Applications of Flow Cytometry in Diagnosis and Evaluation of Red Blood Cell Disorders.

Clinical flow cytometry plays a vital role in the diagnosis and monitoring of various red blood cell disorders. The high throughput, precision, and automation potential of this technique allows for cost-effective and timely analysis compared to older and more manual test methods. Flow cytometric analysis serves as the gold standard diagnostic method for multiple hematological disorders, especially in clinical scenarios where an assay needs to have high sensitivity, high specificity, and a short turnaround time. In this review, we discuss the role of flow cytometric analysis in paroxysmal nocturnal hemoglobinuria, fetal-maternal hemorrhage, and hereditary spherocytosis.

Advances in Hemoglobinopathies and Thalassemia Evaluation.

Hemoglobin (Hb) disorders are among the most prevalent inherited diseases. Despite a limited number of involved genes, these conditions represent a broad clinical and prognostic spectrum. The menu of laboratory tests is extensive. From widely available modalities, for example, complete blood count to rather sophisticated molecular technologies, the investigation of Hb disorders recapitulates an increasing complexity of laboratory workup in other medical fields. This review highlights a current state of biochemical and molecular investigation of Hb disorders and offers a glimpse on technologies that are yet to be fully embraced in clinical practice.

Nivolumab Plus 5-Azacitidine in Pediatric Relapsed/Refractory Acute Myeloid Leukemia (AML): Phase I/II Trial Results from the Therapeutic Advances in Childhood Leukemia and Lymphoma (TACL) Consortium.

Improvements in survival have been made over the past two decades for childhood acute myeloid leukemia (AML), but the approximately 40% of patients who relapse continue to have poor outcomes. A combination of checkpoint-inhibitor nivolumab and azacitidine has demonstrated improvements in median survival in adults with AML. This phase I/II study with nivolumab and azacitidine in children with relapsed/refractory AML (NCT03825367) was conducted through the Therapeutic Advances in Childhood Leukemia & Lymphoma consortium. Thirteen patients, median age 13.7 years, were enrolled. Patients had refractory disease with multiple reinduction attempts. Twelve evaluable patients were treated at the recommended phase II dose (established at dose level 1, 3 mg/kg/dose). Four patients (33%) maintained stable disease. This combination was well tolerated, with no dose-limiting toxicities observed. Grade 3-4 adverse events (AEs) were primarily hematological. Febrile neutropenia was the most common AE ≥ grade 3. A trend to improved quality of life was noted. Increases in CD8+ T cells and reductions in CD4+/CD8+ T cells and demethylation were observed. The combination was well tolerated and had an acceptable safety profile in pediatric patients with relapsed/refractory AML. Future studies might explore this combination for the maintenance of remission in children with AML at high risk of relapse.

Molecular diagnosis of hereditary hemolytic anemias: Recent updates.

Hereditary hemolytic anemia (HHA) is a heterogeneous group of disorders due to genetically caused defects in red blood cell membrane structure, enzymes, heme and globin synthesis, erythroid proliferation, and differentiation. Traditionally, the diagnostic process is complex and includes a plethora of tests from routine to highly specialized ones. The inclusion of molecular testing has significantly improved the diagnostic yield. The value of molecular testing is broader than just rendering the correct diagnosis, as it may also guide therapeutic decisions. As more molecular modalities become available for clinical use, it is imperative to understand their benefits and disadvantages pertaining to the HHA diagnostics. Re-evaluation of the traditional diagnostic workflow may also bring forth additional benefits. This review focuses on the current state of molecular testing for HHA.

Incidentally Detected Solitary Metastatic Melanoma of the Spleen Without Known Primary: A Case Report.

Splenic masses could be secondary to infection or due to benign and malignant cancers. Due to its anatomy and microenvironment, the spleen is relatively protected from cancer spread. However, melanomas are one of the few cancers that metastasize to the spleen, but only 2% of these metastasize as solitary splenic masses. Among such a small fraction, only a handful have been reported without a known primary. Our patient, an elderly male in his early 60s, was diagnosed with metastatic melanoma of the spleen following a biopsy of the incidentally detected isolated splenic mass. Complete ocular, oral, and dermatological inspections were unremarkable for a probable primary. He responded well to immunotherapy and total splenectomy with no recurrence. Due to advanced imaging modalities in the modern era, the probability of isolated splenic masses as an initial presentation will increase, and a high index of clinical suspicion should be maintained for metastatic cancer as one of the differentials.

