FLAER as a standalone reagent for paroxysmal nocturnal hemoglobinuria: Do we need to reconsider the guidelines for testing?

INTRODUCTION: Flow cytometry-based paroxysmal nocturnal hemoglobinuria (PNH) testing involves utilization of monoclonal antibodies against GPI-linked proteins and FLAER. The ability of FLAER to bind to a wide variety of GPI-linked structures and to be utilized across different leukocyte subsets is remarkable. We hypothesize that FLAER as a standalone reagent may be equally effective for detecting PNH clones. The present study intends to compare the results of a FLAER alone-based strategy to the recommended FLAER+GPI-linked protein-based approach for applicability in clinical settings. METHODS: EDTA-anticoagulated blood samples from patients for PNH workup were tested for PNH by multiparametric flow cytometry. A conventional panel comprising gating markers (CD45 for WBC, CD15 for granulocytes, and CD64 for monocytes) and a combination of FLAER and GPI-linked markers, such as CD24 and CD14, henceforth referred to as the "routine panel," was employed. Second, a "FLAER-only panel" comprising the gating markers and FLAER alone (excluding the GPI-linked markers CD24 and CD14) was set up. The samples were processed using the lyse-wash-stain-wash technique, and events were acquired on BC Navios Ex flow cytometer (Beckman Coulter, Inc., USA) and analyzed on Kaluza Software 2.1. The presence of a PNH clone was reported at a value of ≥0.01%. RESULTS: A total of 209 patients were tested. Both panels found a PNH clone in 20.1% of patients (n = 42/209) with a 100% concordance rate. The PNH clone range for granulocytes was 0.01%-89.68%, and for monocyte was 0.04%-96.09% in the routine panel. The range in the FLAER-only panel for granulocytes was 0.01%-89.61%, and for monocytes, it was 0.01%-96.05%. Pearson correlation statistics revealed a significant correlation between the size of the PNH clone of granulocytes and monocytes among the two panels tested (granulocytes r = 0.9999, p < 0.0001, 95% CI = 0.9999 to 1.000; monocytes r = 0.9974, p < 0.0001, 95% CI = 0.9966-0.9980). CONCLUSION: Based on our results, FLAER as a standalone marker is specific and sensitive for identifying PNH clones in granulocytes and monocytes, even for high-sensitivity PNH assay. The proposed "FLAER-only panel" panel is efficient and cost-effective for highly sensitive PNH testing in two different cell lineages, especially in resource-limited clinical settings.

Detection of circulating normal and tumor plasma cells in newly diagnosed patients of multiple myeloma and their associations with clinical and laboratory parameters.

