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Non-specific Low Back Pain: Inflammatory Profiles of Patients with Acute and Chronic Pain.

BACKGROUND
The pathogenesis of low back pain (LBP) remains unclear. However, recent studies suggest that the inflammatory response may be inherent in spinal pain.


PURPOSE
To discern inflammatory profiles in patients with non-specific acute and chronic low back pain (LBP) in relation to those in asymptomatic subjects.


METHODS
Peripheral blood samples were obtained from asymptomatic subjects and patients with non-specific acute and chronic LBP reporting a minimum pain score of 3 on a 10-point visual analogue scale (VAS). The levels of in vitro production of pro-inflammatory (TNFα, IL-1β, IL-6, IL-2, IFN[Latin Small Letter Gamma]) and anti-inflammatory (IL-1 RA, sTNFR2 and IL-10) mediators were determined by specific immunoassays.


RESULTS
The mean VAS scores were comparable between the acute and chronic LBP patient groups. Compared to asymptomatic subjects, the production of TNFα, IL-1β, IL-6 and their ratios to IL-10 levels were significantly elevated in both patient groups (P=0.0001-0.003). In acute LBP group, the ratio of IL-2: IL-10 was also significantly increased (P=0.02). In contrast, the production of IFN[Latin Small Letter Gamma] was significantly reduced compared with the other study groups (P=0.005-0.01), nevertheless, it was positively correlated (P=0.006) with pain scores. In chronic LBP patients, the production of TNFα, IL-1RA and sTNFR2 was significantly increased (P=0.001-0.03) in comparison with the control and acute LBP groups, and TNFα and IL-1β levels were positively correlated (P<0.001) with VAS scores.


CONCLUSION
The inflammatory profiles of patients with acute and chronic LBP are distinct. Nonetheless, in both patient groups, an imbalance between pro- and anti-inflammatory mediator levels favors the production of pro-inflammatory components.