Discovery of a biomarker for ß-Thalassemia by HPLC-MS and improvement from Proton Transfer Reaction - Parallel Ion Parking.

ß-thalassemia is a quantitative hemoglobin (Hb) disorder resulting in reduced production of Hb A and increased levels of Hb A2. Diagnosis of ß-thalassemia can be problematic when combined with other structural Hb variants, so that the separation approaches in routine clinical centers are not sufficiently decisive to obtain accurate results. Here, we separate the intact Hb subunits by high-performance liquid chromatography, followed by top-down tandem mass spectrometry of intact subunits to distinguish Hb variants. Proton transfer reaction-parallel ion parking (PTR-PIP), in which a radical anion removes protons from multiply charged precursor ions and produces charge-reduced ions spanning a limited m/z range, was used to increase the signal-to-noise ratio of the subunits of interest. We demonstrate that the δ/ß ratio can act as a biomarker to identify ß-thalassemia in normal electrospray ionization MS1 and PTR-PIP MS1. The application of PTR-PIP significantly increases the sensitivity and specificity of the HPLC-MS method to identify δ/ß ratio as a thalassemia biomarker.

Clinical utility of targeted next-generation sequencing panel in routine diagnosis of hereditary hemolytic anemia: A national reference laboratory experience.

INTRODUCTION: Hereditary hemolytic anemias (HHA) comprise a heterogeneous group of disorders resulting from defective red blood cell (RBC) cytoskeleton, RBC enzyme deficiencies, and hemoglobin (Hb) synthesis disorders such as thalassemia or sideroblastic anemia. MATERIALS AND METHODS: Our hemolytic anemia diagnostic next-generation sequencing (NGS) panel includes 28 genes encoding RBC cytoskeletal proteins, membrane transporter, RBC enzymes, and certain bilirubin metabolism genes. The panel covers the complete coding region of these genes, splice junctions, and, wherever appropriate, deep intronic or regulatory regions are also included. Four hundred fifty-six patients with unexplained hemolytic anemia were evaluated using our NGS panel between 2015 and 2019. RESULTS: We identified pathogenic/likely pathogenic variants in 111/456 (24%) patients that were responsible for the disease phenotype (e.g., moderate to severe hemolytic anemia and hyperbilirubinemia). Approximately 40% of the mutations were novel. As expected, 45/456 (10%) patients were homozygous for the promoter polymorphism in the UGT1A1 gene, A(TA)7 TAA (UGT1A1*28). 8/45 homozygous UGT1A1*28 cases were associated with additional pathogenic mutations causing hemolytic anemia, likely exacerbating hyperbilirubinemia. The most common mutated genes were membrane cytoskeleton genes SPTA1, and SPTB, followed by PKLR. Complex interactions between SPTA1 low expression alleles, alpha-LELY and alpha-LEPRA alleles, and intragenic SPTA1 variants were associated with hereditary pyropoikilocytosis and autosomal recessive hereditary spherocytosis in 23/111 patients. CONCLUSIONS: Our results demonstrate that hemolytic anemia is underscored by complex molecular interactions of previously known and novel mutations in RBC cytoskeleton/enzyme genes, and therefore, NGS should be considered in all patients with clinically unexplained hemolytic anemia and in neonates with hyperbilirubinemia. Moreover, low expression alleles alpha-LELY and alpha-LEPRA should be included in all targeted HHA panels.

Transient neonatal hemolytic anemia due to the novel gamma globin gene mutation HBG2:C.290T>C, p.Leu97Pro (hemoglobin Wareham).

Unstable gamma globin variants can cause transient neonatal hemolytic anemia. We have identified a novel variant in a newborn who presented with jaundice and anemia requiring phototherapy and red blood cell transfusion. The patient was found to be heterozygous for the mutation HGB2:c.290T>C, p.Leu97Pro, which we have termed hemoglobin (Hb) Wareham. This substitution is expected to generate an unstable hemoglobin with increased oxygen affinity based on the homologous mutation previously described in the beta globin gene, which is termed as Hb Debrousse. The patient fully recovered by 9 months of age as expected with the transition from fetal to adult hemoglobin.

