Anti-nucleosome Antibodies: Association With Clinical Features And Disease Activity In Systemic Lupus Erythematosus Of Chinese Han

Background:Systemic lupus erythematosus (SLE) is a multi-organ or multi-systemic involved systemic autoimmune disease characterized by a wide range of clinical manifestations. The pathogenesis and precise etiology of SLE are still not fully understood. Environmental and ethnic factors seem to play important roles in the development of the disease. SLE is characterized by production of a variety of auto-antibodies, circulating immune complexes and complement consumption. It is known that specific autoantibodies have significance in SLE diagnosis, such as anti-Sm antibody, anti-dsDNA antibody, et al, but most of these antibodies were detected in a low sensitivity and high specificity in SLE. In order to improve the diagnosis in SLE, we need a Serum antibody with high sensitivity and specificity for the diagnosis in SLE. In recent years, more and more evidence showed that anti-nucleosome antibodies which became a focus in the study of SLE were strongly associated with the pathogenesis, disease activity, diagnosis, treatment and prognosis of SLE . Previous studies presented a highly variable prevalence ranging from 37.5% to 100%. More importantly, anti-nucleosome antibodies were considered as one of the American College for Rheumatology (ACR) criteria for the diagnosis of SLE. Anti-nucleosome antibodies not only related to SLE disease activity, but also played a key role in the pathogenesis of lupus nephritis. Most of studies showed that anti-nucleosome antibodies were high sensitive and specific for the diagnosis in SLE, especially when anti-dsDNA antibody and anti-Sm antibody were negative.Objectives: This study aims to explore the clinical and laboratory manifestations of SLE patients, and demonstrate the association between anti-nucleosome antibodies and clinical manifestation, Lupus nephritis(LN), disease activity in Chinese population, and show the correlation of anti-nucleosome antibodies with other autoantibodys.Methods:Using the questionnaire in the form of collection of clinical data, then entered into a database created using software (EPI INFO, Version 3.1), and transformed to the proper format for analysis using software (SPSS, Version 13.0, SPSS Inc., Chicago, IL).Results: Of the 1,427 SLE patients, there were 1,347(94.4%) females and 80 (5.6%) males. The mean age of the patients was 34.8±12.5 years, ranging from 10~81 years. The mean age at onset of disease was 31.2±12.2 years, ranging from 5~81 years. The mean disease duration was 38.7±51.8 months, ranging from 1~480 months. All the SLE patients were self-reported of Chinese Han and diagnosed by the presence of four or more the American College of Rheumatology (ACR) diagnostic criteria(1982), revised in 1997. It showed that the most common initial manifestations of SLE were arthritis (65.7%), malar rash (50.5%) and fever (41.8%). During the evolution of the disease, 697(48.8%) had LN and 422(29.6%) had serositis. The mean age at diagnosis and the mean age at onset of SLE with AnuA positive were slightly younger than the patients with AnuA negative, the disease duration was shorter in AnuA positive patients than in negative patients(P<0.05, respectively). The positive rate of AnuA was obviously higher in active than inactive SLE(P<0.05), and there was a positive correlation between the AnuA and the SLE Disease Activity Index (SLEDAI). The prevalence of malar rash, photosensitivity, arthritis, pericarditis and LN in SLE patients with AnuA positive was higher than those in SLE patients with AnuA negative (P<0.05). They were also more likely coexisted with other serological abnormalities including antinuclear antibodies, anti-dsDNA, anti-Ro/SSA, anti-La/SSB, anti-C1q antibodies, Low serum complement C3 and C4, serum elevated IgG, elevated ESR, anemia, leukopenia and lymphocytopenia(P<0.05). AnuA were significantly associated with hematuria, proteinuria and urinary casts(P<0.05).Conclusions: anti-nucleosome antibodies are closely related to the pathogenesis of SLE and LN. It had potential utility as a diagnostic tool and disease activity marker. The presence of AnuA, anti-C1q antibodies and anti-dsDNA antibodies in SLE are related to disease activity and LN. Combination of those antibodies can strongly promote the diagnosis of active LN.