Advancing Diagnostic Accuracy and Quality of Patient Care Through the Implementation of a Flow Cytometry Quality Assurance Program.

CONTEXT.­: Flow cytometry immunophenotypic analysis plays an important role in the diagnosis, classification, and disease monitoring of hematologic neoplasms. The interpretation of flow cytometry testing can be challenging. OBJECTIVE.­: To explore ways to improve diagnostic accuracy and in turn enhance the quality of patient care. DESIGN.­: A flow cytometry quality assurance (QA) program was developed. Cases from various complex flow cytometry panels were randomly selected and cross-reviewed. The outcomes of the QA review were categorized into 3 groups: complete agreement, minor discrepancy, and major discrepancy. Each discrepancy underwent a process of documentation, discussion, and resolution. Here we summarize our 3 years of experience with this program. RESULTS.­: In total, 6166 cases were evaluated; 6028 cases (97.7%) showed complete concordance, 120 cases (2.0%) showed minor discrepancies, and 18 cases (0.3%) showed major discrepancies. Among the top 5 panels evaluated, the panel evaluating mature T-cell abnormalities showed the highest rate of discrepancy, whereas the panel for evaluation of myelodysplastic syndromes showed the lowest discrepancy rate. When analyzing the trends of concordance and discrepancy over time, we observed a statistically significant decrease in discrepancy rate over time, from 4% at the beginning of the 6-month period to 1.5% in the final 6-month period. CONCLUSIONS.­: The overall concordance rate was 97.7%. The remaining 2.3% of cases showed discrepancies that required a correction, underscoring the value and necessity of having a QA program. The overall discrepancy rates exhibited a gradual decline over time, indicative of the positive impact of the QA program on enhancing diagnostic competency and accuracy over time.

Long-term results of the sequential combination of cladribine and rituximab in Hairy cell leukemia.

We report on the long-term efficacy and safety of a phase 2 trial of sequential cladribine and rituximab in hairy cell leukemia (HCL). One-hundred and thirty-nine patients were enrolled: 111 in the frontline setting, 18 in first relapse, and 10 with variant HCL (HCLv). A complete response (CR) was achieved in 133 of 137 evaluable participants (97%) with measurable residual disease (MRD) negativity in 102 (77%). MRD status was not associated with significant differences in event-free survival (EFS) or overall survival (OS). With a median follow-up of 7.8 years (range: 0.40-18.8), eight patients have experienced disease relapse (5.8%), 4/111 with newly diagnosed HCL (3·6%) and 4/10 with HCLv (40%) (p = 0.002). The 10-year EFS and OS rates were 86.7% and 91.1%, respectively. Grade 3 adverse events were observed in 28 participants (20·1%), mostly due to infections. Treatment of HCL with sequential cladribine followed by rituximab is associated with excellent efficacy and safety results both in the frontline and relapsed settings.

Integrative immunophenotypic and genetic characterization of acute myeloid leukemia with CBFB rearrangement.

OBJECTIVES: We sought to characterize the immunophenotype of acute myeloid leukemia (AML) with CBFB rearrangement and correlate the results with cytogenetic and molecular data. METHODS: Sixty-one cases of AML with CBFB rearrangement were evaluated. RESULTS: The sample population consisted of 33 men and 28 women, with a median age of 49 years. Flow cytometry immunophenotypic analysis showed that myeloblasts were positive for CD34 and CD117 in all cases, and myeloperoxidase was positive in 52 of 55 (95%) cases. The most common abnormalities included decreased CD38 in 90%, increased CD13 in 85%, increased CD123 in 84%, and decreased HLA-DR in 84% of cases. Monocytes were increased, with a mature immunophenotype, and accounted for 23.7% of total cells. Among 60 cases with available karyotype, inv(16)(p13.1q22) was most common in 50 (83%) cases, followed by t(16;16) (p13.1;q22) in 6 (10%). Type A CBFB::MYH11 transcript was most common, detected in 84% of cases. Mutational analysis showed mutations of NRAS in 37%, FLT3 in 25%, and KIT in 24% of cases. Comparing cases with type A vs non-type A transcripts, blasts in type A cases more frequently exhibited CD64 positivity and increased CD13 levels while showing a lower frequency of CD7 and CD56 expression. Trisomy 22 and mutations in KIT, NF1, and TET2 were identified only in cases with type A transcript. CONCLUSIONS: Myeloblasts of AML with CBFB rearrangement are positive for CD34, CD117, and myeloperoxidase. These neoplasms most frequently carry inv(16)(p13.1q22) and type A fusion transcript. NRAS mutation was the most common mutation. Some immunophenotypic and genetic correlations occurred with different types of transcripts.

