Herpes zoster (HZ), especially postherpetic neuralgia, is one of the most typical types of clinical neuralgia. The incidence rate of HZ in China is approximately 7.7%. Among them, 29.8% of HZ patients eventually develop PHN. About 20% of PHN patients suffer from severe neuralgia for more than one year, or even ten years. It is worth noting that patients with neuralgia are prone to comorbidities such as depression, anxiety and sleep disorders, which seriously affect their work efficiency and quality of life. This is a great torment to both the patients and their families, and it also imposes a heavy burden on the medical system.

Professor Xiao Lizu, a collaborator of our team, has discovered in clinical practice that spinal cord electrical stimulation for HZ patients can significantly reduce the risk of developing PHN. Other therapies for reducing the risk of PHN include multiple parvertebral injections of local anesthetics/steroids, which require patients to return for repeated visits. Although these intervention measures have good effects, they may bring additional economic burdens to patients, treatment side effects and prolong their hospital stays. Therefore, they are not suitable for all patients. From this perspective, our development of early screening methods and selective non-pharmacological intervention only for high-risk patients will improve the overall treatment status of HZ, effectively reduce the incidence of PHN, and alleviate the burden on medical insurance and the medical system at the same time.

This project aims to conduct the following research by analyzing the intestinal flora of patients: identifying biomarkers with the ability to predict the risk of PHN in patients, constructing a machine learning classifier for risk prediction, and developing an early screening kit based on this.

Furthermore, traditional studies mostly focus on a single pathological link and lack systematic multi-dimensional analysis. In recent years, the cerebral lymphatic system, as a key pathway for the clearance of metabolic wastes in the brain, has attracted widespread attention. Furthermore, the role of the gut-brain axis in pain regulation has gradually been recognized. Therefore, it is of great scientific significance to integrate and explore the pathological mechanism of PHN from three dimensions: the lymphatic system, neuroinflammation, and intestinal flora.

This project assumes that patients with PHN have a pathological triad of "lymphoid dysfunction - neuroinflammatory activation - intestinal flora imbalance". The specific manifestations are as follows: Impaired lymphoid clearance function (decreased DTI-ALPS index and increased free water), activated systemic inflammatory response (elevated TNF-α and IL-6), and disordered intestinal flora structure (decreased α diversity and increased opportunistic pathogenic bacteria). The three interact with each other and have a synergistic effect, jointly participating in the pathogenesis of PHN.The expected outcome of this project may provide new options for pain management of the large group of neuralgia patients, improve their quality of life, and has great practicality and practical value.

Inclusion Criteria:

• The definite diagnoses were PHN (disease course ≤ 1 month), PHN (1 month < disease course < 2 months), and PHN (disease course > 3 months); Age equal to 50 years old; Not accompanied by other chronic pain diseases; Sign the informed consent form.

Exclusion Criteria:

• There are underlying digestive system diseases such as irritable bowel syndrome and inflammatory bowel disease; There are obvious gastrointestinal discomfort symptoms such as diarrhea and abdominal distension; There is immunosuppression or autoimmune disease; Antibiotics, acid suppressants or drugs that interfere with the intestinal flora have been used within the past month; Have a history of mental illness or abuse of tobacco and alcohol (2 packs per day)

Individuals among patients with herpes zoster (HZ) who eventually develop PHN (according to the diagnostic criteria of PHN, such as persistent pain for ≥3 months)