Meta-Analysis of 52 Trials: Acupuncture Relieves Pain and Reduces Inflammation in Ankylosing Spondylitis

Ankylosing spondylitis (AS) is a chronic inflammatory spondyloarthropathy that affects primarily the spine and sacroiliac joints, presenting with inflammatory low back pain, progressive morning stiffness, and risk of structural ankylosis. Although nonsteroidal anti-inflammatory drugs and biologic agents (TNF-α and IL-17 inhibitors) are pillars of treatment, many patients maintain residual symptoms or have intolerance or contraindications to biologic agents. A systematic review and meta-analysis published in Frontiers in Neurology compiled 52 randomized clinical trials with more than 2,600 patients to evaluate the effect of acupuncture as an adjunctive therapy, demonstrating significant reductions in both clinical symptoms and inflammatory biomarkers.

Immunologic modulation: the differentiator of this analysis

The differentiator of this meta-analysis compared with previous reviews on acupuncture in AS is the systematic evaluation of immunologic markers. In addition to the usual clinical outcomes (pain, stiffness, BASDAI, and BASFI), Wang and colleagues analyzed inflammatory cytokines: interleukin-6 (IL-6), interleukin-17 (IL-17), tumor necrosis factor alpha (TNF-α), and immunoglobulin A (IgA). For all of these markers, the acupuncture-treated group showed significant reductions compared with control, suggesting that clinical effects are accompanied by modulation of the inflammatory immune profile characteristic of the disease.

Proposed mechanism

The authors propose that acupuncture acts in AS through a neuro-immune-endocrine network. Stimulation of these acupoints has been associated with modulation of the HPA axis and parasympathetic innervation in experimental models, with possible reduction of pro-inflammatory cytokines. Points such as ST-36, SP-6, and GV-14 have shown immunomodulatory action in experimental models of inflammatory arthritis, which is compatible with the findings of this meta-analysis in patients with AS.

Substantial heterogeneity identified across studies — arising from variations in point protocols, number of sessions, and populations — imposes caution in interpretation. The authors highlight that 20 of the 52 RCTs were classified as having low risk of bias, which represents a reasonable basis for the general conclusions. Prospective trials with standardization of protocols and long-term follow-up are needed to define the positioning of acupuncture in management algorithms for ankylosing spondylitis.