Multicolor flow cytometric immunophenotyping is highly sensitive and specific in identifying aberrant mast cells in the diagnostic workup of systemic mastocytosis.

OBJECTIVES: Flow cytometric immunophenotyping (FCI) is a fast and sensitive method for characterizing hematolymphoid neoplasms. It is not widely used in the workup of systemic mastocytosis (SM), in part because of the technical challenges and in part because the utility of FCI in assessing mast cells is not well understood. The objectives of this study were to assess the diagnostic utility of FCI in establishing a diagnosis of SM and distinguishing SM from nonneoplastic mast cells and to examine the immunophenotypic findings among SM subtypes. METHODS: We performed FCI on bone marrow samples suspicious for SM using a panel consisting of CD2, CD25, CD30, CD45, CD117, and HLA-DR. RESULTS: The cohort included 88 SM cases: 67 without an associated hematologic neoplasm (AHN) (PureSM) and 21 with an AHN (SM-AHN). We also assessed 40 normal/reactive controls. Overall, FCI was adequate for interpretation in 87 of 88 (99%) cases and detected at least 1 immunophenotypic aberrancy in 100% of SM cases. CD2, CD25, and CD30 were positive in 78%, 98%, and 90% of SM cases vs 0%, 13%, and 13% of cases with normal/reactive mast cells (P < .0001 for all). Two or 3 abnormalities were observed in 92% of SM cases but not in normal/reactive mast cells. Among SM cases, SM-AHN showed statistically significant less CD2 (38% vs 91%, P < .0001) and less co-expression of all 3 aberrant markers (CD2, CD25, and CD30 positive in 38% vs 86% of cases; P < .0001) than PureSM. Immunohistochemical analysis showed consistently weaker or focal expression of CD2, CD25, and CD30 than FCI, with CD2 and CD30 being falsely negative in 40% and 50% cases, respectively. A KIT D816V mutation was detected in 67% of PureSM cases and 76% of SM-AHN cases. CONCLUSIONS: Flow cytometric immunophenotyping is a quick, sensitive, high-yield tool for evaluating the immunophenotype of mast cells. An abnormal FCI finding should prompt careful histologic evaluation and sensitive KIT D816V mutation testing to address the possibility of SM. CD2, CD25, and CD30 are important markers for the detection of immunophenotypic aberrancy of mast cells, and their frequencies of aberrancy differ across SM subtypes.

Phase 2 study of inotuzumab ozogamicin for measurable residual disease in acute lymphoblastic leukemia in remission.

ABSTRACT: The detection of measurable residual disease (MRD) is the strongest predictor of relapse in acute lymphoblastic leukemia (ALL). Using inotuzumab ozogamicin in the setting of MRD may improve outcomes. Patients with ALL in first complete remission (CR1) or beyond (CR2+) with MRD ≥ 1 × 10-4 were enrolled in this phase 2 trial. Inotuzumab was administered at 0.6 mg/m2 on day 1 and 0.3 mg/m2 on day 8 of cycle 1, then at 0.3 mg/m2 on days 1 and 8 of cycles 2-6. Twenty-six consecutive patients with a median age of 46 years (range, 19-70 years) were treated. Nineteen (73%) were in CR1 and seven (27%) in CR2+; 16 (62%) had Philadelphia chromosome-positive ALL. Fifteen (58%) had baseline MRD ≥ 1 × 10-3. A median of 3 cycles (range, 1-6) were administered. Eighteen (69%) patients responded and achieved MRD negativity. After a median follow-up of 24 months (range, 9-43), the 2-year relapse-free survival rate was 54% and the 2-year overall survival rate was 60% in the entire cohort. Most adverse events were low grade; sinusoidal obstruction syndrome was noted in 2 patients (8%). In summary, inotuzumab ozogamicin resulted in favorable survival, MRD negativity rates, and safety profiles for patients with ALL and MRD-positive status. This study was registered at www.ClinicalTrials.gov as #NCT03441061.

