Chromosome 7 abnormalities in patients with myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) heralds a poor prognosis. However its prevalence, morphological characteristics and clinical impact in MDS and AML in Indian subcontinent is sparsely reported. This was an observational cross-sectional study performed to evaluate the clinico-pathological profiles of MDS/AML patients with chromosome 7 abnormalities over a period of 4 years. 724 cases of MDS (n = 150) and AML (n = 574) were evaluated. Abnormal karyotype was detected in 49% (43/88) patients of MDS and 44% (127/289) cases of AML. Chromosome 7 abnormalities were detected in 18% cases of MDS (16/88) and 6.5% (19/289) cases of AML. Sole chromosome 7 abnormalities were detected in 5.7% (5/88) and 2.7% (8/289) and in adjunct to complex abnormalities in 7.9 and 3.1% cases of MDS and AML respectively. Morphologically, dyserythropoiesis, dysmyelopoiesis and eosinophilia were seen in 100, 66 and 56% cases of MDS and 38, 40 and 21% cases of AML. Majority of the patients had an aggressive natural course and outcome was dismal. Chromosome 7 abnormalities are strongly associated with the presence of morphological dysplasia and eosinophilia, irrespective of the type of aberration. It is invariably associated with very poor outcome.

To study the utility and advantage of CD157 in the paroxysmal nocturnal hemoglobinuria (PNH) screening along with its ability to replace CD24 and CD14. This was a confirmatory study to analyse the role and advantage of CD157 in a single tube five color combination to identify the PNH clones. A serial tenfold dilution experiments was carried out for sensitivity assessment. Reproducibility was checked in the intra-assay and inter-assay experiments. The results obtained with CD157 based assay were compared with the routinely used single tube six color CD24/CD14 based assay. CD157 showed a high degree of sensitivity at the level of 10. PNH positive clone sizes were precise with CVs of inter-assay and intra-assay precision analysis for polymorphs/monocytes ranging from 2.94 to 4.31/2.52 to 8.93, and 0.91 to 3.23/1.65 to 5.33%; respectively. The results were similar to those obtained from CD24/CD14 based assay (R > 0.993). There was no false positive or false negative result. CD157 was found better in delineating the type II clones. CD157 can be used as a common PNH leucocyte marker with high degree of sensitivity and precision. It can replace CD24 and CD14 from the currently used assays and thus bring down the cost of PNH screening.

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S-gene target failure (SGTF) is neither specific nor accurate for identification of Omicron lineage of SARS-CoV-2. We observed N-gene target failure (NGTF) in 402 out of 412 SARS-CoV2 positive cases from December to mid-January 2022 using a commercially available assay. This phenomenon was not observed with more than 15,000 cases tested previously. We sequenced the genome of five samples with NGTF and compared these results with six cases where NGTF was not seen. We confirm that cases with NGTF were the Omicron lineage while cases with preserved N-gene amplification belonged to Delta lineage. We discovered that the ERS31-33 deletion (nucleotide 28362-28370del) overlaps with N gene probe used, explaining NGTF. As the 'stealth' Omicron variant also harbors ERS31-33 deletion, this approach will work for the detection of 'stealth' Omicron variant as well. We suggest that NGTF can be used as a low cost, rapid screening strategy for detection of Omicron.

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Detection of measurable residual disease (MRD) is of significant value in the management of acute myeloid leukemia (AML) patients. Along with multicolor flowcytometry (MFC), molecular techniques form an integral tool in AML MRD detection. Multiple studies have reiterated the role of molecular MRD evaluation in AML at defined timepoints during the course of therapy, helping in risk stratification, prediction of relapse, and as guide for pre-emptive therapy. The latest World Health Organization (WHO) classification (WHO-HEME5) has refined the classification of AML bringing forth newer entities defined by molecular abnormalities, especially fusions. AML is a clonally heterogeneous disease characterized by a spectrum of multiple molecular abnormalities including gene mutations and fusions. Accordingly, the molecular methods employed are also diverse and need robust technical standardization in clinical laboratories. Real-time quantitative polymerase chain reaction (PCR), digital PCR, and next-generation sequencing (NGS) are the major molecular platforms for AML MRD. The European LeukemiaNet (ELN) MRD Working Party consensus document recently updated in 2021 for the first time has reflected on the technical recommendations for NGS MRD in AML and stressed the value of an integrated approach. It is, therefore, desirable for physicians, scientists, and pathologists alike to thoroughly understand these molecular methods for appropriate utilization and interpretation. In this article, we discuss the various facets of molecular methods for MRD detection in AML including technical requirements, advantages, drawbacks, and applications.

A 7-year-old boy presented with a short history of fever and facial palsy. Laboratory workup revealed 10% blasts in peripheral blood. Blasts and maturing myeloid cells in bone marrow showed distinct myeloperoxidase (MPO)-negative pale waxy cytoplasmic inclusions along with features of dysmyelopoiesis (panels A-C, inclusions highlighted by the arrows; original magnification 3100, May Grunwald Giemsa stain [A-B], myeloperoxidase stain [C]). Flow cytometry revealed that the blasts expressed CD33, CD13, CD117, HLA-DR, CD34, MPO, and aberrant CD19. Conventional karyotyping revealed t(8;21) and loss of Y (2Y). Reverse transcription polymerase chain reaction (RT-PCR) revealed AML1-ETO fusion transcript (panel D; RT-PCR for AML1-ETO; NC, negative control; PC, positive control). Because the patient was lost to follow-up, we did not perform further workup.Acute myeloid leukemia (AML) with t(8;21) shows a wide spectrum of morphological abnormalities, particularly dyspoiesis, long slender Auer rods, and eosinophilia. Waxy pale cytoplasmic inclusions have rarely been described and form part of the Nucifora score for the morphologic characterization of AML with t(8;21). To the best of our knowledge, the presence of such lamellar stacks simulating MPO-negative Auer rod-like structures has not been reported previously. A possible mechanism for this phenomenon could be MPO enzyme-deficient lysosomes, but confirmation by electron microscopy and enzyme studies is required.For additional images, visit the ASH IMAGE BANK, a reference and teaching tool that is continually updated with new atlas and case study images. For more information visit http://imagebank.hematology.org.

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