A case of azathioprine-induced aplastic anemia.

Azathioprine (AZA) is an immunosuppressant that is widely used to treat many disease states including rheumatoid arthritis. We present a patient who was treated with AZA for rheumatoid arthritis and subsequently hospitalized for severe myelosuppression due to acquired aplastic anemia. Upon genetic testing it was found that the patient was thiopurine methyltransferase (TMPT) deficient, a well-documented risk factor for myelosuppression in patients taking azathioprine. We advocate for TPMT and nudix hydrolase 15 (NUDT15) testing prior to initiation of AZA treatment, or close monitoring with a complete blood count post-AZA initiation to avoid these serious side effects.

Characterization of Structural Hemoglobin Variants by Top-Down Mass Spectrometry and R Programming Tools for Rapid Identification.

Hemoglobinopathies are one of the most prevalent genetic disorders, affecting millions throughout the world. These are caused by pathogenic variants in genes that control the production of hemoglobin (Hb) subunits. As the number of known Hb variants has increased, it has become more challenging to obtain unambiguous results from routine chromatographic assays employed in the clinical laboratory. Top-down proteomic analysis of Hb by mass spectrometry is a definitive method to directly characterize the sequences of intact subunits. Here, we apply "chimeric ion loading" to characterize Hb ß subunit variants. In this technique, product ions derived from complementary dissociation techniques are accumulated in a multipole storage device before delivery to a 21 T Fourier-transform ion cyclotron resonance mass spectrometer for simultaneous detection. To further improve the efficiency of identification of Hb variants and localization of the mutation site(s), we developed an R programming script, "Variants Identifier", to search top-down data against a database containing accurate intact mass differences and diagnostic ions from investigated Hb variants. A second R script, "PredictDiag", was developed and employed to determine relevant diagnostic ions for additional Hb variants with known sequences. These two R scripts were successfully applied to the identification of a Hb δ-ß fusion protein and other Hb variants. The combination of chimeric ion loading and the above R scripts enables rapid and reliable interpretation of top-down mass spectrometry data, regardless of activation type, for Hb variant identification.

A Case Report of Misdiagnosed Breast Implant-associated Anaplastic Large Cell Lymphoma with Lymphatic Extension.

Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is a rare peripheral T-cell lymphoma associated with textured implants and usually presents as a late-onset periprosthetic seroma. We present a 70-year-old woman with a history of left breast invasive ductal carcinoma treated with mastectomy and textured implant-based reconstruction, and subsequent adjuvant chemotherapy due to lymphovascular extension. Eleven years following her reconstruction, the patient developed a periprosthetic seroma. Fine needle aspiration and partial capsulectomy were performed, but appropriate pathologic evaluation was not initially submitted. She then presented with lymphadenopathy, which was biopsied and revealed BIA-ALCL within an axillary lymph node. Despite implant explantation, complete capsulectomy, axillary lymph node dissection, and excision of groin lymphadenopathy, no evidence of primary ALCL was appreciated. This initially misdiagnosed case demonstrates the importance of following the National Comprehensive Cancer Network guidelines when a patient presents with late onset breast periprosthetic effusions.

Thirty-five males with severe (Class 1) G6PD deficiency (c.637G>T) in a North American family of European ancestry.

In North America, jaundiced neonates are not usually tested for G6PD deficiency if the family is of European ancestry. However, we describe such a family where ≥35 males have had severe (Class I) G6PD deficiency. Many of the jaundiced neonates did not have this diagnosis considered, at least three of whom developed bilirubin neurotoxicity. Over seven generations 35 affected males were identified. Three developed signs of kernicterus spectrum disorder; three had exchange transfusions for hyperbilirubinemia; and nine received one or more blood transfusions during childhood.

Laboratory approach to investigation of anemia in pregnancy.