Durvalumab-induced Pure White Cell Aplasia.

Immune checkpoint inhibitors (ICI) have gained approval as a treatment for a wide array of cancers. Their mechanism of action prevents the inactivation of cytotoxic T-cells, allowing for its cytotoxic response. However, the upregulation of the immune system by ICI also leads to many undesired adverse events known as immune-related adverse events (irAEs), ranging from dermatologic manifestations, such as rashes, to inflammation of mucous membranes, to hematologic toxicities. Here, we report a case of ICI-induced pure white cell aplasia, secondary to the agent durvalumab, which responded to treatment with filgrastim, prednisone, and cyclosporine. ICI-neutropenia accounts for 0.6% of all irAEs or 17% of hematologic irAEs. Given the rarity of hematologic irAEs, the available treatment guidelines are based on expert consensus. As ICI becomes more widely used, we can expect an increase in the prevalence of rare irAEs as well. This case report aims to present a rare side effect of ICI and demonstrate its response to immunosuppressive therapy while providing guidance for future clinicians and further elucidating the mechanism behind these irAEs.

Validation of a 12-color flow cytometry assay for acute myeloid leukemia minimal/measurable residual disease detection.

BACKGROUND: Acute myeloid leukemia (AML) minimal/measurable residual disease (MRD) by multicolor flow cytometry is a complex laboratory developed test (LDT), challenging for implementation. We share our experience in the validation of a 12-color AML MRD flow cytometry assay to meet stringent regulatory requirements. METHODS: We worked under the guidelines of the CLSI HL62 publication, illustrated the details of the validation process that was tailored to uniqueness of AML MRD, and tested its clinical validity in 61 patients. The "trueness" was determined by correlating with concurrent molecular genetic testing and follow-up bone marrow examinations. RESULTS: Under assay specificity, we shared the details of panel design, analysis, and criteria for interpretation and reporting. The assay accuracy was assessed by testing known positive and negative samples and correlating with molecular genetic testing and follow-up bone marrow examination. The limit of detection (LOD) and limit of quantification (LOQ) were validated to a level between 0.01% and 0.1%, varied from the leukemia-associated immunophenotypes (LAIP) and the numbers of events obtained for analysis. Assay linearity, precision and carry over studies all met acceptable criteria. In the clinical validity test, the concordance was 93%, specificity 98% and sensitivity 83%. The most challenging aspects of the assay were the discrimination of pre-leukemic cells (persistent clonal hematopoiesis) or underlying myelodysplastic clones from AML MRD with immunophenotypic switch or subclone selection. CONCLUSION: The validation met all criteria and obtained FDA IDE (investigational device exemption) approval. This study provides ample technical and professional details in setting up the AML MRD flow cytometry assay and illustrates through the example of the "fit for purpose" validation process. We also highlight the need for further characterization of abnormal blasts bearing the potential for AML relapse.

A Throwing Knife Injury to the Neck: Management of a Unique Airway Situation.

Penetrating neck injuries (PNIs) can present as a simple wound or can be complicated by a disruption of the airway or associated vasculature. As such, stabilization of the vasculature and the airway is paramount. Here we present a case in which a hemodynamically stable 28-year-old female presents with a PNI involving the oropharynx and laryngopharynx.

Results of salvage therapy with mini-hyper-CVD and inotuzumab ozogamicin with or without blinatumomab in pre-B acute lymphoblastic leukemia.