INTRODUCTION: Circulating plasma cells (CPCs) are frequently noted in variable frequencies in the entire spectrum of plasma cells neoplasms. With advent of high sensitivity multi-parametric flow cytometry, it is not only possible to detect CPCs present in very low numbers, but also to categorise them into circulating tumor plasma cells (CTPCs) and circulating normal plasma cells (CNPCs), based on their marker-profile. This study used multi-colour flow cytometry to evaluate the load of both CTPCs & CNPCs at the time of diagnosis and at six months' time-point of therapy, and evaluated associations of both with clinical and laboratory parameters. METHODS: Twenty one newly diagnosed MM patients were enrolled. Six to nine millilitres of EDTA-anticoagulated peripheral blood sample was used for flow cytometry. A ten colour antibody panel was used for analysis of CPCs, which were categorised further into CTPCs and CNPCs. Approximately 4.8 million events were acquired for the analysis. The percentage &absolute numbers of CTPCs and CNPCs were noted and the proportion of CTPCs out of all CPCs (CTPCs + CNPCs) were also calculated for evaluating their statistical associations. RESULTS: All 21 patients of newly diagnosed MM showed presence of CPCs (CTPCs and/or CNPCs) at the time of diagnosis. The CTPCs were detected in 76 % of the study population. The median percentage and absolute counts of CTPCs were 0.52 % and 54.9 cells /µL, respectively. CNPCs were found in 95 % and the median percentage and absolute counts of CNPCs were 0.025 % and 2.66 cells/µL. After six months of therapy, CPCs (CTPCs and/or CNPCs) were found in all nine patients evaluated for this assay. CTPCs were found 33 %, with a median of 0.075 % and CNPCs were found in 89 % with a median of 0.01 %. Our study showed that the load of CTPCs was found to be higher in patients with presence of lytic bone lesions, plasmacytoma, presence of PCs on peripheral blood film by light microscopy, presence of Chr 1p32 deletion, expression of CD56 and CD81 on CTPCs, and in patients with absence of very good partial response (VGPR). Conversely, the load of CTPCs was significantly lower in patients with concomitant amyloidosis. Also, percentage of bone marrow plasma cells exhibited a significant positive correlation with the absolute count of CTPCs. We observed that the mean percentage of CNPCs was significantly higher in female patients. The load of CNPCs was lower in patients with thrombocytopenia and with hypoalbuminemia. CONCLUSION: Increased burden of CTPCs was associated with presence of lytic lesions, plasmacytomas, Chr 1p32 deletion, expression of CD56 and CD81 on tumor cells and with failure to achieve very good partial response. The CNPCs were lower in patients with thrombocytopenia and with hypoalbuminemia. To best ot our knowledge, this is the first study from India on the relevance of circulating tumor plasma cells and the first study in the world to analyse the associations of circulating normal plasma cells in newly diagnosed patients of multiple myeloma. The study also highlights the utility of multi-parametric flow cytometry in identification and enumeration of circulating plasma cells. MICRO ABSTRACT: Circulating plasma cells indicates poorer outcomes in patients of multiple myeloma. Twenty one newly diagnosed multiple myeloma patients were evaluated by flow cytometry to enumerate and characterise circulating tumor plasma cells (CTPCs) and circulating normal plasma cells (CNPCs). Higher load of CTPCs correlated with known poor prognostic markers and poor response to therapy.

Autopsy findings of acute erythroid leukemia.

Acute erythroid leukemia (AEL) is an exceedingly uncommon but distinct hematological malignancy that shows neoplastic proliferation of erythroid precursors with maturation arrest and no significant myeloblasts. We describe an autopsy case of this rare entity in a 62-year-old man with co-morbidities. He underwent a bone marrow (BM) examination for pancytopenia during the first outpatient department visit, which revealed an increased number of erythroid precursors with dysmegakaryopoiesis suggesting the possibility of Myelodysplastic syndromes (MDS). Thereafter, his cytopenia got worsened, warranting blood and platelet transfusions. Four weeks later on the second BM examination, AEL was diagnosed based on morphology and immunophenotyping. Targeted resequencing for myeloid mutations revealed TP53 and DNMT3A mutations. He was initially managed along febrile neutropenia with the stepwise escalation of antibiotics. He developed hypoxia attributed to anemic heart failure. Subsequently, he had hypotension and respiratory fatigue pre-terminally and succumbed to his Illness. A complete autopsy showed infiltration of various organs by AEL and leukostasis. Besides, there was extramedullary hematopoiesis, arterionephrosclerosis, diabetic nephropathy (ISN-RPS class II), mixed dust pneumoconiosis, and pulmonary arteriopathy. The histomorphology of AEL was challenging, and the differential diagnoses were many. Thus, this case highlights the autopsy pathology of AEL, an uncommon entity with a strict definition, and its relevant differentials.

A prospective survey on trephine biopsy of bone and bone marrow: an experience with 274 Indian patients' biopsies.

Trephine bone marrow biopsy is an effective technique for diagnosing hematological malignancies in patients of different ages. During trephine biopsy, bone marrow cores are obtained for detailed morphological evaluation to look for any abnormality and arrive at a diagnosis. The primary goal of this work is to perform a survey on Indian patients of various ages for the trephine bone marrow biopsy process. In the present study, data related to 274 trephine biopsy samples from 300 patients were acquired at the Post Graduate Institute of Medical Education and Research (PGIMER) in Chandigarh, India. Pain was found to be the sole major procedure-related complication, and patients reported no/less pain in 41 BMB (14.96%) patients, moderate pain in 82 (29.92%) cases, and unbearable pain in 151 (55.1%) BMB cases. In addition, the patients were evaluated by the authors and hematologist as non-anxious for the procedure in 34 (12.4%), anxious in 92 (33.57%), and very/highly anxious in 148 (56%) cases. The bone texture of the patients significantly affected the needle bending, number of repetitions required, and size of the bone marrow sample. This demonstrates the need for improvement in the biopsy procedure. To this end, a survey was conducted to assess the numerous difficulties and diagnostic outcomes throughout the trephine biopsy process.

