Morizot, Romain, de Korwin, Jean-Dominique, Feugier, Pierre et al. · Journal of clinical medicine · 2021 · DOI
Researchers studied a rare blood condition called persistent polyclonal B-cell lymphocytosis (PPBL) and found that most patients with PPBL experience symptoms very similar to ME/CFS, including severe fatigue that doesn't improve with rest, worsening after physical activity, sleep problems, and difficulty thinking clearly. Out of 39 patients surveyed, 72% met the official criteria for ME/CFS, and nearly all reported chronic fatigue lasting more than 6 months. This finding suggests these two conditions may share common underlying features, though more research is needed to understand why.
This study provides evidence that ME/CFS-like symptoms are prevalent in another rare condition, which could help clinicians recognize ME/CFS in underdiagnosed populations and may offer clues about shared biological mechanisms underlying post-exertional malaise and cognitive dysfunction. Understanding symptom overlap across conditions could advance biomarker research and improve diagnostic accuracy for ME/CFS.
This study does not prove that PPBL causes ME/CFS or vice versa, nor does it establish a causal relationship between the two conditions. The lack of a control group means we cannot determine whether these symptoms are uniquely common in PPBL or represent baseline prevalence in similar populations. Additionally, patient self-reporting without objective confirmation of symptom severity limits conclusions about actual disease burden.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
The first block is for the primary paper and is the citation you should use in research work. The atlas-snapshot line only applies if you are specifically referring to this atlas’s reading of the paper on the date shown.
Primary citation
Morizot, Romain, de Korwin, Jean-Dominique, Feugier, Pierre, Broséus, Julien, Troussard, Xavier, & Lesesve, Jean-François (2021). Patients with Persistent Polyclonal B-Cell Lymphocytosis Share the Symptomatic Criteria of Systemic Exertion Intolerance Disease.. Journal of clinical medicine. https://doi.org/10.3390/jcm10153374
BibTeX
@article{mecfsatlas-morizot-2021-patients-persistent,
author = {Morizot, Romain and de Korwin, Jean-Dominique and Feugier, Pierre and Broséus, Julien and Troussard, Xavier and Lesesve, Jean-François},
title = {Patients with Persistent Polyclonal B-Cell Lymphocytosis Share the Symptomatic Criteria of Systemic Exertion Intolerance Disease.},
journal = {Journal of clinical medicine},
year = {2021},
doi = {10.3390/jcm10153374},
note = {PubMed: 34362156},
url = {https://www.mecfsatlas.com/evidence/morizot-2021-patients-persistent},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-30. https://www.mecfsatlas.com/evidence/morizot-2021-patients-persistent
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