BACKGROUND: Historically, adults with relapsed-refractory acute lymphoblastic leukemia (ALL) experienced poor outcomes with intensive chemotherapy. This mature analysis explores the benefit of the addition of sequential blinatumomab to low-intensity mini-Hyper-CVD chemotherapy with inotuzumab ozogamicin in this setting. METHODS: Mini-Hyper-CVD (cyclophosphamide and dexamethasone at 50% dose reduction, no anthracycline, methotrexate at 75% dose reduction, cytarabine at 83% dose reduction) was combined with inotuzumab during the first 4 courses. From Patient #68 and onwards, inotuzumab was given in reduced and fractionated doses, and blinatumomab was added sequentially for 4 courses. Maintenance therapy with prednisone, vincristine, 6-mercaptopurine and methotrexate was given for 12 courses, and blinatumomab for 4 additional courses. RESULTS: Among 110 patients (median age, 37 years) treated, 91 (83%) responded (complete response, 69 patients, 63%). Measurable residual disease negativity was documented in 75 patients (82% of responders). Fifty-three patients (48%) received allogeneic stem cell transplantation (SCT). Hepatic sinusoidal obstruction syndrome occurred in 9/67 patients (13%) on the original inotuzumab schedule and in 1/43 (2%) on the modified schedule. With a median follow-up of 48 months, the median overall survival (OS) was 17 months, and the 3 year OS was 40%. The 3 year OS was 34% with mini-Hyper-CVD plus inotuzumab and 52% with additional blinatumomab (P = 0.16). By landmark analysis at 4 months, the 3 year OS was 54%, similar between patients who did or did not receive allogeneic SCT. CONCLUSION: Low-intensity mini-Hyper-CVD plus inotuzumab with or without blinatumomab showed efficacy in patients with relapsed-refractory ALL, with better survival after the addition of blinatumomab. Trial registration The trial was registered on clinicaltrials.gov with the identifier NCT01371630.

Venetoclax consolidation in high-risk CLL treated with ibrutinib for ≥1 year achieves a high rate of undetectable MRD.

Patients receiving ibrutinib for CLL rarely achieve undetectable measurable residual disease (U-MRD), necessitating indefinite therapy, with cumulative risks of treatment discontinuation due to progression or adverse events. This study added venetoclax to ibrutinib for up to 2 years, in patients who had received ibrutinib for ≥12 months (mo) and had ≥1 high risk feature (TP53 mutation and/or deletion, ATM deletion, complex karyotype or persistently elevated ß2-microglobulin). The primary endpoint was U-MRD with 10-4 sensitivity (U-MRD4) in bone marrow (BM) at 12mo. Forty-five patients were treated. On intention-to-treat analysis, 23/42 (55%) patients improved their response to CR (2 pts were in MRD + CR at venetoclax initiation). U-MRD4 at 12mo was 57%. 32/45 (71%) had U-MRD at the completion of venetoclax: 22/32 stopped ibrutinib; 10 continued ibrutinib. At a median of 41 months from venetoclax initiation, 5/45 patients have progressed; none have died from CLL or Richter Transformation. In 32 patients with BM U-MRD4, peripheral blood (PB) MRD4 was analyzed every 6 months; 10/32 have had PB MRD re-emergence at a median of 13 months post-venetoclax. In summary, the addition of venetoclax in patients treated with ≥12mo of ibrutinib achieved high rate of BM U-MRD4 and may achieve durable treatment-free remission.

Undetectable measurable residual disease is associated with improved outcomes in AML irrespective of treatment intensity.

Acute myeloid leukemia (AML) can be treated with either high- or low-intensity regimens. Highly sensitive assays for measurable residual disease (MRD) now allow for a more precise assessment of response quality. We hypothesized that treatment (Rx) intensity may not be a key predictor of outcomes, assuming that an optimal response to therapy is achieved. We performed a single-center retrospective study including 635 patients with newly diagnosed AML responding to either intensive cytarabine/anthracycline-based chemotherapy (IA; n = 385) or low-intensity venetoclax-based regimens (LOW + VEN; n = 250) and who had adequate flow cytometry-based MRD testing performed at the time of best response. The median overall survival (OS) was 50.2, 18.2, 13.6, and 8.1 months for the IA MRD-, LOW + VEN MRD-, IA MRD+, and LOW + VEN MRD+ cohorts, respectively. The 2-year cumulative incidence of relapse (CIR) was 41.1%, 33.5%, 64.2%, and 59.9% for the IA MRD-, LOW + VEN MRD-, IA MRD+, and LOW + VEN MRD+ cohorts, respectively. The CIR was similar between patients within MRD categories irrespective of the treatment regimen received. The IA cohort was enriched for younger patients and favorable AML cytogenetic/molecular categories. Using multivariate analysis, age, best response (complete remission [CR]/CR with incomplete hematologic recovery/morphologic leukemia-free state), MRD status, and European LeukemiaNet (ELN) 2017 risk remained significantly associated with OS, whereas best response, MRD status, and ELN 2017 risk were significantly associated with CIR. Treatment intensity was not significantly associated with either OS or CIR. Achievement of MRD- CR should be the key objective of AML therapy in both high- and low-intensity treatment regimens.