Cerebrospinal fluid infiltration by chronic myeloid leukaemia: Evaluation of cytomorphological features.

BACKGROUND AND AIM: To describe the cytomorphological findings of all cerebrospinal fluid (CSF) cytology samples showing infiltration by chronic myeloid leukaemia (CML) and their correlation with haematological findings. MATERIALS AND METHODS: A retrospective analysis of all CSF samples reported as showing infiltration by CML on cytology from January 2014 to December 2021 was performed. RESULTS: A total of 10 cases with positive CSF cytology were evaluated. The mean age of the patients was 34.1 years (range 17-70 years). There were more males than females. All cases were pre-diagnosed cases of CML on haematological investigations. On cytology, the smears showed atypical/immature blast-like cells, with a high nucleo-cytoplasmic ratio, opened-up chromatin, 1-2 conspicuous nucleoli and a scant to moderate amount of agranular to fine granular cytoplasm along with occasional granulocytic precursors. The shortest time interval for CSF positivity in a known case of CML was 5 months, and the longest interval was 11 years. CONCLUSION: It is extremely uncommon to encounter CML infiltration in CSF. Timely analysis of CSF cytology samples can allow quick diagnosis and alter the patient management protocol.

Autopsy findings of acute erythroid leukemia

ABSTRACT Acute erythroid leukemia (AEL) is an exceedingly uncommon but distinct hematological malignancy that shows neoplastic proliferation of erythroid precursors with maturation arrest and no significant myeloblasts. We describe an autopsy case of this rare entity in a 62-year-old man with co-morbidities. He underwent a bone marrow (BM) examination for pancytopenia during the first outpatient department visit, which revealed an increased number of erythroid precursors with dysmegakaryopoiesis suggesting the possibility of Myelodysplastic syndromes (MDS). Thereafter, his cytopenia got worsened, warranting blood and platelet transfusions. Four weeks later on the second BM examination, AEL was diagnosed based on morphology and immunophenotyping. Targeted resequencing for myeloid mutations revealed TP53 and DNMT3A mutations. He was initially managed along febrile neutropenia with the stepwise escalation of antibiotics. He developed hypoxia attributed to anemic heart failure. Subsequently, he had hypotension and respiratory fatigue pre-terminally and succumbed to his Illness. A complete autopsy showed infiltration of various organs by AEL and leukostasis. Besides, there was extramedullary hematopoiesis, arterionephrosclerosis, diabetic nephropathy (ISN-RPS class II), mixed dust pneumoconiosis, and pulmonary arteriopathy. The histomorphology of AEL was challenging, and the differential diagnoses were many. Thus, this case highlights the autopsy pathology of AEL, an uncommon entity with a strict definition, and its relevant differentials.

A novel ATRX splice variant causing acquired HbH disease in myelodysplastic syndrome with excess blasts-1.

A 60-year-old male with myelodysplastic syndrome with excess blasts-1 had unexplained microcytic hypochromic anemia. The cause of his anemia was revealed on supravital staining, hemoglobin studies and next-generation sequencing to be a novel hemizygous potentially pathogenic missense/splice site variant NM_000489.5:c.6848A>C, (p.Lys2283Thr) in exon 31 of the ATRX gene.

Invasive Pulmonary Aspergillosis and Tuberculosis Complicated by Hemophagocytic Lymphohistiocytosis - Sequelae of COVID-19 in a Liver Transplant Recipient.

Liver transplant recipients are at an increased risk of opportunistic infections due to the use of immunosuppression. Coronavirus disease of 2019 (COVID-19) increases the risk of these infections further due to associated immune dysfunction and the use of high-dose steroids. We present a case of a liver transplant recipient who developed disseminated tuberculosis and invasive pulmonary aspergillosis complicated by acquired hemophagocytic lymphohistiocytosis after recovering from severe COVID-19.

Congenital erythrocytosis.

