Effects of BCG-PSN on the Levels of Inflammatory Factors and Th1/Th2 Differentiation in Chronic Spontaneous Urticaria: Meta-Analysis and Systematic Review

Background. Bacillus Calmette–Guerin polysaccharide nucleic acid (BCG-PSN), as an immune modulator, can effectively regulate the immune function of the body, control the release of histamine inflammatory substances, and achieve allergic effects against chronic spontaneous urticaria (CSU). This study aimed to evaluate the effectiveness of BCG-PSN on the levels of inflammatory factors and Th1/Th2 differentiation in CSU. Methods. A systemic literature search of BCG-PSN treatment of CSU was performed using the PubMed, Cochrane Library, Web of Science, CBM, and other databases. A quantitative meta-analysis was conducted according to the guidelines of the Cochrane Handbook. Review manager software 5.4 was used for meta-analysis. Results. Twenty-seven studies pertaining to 2840 patients were included. The duration of treatment was 4 to 12 weeks. BCG-PSN can increase CD3+T levels (MD = 6.06; 95% CI: 5.30 to 6.82; $p$ < 0.00001; I2 = 31%), CD4+T levels (MD = 5.41; 95% CI: 4.82 to 6.01; $p$ < 0.00001; I2 = 40%), and CD4+/CD8+(MD = 0.33; 95% CI: 0.28 to 0.38; $p$ < 0.00001; I2 = 15%); at the same time, BCG-PSN can downregulate CD8+T levels (MD = −3.28; 95% CI: −3.82 to −2.74; $p$ < 0.00001; I2 = 32%). Furthermore, BCG-PSN could downregulate IL-4 levels (MD = −4.06, 95% CI: −5.15 to −2.97, $p$ < 0.00001; I2 = 0%), TNF-α levels (MD = −2.34; 95% CI: −3.01 to −1.66; $p$ < 0.00001; I2 = 26%) and upregulate IL-10 levels (MD = 25.59, 95% CI: 23.50 to 27.69, $p$ < 0.00001; I2 = 0%) and INF-γ levels (MD = 4.62, 95% CI: 3.79 to 5.45, $p$ < 0.00001; I2 = 5%). Conclusions. BCG-PSN can regulate the levels of inflammatory factors and Th1/Th2 differentiation in CSU. However, the long-term effectiveness and more objective experimental indicators of BCG-PSN remain to be further studied. Trial Registration. This trial is registered with PROSPERO ID: CRD42022332475.