ICSH Recommendations for Monocyte Cell Lineage Morphologic Identification, Nomenclature Harmonization, and
Gina Zini1,2, Yoon Hwan Chang3, Giuseppe d'Onofrio1
1Università Cattolica del Sacro Cuore, Rome, Italy.
Insights
Standardized classification of monocytes and their precursors improves diagnostic accuracy for hematologic disorders. New guidelines harmonize nomenclature and morphology, aiding automated tools and consistent global reporting.
Area of Science:
- Hematology
- Immunology
- Cell Biology
Background:
- Monocytes are crucial for immune responses, inflammation, and tissue repair within the Mononuclear Phagocyte System.
- Inconsistent nomenclature and morphology hinder accurate identification of monocyte lineage cells, impacting diagnosis of hematologic disorders.
- The rise of automated and AI-driven diagnostics necessitates standardized criteria for monocyte classification.
Purpose of the Study:
- To establish standardized morphological definitions for monocytes and their precursors.
- To harmonize nomenclature for monocyte lineage cells.
- To evaluate the clinical utility of monocytes as biomarkers.
Main Methods:
- Convening the International Council for Standardization in Haematology (ICSH) Monocyte Working Group (MWG).
- Collecting data from global laboratories and conducting an extensive literature review.
- Consensus feedback from the ICSH General Assembly and proposing a three-category morphological classification.
Main Results:
- A proposed three-category morphological classification: blasts and blast equivalents (monoblasts and promonocytes), immature monocytes, and mature monocytes.
- Reaffirmation of morphological analysis, cytochemical staining, and flow cytometry for diagnosis.
- Recognition of emerging automated parameters (e.g., monocyte distribution width - MDW) and ratios (e.g., lymphocyte/monocyte - LMR, neutrophil/monocyte - NMR) as adjunctive biomarkers.
Conclusions:
- Harmonized recommendations aim to enhance diagnostic accuracy for hematologic disorders.
- Standardized criteria will support the development and implementation of machine learning tools in diagnostics.
- These guidelines will facilitate consistent and reproducible reporting of monocyte analysis across laboratories worldwide.
Abstract:
Monocytes are key components of the Mononuclear Phagocyte System, crucial in immune defense, inflammation, and tissue repair. Accurate identification and classification of monocyte lineage cells are essential for diagnosing both reactive and clonal hematologic disorders. However, morphological criteria and nomenclature inconsistencies have hindered reproducibility, particularly with the rise of automated and AI-driven diagnostic tools. The International Council for Standardization in Haematology (ICSH) Monocyte Working Group (MWG) was convened to establish standardized morphological definitions, harmonize nomenclature for monocytes and their precursors, and evaluate their clinical utility as biomarkers. Data were collected from global laboratories, combined with an extensive literature review and consensus feedback from the ICSH General Assembly. The MWG proposes a three-category morphological classification: blasts and blast equivalents (monoblasts and promonocytes), immature monocytes, and mature monocytes. The recommendations reaffirm the importance of morphological analysis, cytochemical staining, and flow cytometry for accurate diagnosis. Emerging automated parameters, such as monocyte distribution width (MDW), and ratios like lymphocyte/monocyte (LMR) and neutrophil/monocyte (NMR), are also recognized as valuable adjunctive biomarkers. Cytogenetic and molecular results may also impact the utilization of monocytes as a biomarker. These harmonized recommendations aim to improve diagnostic accuracy, support the development of machine learning tools, and facilitate consistent reporting across laboratories worldwide.
