatic groups (Groups 2 and 4) had higher ICU admissions (1.9% and 6.0%, respectively, P=0.003) than asymptomatic groups (Groups 1 and 3). Composite end-point was highest in Group 4 (24.0%), followed by Group 3 (8.6%), Group 2 (4.8%) and Group 1 (2.4%) (P<0.001). The presence of fever (OR 4.096, 95% CI 1.737-9.656, P=0.001) was associated with the composite end-point after adjusting for age, pulse rate, comorbidities, lymphocyte, ferritin and CRP. Presence of symptoms was not associated with the composite end-point. DISCUSSION/CONCLUSION: In this COVID-19 cohort, presence of fever was a predictor of adverse outcomes. This has implications on the management of febrile but asymptomatic COVID-19 patients.

Low IPSS score and bone marrow hypocellularity in MDS patients predict hematological responses to antithymocyte globulin.

Immunosuppressive therapy has been shown to induce sustained hematological responses in a subset of patients with myelodysplastic syndromes (MDS). In particular, antithymocyte globulin (ATG), a polyclonal immunoglobulin induces hematological responses in up to 60% of MDS patients. We report herein on the results of a retrospective multicenter study on the use of ATG in the treatment of 96 patients with MDS. Patients were evaluated for duration of response to ATG, as well as survival after administration of ATG. The median age of the cohort was 54.7 years (range: 19-75 years), with a median follow-up of 33.8 months (range: 0.8-133 months). A total of 40 patients (42%) achieved a hematological response, of which 30 patients (75%) had a durable hematological response lasting a median duration of 31.5 months (range: 6-92 months). On multivariate analysis, both low International Prognostic Scoring System (IPSS) and bone marrow (BM) hypocellularity were independent predictive factors for improved response to ATG (IPSS Int-2/high: odds ratio (OR) 0.08, P=0.018 and BM normo/hypercellularity: OR 0.49, P=0.012). In addition, IPSS was the sole predictor of overall survival, with Int-2/high risk patients having a significantly poorer survival outcome (OR 0.08, P<0.01). In conclusion, this study identifies BM hypocellularity and a low IPSS as important factors predicting response to ATG.

Clonal gammopathies following alemtuzumab-based reduced intensity conditioning haematopoietic stem cell transplantation: association with chronic graft-versus-host disease and improved overall survival.

The presence of clonal gammopathies (CG) has been reported following both conventional myeloablative and autologous haematopoietic stem cell transplantation (HSCT). We monitored the occurrence of CG in a cohort of patients with myeloid malignancies receiving FBC (fludarabine-busulphan-alemtuzumab)-based reduced intensity conditioned (RIC) HSCT, and assessed its correlation with infections, graft-versus-host disease (GvHD) and survival. Serial serum protein electrophoresis was analysed in a total of 138 patients and CG were detected in 49 patients (36%). The predominant Ig isotype was IgG (82%). There was no difference in the incidence of viral infections between patient groups. However, patients with gammopathies were more likely to have had prior chronic GvHD (OR 2.7, 95% CI 1.3-5.5, P<0.001). On multivariate analysis, the only factors that were found to influence overall survival (OS) were presence of gammopathies, which was associated with an improved OS (OR 0.35 95% CI 0.14-0.86, P=0.02) as well as disease stage, patients with advanced disease having a higher risk of death (OR 2.20 95% CI 1.18-4.11, P=0.02). Disease stage was the only variable that influenced relapse incidence on multivariate analysis (OR 4.22 95% CI 1.82-9.78, P<0.01). Clonal gammopathies are a frequent but benign occurrence following alemtuzumab-based RIC HSCT, and their appearance may define a group of patients with a favourable overall outcome.

An exploration of the applicability of the refined disease risk index and its integration with other independent risk factors for individualized prognostication.

