Autoantibody to MDM2: A potential serological marker of primary Sjogren's syndrome.
BACKGROUND
Primary Sjogren's Syndrome (pSS) is one of the autoimmune diseases characterized by polyclonal autoantibody production. The human homologue of the mouse double minute 2 (MDM2) is an important negative regulator of p53. Our previous study indicated that autoantibody to MDM2 can be detected in systemic lupus erythematosus patients. The purpose of this study is to study anti-MDM2 autoantibody in pSS patients.


METHODS
Anti-MDM2 autoantibody in sera from 100 pSS patients and 74 normal controls was investigated by ELISA. Positive samples were further confirmed by western blotting. Expression of MDM2 in labial gland tissue from pSS patients and normal controls was checked by immunohistochemistry. The difference in clinical characteristics and laboratory findings between anti-MDM2 positive and anti-MDM2 negative pSS patients was analyzed.


RESULTS
The presence of anti-MDM2 autoantibody in pSS patients was 21.0%, significantly higher than normal controls (5.40%). MDM2 was overexpressed in labial gland from pSS patients. pSS patients with positive anti-MDM2 were characterized by longer disease duration and more lymphocytes focal gathering in labial gland. Prevalence of anemia, thrombocytopenia and anti-SSB was significantly higher in pSS patients with anti-MDM2 autoantibody. Titer of anit-MDM2 was negatively associated with hemoglobin level, platelet count, complement 3 level and complement 4 level, positively associated with European Sjogren's syndrome disease activity index (ESSDAI) and level of IgG.


CONCLUSIONS
Anti-MDM2 autoantibody may be used as a potential serological biomarker in pSS disease activity evaluation. Study on the role of anti-MDM2 or MDM2 in pSS may help us know the pathogenesis mechanism of pSS better.
Department of Rheumatology and Clinical Immunology, The First Affiliated Hospital of Xiamen University, Xiamen, China.
Yuan
Y
Liu
Medical College, Xiamen University, Xiamen, Fujian, China.
Xining
X
Liao
Department of Endocrinology, The ChengGong Hospital Affiliated to Xiamen University, Xiamen, Fujian, China.
Ying
Y
Wang
Department of Rheumatology and Clinical Immunology, The First Affiliated Hospital of Xiamen University, Xiamen, China.
Shiju
S
Chen
Department of Rheumatology and Clinical Immunology, The First Affiliated Hospital of Xiamen University, Xiamen, China.
Yuechi
Y
Sun
Department of Rheumatology and Clinical Immunology, The First Affiliated Hospital of Xiamen University, Xiamen, China.
Qingyan
Q
Lin
Department of Rheumatology and Clinical Immunology, The First Affiliated Hospital of Xiamen University, Xiamen, China.
Guixiu
G
Shi
D001323:Autoantibodies / Q000097:blood* / Q000276:immunology; D015415:Biomarkers / Q000097:blood*; D015153:Blotting, Western; D016022:Case-Control Studies; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D051736:Proto-Oncogene Proteins c-mdm2 / Q000276:immunology*; D012859:Sjogren's Syndrome / Q000097:blood* / Q000175:diagnosis / Q000276:immunology
D001323:Autoantibodies; D015415:Biomarkers; C497206:MDM2 protein, human; D051736:Proto-Oncogene Proteins c-mdm2
Immune response; Immunity; Immunology and Microbiology Section; anti-MDM2 autoantibody; biomarker; primary Sjogren’s syndrome