P499: APPLICABILITY OF 2022 CLASSIFICATIONS OF ACUTE MYELOID LEUKEMIA IN THE REAL-WORLD SETTING

Background: The increasing knowledge of molecular characterization in acute myeloid leukemia (AML) led to the necessity to fully evaluate the genetic profile also for clinical purposes. These efforts resulted in the release of 2022 new editions of AML classification and prognostication systems, including the 5th edition of The World Health Organization (WHO) classification, the International Consensus Classification (ICC), and the European LeukemiaNet (ELN) recommendations for AML prognosis. Aims: We aimed to provide a real-world application of the WHO 2022, ICC and ELN 2022 classifications in the real-world setting, to unravel differences and similarities, and to test their implementation in clinical AML diagnosis. We particularly focused on secondary AML, myelodysplasia (MDS) related. Methods: We selected a cohort of 1001 cases diagnosed with AML according to the WHO 2016 and the ELN 2017 classifications. Where available (44.9% of cases), information concerning a previous history of an antecedent MDS or MDS/Myeloproliferative neoplasm (MPN), as well as a previous exposure to cytotoxic therapies were considered for defining secondary AML (s-AML) and therapy-related AML (t-AML), respectively. Survival outcome was available for 84.4% patients. Results: The overall diagnostic changes between the WHO 2016, compared to WHO 2022 and ICC classifications were 22.8% and 23.7% respectively, with a 13.1% difference in patients’ distribution between ICC and WHO 2022. The “not otherwise specified” (NOS) by ICC and “defined by differentiation” by WHO 2022 categories shrank compared to WHO 2016 (24.1% and 26.8% respectively, vs 38.7%), particularly due to an expansion of MDS-related categories. The 92.7% and the 74.4% of RUNX1-mutated AML were re-classified respectively by the ICC into AML with MDS-related gene mutations and by WHO 2022 into the AML myelodysplasia related (MR) category, although the latter considers RUNX1 mutations lacking of sufficient unifying characteristics. Of 397 cases with a MDS-related AML according to ICC, 55.9% were definable by the presence of a MDS-related karyotype. More than 75.0% of s-AML and t-AML cases presented a MDS-related genetic profile according to both new 2022 diagnostic classifications. The overall re-stratification between ELN 2017 and 2022 accounted for 12.9% (4.0% favorable to intermediate and 8.1% intermediate to adverse risk). The majority of s-AML and t-AML (83.1%) fell into the ELN 2022 adverse risk group. Stratifying the 213 AML classified as favorable risk by ELN 2017, the difference in OS between ELN 2022-defined favorable and intermediate risk groups was statistically significant (p<0.01). We also focused on the heterogeneous group of patients with normal karyotype and adverse risk mutations according to the ELN 2022: the survival outcome was significantly inferior in patients with multiple versus single MDS-related gene mutations (p<0.05). Summary/Conclusion: The 2022 revisions of AML classification led to a significant improvement of diagnostic schemes. In the real-world setting, conventional cytogenetics, usually easily available and less expensive than molecular characterization, correctly stratified 56% of AML MDS-related, thereby maintaining a diriment diagnostic role. Although the secondary nature of AML (prior MDS or MDS/MPN and therapy-related) is now applied as “diagnostic qualifiers”, it maintains a predictive role for defining an adverse outcome according to the ELN 2022. Considering the similarities between WHO and ICC diagnostic schemes, a tentative to generate a unified model taking into account practical and socio-economic issues is desirable

Clinical, immunological, and molecular features of typical and atypical severe combined immunodeficiency: Report of the italian primary immunodeficiency network

Severe combined immunodeficiencies (SCIDs) are a group of inborn errors of the immune system, usually associated with severe or life-threatening infections. Due to the variability of clinical phenotypes, the diagnostic complexity and the heterogeneity of the genetic basis, they are often difficult to recognize, leading to a significant diagnostic delay (DD). Aim of this study is to define presenting signs and natural history of SCID in a large cohort of patients, prior to hematopoietic stem cell or gene therapies. To this purpose, we conducted a 30-year retro-prospective multicenter study within the Italian Primary Immunodeficiency Network. One hundred eleven patients, diagnosed as typical or atypical SCID according to the European Society for Immune Deficiencies criteria, were included. Patients were subsequently classified based on the genetic alteration, pathogenic mechanism and immunological classification. A positive relationship between the age at onset and the DD was found. SCID patients with later onset were identified only in the last decade of observation. Syndromic SCIDs represented 28% of the cohort. Eight percent of the subjects were diagnosed in Intensive Care Units. Fifty-three percent had an atypical phenotype and most of them exhibited a discordant genotype-immunophenotype. Pre-treatment mortality was higher in atypical and syndromic patients. Our study broadens the knowledge of clinical and laboratory manifestations and genotype/phenotype correlation in patients with SCID and may facilitate the diagnosis of both typical and atypical forms of the disease in countries where newborn screening programs have not yet been implemented

