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Chronic urticaria (CU) is characterized by the occurrence of wheals lasting for more than 6 weeks. The role of platelet activation in the pathophysiology of this condition has not been clearly studied. We undertook a cross-sectional study among 45 patients with CU and 45 age- and gender-matched healthy controls. The severity of the disease was assessed using the urticaria severity score. The autologous plasma skin test (APST) was done in all cases of CU. The platelet count and indices were estimated by an automated haematological laser optical analyzer. Platelet aggregation and soluble P-selectin levels were estimated in all study participants. It was observed that there was a significantly higher mean platelet volume (MPV) and platelet distribution width (PDW) in patients with CU when compared to controls. Platelet aggregation and soluble P-selectin levels were significantly higher in patients with CU, as compared to controls. Urticaria severity score correlated positively with platelet aggregability and soluble P-selectin levels. APST-positive patients had significantly higher platelet aggregation and higher soluble P-selectin levels, when compared to the APST-negative patients, indicating more platelet activation in the autoimmune group. There is significant platelet activation in patients with CU, especially in those with autoreactivity.

Background: Recent studies implicate the role of immune-inflammatory responses in chronic spontaneous urticaria (CSU). Although it is well known that platelets release inflammatory mediators and reactive oxygen species upon activation, their role in CSU is poorly characterized. The present study was designed to evaluate platelet oxidative stress [platelet malondialdehyde (MDA), platelet superoxide dismutase (SOD), platelet glutathione peroxidase (GPx)] and systemic inflammatory markers [plasma Interleukin-6 (IL-6), high sensitivity C-reactive protein (hs-CRP)] in patients with CSU and their association with disease severity., Methods: Forty-five patients with CSU and 45 age- and gender-matched healthy controls were included in the study. Severity grading was completed according to the urticaria severity score (USS). Autologous plasma skin test (APST) was done in all patients with CSU. Platelet MDA, SOD and GPx and inflammatory markers plasma IL-6 and hs-CRP were assayed in all study participants., Results: In patients with CSU, platelet SOD and GPx were significantly lowered, while platelet MDA levels were significantly elevated in comparison to healthy controls. Both IL-6 and hs-CRP were significantly elevated in patients with CSU and correlated with platelet oxidative stress parameters (p<0.05). Platelet MDA, SOD and GPx and inflammatory markers (plasma IL-6 and hs-CRP) showed a significant correlation with USS in patients with CSU., Conclusions: Our results indicate significant systemic inflammation and platelet oxidative stress in patients with CSU.