Reprint of "Residual pain in rheumatoid arthritis: Is it a real problem?"

Pain is a significant issue in rheumatoid arthritis (RA) and can have a negative impact on patients' quality of life. Despite optimal control of inflammatory disease, residual chronic pain remains a major unmet medical need in RA. Pain in RA can be secondary to inflammation but can also generate neuroendocrine responses that initiate neurogenic inflammation and enhance cytokine release, leading to persistent hyperalgesia. In addition to well-known cytokines such as TNFα and IL-6, other cytokines and the JAK-STAT pathway play a role in pain modulation and inflammation. The development of chronic pain in RA involves processes beyond inflammation or structural damage. Residual pain is often observed in patients even after achieving remission or low disease activity, suggesting the involvement of non-inflammatory and central sensitization mechanisms. Moreover, fibromyalgia syndrome (FMS) is prevalent in RA patients and may contribute to persistent pain. Factors such as depression, sleep disturbance, and pro-inflammatory cytokines may contribute to the development of fibromyalgia in RA. It is essential to identify and diagnose concomitant FMS in RA patients to better manage their symptoms. Further research is needed to unravel the complexities of pain in RA. Finally, recent studies have shown that JAK inhibitors effectively reduce residual pain in RA patients, suggesting pain-reducing effects independent of their anti-inflammatory properties.

Antiphospholipid antibody carriers and patients with quiescent antiphospholipid syndrome show persistent subclinical complement activation.

OBJECTIVES: Complement activation has been advocated as one mechanism by which antiphospholipid antibodies (aPLs) can induce thrombosis. In patients with catastrophic aPL syndrome or re-thrombosis, enhanced complement activation was shown, even in quiescent phase of the disease. We aimed to assess complement activation and to investigate its association to clinical variables in aPL positive patients with a favorable disease course. METHODS: Subjects with at least two consecutive positive aPL antibody results obtained ≥12 weeks apart were enrolled. They were subjects without history of thrombosis or pregnancy morbidity (aPL carriers), patients with pregnancy morbidity alone (OAPS), and/or with arterial, venous, or small-vessel thrombosis (TAPS); all patients should have been free of symptoms for ≥2 years. Patients affected with systemic autoimmune diseases were excluded. Healthy age and sex-matched subjects were included as controls. Plasma C5a and C5b-9 levels were assessed by commercially available ELISA assays. Non-parametric Mann-Whitney test and Spearman's correlation were applied. RESULTS: Thirty-seven OAPS, 38 TAPS, 42 aPL carriers, and 30 healthy subjects were enrolled. Median C5a and C5b-9 levels were significantly higher in quiescent aPL positive patients (OAPS, TAPS, aPL carriers) compared with controls: C5a ng/ml 10.61 (IQR 6.87-15.46) vs 4.06 (2.66-7.35), p< 0.001; C5b-9 ng/ml 283.95 (175.8-439.40) vs 165.90 (124.23-236.8), p< 0.001. Similar C5a and C5b-9 levels were observed in OAPS and TAPS patients and aPL carriers. A positive correlation between C5b-9 median levels and the number of aPL positive tests was found (p= 0.002). CONCLUSIONS: The persistence of aPL antibodies is associated to a persistent subclinical activation of the complement cascade.

Residual pain in rheumatoid arthritis: Is it a real problem?

Pain is a significant issue in rheumatoid arthritis (RA) and can have a negative impact on patients' quality of life. Despite optimal control of inflammatory disease, residual chronic pain remains a major unmet medical need in RA. Pain in RA can be secondary to inflammation but can also generate neuroendocrine responses that initiate neurogenic inflammation and enhance cytokine release, leading to persistent hyperalgesia. In addition to well-known cytokines such as TNFα and IL-6, other cytokines and the JAK-STAT pathway play a role in pain modulation and inflammation. The development of chronic pain in RA involves processes beyond inflammation or structural damage. Residual pain is often observed in patients even after achieving remission or low disease activity, suggesting the involvement of non-inflammatory and central sensitization mechanisms. Moreover, fibromyalgia syndrome (FMS) is prevalent in RA patients and may contribute to persistent pain. Factors such as depression, sleep disturbance, and pro-inflammatory cytokines may contribute to the development of fibromyalgia in RA. It is essential to identify and diagnose concomitant FMS in RA patients to better manage their symptoms. Further research is needed to unravel the complexities of pain in RA. Finally, recent studies have shown that JAK inhibitors effectively reduce residual pain in RA patients, suggesting pain-reducing effects independent of their anti-inflammatory properties.