- Author:
	        		
		        		
		        		
			        		Su Dok SONG
			        		
			        		
			        		
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			        		Think You KIM
			        		
			        		
		        		
		        		
		        		
			        		
			        		Author Information
			        		
 - Publication Type:Case Report
 - Keywords: Autoantibody; Proliferating cell nuclear antigen; Rheumatoid arthritis
 - MeSH: Antibodies*; Arthralgia; Arthritis, Rheumatoid*; Autoantibodies; Autoimmune Diseases; Blood Sedimentation; C-Reactive Protein; Classification; Female; Hand; Humans; Immunodiffusion; Joints; Lupus Erythematosus, Systemic; Proliferating Cell Nuclear Antigen; Rheumatic Diseases; Rheumatoid Factor; Wrist
 - From:Laboratory Medicine Online 2015;5(2):106-109
 - CountryRepublic of Korea
 - Language:Korean
 - Abstract: 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.
 
            
