Lymphocytic Variant Hypereosinophilic Syndrome: Case Series From a Tertiary Referral Center in Canada
ABSTRACT Background Lymphocytic variant hypereosinophilic syndrome (L‐HES) is a rare disorder characterized by persistent eosinophilia driven by aberrant T‐cell populations. Diagnosis remains challenging due to the lack of standardized diagnostic criteria. Methods We retrospectively analyzed 18 pati...
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| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Wiley
2025-04-01
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| Series: | eJHaem |
| Subjects: | |
| Online Access: | https://doi.org/10.1002/jha2.1109 |
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| Summary: | ABSTRACT Background Lymphocytic variant hypereosinophilic syndrome (L‐HES) is a rare disorder characterized by persistent eosinophilia driven by aberrant T‐cell populations. Diagnosis remains challenging due to the lack of standardized diagnostic criteria. Methods We retrospectively analyzed 18 patients diagnosed with L‐HES between 2016 and 2023. Comprehensive flow cytometry was performed on peripheral blood samples. Results Nine patients demonstrated the classic sCD3−CD4+CD5+CD2+CD45RO+CD45RA− immunophenotype, ranging from 0.6% to 70% of total lymphocytes. Two patients showed variant sCD3−CD4+ phenotypes, five had expanded (> 10%) sCD3+CD4+CD7− T‐cells, and two displayed aberrant CD8+ T‐LGL populations. Clonality was established in all patients with nonclassic phenotypes by molecular TCR testing or based on uniform TRBC1. We assessed a serial gating strategy to quantify the classic L‐HES phenotype and found this to be highly sensitive and specific with an estimated limit of detection of 0.06% of lymphocytes. Using this strategy, we identified decreased but detectable abnormal T‐cells in all classic phenotype patients reassessed posttreatment, down to as low as 0.3% of lymphocytes. The identification of T‐LGL phenotypes with eosinophilia is a novel finding. Conclusion Our study highlights the diverse immunophenotypic spectrum of L‐HES, emphasizing the importance of comprehensive flow cytometry analysis for accurate diagnosis. |
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| ISSN: | 2688-6146 |