Proteomics in molecular diagnosis: typing of amyloidosis.

Amyloidosis is a group of disorders caused by deposition of misfolded proteins as aggregates in the extracellular tissues of the body, leading to impairment of organ function. Correct identification of the causal amyloid protein is absolutely crucial for clinical management in order to avoid misdiagnosis and inappropriate, potentially harmful treatment, to assess prognosis and to offer genetic counselling if relevant. Current diagnostic methods, including antibody-based amyloid typing, have limited ability to detect the full range of amyloid forming proteins. Recent investigations into proteomic identification of amyloid protein have shown promise. This paper will review the current state of the art in proteomic analysis of amyloidosis, discuss the suitability of techniques based on the properties of amyloidosis, and further suggest potential areas of development. Establishment of mass spectrometry aided amyloid typing procedures in the pathology laboratory will allow accurate amyloidosis diagnosis in a timely manner and greatly facilitate clinical management of the disease.

Combination bone marrow imaging using positron emission tomography (PET)-MRI in plasma cell dyscrasias: correlation with prognostic laboratory values and clinicopathological diagnosis.

OBJECTIVE: This prospective observational study of positron emission tomography (PET)-MRI findings in 16 consecutive newly diagnosed patients with a plasma cell dyscrasia describes and compares MRI-detected myeloma lesions with 18F-fludeoxyglucose PET-avid myeloma lesions, and correlates quantitative imaging findings to a range of biochemical and prognostic parameters. METHODS: Simultaneously acquired whole body PET and MRI images were evaluated qualitatively for the presence of focal or generalised abnormalities of bone marrow (BM) on either modality. Quantitative analysis comprised mean standardised uptake values (SUVmean) and fractional water content of the BM measured from PET and chemical shift MRI images of the second to fourth lumbar vertebrae. RESULTS: Final diagnoses comprised symptomatic myeloma (n = 10), asymptomatic myeloma (n = 4) and monoclonal gammopathy of uncertain significance (n = 2). 8/10 patients with symptomatic myeloma demonstrated BM abnormalities on qualitative assessment of MRI compared to 4/10 on PET. BM SUVmean inversely correlated with serum albumin (r = 0.57, p = 0.017). BM water fraction correlated with trephine cellularity and blood platelet count (r = 0.78, p = 0.00039 and r = 0.61, p = 0.0013 respectively). BM water fraction correlated with SUVmean in patients with low plasma cell burden (r = 0.91, p = 0.0015) but not in patients with high plasma cell burden (r = 0.18, p = 0.61). CONCLUSION: PET-MRI shows promise in both morphological and functional multiparametric quantitative assessment of myeloma. ADVANCES IN KNOWLEDGE: For the first time, multiparametric imaging in myeloma has been shown to predict BM abnormalities and correlate with known biochemical prognostic markers, moving PET-MRI beyond simple diagnostic applications into potential prognostic and treatment selection applications.

Safety and efficacy of pegfilgrastim compared to granulocyte colony stimulating factor (G-CSF) supporting a dose-intensive, rapidly cycling anti-metabolite containing chemotherapy regimen (Hyper-CVAD) for lymphoid malignancy.

Pegfilgrastim (Neulasta) has proven efficacy as supportive therapy in a variety of 21-day chemotherapy regimens, but has not been studied in dose intensive, rapidly cycling regimens utilising cell-cycle active drugs (e.g. anti-metabolites) such as hyper-CVAD. This study examined whether pegfilgrastim was safe and lead to similar kinetics of neutrophil recovery as daily granulocyte colony stimulating factor (G-CSF). Using retrospective analysis, patients receiving pegfilgrastim (6 mg) were matched with controls (G-CSF 5 microg kg-1 per day) for a cycle of chemotherapy, prior chemotherapy, dose of cytarabine received, age (<60 or >60 years), diagnosis and bone marrow involvement. The primary endpoint was duration of grade IV neutropenia (absolute neutrophil count, ANC < 500 microl-1). Secondary endpoints included time to neutrophil recovery, incidence of febrile neutropenia, positive blood cultures and delay in subsequent chemotherapy. This study identified 124 pegfilgrastim supported cycles in 43 patients and successfully matched them to 124 G-CSF supported cycles from 38 patients treated between January 1999 and July 2005. There were no significant differences between pegfilgrastim and G-CSF groups in baseline or treatment-related variables. The median duration of grade IV neutropenia was 4 days in both groups (P = 0.55). Time to neutrophil recovery, incidence of febrile neutropenia, positive blood cultures and delay in subsequent chemotherapy were similar in both groups. Once per cycle dosing of pegfilgrastim appears safe and as effective as daily G-CSF for supporting the hyper-CVAD chemotherapy regimen.

Cardiac Amyloid Imaging with 18F-Florbetaben PET: A Pilot Study.