Frontline combination of ponatinib and hyper-CVAD in Philadelphia chromosome-positive acute lymphoblastic leukemia: 80-months follow-up results.

The combination of ponatinib, a third-generation BCR::ABL1 tyrosine kinase inhibitor, with hyper-CVAD chemotherapy resulted in high rates of complete molecular remissions and survival, without the need for stem cell transplantation (SCT) in most patients with Philadelphia chromosome(Ph)-positive acute lymphocytic leukemia (ALL). Confirming these results in a large cohort of patients with longer follow-up would establish this regimen as a new standard of care. Adults with newly diagnosed Ph-positive ALL were treated with the hyper-CVAD regimen. Ponatinib was added as 45 mg daily × 14 during induction, then 45 mg daily continuously (first 37 patients) or 30 mg daily continuously, with dose reduction to 15 mg daily upon achievement of a complete molecular response (CMR; absence of a detectable BCR::ABL1 transcript by quantitative reverse transcription polymerase-chain reaction at a sensitivity of 0.01%). Maintenance therapy consisted of daily ponatinib and vincristine-prednisone monthly for 2 years, followed by daily ponatinib indefinitely. Twelve intrathecal injections of cytarabine alternating with methotrexate were given as central nervous system prophylaxis. The trial is registered on clinicaltrials.gov with the identifier NCT01424982. Eighty-six patients were treated. Their median age was 46 years (range, 21-80). All 68 patients with active disease at the initiation of therapy achieved complete response (CR) The cumulative CMR rate was 86%. Twenty- patients (23%) underwent allogeneic SCT. With a median follow-up of 80 months (range, 16-129 months), the estimated 6-year event-free survival rate was 65% and the overall survival rate was 75%. There was no difference in outcome by performance of allogeneic SCT in first CR. Common grade 3-5 adverse events included infection (n = 80, 93%), increased liver transaminases (n = 26, 31%) and total bilirubin (n = 13, 15%), hypertension (n = 15, 17%), pancreatitis (n = 13, 15%), hemorrhage (n = 12, 13%), and skin rash (n = 9, 10%). Two ponatinib-related deaths from myocardial infarction (3%; at months 2.6 and 4.3, respectively; both in CR) in the first 37 patients treated led to the ponatinib dose-modifications mentioned earlier, with no further ponatinib-related deaths observed. The long-term results of ponatinib and hyper-CVAD continue to demonstrate excellent outcome results and acceptable safety data, indicating that this strategy is another standard of care approach in frontline Ph-positive ALL.

A Multi-institutional Analysis of Late Complications in Scapula, Fibula, and Osteocutaneous Radial Forearm Free Flaps.

