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OBJECTIVES: New interleukins (ILs), especially members of IL-1 and IL-12 families, have recently been reported to be involved in the development and regulation of autoimmune and inflammatory diseases. In this study, we aimed to explore the impact of these new ILs in psoriasis (Ps) and psoriatic arthritis (PsA). METHODS: Forty PsA patients, 20 Ps patients, and 20 healthy controls (HCs) were recruited. Blood samples were obtained for detecting the levels of ILs, IL-12/23p40, and tumor necrosis factor α (TNF-α). The severity of skin lesions was assessed by the Psoriasis Area and Severity Index (PASI). Arthritis activities of PsA patients were assessed by the PsA Joint Activity Index. For PsA patients, circulating osteoclastogenesis-related cytokines (osteoprotegerin and receptor activator of nuclear factor-κB ligand) and numbers of osteoclast precursors were evaluated. Radiographic features of affected joints in these patients were scored for erosion, joint-space narrowing, osteolysis, and new bone formation. Correlations among levels of these ILs, Ps, and PsA disease activities and bone erosions were studied. RESULTS: Ps and PsA patients had higher serum levels of TNF-α, IL-12/23p40, and IL-33. Serum levels of IL-34 and IL-35 were higher in PsA patients than in Ps patients and HCs. Patients with pustular Ps had higher serum levels of IL-36α and IL-38 than patients with Ps vulgaris or HCs. Increased serum levels of IL-36α were positively correlated with PASI. CONCLUSION: Certain ILs were elevated in the circulation of patients with Ps and PsA, which might contribute to the pathogenesis of skin lesions and arthritis.
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Objective To investigate the relationship between interleukin (IL)-34 and bone erosions in psoriatic arthritis (PsA) patients.Methods Forty PsA patients,20 psoriasis (Ps) patients and 20 healthy volunteers were recruited into this study.The levels of IL-34 and osteoclast related cytokines [including tumor necrosis factor (TNF)-α,receptor activator of nuclear factor-κB ligand (RANKL),osteoclast precursors (OPG)] were detected in the serum samples of all subjects.The correlations among IL-34,the number of osteoclast precursors (OCP),disease activity and imaging scores were analyzed.All data were analyzed by graphpad prism 6.Differences between groups was analyzed with One-way analysis of variance,q tests,and Spearman's correlation was used to explore the relation between disease activity/radiographic scores and laboratory results and followed by linear regressions.Results The serum level of IL-34 in patients with PsA [(328±476) pg/ml] was higher than that in Ps [(33±52) pg/ml,q =3.92,P＜0.01] and healthy controls [(32±32) pg/ml,q =3.93,P＜0.01],the erosive PsA group were higher than the non-erosive PsA group [(449±527) pg/ml and (47±24) pg/ml,q=4.04,P＜0.01].The levels of TNF-α,RANKL and OCP in patients with PsA [(125±79) pg/ml,(488± 475) pg/ml and (17.7±4.8) 5 sigh views] were higher than those in PS [(40±22) pg/ml,(26±3) pg/ml and (5.2± 0.8),q=7.32,6.14 and 2.94,P＜0.01] and healthy controls [(41±19) pg/ml,(65±8) pg/ml and (6.2±1.8),q=6.67,5.62 and 2.71,P＜0.01],whereas the OPG/RANKL ratio in PsA patients (0.5±0.4) was significantly lower than Ps patients (4.3±2.7,q=-3.30,P＜0.01) and healthy controls (1.8±0.6,q=-1.72,P＜0.01).IL-34,TNF-α and RANKL levels were all positively correlated with OCP (r=0.10,P＜0.05;r=0.12,P＜0.05;r=0.13,P＜0.(5,respectively).Conclusion The level of IL-34 is not only high in patients with PsA but also positively correlates with the number of OCP.In PsA,IL-34 is probably related to the OCP and osteoclast differentiation,and further participates in the process of bone destruction.Therefore,IL-34 is promising to become a new target or alternative choice for the treatment of PsA.