Anti-Proliferating Cell Nuclear Antigen Antibodies Detected in Rheumatoid Arthritis: A Case Report

Rheumatoid arthritis (RA) is an autoimmune disease that results in a chronic inflammatory disorder, which principally attacks the small joints. Several autoantibodies, such as rheumatoid factor (RF) and anti-cyclic citrullinated peptide (CCP) antibody, are known to be associated with RA. Anti-proliferating cell nuclear antigen (PCNA) antibodies are mainly observed in patients with systemic lupus erythematosus (SLE). Indeed, a high titer of these antibodies is considered highly suggestive of SLE; however, anti-PCNA antibodies also appear in other autoimmune diseases. Two previous reports described RA patients with low titers of anti-PCNA antibodies, respectively. In this report, we describe a case of an RA patient exhibiting a high titer (>1:2,560) of anti-PCNA antibodies. The 56-yr-old female patient, with no underlying disease or medication history, presented with multiple joint pain and morning stiffness that had begun 6 months prior. The erythrocyte sedimentation rate (ESR) and RF were elevated (102 mm/hr and 77 IU/mL, respectively), and C-reactive protein (CRP) was 0.8 mg/dL. While the test for anti-CCP antibodies was negative, an anti-PCNA pattern (>1:2,560) and a homogeneous pattern (1:320) were detected by autoimmune target (AIT) test. The presence of anti-PCNA antibodies was subsequently confirmed using the double immunodiffusion method. The anti-dsDNA test was also positive (1:160). X-ray imaging showed soft tissue swelling of multiple joints of both hands and wrists. According to the 2010 American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) classification criteria, the patient was classified as having RA. This is the first case to describe high titers anti-PCNA antibodies associated with RA.

Atypical Wegener's Granulomatosis Accompanied with Rheumatoid Arthritis: A Case Report

Wegener's granulomatosis (WG) is highly correlated with cytoplasmic antineutrophil cytoplasmic antibodies (c-ANCA). Patients with rheumatoid arthritis (RA) rarely contract WG. Although several concurrent cases have been reported overseas, there are no known cases in Korea. Here we report a unique case of RA with atypical WG testing positive for perinuclear ANCA (p-ANCA) and negative for anti-myeloperoxidase (MPO) antibodies. The 62-yr-old female patient presented with multiple joint pain and showed typical blood test results for RA, i.e., an elevated erythrocyte sedimentation rate and C-reactive protein concentration, and positive for rheumatoid factor and anti-cyclic citrullinated peptide antibodies. RA was clear based on a total score of 10 when applying the classification criteria developed by the American College of Rheumatology/European League Against Rheumatism (2010). In an autoimmune target test, speckled and skeleton patterns were observed. In an ANCA test, p-ANCA was observed (titer, 1:2,560), and tests for anti-proteinase 3 (PR3) and anti-MPO antibodies were negative. After admission, multiple nodules were detected on a chest X-ray and a computed tomography scan. We suspected that she had rheumatic nodules or vasculitis and performed an open lung biopsy. We detected necrotic granulomatous vasculitis, classified as WG, thus leading to WG diagnosis. In conclusion, WG was diagnosed in an RA patient who was negative for c-ANCA (negative PR3) and positive for p-ANCA (negative anti-MPO), and this peculiar finding is likely to improve diagnosis in cases of RA with atypical WG.