Erythrocytosis, or increased red cell mass, may be labeled as primary or secondary, depending on whether the molecular defect is intrinsic to the red blood cells/their precursors or extrinsic to them, the latter being typically associated with elevated erythropoietin (EPO) levels. Inherited/congenital erythrocytosis (CE) of both primary and secondary types is increasingly recognized as the cause in many patients in whom acquired, especially neoplastic causes have been excluded. During the past two decades, the underlying molecular mechanisms of CE are increasingly getting unraveled. Gain-in-function mutations in the erythropoietin receptor gene were among the first to be characterized in a disorder termed primary familial and congenital polycythemia. Another set of mutations affect the components of the oxygen-sensing pathway. Under normoxic conditions, the hypoxia-inducible factor (HIF), upon hydroxylation by the prolyl-4-hydroxylase domain protein 2 (PHD2) enzyme, is degraded by the von Hippel-Lindau protein. In hypoxic conditions, failure of prolyl hydroxylation leads to stabilization of HIF and activation of the EPO gene. CE has been found to be caused by loss-of-function mutations in VHL and PHD2/EGLN1 as well as gain-of-function mutations in HIF-2α (EPAS1), all resulting in constitutive activation of EPO signaling. Apart from these, globin gene mutations leading to formation of high oxygen affinity hemoglobins also cause CE. Rarely, bisphosphoglycerate mutate mutations, affecting the 2,3-bisphosphoglycerate levels, can increase the oxygen affinity of hemoglobin and cause CE. This narrative review examines the current mutational spectrum of CE and the distinctive pathogenetic mechanisms that give rise to this increasingly recognized condition in various parts of the world.

Diagnosis of hairy cell leukaemia by fine needle aspiration cytology of lymph node.

BACKGROUND: Hairy cell leukaemia (HCL) is a rare lymphoproliferative disorder of B cell origin, and uncommonly it affects the lymph node. Fine needle aspiration cytology (FNAC) of lymph node of HCL has rarely been described. CASE DESCRIPTION AND DIAGNOSIS: A 41-year-old man presented with pallor, fever, tachycardia, generalized lymphadenopathy, and massive splenomegaly. The FNAC of the cervical lymph node was done. The smears showed many atypical lymphocytes with a plasmacytoid appearance. There were many large cells with round to reniform shaped nuclei having with hair-like cytoplasmic processes. Flow cytometry (FCM) revealed a clonal B cell population with light chain restriction and positive CD20, CD79b, CD22, CD11c, CD25, CD103, CD123, and CD200 markers. CONCLUSION: The characteristic cytological features such as atypical lymphoid cells, large cells with hairy projections along with FCM findings, are helpful in the diagnosis of HCL.

Genetic basis of unexplained erythrocytosis in Indian patients.

OBJECTIVE: To evaluate the spectrum of genetic defects in Indian patients with unexplained erythrocytosis. METHODS: Fifteen families (18 patients) with unexplained erythrocytosis were enrolled after excluding polycythemia vera and secondary erythrocytosis. Focused Sanger sequencing from genomic DNA was performed for EPOR (exon 8), VHL (exons 2-3), EGLN1 (exons 2-5), EPAS1 (exon 12), and all exons of HBB, HBA1, and HBA2 genes. RESULTS: Eleven of the 18 patients (including two pairs of brothers) had Chuvash polycythemia, that is, homozygosity for VHL:c.598C > T (p.Arg200Trp). Three patients (two of whom were brothers) had HBB mutations associated with increased oxygen-affinity hemoglobin-one had a heterozygous Hb McKees Rocks HBB:c.438T > A (p.Tyr146*), and two brothers showed heterozygous Hb Rainier HBB:c.437A > G (p.Tyr146Cys). No pathogenic variants were found in the remaining four cases. CONCLUSION: A gene-by-gene Sanger sequencing approach could determine a genetic basis for erythrocytosis in 11 of the 15 (73%) Indian families, with homozygous VHL:c.598C > T (p.Arg200Trp) being the commonest pathogenic variant. This first study from the Indian subcontinent provides a rationale for analyzing this variant in patients with suspected congenital erythrocytosis from this region. Rare first occurrences of Hb McKees Rocks and Hb Rainier in Indians are also being reported.