ArticleBiomedicines2023
An Observational Study on Chronic Pain Biomarkers in Fibromyalgia and Osteoarthritis Patients: Which Role for Mu Opioid Receptor's Expression on NK Cells?
Article in Biomedicines, 2023. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 13 papers, 2 of them syntheses that pooled it.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
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Who cites it
13 citing papers in PubMed, 2 syntheses or guidelines pooled it, 13 citations in OpenAlex.
- The Role of the Antidepressants in Managing Chemotherapy-Induced Neuropathic Pain: A Systematic Review.Pharmacology research & perspectives · 2026Pooled it
- Does Vitamin D Supplementation Impact Fibromyalgia-Related Pain? A Systematic Review and Meta-Analysis.Nutrients · 2025Pooled it
- Modulation of Mu-Opioid Receptor Expression and Functional Impairment of Natural Killer Cells in Neuropathic Pain: Implications for Biomarker Discovery and Personalized Therapies.Pharmaceuticals (Basel, Switzerland) · 2026Article
- Nociplastic pain: the prominent role of non-neuronal cells in central and peripheral sensitization.Frontiers in immunology · 2026Review
- In Search of Molecular Correlates of Fibromyalgia: The Quest for Objective Diagnosis and Effective Treatments.International journal of molecular sciences · 2025Review
- Mu-opioid receptor expression on B cells as a potential biomarker for chronic pain: a follow-up study with patients with fibromyalgia.Pain reports · 2025Article
- Neuroinflammatory and Immunological Aspects of Fibromyalgia.Brain sciences · 2025Review
- Role of Vitamin D Status and Alterations in Gut Microbiota Metabolism in Fibromyalgia-Associated Chronic Inflammatory Pain.Biomedicines · 2025Article
- Innate Immunity and Synovitis: Key Players in Osteoarthritis Progression.International journal of molecular sciences · 2024Review
- Inflammation, Autoimmunity, and Infection in Fibromyalgia: A Narrative Review.International journal of molecular sciences · 2024Review
- Effect of Intraoperative Opioid Dose on Perioperative Neutrophil-to-Lymphocyte Ratio and Lymphocyte-to-Monocyte Ratio in Glioma.Journal of inflammation research · 2024Article
- Pain Biomarkers in Fibromyalgia Syndrome: Current Understanding and Future Directions.International journal of molecular sciences · 2023Review
- Fibromyalgia and Irritable Bowel Syndrome Interaction: A Possible Role for Gut Microbiota and Gut-Brain Axis.Biomedicines · 2023Review
Corrections and comments
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Authors and funding
16 authors at 4 institutions in 1 country.
Funding
Abstract
The evaluation of chronic pain is challenging because of the lack of specific biomarkers. We identified the Mu opioid receptor-positive (Mu+) B cell percentage of expression, named Mu-Lympho-Marker (MLM), as a candidate marker for chronic pain in fibromyalgia (FM) and osteoarthritis (OA) patients. Here, we investigate the role of MLM on natural killer (NK) cells in the same patients. Twenty-nine FM and twelve OA patients were analyzed, and twenty-three pain-free subjects were considered as the control group. Blood samples were collected to perform immunophenotyping and Western blot analysis. Biological and clinical data were statistically analyzed. The final results showed that the percentage of NK cells expressing Mu was statistically lower in FM and OA patients than in pain-free subjects, as already demonstrated for B cells. A Western blot analysis was performed in order to detect NK cells' functional status. Moreover, the correlation analysis of MLM expression with pharmacological therapy did not show any significant results. In conclusion, here, we confirm the role of MLM as a suitable marker for chronic pain and underline NK cells as a new possible immune cell type involved in the "Mu opioid receptor reserve theory".
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.