Interleukin-22 (IL-22), an inflammatory cytokine in IL-10 family, can play a role in epithelia and fibroblasts in various tissues and organs. As an inflammatory cytokine, IL-22 has potential pathogenic effect by enhancing inflammation in some inflammatory tissues. However, IL-22 can also promote cell proliferation and tissue regeneration. This review provides an overview of the structure and source of IL-22, its receptor and signaling transduction, and its function in repair and regeneration of tissues and organs.

Primary Sjögren's syndrome (pSS) is a systemic autoimmune disease with high prevalence and possible poor prognosis. Though the pathogenesis of pSS has not been fully elucidated, B cell hyperactivity is considered as one of the fundamental abnormalities in pSS patients. It has long been identified that Janus kinases-signal transducer and activator of transcription (JAK-STAT) signaling pathway contributes to rheumatoid arthritis and systemic lupus erythematosus. Recently, increasing numbers of studies have provided evidence that JAK-STAT pathway also has an important role in the pathogenesis of pSS via direct or indirect activation of B cells. Signal transducer and activator of transcription 1 (STAT1), STAT3, and STAT5 activated by various cytokines and ribonucleic acid contribute to pSS development, respectively or synergically. These results reveal the potential application of Janus kinase inhibitors for treatment of pSS, which may fundamentally improve the quality of life and prognosis of patients with pSS.

Objective:To investigate the clinical characteristics of patients with rheumatic diseases and abnormal liver function, as well as determine the proportion and severity of liver function abnormalities.Methods:Cross-sectional study. Data were collected from patients registered in the Chinese Rheumatism Date Center from 2011 to 2021. The rheumatic diseases analyzed in this study were rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), Sjogren syndrome (SS), ankylosing spondylitis (AS), and gout. Patient data, including demographic characteristics [ such as age, sex, body mass index,(BMI), and smoking history], liver function test results [including alanine aminotransferase (ALT), aspartate aminotransferase, alkaline phosphatase(ALP), and total bilirubin], and use of anti-rheumatic immune drugs and liver-protective drugs, were collected and compared between groups with normal and abnormal liver functions. In addition, the proportions of abnormal liver function were compared between sex and age groups.Results:A total of 116 308 patients were included in this study, including 49 659 with RA, 17 597 with SLE, 9 039 with SS, 11 321 with AS, and 28 692 with gout. The lowest proportion of liver function abnormalities was observed in patients with RA[11.02% (5 470/49 659)], followed by those with SS[17.97% (1 624/9 039)] and AS [18.22% (2 063/11 321) ], whereas patients with SLE [21.14% (3 720/17 597) ] and gout [28.73% (8 242/28 692)] exhibited the highest proportion of these abnormalities. Elevated ALT, mostly classified as grade 1, was the most commonly noted liver function abnormality, whereas elevated ALP was the least common. Some patients who took liver-protective drugs had normal liver function, with the lowest percentage observed in patients with gout [7.45% (36/483) ] and ranging from 21.7% to 30.34% in patients with RA, SLE, SS, and AS. The proportion of liver function abnormalities was higher in males than in females for all disease types [RA: 13.8%(1 368/9 906) vs. 10.3%(4 102/39 753); SLE: 33.6% (479/1 424) vs. 20.0% (3 241/16 173); SS: 25.4%(111/437) vs. 17.6%(1 513/8 602); AS: 20.1%(1 629/8 119) vs. 13.6% (434/3 202); and gout: 29.3% (8 033/27 394) vs. 16.1% (209/1 298)]. In RA, SLE, and AS, the proportions of liver function abnormalities were similar across all age groups. In SS, the proportion of liver function abnormalities increased with age [<40 years: 14.9%(294/1 979); 40-59 years: 18.1%(858/4 741); ≥60 years: 20.4%(472/2 319)], whereas a reversal of this trend was observed in gout [<40 years: 34.9%(4 294/12 320); 40-59 years: 25.5%(2 905/11 398);≥60 years: 21.0%(1 042/4 971)].Conclusions:The proportions of combined liver function abnormalities in patients with rheumatologic diseases were high, and the utilization rates of liver-protective drugs were low. It is necessary to pay more attention to monitoring patients′ liver function, timely administer liver-protective drugs, and optimize liver-protective regimens during the treatment of rheumatic diseases.