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-1 beta compared with the control group. Conclusion: This meta-analysis provides compelling evidence that CRP, Hcy, IL-1 beta, 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.