The refined disease risk index (DRI) is a powerful prognostic model based solely on the disease type and stage for predicting survival outcomes of various hematological malignancies after allogeneic transplant. Here, we analyzed our series of 690 patients transplanted over the past 15 years, and showed that besides overall survival (OS), the refined DRI is also able to segregate event-free survival and relapse mortality in our cohort of largely Southeast Asian patients with a long and complete follow-up. Stratification by refined DRI remains statistically significant even when broken down by specific diseases each with a smaller number of patients, as well as for a small subset of patients younger than 18 years old, providing a robust model for prognostication. Multivariable analysis shows that refined DRI, age, year of transplant and donor type are independent risk factors for OS. We further demonstrated here that prognostication for a given patient with a specific disease can be made more discriminating by integrating independent risk factors such as age and donor type with the refined DRI. The future development of prognostic system incorporating the refined DRI with patient- and transplant-related risk factors will provide a more precise estimate of transplant outcome.

Loss of the NF2 gene and merlin occur by the tumorlet stage of schwannoma development in neurofibromatosis 2.

Loss of the neurofibromatosis 2 (NF2) gene-encoded protein merlin is a universal finding in sporadic and NF2-associated schwannomas. Certain NF2 patients may develop numerous minute Schwann cell tumorlets of the spinal nerve roots in addition to larger, frank schwannomas and thereby provide an opportunity to investigate the timing of NF2 gene/merlin loss in Schwann cell tumorigenesis. We studied an NF2 patient with a germline NF2 gene frameshift mutation who had many Schwann cell tumorlets and schwannomas. Loss of heterozygosity studies of DNA from microdissected specimens showed allelic loss of the NF2 region of chromosome 22q in tumorlets as well as schwannomas. Immunohistochemistry further demonstrated loss of merlin expression in tumorlets as well as schwannomas, with intact expression in adjacent nerve. Thus, loss of both NF2 alleles and merlin occur early in Schwann cell tumorigenesis, before the tumorlet stage. The study of tumorlets and schwannomas in such patients may also provide an opportunity to elucidate mechanisms responsible for the subsequent growth of Schwann cell lesions into symptomatic tumors.

Alemtuzumab based reduced intensity conditioning allogeneic haematopoietic stem cell transplantation for myelofibrosis.

We report the results of 11 patients myelofibrosis, who have received a uniform alemtuzumab-based RIC HSCT. The median recipient age was 51 years. Stem cells were obtained from 8 full HLA-matched and 3 HLA-mismatched donors. The 2-year OS and TRM at 2-years was 46% and 54% with no disease relapse observed. For patients with a full HLA-matched donor, the 2-year TRM and OS was 37.5% and 62.5%. All 4 JAK2 V617F mutant positive patients achieved molecular remission after a median of 90 days post-transplant, and the median time to regression of bone marrow fibrosis was 180 days.

Impact of pretransplant comorbidities on alemtuzumab-based reduced-intensity conditioning allogeneic hematopoietic SCT for patients with high-risk myelodysplastic syndrome and AML.

We report a retrospective analysis of 128 consecutive patients with high-risk myelodysplastic syndrome (MDS) and AML who received an alemtuzumab-based reduced-intensity conditioning hematopoietic SCT (RIC HSCT). The median recipient age was 53 years (range 21-72 years). A total of 49 (38%) recipients had a sibling donor and 79 (62%) had a volunteer-unrelated donor. The hematopoietic cell transplantation-specific comorbidity index (HCT-CI) was assigned to all patients with a score of 0 in 40 (31%), of 1-2 in 45 (35%) and >or=3 in 43 (34%) patients. The 3-year non-relapse mortality (NRM) was 31%, disease-free survival (DFS) was 41% and overall survival (OS) was 46%. The 3-year NRM for patients with a HCT-CI score of 0, 1-2 or >or=3 was 16, 24 and 42%, respectively. The 3-year DFS and OS by HCT-CI was 58 and 69% (score 0), 39 and 39% (score 1-2) and 24 and 32% (score >or=3), respectively. On multivariate analysis, HCT-CI was an independent variable affecting 3-year NRM, DFS and OS (P-value=0.04, 0.01 and <0.01, respectively). Although the disease stage at the time of transplant was an additional independent predictive variable on transplant outcomes, recipient age (>or<50 years) did not have a significant predictive impact. In MDS or AML patients with advanced disease receiving alemtuzumab-based RIC HSCT, the HCT-CI provides an important means of stratifying patients with a high risk of inferior transplant outcomes.

Allogeneic haematopoietic SCT for chronic myelomonocytic leukaemia: a single-centre experience.