Targeted NGS Platforms for Genetic Screening and Gene Discovery in Primary Immunodeficiencies

Background: Primary Immunodeficiencies (PIDs) are a heterogeneous group of genetic immune disorders. While some PIDs can manifest with more than one phenotype, signs, and symptoms of various PIDs overlap considerably. Recently, novel defects in immune-related genes and additional variants in previously reported genes responsible for PIDs have been successfully identified by Next Generation Sequencing (NGS), allowing the recognition of a broad spectrum of disorders.Objective: To evaluate the strength and weakness of targeted NGS sequencing using custom-made Ion Torrent and Haloplex (Agilent) panels for diagnostics and research purposes.Methods: Five different panels including known and candidate genes were used to screen 105 patients with distinct PID features divided in three main PID categories: T cell defects, Humoral defects and Other PIDs. The Ion Torrent sequencing platform was used in 73 patients. Among these, 18 selected patients without a molecular diagnosis and 32 additional patients were analyzed by Haloplex enrichment technology.Results: The complementary use of the two custom-made targeted sequencing approaches allowed the identification of causative variants in 28.6% (n = 30) of patients. Twenty-two out of 73 (34.6%) patients were diagnosed by Ion Torrent. In this group 20 were included in the SCID/CID category. Eight out of 50 (16%) patients were diagnosed by Haloplex workflow. Ion Torrent method was highly successful for those cases with well-defined phenotypes for immunological and clinical presentation. The Haloplex approach was able to diagnose 4 SCID/CID patients and 4 additional patients with complex and extended phenotypes, embracing all three PID categories in which this approach was more efficient. Both technologies showed good gene coverage.Conclusions: NGS technology represents a powerful approach in the complex field of rare disorders but its different application should be weighted. A relatively small NGS target panel can be successfully applied for a robust diagnostic suspicion, while when the spectrum of clinical phenotypes overlaps more than one PID an in-depth NGS analysis is required, including also whole exome/genome sequencing to identify the causative gene

LGL Clonal Expansion and Unexplained Cytopenia: Two Clues Don’t Make an Evidence

Clonal expansions of large granular lymphocytes (LGL) have been reported in a wide spectrum of conditions, with LGL leukemia (LGLL) being the most extreme. However, the boundaries between LGLL and LGL clones are often subtle, and both conditions can be detected in several clinical scenarios, particularly in patients with cytopenias. The intricate overlap of LGL clonal expansion with other disease entities characterized by unexplained cytopenias makes their classification challenging. Indeed, precisely assigning whether cytopenias might be related to inadequate hematopoiesis (i.e., LGL as a marginal finding) rather than immune-mediated mechanisms (i.e., LGLL) is far from being an easy task. As LGL clones acquire different pathogenetic roles and relevance according to their diverse clinical settings, their detection in the landscape of bone marrow failures and myeloid neoplasms has recently raised growing clinical interest. In this regard, the current availability of different diagnostic techniques, including next generation sequencing, shed light on the relationship between LGL clones and cytopenias, paving the way towards a better disease classification for precision medicine treatments. Herein, we discuss the clinical relevance of LGL clones in the diagnostic algorithm to be followed in patients presenting with cytopenias, offering a foundation for rational management approaches

AquaLog: an ontology-driven question answering system for organizational semantic intranets

The semantic web vision is one in which rich, ontology-based semantic markup will become widely available. The availability of semantic markup on the web opens the way to novel, sophisticated forms of question answering. AquaLog is a portable question-answering system which takes queries expressed in natural language and an ontology as input, and returns answers drawn from one or more knowledge bases (KBs). We say that AquaLog is portable because the configuration time required to customize the system for a particular ontology is negligible. AquaLog presents an elegant solution in which different strategies are combined together in a novel way. It makes use of the GATE NLP platform, string metric algorithms. WordNet and a novel ontology-based relation similarity service to make sense of user queries with respect to the target KB. Moreover it also includes a learning componment, which ensures that the performance of the system improves over the time, in response to the particular community jargon used by end users