Anemia is a global health problem in all age groups. According to World Health Organization (WHO), approximately 40% of pregnant women are anemic. Iron deficiency anemia (IDA) due to nutritional deficiency is the most common cause. The incidence of IDA varies worldwide depending on the socioeconomic status, but it remains the leading cause even in developed countries. Physiologic anemia of pregnancy due to relatively higher expansion of blood volume in comparison with elevated red blood cell mass also occurs frequently. Complete blood count (CBC) in the first trimester is recommended for all pregnant women to screen for anemia. The screening of pregnant women for IDA in absence of anemia is still debatable. If IDA is suspected, ferritin level of <30 ng/ml is diagnostic. Iron supplementation is recommended for all pregnant women to compensate the increased demand.

Clinical Outcomes of Platinum-ineligible Patients with Advanced Urothelial Carcinoma Treated With First-line PD1/L1 Inhibitors.

BACKGROUND: PD1/L1 inhibitors are approved by FDA as first-line therapy for patients with advanced urothelial carcinoma (aUC) who are cisplatin-ineligible with high tumor PD-L1 expression or are platinum-ineligible regardless of PD-L1 expression. However, the outcomes when employing PD1/L1 inhibitors for platinum-ineligible patients are unclear. This retrospective analysis evaluates the clinical outcomes of first-line PD1/L1 inhibitors in patients with aUC deemed to be platinum-ineligible. METHODS: Data were retrospectively collected from 8 academic institutions. The following criteria were used to define platinum ineligibility: creatinine clearance (CrCl) < 30 mL/min; Eastern Cooperative Oncology Group (ECOG) performance status (PS) 3; CrCl 30 to 59 mL/min and ECOG PS 2; elderly and/or comorbidities. Patient characteristics, responses and treatment-related toxicities were identified. Survival curves were estimated by the Kaplan-Meier method. A Cox regression analysis was conducted to explore the association of baseline variables with response and survival. RESULTS: A total of 79 platinum-ineligible patients with aUC were eligible. Patients were treated with atezolizumab (51.9%), pembrolizumab (35.5%), nivolumab (8.9%), or durvalumab (3.8%). The objective response rate was 27.9%. The median overall survival was 45 weeks (95% confidence interval [CI], 32-80), and the median treatment failure-free survival was 16 weeks (95% CI, 9-18). Treatment-related toxicity of any grade and grade ≥ 3 was seen in 41.8% and 31.7% of patients, respectively. Anemia and liver metastasis were associated with worse survival. CONCLUSION: The efficacy of first-line PD1/L1 inhibitors for platinum-ineligible patients with aUC in the real world appears comparable to those reported in trials of unselected cisplatin-ineligible patients, whereas grade ≥ 3 toxicities appear more common. Further validation is required including data based on PD-L1 status and other biomarkers. Platinum-ineligible patients with aUC warrant evaluation of novel, safe, and effective agents.

Two Clonally Distinct B-Cell Lymphomas Reveal the Diagnosis of XLP1 in a Male Child and His Asymptomatic Male Relatives: Case Report and Review of the Literature.

X-linked lymphoproliferative disease type 1 (XLP1) is a primary immunodeficiency disorder caused by pathogenic variants in the SH2D1A gene (SH2 domain containing protein 1A). Patients with XLP1 may present acutely with fulminant infectious mononucleosis, hemophagocytic lymphohistiocytosis, and/or B-cell non-Hodgkin lymphoma (B-NHL). We report a boy who developed 2 clonally distinct B-NHL 4 years apart and was found to have previously unrecognized XLP1. The report highlights the importance of clonal analysis and XLP1 testing in males with presumed late recurrences of B-NHL, and the role of allogeneic stem cell transplant (allo-SCT) in XLP1 patients and their affected male relatives.

Bone marrow necrosis in pediatric malignancies: 10-Year retrospective review and review of literature.

Bone marrow necrosis (BMN) is a rare pathologic finding, but when encountered is most often associated with malignancy. In adults, its presence correlates with an inferior prognosis, however in children the prognostic implication is unclear. We performed a retrospective review of 3,760 bone marrow specimens in patients ≤18 years over a 10-year period. BMN was identified in less than 1% of specimens and only in patients with leukemia, lymphoma, or neuroblastoma. BMN contributed to a delay in diagnosis; however, advanced medical imaging may serve as a tool to localize nonnecrotic areas for bone marrow sampling, facilitating an expedited diagnosis.