The Clinical Features Of NOD2-associated Diseases And Potential Pathogenic Mechanism Of Yao Syndrome

The clinical and genotypic characteristics of NOD2-associated diseasesObjective:Nucleotide-binding oligomerization domain(NOD)2-associated diseases include Blau syndrome(BS),YAO syndrome(YAOS),and Crohn’s disease(CD).We aimed to summarize the clinical and genotypic characteristics of NOD2-associated diseases.Methods:From August 2015 to December 2021,a total of 7 patients with YAOS and 8 patients with BS were diagnosed and followed up in the Adult Autoinflammatory Diseases Specialized Clinic(age≥16 years)of the Department of Rheumatology and Immunology,Peking Union Medical College Hospital.And 20 adult patients with CD were randomly selected from the inpatients during the same period.(1)Clinical data were collected from each group,and whole-exome gene sequencing were performed in all YAOS and BS patients.(2)Four patients with BS were treated with infliximab(IFX)and followed up for 18 months.The data of BS patients in the process of visits and follow-ups were analyzed.Results:(1)The median age at onset of BS patients was 3.5 years old,with a male to female ratio of 5:3.The clinical manifestations were mainly uveitis,arthritis and rash,and the most common variant was NOD2 R334W.The median age at onset of YAOS patients was 38 years old,with a male to female ratio of 2:5.The clinical presentations were dominated by periodic fever,arthralgia/arthritis,gastrointestinal symptoms and swelling of the lower extremities,and the most common variant was NOD2 Q902K.The median age at onset of CD patients was 22 years,and the clinical manifestations were primarily gastrointestinal symptoms.Fever,rash and arthritis were rare.A comparative analysis between the three groups revealed that BS patients differed significantly from the other two groups in terms of onset age,family history,joint manifestations,uveitis.Fever and bilateral lower limb edema were more common in YAOS patients than the other two group patients.Compared with BS patients and YAOS patients,there was a statistically significant difference in the frequency of perianal lesions and hematochezia of CD patients.(2)Four BS patients received IFX plus methotrexate,and all achieved clinical remission at the first follow-up of 6 months.Two patients relapsed after they lengthened the interval of IFX and discontinued methotrexate.Conclusions:(1)There is variability in the clinical manifestations and genotypes of different subgroups of NOD2-associated diseases.Age of onset,typical clinical manifestations and loci of genetic variants can help clinicians to differentiate these three disorders.(2)Early recognition and effective treatment of BS are very important to avoid irreversible organ damage.TNF-α inhibitors such as IFX may be a promising approach for BS patients who have unsatisfactory response to corticosteroids and traditional diseasemodifying antirheumatic drugs(DMARDs).The potential pathogenic mechanism of Yao syndromeObjective:The study was performed to observe the potential pathogenic mechanism of Yao syndrome(YAOS).Meanwhile,we also explored the therapeutic effect of Gefitinib.Methods:Blood,articular synovial tissue and small intestinal mucosa from 1 patient with YAOS were collected.We also collected blood sample from another 2 patients with YAOS.These patients were diagnosed and followed up in the Adult Autoinflammatory Diseases Specialized Clinic(age≥16 years)of the Department of Rheumatology and Immunology,Peking Union Medical College Hospital.PBMCs and articular synovial cells were isolated and cultured.The secretion levels of pro-inflammatory cytokines IL-1β,TNF-α and IL-6 in the supernatant of PBMCs and articular synovial cells were detected by ELISA.The articular synovial cells were treated with Gefitinib or CAI,and the secretion levels of IL1β,TNF-α and IL-6 were detected by ELISA.The expression of NOD2-RIP2-NFκB/MAPK inflammatory signal pathway related proteins in PBMCs were detected by Western Blot,while in small intestinal mucosa and articular synovial tissue were detected by immunohistochemistry.Results:(1)The level of IL-1β in serum of patients with YAOS was significantly higher than that of healthy controls.The levels of TNF-α and IL-6 in the supernatant of PBMCs of patients with YAOS were significantly higher than those of healthy controls.And the levels of IL1β and IL-6 secreted by synovial cells of joints from patients with YAOS were significantly higher than those in patients with OA and RA.In PBMCs from YAOS patients,the expression levels of p-RIP2,p-p65,p-p38,p-ERK and p-JNK were significantly increased,while the expression levels of p65 and p38 were decreased;the expression levels of p-RIP2,p-p65 and p-p38 in small intestinal mucosa were significantly increased;and the expression levels of p-p65 and p-p38 in articular synovial tissue were significantly increased.(2)Gefitinib significantly inhibited the secretion of IL-1β and IL-6 by synoviocytes in patients with YAOS,and the inhibitory effect increased with the increase of drug concentration.CAI had no significant effect on the secretion of IL-1β,TNF-α and IL-6 by synoviocytes from patients with YAOS.Conclusions:(1)In patients with YAOS,the levels of pro-inflammatory cytokines IL-1β,TNF-α and IL6 are increased,RIP2,NF-κB inflammatory pathway and MAPK inflammatory pathway are significantly activated,and the phosphorylation of RIP2,p65 and p38 protein may play a key role in the pathogenesis.NOD2 Q902K mutation is a gain-of-function mutation.(2)Gefitinib inhibits the secretion of IL-1β and IL-6 by synovial cells in patients with YAOS.Gefitinib may have a therapeutic effect on YAOS.