Circulating Level of Myelin Basic Protein Predicts Postherpetic Neuralgia: A Prospective Study

Validity of Plasma Neuropeptide Y in Combination with Clinical Factors in Predicting Neuralgia Following Herpes Zoster

Background

Numerous lines of evidence suggest that neuropeptide Y (NPY) is critically involved in the modulation of neuropathic pain. Postherpetic neuralgia (PHN) is characterized by prolonged duration, severe pain, and significant treatment resistance, substantially impairing patients' quality of life. This study aims to evaluate the potential of plasma NPY levels in patients with PHN as a predictive biomarker for the development of this condition.

Methods

Between February 2022 and December 2023, 182 patients with herpes zoster (HZ) were recruited. Thirty-eight volunteers with no history of HZ were also recruited as controls. Clinical factors, NPY, brain-derived neurotrophic factor (BDNF), and nerve growth factor (NGF) were assessed within 3 days of healing. Logistic regression analysis was used to predict the development of PHN.

Results

NPY levels were lower and BDNF and NGF were higher in HZ patients than those in controls. Only NPY levels were lower in patients with PHN (n = 59) compared with those without PHN (n = 123). Age, acute pain severity, and rash area were independent predictors of PHN, as were NPY levels. The area under the curve (AUC) to predict the development of PHN based on the combination of NPY levels and clinical factors was 0.873 (95% CI: 0.805 to 0.940), and the AUC was 0.804 based on only clinical factors (AUC: 0.804, 95% CI: 0.728 to 0.881).

Conclusion

Low plasma NPY levels are a predictor of developing PHN in patients with HZ. Combining clinical predictors with NPY levels may improve predictive accuracy.

Identifying and Evaluating Biological Markers of Postherpetic Neuralgia: A Comprehensive Review

Postherpetic neuralgia (PHN) manifests as persistent chronic pain that emerges after a herpes zoster outbreak and greatly diminishes quality of life. Unfortunately, its treatment efficacy has remained elusive, with many therapeutic efforts yielding less than satisfactory results. The research to discern risk factors predicting the onset, trajectory, and prognosis of PHN has been extensive. However, these risk factors often present as nonspecific and diverse, indicating the need for more reliable, measurable, and objective detection methods. The exploration of potential biological markers, including hematological indices, pathological insights, and supportive tests, is increasing. This review highlights potential biomarkers that are instrumental for the diagnosis, management, and prognosis of PHN while also delving deeper into its genesis. Drawing from prior research, aspects such as immune responsiveness, neuronal injury, genetic makeup, cellular metabolism, and pain signal modulation have emerged as prospective biomarkers. The immune spectrum spans various cell subtypes, with an emphasis on T cells, interferons, interleukins, and other related cytokines. Studies on nerve injury are directed toward pain-related proteins and the density and health of epidermal nerve fibers. On the genetic and metabolic fronts, the focus lies in the detection of predisposition genes, atypical protein manifestations, and energy-processing dynamics, with a keen interest in vitamin metabolism. Tools such as functional magnetic resonance imaging, electromyography, and infrared imaging have come to the forefront in the pain signaling domain. This review compiles the evidence, potential clinical implications, and challenges associated with these promising biomarkers, paving the way for innovative strategies for predicting, diagnosing, and addressing PHN.

Humoral Cytokine Levels in Patients with Herpes Zoster: A Meta-Analysis

Background

The neurocutaneous disease caused by the reactivation of varicella-zoster virus (VZV) is called herpes zoster (HZ). The virus remains in the spinal cord back root after the chickenpox disappears. Diminished immune function can reactivate VZV, causing severe neuropathic pain that can last for months or even years, leading to postherpetic neuralgia (PHN), which severely affects the patient's quality of life. Much literature compares various cytokine levels in the body fluids HZ and PHN patients; however, no studies comprehensively evaluate them.

Methods

The Cochrane Library, PubMed, Web of Science, and Medline were screened for studies on cytokine levels in body fluids of HZ and PHN patients in the English language. Healthy individuals were selected as the control group, and the standardized mean difference (SMD) between the case and control groups was imputed using a fixed-effects or random-effects model and expressed as a 95% confidence interval (CI). The Newcastle-Ottawa Scale (NOS) was used to assess article quality.

Results

This meta-analysis included 13 articles with 1373 participants. Compared with the control group, the HZ group had significantly higher levels of interleukin (IL)-4, IL-6, IL-10, Hcy, and C-reactive protein (CRP), whereas the levels of CD3+ T and CD4+ T lymphocytes were reduced. Additionally, PHN patients had significantly higher levels of IL-6 and IL-1β compared with the control group.

Conclusion

This meta-analysis provides compelling evidence that CRP, Hcy, IL-1β, IL-4, IL-6, IL-8, and IL-10 are associated with the genesis and development of HZ and PHN. These markers can be used to improve the diagnosis and treatment of these diseases.Furthermore, for making the results more convincing, it is necessary to harmonize sample acquisition techniques and analytical methods and also require larger, more rigorously designed studies with broader subgroups and sex/age-matched controls.