OBJECTIVES: (1) Evaluate the association of flap type with late complications in patients undergoing osseous head and neck reconstruction with the fibula free flap (FFF), osteocutaneous radial forearm free flap (OCRFFF), and scapula free flap (SFF). (2) Compare the prevalence of late complications based on minimum duration of follow-up. STUDY DESIGN: Retrospective cohort study. SETTING: Multiple academic medical centers. METHODS: Patients undergoing FFF, OCRFFF, or SFF with ≥6-month follow-up were stratified by type of flap performed. The association of flap type with late complications was analyzed via univariable and multivariable logistic regression, controlling for relevant clinical risk factors. Additionally, the frequency of late complications by minimum duration of follow-up was assessed. RESULTS: A total of 617 patients were analyzed: 312 (50.6%) FFF, 230 (37.3%) OCRFFFF, and 75 (12.2%) SFF. As compared with the SFF, the FFF (adjusted odds ratio [aOR], 3.05; 95% CI, 1.61-5.80) and OCRFFF (aOR, 2.17; 95% CI, 1.12-4.22) were independently associated with greater odds of overall late recipient site wound complications. The SFF was independently associated with the lowest odds of hardware exposure when compared with the FFF (aOR, 2.61; 95% CI, 1.27-5.41) and OCRFFF (aOR, 2.38; 95% CI, 1.11-5.12). The frequency of late complications rose as minimum duration of follow-up increased until plateauing at 36 months. CONCLUSIONS: This multi-institutional study suggests that the long-term complication profile of the SFF and OCRFFF compares favorably to the FFF. The SFF may be associated with the fewest overall late recipient site complications and hardware exposure, while the FFF may be associated with the most of these 3 options.

Consensus opinion from an international group of experts on measurable residual disease in hairy cell leukemia.

A significant body of literature has been generated related to the detection of measurable residual disease (MRD) at the time of achieving complete remission (CR) in patients with hairy cell leukemia (HCL). However, due to the indolent nature of the disease as well as reports suggesting long-term survival in patients treated with a single course of a nucleoside analog albeit without evidence of cure, the merits of detection of MRD and attempts to eradicate it have been debated. Studies utilizing novel strategies in the relapse setting have demonstrated the utility of achieving CR with undetectable MRD (uMRD) in prolonging the duration of remission. Several assays including immunohistochemical analysis of bone marrow specimens, multi-parameter flow cytometry and molecular assays to detect the mutant BRAF V600E gene or the consensus primer for the immunoglobulin heavy chain gene (IGH) rearrangement have been utilized with few comparative studies. Here we provide a consensus report on the available data, the potential merits of MRD assessment in the front-line and relapse settings and recommendations on future role of MRD assessment in HCL.

Perioperative Outcomes in Patients Who Underwent Fibula, Osteocutaneous Radial Forearm, and Scapula Free Flaps: A Multicenter Study.

Importance: Studies comparing perioperative outcomes of fibula free flaps (FFFs), osteocutaneous radial forearm free flaps (OCRFFFs), and scapula free flaps (SFFs) have been limited by insufficient sample size. Objective: To compare the perioperative outcomes of patients who underwent FFFs, OCRFFFs, and SFFs. Design, Setting, and Participants: This cohort study assessed the outcomes of 1022 patients who underwent FFFs, OCRFFFs, or SFFs for head and neck reconstruction performed at 1 of 6 academic medical centers between January 2005 and December 2019. Data were analyzed from September 17, 2021, to June 9, 2022. Main Outcomes and Measures: Patients were stratified based on the flap performed. Evaluated perioperative outcomes included complications (overall acute wound complications, acute surgical site infection [SSI], fistula, hematoma, and flap failure), 30-day readmissions, operative time, and prolonged hospital length of stay (75th percentile, >13 days). Patients were excluded if data on flap type or clinical demographic characteristics were missing. Associations between flap type and perioperative outcomes were analyzed using logistic regression, after controlling for other clinically relevant variables. Adjusted odds ratios (aORs) with 95% CIs were generated. Results: Perioperative outcomes of 1022 patients (mean [SD] age, 60.7 [14.5] years; 676 [66.1%] men) who underwent major osseous head and neck reconstruction were analyzed; 510 FFFs (49.9%), 376 OCRFFFs (36.8%), and 136 SFFs (13.3%) were performed. Median (IQR) operative time differed among flap types (OCRFFF, 527 [467-591] minutes; FFF, 592 [507-714] minutes; SFF, 691 [610-816] minutes). When controlling for SSI, FFFs (aOR, 2.47; 95% CI, 1.36-4.51) and SFFs (aOR, 2.95; 95% CI, 1.37-6.34) were associated with a higher risk of flap loss than OCRFFFs. Compared with OCRFFFs, FFFs (aOR, 1.77; 95% CI, 1.07-2.91) were associated with a greater risk of fistula after controlling for the number of bone segments and SSI. Both FFFs (aOR, 1.77; 95% CI, 1.27-2.46) and SFFs (aOR, 1.68; 95% CI, 1.05-2.69) were associated with an increased risk of 30-day readmission compared with OCRFFFs after controlling for Charlson-Deyo comorbidity score and acute wound complications. Compared with OCRFFFs, FFFs (aOR, 1.78; 95% CI, 1.25-2.54) and SFFs (aOR, 1.96; 95% CI, 1.22-3.13) were associated with a higher risk of prolonged hospital length of stay after controlling for age and flap loss. Conclusions and Relevance: Findings of this cohort study suggest that perioperative outcomes associated with OCRFFFs compare favorably with those of FFFs and SFFs, with shorter operative times and lower rates of flap loss, 30-day readmissions, and prolonged hospital length of stay. However, patients undergoing SFFs represented a more medically and surgically complex population than those undergoing OCRFFFs or FFFs.

