Interleukin (IL)-1 family cytokine in primary immune thrombocytopenia: a comparison with systemic lupus erythematosus-associated thrombocytopenia

Abstract Background : Primary immune thrombocytopenia (ITP) is an autoimmune-mediated disorder characterized by decreased platelet count. Systemic lupus erythematosus (SLE) is also an autoimmune disease which thrombocytopenia is a common hematologic manifestation. Interleukin (IL)-1 family cytokines are major proinflammatory and immunoregulatory mediators. This study aimed to investigate the role of IL-1 cytokines in patients with ITP and SLE and the potential pathophysiologic mechanism to differentiate SLE-associated thrombocytopenia (SLE-TP) from ITP. Methods : Multiplex cytokine assay and real-time polymerase chain reaction (RT-PCR) were used to measure the IL-1 cytokines in 17 newly diagnosed ITP patients, 17 SLE-TP patients, 19 SLE patients without thrombocytopenia (SLE-NTP) and 10 healthy controls. Results : The serum levels of IL-1β, IL-18, IL-36α, IL-36β, IL-36γ and IL-33 were decreased significantly in ITP patients as compared with SLE-TP, SLE-NTP patients and healthy controls ( p <0.05). There was no significantly difference in the serum level of IL-37 between ITP and SLE-TP patients, however, there is a positive correlation between platelet count with IL-37 level in ITP patients. Our data suggested that serum IL-1β, IL-18, IL-36α, IL-36β, IL-36γ, IL-33 and IL-37 were involved in the pathogenesis of ITP. Conclusions : Serum IL-1β, IL-18, IL-36α, IL-36β, IL-36γ and IL-33 could be considered biomarkers to differentiate SLE-TP from ITP patients.