Conti, F, Pittoni, V, Sacerdote, P et al. · Clinical and experimental rheumatology · 1998
Researchers measured levels of beta-endorphin, a natural chemical in the body that helps reduce pain and promotes well-being, in immune cells from ME/CFS patients and healthy people. They found that ME/CFS patients had significantly lower levels of this chemical compared to healthy controls. The authors suggest this difference might help explain why ME/CFS causes fatigue and weakness.
This study provides biological evidence for a potential mechanism underlying ME/CFS symptoms by identifying a specific biochemical abnormality in immune cells. Understanding whether low beta-endorphin contributes to fatigue and pain could eventually lead to new diagnostic markers or targeted treatments for this debilitating condition.
This study does not prove that low beta-endorphin causes ME/CFS fatigue—it only shows an association. It also does not establish whether peripheral PBMC beta-endorphin levels accurately reflect central nervous system levels, nor does it explain whether the low beta-endorphin is a cause, consequence, or marker of chronic immune activation in ME/CFS.
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
Conti, F, Pittoni, V, Sacerdote, P, Priori, R, Meroni, P L, & Valesini, G (1998). Decreased immunoreactive beta-endorphin in mononuclear leucocytes from patients with chronic fatigue syndrome.. Clinical and experimental rheumatology. https://pubmed.ncbi.nlm.nih.gov/9844768/
BibTeX
@article{mecfsatlas-conti-1998-decreased-immunoreactive,
author = {Conti, F and Pittoni, V and Sacerdote, P and Priori, R and Meroni, P L and Valesini, G},
title = {Decreased immunoreactive beta-endorphin in mononuclear leucocytes from patients with chronic fatigue syndrome.},
journal = {Clinical and experimental rheumatology},
year = {1998},
note = {PubMed: 9844768},
url = {https://www.mecfsatlas.com/evidence/conti-1998-decreased-immunoreactive},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-30. https://www.mecfsatlas.com/evidence/conti-1998-decreased-immunoreactive
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