Flow cytometry immunophenotypic features of pure erythroid leukemia and the distinction from reactive erythroid precursors.

BACKGROUND: The immunophenotype of pure erythroid leukemia (PEL) as determined by flow cytometry immunophenotypic analysis is not well characterized. The immunophenotypic difference between PEL and reactive conditions is under-explored. METHODS: We assessed and compared the immunophenotype of 24 PEL cases and 28 reactive cases containing early erythroid precursors by flow cytometry. RESULTS: The neoplastic erythroid cells in all PEL cases were positive for CD36 and CD71. CD45 was also positive in all cases, but the expression level was often dimmer than granulocytes. CD117 expression ranged from partial to uniform, and CD235a was often only positive in the CD117-dim to negative cells, corresponding to more differentiated subset. PEL cases frequently (87%) showed decreased or negative CD38 expression, contrasting to reactive early erythroid precursors that showed bright CD38 (p < 0.0001). CD7 (25%) and CD13 (29%) aberrant expressions were only observed in PEL but not in the reactive erythroid cells. Normal early erythroid precursors in all reactive bone marrows showed partial expression of CD4; In contrast, aberrant CD4 expression was detected in 71% PEL cases, either uniformly positive (50%) or completely negative (21%). While normal/reactive bone marrows almost always contained a small subset of CD34-positive early erythroid precursors, the neoplastic pronormoblasts in all PEL cases were CD34 negative. Although not increased in number, CD34-positive myeloblasts were frequently detected in PEL and demonstrated an aberrant immunophenotype in 90% PEL cases. CONCLUSIONS: PEL shows a distinctive immunophenotype which can be distinguished from reactive erythroid precursors by flow cytometry immunophenotyping.

How riparian and floodplain restoration modify the effects of increasing temperature on adult salmon spawner abundance in the Chehalis River, WA.

Stream temperatures in the Pacific Northwest are projected to increase with climate change, placing additional stress on cold-water salmonids. We modeled the potential impact of increased stream temperatures on four anadromous salmonid populations in the Chehalis River Basin (spring-run and fall-run Chinook salmon Oncorhynchus tshawytscha, coho salmon O. kisutch, and steelhead O. mykiss), as well as the potential for floodplain reconnection and stream shade restoration to offset the effects of future temperature increases. In the Chehalis River Basin, peak summer stream temperatures are predicted to increase by as much as 3°C by late-century, but restoration actions can locally decrease temperatures by as much as 6°C. On average, however, basin-wide average stream temperatures are expected to increase because most reaches have low temperature reduction potential for either restoration action relative to climate change. Results from the life cycle models indicated that, without restoration actions, increased summer temperatures are likely to produce significant declines in spawner abundance by late-century for coho (-29%), steelhead (-34%), and spring-run Chinook salmon (-95%), and smaller decreases for fall-run Chinook salmon (-17%). Restoration actions reduced these declines in all cases, although model results suggest that temperature restoration alone may not fully mitigate effects of future temperature increases. Notably, floodplain reconnection provided a greater benefit than riparian restoration for steelhead and both Chinook salmon populations, but riparian restoration provided a greater benefit for coho. This pattern emerged because coho salmon tend to spawn and rear in smaller streams where shade restoration has a larger effect on stream temperature, whereas Chinook and steelhead tend to occupy larger rivers where temperatures are more influenced by floodplain connectivity. Spring-run Chinook salmon are the only population for which peak temperatures affect adult prespawn survival in addition to rearing survival, making them the most sensitive species to increasing stream temperatures.