Haematopoietic SCT (HSCT) offers the only potentially curative option in chronic myelomonocytic leukaemia (CMML). In this study, we report on single-centre results of 18 patients with CMML who have undergone allogeneic HSCT. The median age of patients was 54 years. Seven patients had AML, which had transformed from CMML. Overall, 11 patients received stem cells from an unrelated donor. A total of 15 patients received a T-cell-depleted fludarabine/BU-based reduced-intensity conditioning HSCT. The actuarial 3-year OS, non-relapse mortality (NRM) and relapse incidence for the cohort was 31±11%, 31±14% and 47±13%, respectively. Patients with favourable cytogenetics had a 3-year disease-free survival of 65±17%, whereas none of the seven patients with intermediate or poor risk cytogenetics survived beyond 2 years (P<0.01). No patients with favourable risk cytogenetics died from NRM causes, while the 2-year NRM for the intermediate/poor risk cytogenetics subgroup was 71±22% (P<0.02). In terms of disease status at transplantation, patients who had <5% BM blasts had a 3-year disease-free survival of 46.9±19% compared with those with >5% blasts at the time of transplantation (that is, 20.0±13%). Recipient age, type of conditioning regimen or stem cell dose did not have a significant impact on overall outcomes. Our data support existing evidence that allogeneic HSCT is a feasible therapeutic option for CMML, with the ability to attain long-term remission among patient subgroups.

Impact of pre-transplant serum ferritin on outcomes of patients with myelodysplastic syndromes or secondary acute myeloid leukaemia receiving reduced intensity conditioning allogeneic haematopoietic stem cell transplantation.

We report on a retrospective analysis examining the influence of pre-transplant serum ferritin on transplant outcomes of 99 MDS patients receiving reduced intensity conditioning (RIC) HSCT. The median pre-transplant ferritin value was 1992 ng/ml (range: 6-9580 ng/ml). No patients received iron chelation therapy preceding transplantation. On univariate analysis, there was a strong correlation between a higher pre-transplant serum ferritin (>1500 ng/ml) and a significantly inferior 3-year OS (64.6+/-7.5% vs 39.6+/-7.3%, p=0.01). However, pre-transplant serum ferritin did not influence 3-year TRM (20.2+/-7% vs 27.4+/-7%, p=0.24). There was no difference in infection-related mortality, and incidence of acute or chronic GvHD between cohorts. On multivariate analysis, a raised serum ferritin (HR: 2.00, 95% CI: 0.97-3.57, p=0.03), and the presence of >5% bone marrow blasts at time of transplantation (HR: 2.14, 95% CI: 0.84-4.58, p=0.06) were independent predictors of an inferior overall survival. However, pre-transplant serum ferritin was not a significant predictor of disease-free survival, relapse or TRM. When compared with myeloablative regimens, RIC regimens may attenuate the impact of iron overload related end-organ toxicity. Prospective studies incorporating alternative biomarkers of iron metabolism alongside serum ferritin levels are needed to improve our understanding of the significance of iron overload in MDS patients undergoing allogeneic transplantation.

Results of a phase I/II British Society of Bone Marrow Transplantation study on PCR-based pre-emptive therapy with valganciclovir or ganciclovir for active CMV infection following alemtuzumab-based reduced intensity allogeneic stem cell transplantation.

This multi-centre randomized study assessed the bioavailability of ganciclovir in patients undergoing alemtuzumab-based reduced intensity conditioning (RIC) haematopoietic stem cell transplantation (HSCT) after oral administration of valganciclovir. Patients were randomized to 2 groups receiving either oral valganciclovir (900 mg twice daily) or intravenous ganciclovir (5mg/kg twice daily) for 14 days. Twenty-seven patients were recruited and 18 patients (67%) completed allocated treatment resulting in clearance of cytomegolovirus (CMV) DNA load at a median of 14 days. The bioavailability of ganciclovir from valganciclovir was 73% (95% CI: 34-112%). The average exposure in the valganciclovir group (36.9+/-14.9 microg h/ml) was higher than the ganciclovir cohort (27.9+/-7.5 microg h/ml). When compared with intravenous ganciclovir, oral valganciclovir had high bioavailability in patients undergoing alemtuzumab-based RIC HSCT.

