Novel Autoantibody and Autoantigen in Sjögren’s Syndrome

Mini Review

Immun Res. 2016; 3(1): 1025.

Novel Autoantibody and Autoantigen in Sjögren’s Syndrome

Nozawa K* and Uomori K

Department of Rheumatology, Juntendo University Faculty of Medicine, Tokyo, Japan

*Corresponding author: Kazuhisa Nozawa, Department of Rheumatology, Juntendo University Faculty of Medicine, Tokyo, Japan

Received: August 29, 2016; Accepted: September 19, 2016; Published: September 22, 2016


Over the past more than 30 years since the identification of the now classic anti-SS-A/Ro and anti-SS-B/La autoantibodies in Sjögren’s syndrome, there have been a few new and interesting autoantibodies including antifodrin, anti-M3 muscarinic receptor, and other autoantibodies reported to be closely linked to this disease. We have recently identified a novel autoantibody predominantly recognized in Sjögren’s syndrome specifically reacting with NA14 (nuclear autoantigen 14 kDa)/SSNA1 (Sjögren Syndrome Nuclear Autoantigen 1). This review describes the current data available for anti-NA-14 antibody in their usefulness of diagnosis and the nature of the autoantibody production in Sjögren’s syndrome.

Keywords: Autoantigen; Autoantibody; Systemic autoimmune disease; Sjögren’s syndrome


NA14: Nuclear Autoantigen 14 kDa; PM/DM; Polymyositis/ Dermatomyositis; RA; Rheumatoid Arthritis; SLE: Systemic Lupus Erythematosus; SS: Sjögren’s Syndrome; SSc: Scleroderma; IIF: Indirect Immunofluorescence; IP-10: Interferon-gamma (IFN-γ)- inducible Protein of 10 kDa; BAFF: B cell-Activating Factor belonging to the tumor necrosis Factor Family


Sjögren’s syndrome (SS) is a systemic autoimmune disease in which the immune response is activated to attack and destroy the exocrine glands that produce tears and saliva [1]. The disease may be isolated (primary SS) or it may occur in association with other rheumatic diseases (secondary SS). The etiology of SS remains unknown but the pathogenesis of exocrine cell damage is apparently immuno dysregulation involving aberrant regulation of cytokines production or apoptosis. The central clues of the hypothesis come from the observation that the immune system in SS targets a restricted and highly specific group of intracellular autoantigens [2,3]. The predominant target autoantigens in SS are the ribonucleoprotein autoantigens SS-A/Ro and SS-B/La [3], which are included in the disease diagnostic criteria [4]. Although autoantibodies to SS-A/ Ro and SS-B/La are indicative of SS, the autoimmune response to these autoantigens is not specific for SS since there are patients not having these autoantibodies with some frequency in SS and having autoantibodies to other intracellular autoantigens.

Nuclear autoantigen 14 kDa (NA-14)/Sjögren’s syndrome nuclear antigen-1 (SSNA-1) was originally identified as a novel autoantigen recognized by autoimmune serum from a patient with SS [5]. In the present study, we have reported that the anti-NA-14 autoantibody was frequently recognized in patients with SS compared to patients with other connective tissue diseases [6,7]. In this review, we discuss the characterization of anti-NA-14 antibody, and possible mechanisms for the autoantibody production against in SS.

Characterization of Anti-NA-14 Antibody in Patients with Sjögren’s Syndrome

As shown in Table1, we found that the anti-NA-14 autoantibody was predominantly recognized in patients with SS compared to patients with other connective tissue diseases [6,7]. The prevalence of anti-NA14 antibody were 18/132 (13.6%) primary SS, 0/50 (0%) secondary SS, 2/100 (2%) SLE, 1/43 (2.3%) SSc, 0/54 RA (0%), and 1/29 (3.4%) PM/DM (Table 1). The staining patterns of anti-NA-14 antibodies in IIF microscopy of HEp-2 cells strongly indicated that the cellular distribution of NA-14 was enriched in mitotic-phase cells since staining pattern of anti-NA-14 antibody was almost identical to anti-CENP-F (mitosin) antibody, which is reliable hallmark of the mitotic phase (Figure 1). Therefore, anti-NA-14 antibody can be classified as novel autoantibody reacting with cell cyclerelated autoantigens. In clinical profile, although we could not find involvement of specific organs damage in anti-NA-14 antibodies positive patients with pSS compared to anti-NA-14 negative patients, anti-NA-14 antibodies positive patients with pSS revealed significant elevation of serum IgA level. In contrast to IgA, significant elevation of both serum IgG and IgM levels was not recognized [7].