Blinatumomab is associated with favorable outcomes in patients with B-cell lineage acute lymphoblastic leukemia and positive measurable residual disease at a threshold of 10-4 and higher.

The presence of measurable residual disease (MRD) is the strongest predictor of relapse in acute lymphoblastic leukemia (ALL). We conducted a prospective, single-arm, phase II study in adults with B-cell ALL with MRD ≥1 × 10-4 after ≥3 months from the start of frontline therapy or one month from any salvage therapy. Blinatumomab was administered at a standard dosing of 28 micrograms daily as a continuous infusion for up to five cycles and up to four additional maintenance cycles. Thirty-seven patients with a median age of 43 years (range, 22-84 years) were treated. Twenty-seven patients (73%) were treated in first complete remission (CR) and 10 patients (27%) in second CR and beyond. Eighteen patients (49%) had Philadelphia-chromosome positive ALL and received concomitant tyrosine kinase inhibitor therapy. Twenty-three patients (62%) had a baseline MRD ≥10-3 . A median of three cycles (range, 1-9 cycles) were administered. Overall, 27 patients (73%) achieved MRD-negative remission. With a median follow-up of 31 months (range, 5-70 months), the estimated 3-year relapse-free survival (RFS) rate was 63% (95% confidence interval [CI], 43%-77%) and overall survival (OS) rate 67% (95% CI, 46%-81%). These rates were 51% (95% CI, 27%-70%) and 61% (95% CI, 36%-78%) in patients with baseline MRD ≥1 × 10-3 , and 83% (95% CI, 45%-95%) and 77% (95% CI, 32%-95%) in patients with baseline MRD <10-3 respectively. The rates of adverse events were consistent with previous studies of blinatumomab. In summary, blinatumomab induced MRD negativity in most patients and resulted in high rates of RFS and OS. This study is registered at www.clinicaltrials.gov as #NCT02458014. Funding was provided by Amgen Inc.

Acute promyelocytic leukemia: Immunophenotype and differential diagnosis by flow cytometry.

BACKGROUND: Prompt diagnosis of acute promyelocytic leukemia (APL) is critical for patient care. In this study, we aimed to characterize the immunophenotype of APL and explore immunophenotypic difference between APL and its mimics using flow cytometric analysis. METHODS: Eighty-five cases were collected, including 47 APL, 26 NPM1-mutated acute myeloid leukemia (AML) and 12 KMT2A-rearranged AML with an APL-like immunophenotype. Immunophenotypes were analyzed using flow cytometric analysis. RESULTS: APL showed four distinct patterns (designated a-d) based on CD45/SSC plots. Blasts in patterns a-c showed high side scatter, whereas blasts in pattern d had low side scatter and were located in the traditional blast gate. Compared with patterns a-c, pattern d of APL (APL-D) was more often positive for CD2 (p = 0.0005) and CD34 (p = 0.0002) in blasts. All NPM1-mutated AML and KMT2A-rearranged AML cases with an APL-like immunophenotype had blasts in the traditional blast gate on CD45/SSC, mimicking APL-D. In comparison, uniform CD13 and positive CD64 were seen in 100% (n = 13) APL-D cases and in only 2 of 26 (8%) NPM1-mutated AML cases (p < 0.0001). In addition, APL-D cases were more likely to be positive for CD2 and/or CD34 than NPM1-mutated AML (p < 0.0001 and p = 0.0007, respectively). In comparison with APL-D, KMT2A-rearranged AML cases were less often positive for myeloperoxidase (MPO) (p = 0.001), with none being strongly positive. Similar to NPM1-mutated AML and different from APL-D, KMT2A-rearranged AML cases were rarely positive for CD34 and all negative for CD2. CONCLUSIONS: APL and its immunophenotypic mimics share some immunophenotypic similarities but can be distinguished by CD2, CD13, CD34, CD64, and MPO.