Lamivudine prophylaxis and treatment of hepatitis B Virus-exposed recipients receiving reduced intensity conditioning hematopoietic stem cell transplants with alemtuzumab.

Individuals with past exposure to hepatitis B virus (HBV) may reactivate HBV following bone marrow transplantation. Alemtuzumab (CAMPATH)-based reduced intensity conditioning bone marrow transplantation has been associated with a high incidence of viral infections. Lamivudine prophylaxis for HBV should be instituted in this setting. The management of 240 CAMPATH-based reduced intensity conditioning bone marrow transplantation, carried out over an 8-year period at Kings College Hospital, was reviewed. Hepatitis B core total antibody (anti-HBc) testing identified recipients and donors with previous HBV exposure. Fifteen donor-recipient pairs were identified as being at risk of HBV reactivation. Eight recipients of anti-HBc negative donors were HBsAg negative, anti-HBc positive pre-transplantation. Five anti-HBc negative recipients received transplants from HBsAg negative, anti-HBc positive donors. Two HBV carrier recipients had one anti-HBc negative and one positive donor, respectively. Pre-transplant lamivudine prophylaxis was given to 8/10 (80%) anti-HBc positive recipients. Although HBsAg and HBV DNA were detected 4 months after bone marrow transplantation in one patient who did not receive prophylaxis, a good antiviral response was documented on starting lamivudine. The two HBV carrier recipients had stopped lamivudine at 8 and 31 months post-bone marrow transplantation, respectively, and died of liver failure with a sharp rise in HBV DNA levels. The five anti-HBc negative recipients with anti-HBc positive donors remained HBsAg and HBV DNA negative. Although lamivudine prophylaxis prevented HBV reactivation, it is unclear at what stage post-transplantation prophylaxis can be discontinued. Close monitoring of liver function tests (LFTs), HBsAg, and HBV DNA must be undertaken even after stopping antiviral prophylaxis.

Cardiac presentation of ALK positive anaplastic large cell lymphoma.

Cardiac involvement as an initial presentation of malignant lymphoma is a rare occurrence. We report the case of an immunocompetent 29-year-old male who presented with syncope and arrythmias secondary to a ventricular cardiac mass. Transcutaneous cardiac biopsy was non-diagnostic, therefore an open cardiac biopsy was performed from which a provisional diagnosis of a cardiac inflammatory pseudotumour was made. Six months after presentation, he developed several subcutaneous lesions with systemic symptoms. Histological and immunophenotypic review of the initial cardiac biopsy revealed features consistent with a diagnosis of CD30, ALK1 positive anaplastic large cell lymphoma (ALCL). Despite intensive treatment with combination chemotherapy, there was significant progression of disease, and he died 11 months after diagnosis. The overall prognosis of cardiac lymphoma remains poor, which may be due to the often late presentation of the tumour. To our knowledge, this is the first reported case of a cardiac ALK positive ALCL. Although rare, cardiac presentation of ALCL should be added to the list of differential diagnoses of cardiac lymphomas.

Differential binding of traffic-related proteins to phosphatidic acid- or phosphatidylinositol (4,5)- bisphosphate-coupled affinity reagents.

Phosphatidic acid (PA) is an important bioactive lipid, but its molecular targets remain unknown. To identify such targets, we have synthesized and coupled PA to an agarose-based matrix, Affi-Gel 10. Using this matrix as an affinity reagent, we have identified a substantial number of potential PA-binding proteins from brain cytosol. One class of such proteins is known to be involved in intracellular traffic and it included coatomer, ADP-ribosylation factor (Arf), N-ethylmaleimide-sensitive factor (NSF), and kinesin. Binding of these proteins to PA beads was suppressed by soluble PA, and it occurred preferentially over binding to beads coupled to phosphatidylinositol (4,5)-bisphosphate. For coatomer, Arf, and NSF, we verified direct binding to PA beads using purified proteins. For recombinant Arf1 and Arf6, binding to PA required myristoylation. In addition, for NSF and Arf6, an ATPase and a GTPase, respectively, binding to PA beads was extremely sensitive to the nucleotide state of the protein. Binding to PA may be a property linking together distinct participants in one complete round of membrane transport from a donor to an acceptor compartment.