Effect and Immune Mechanism of BCG-PSN on Postherpetic Neuralgia: A Single-Masked, Randomised Controlled Trial

To investigate the therapeutic effect of the immune modulator Bacillus Calmette-Guerin polysaccharide and nucleic acid injection (BCG-PSN) on postherpetic neuralgia (PHN), and measure immune-related markers to elucidate the immune mechanism of BCG-PSN in treating patients with PHN with neuropathic pain. Single-masked randomised controlled trial. Place and Duration of the Study: Department of Dermatology, Zhongnan Hospital, Wuhan University, Wuhan, Hubei, China, from January 2022 to December 2023. Ninety-eight patients with PHN were randomly assigned to receive oral administration of gabapentin (control group, n = 49), or a combination of gabapentin and locally injected BCG-PSN (BCG-PSN group, n = 49) for eight weeks. Two-sample and paired t-tests were used to measure the visual analogue scale (VAS) and quality of life (QOL) scores. Immune-related markers were measured in peripheral blood samples using flow cytometric staining. The χ2 test was used to compare the incidence of adverse reactions. The VAS and QOL scores in the BCG-PSN group were significantly better than those of the control group (p <0.001 and p = 0.002). The CD3+, CD4+, CD19+, and CD56+ cells and the CD4+/CD8+ ratio of the BCG-PSN group were statistically lower than those of the control group (p <0.05). No significant differences were observed in the incidence of adverse reactions between the two groups (p = 0.804). The results indicated that BCG-PSN could effectively alleviate pain and improve immune function in patients with PHN. BCG-PSN, Postherpetic neuralgia, Immune modulation, Neuropathic pain, Gabapentin.