Our aim was to determine the feasibility of 18F-florbetaben PET in diagnosing cardiac amyloidosis. METHODS: 18F-florbetaben PET was performed on 14 patients: 5 amyloid light chain, 5 amyloid transthyretin, and 4 control with hypertensive heart disease. Qualitative and quantitative assessments of 18F-florbetaben activity were performed using the SUVmean of the left ventricular myocardium and blood pool and calculation of target-to-background SUV ratio. Myocardial 18F-forbetaben retention was also calculated as the percentage mean myocardial SUV change between 0 and 5 min and 15 and 20 min after radiotracer injection. Global left ventricular longitudinal and right ventricular free wall longitudinal strain were calculated using 2-dimensional speckle-tracking echocardiography. RESULTS: Target-to-background SUV ratio and percentage myocardial 18F-forbetaben retention were higher in amyloid patients than in hypertensive controls. A cutoff of 40% was able to differentiate between cardiac amyloid patients and hypertensive controls. Percentage myocardial 18F-forbetaben retention was an independent determinant of both global left ventricular longitudinal and right ventricular free wall longitudinal strain via an inverse curve relationship. CONCLUSION: 18F-florbetaben PET imaging can accurately identify and differentiate between cardiac amyloidosis and hypertensive heart disease. Percentage myocardial 18F-florbetaben retention was an independent determinant of myocardial dysfunction in cardiac amyloidosis.

Predictive value of karyotype on outcome of autotransplants for acute myeloid leukemia in second remission.

The impact of karyotype on the outcome of patients who undergo autotransplant for acute myeloid leukemia (AML) in second remission (CR2) has not been explored. We evaluated the outcomes of 40 patients who proceeded to autotransplant for AML in CR2 at 2 centers. The median age at autotransplant was 50 years (18-64 years) and the median duration of first remission was 15 months (0.8-51 months). High-dose therapy was melphalan 140-160 mg/m2 plus etoposide 60 mg/kg with or without total body irradiation (22), a busulfan-based regimen (17), and cyclophosphamide alone (1). Six patients (15%) died of treatment-related causes within the first 100 days. Event-free and overall survival at 3 years were both 38% (95% confidence interval 23-53%). At a median follow-up of 76 months (2?-?170) in surviving patients, 13 (32.5%) are alive and disease free. Graft purging did not significantly influence survival outcome (P=0.94), although platelet engraftment was significantly delayed (P=0.02). The relative risk of an event (relapse or death) for the karyotype risk groups was favorable 1.0; intermediate 4.2 (1.2-14.7); adverse 9.9 (1.5-63.9); unknown 2.3 (0.6-8.8) (P=0.028). We conclude that patients with AML in CR2 who undergo autotransplant can have durable remissions and those with a good risk karyotype are the most likely to obtain long-term disease-free survival.

High dose methotrexate and extended hours high-flux hemodialysis for the treatment of primary central nervous system lymphoma in a patient with end stage renal disease.

This report discusses the case of a 52 year old female with post-transplant lymphoproliferative disorder, confined to the central nervous system, which was managed with high dose methotrexate (HDMTX) in the context of end stage renal disease. The patient received two doses of HDMTX followed by extended hours high-flux hemodialysis, plasma methotrexate concentration monitoring and leucovorin rescue. The hemodialysis technique used was effective in clearing plasma methotrexate and allowed delivery of HDMTX to achieve complete remission with limited and reversible direct methotrexate-related toxicity. Dialysis-dependent renal failure does not preclude the use of HDMTX when required for curative therapy of malignancy.

Prolonged haematological toxicity from the hyper-CVAD regimen: manifestations, frequency, and natural history in a cohort of 125 consecutive patients.

The hyperfractionated cyclophosphamide, vincristine, doxorubicin and dexamethasone (hyper-CVAD) regimen has impressive efficacy in several haematological malignancies but is associated with considerable short-term haematological toxicity. Secondary myelodysplasia (MDS) or acute myeloid leukaemia (AML) also occurs. In this retrospective study, we also describe other prolonged haematological sequelae of this regimen. One hundred and twenty-five patients were treated with a median of six hyper-CVAD cycles and followed for a median of 28 months. Follow-up for cytopenias was censored at the next cytotoxic therapy. At 3 months post-therapy, 77 patients were evaluable. Cytopenias persisted in 59% of patients. Requirement for dose attenuation was the only factor significantly associated with persisting cytopenias (p<0.05). The median time to normalisation of counts for those with post-treatment cytopenias in the respective lineages was 9 months (range, 6-12) for anaemia, 6 months (range, 6-30) for neutropenia and 9 months (range, 6-30) for thrombocytopenia. MDS/AML was diagnosed in four patients at 4, 21, 24 and 37 months after therapy with a cumulative incidence rate of 4.43% at 4 years. These results indicate a considerable rate of prolonged haematological toxicity after hyper-CVAD and a modest rate of MDS at this limited follow-up. These findings likely reflect cumulative damage to haematopoietic stem cells.