Clinical significance of anti-filaggrin antibody recognizing uncitrullinated filaggrin in rheumatoid arthritis

Filaggrin is expressed in the cornified layer of epidermis and known to be one of the antigenic targets in rheumatoid arthritis. Although the citrulline residue in filaggrin is thought to be an antigenic determinant recognized by autoantibodies, the diagnostic sensitivity of synthetic citrullinated peptide is variable. To investigate the implication of anti-filaggrin antibodies recognizing uncitrullinated filaggrin in rheumatoid arthritis, we assayed antibody titers using unmodified recombinant filaggrin in the sera from 73 patients with rheumatoid arthritis, 150 patients with other connective tissue diseases and 70 normal controls. We also performed the correlation analysis between antibody titers and the clinical variables in patients with rheumatoid arthritis. Titers of IgG anti-filaggrin antibodies were significantly higher in rheumatoid arthritis patients compared to normal controls (P=0.02), but not in patients with osteoarthritis, ankylosing spondylitis or systemic lupus erythematosus. IgG anti-filaggrin antibodies were more frequently found in patients with rheumatoid arthritis compared to normal controls (12.3% vs 1.4% respectively, P=0.04). An anti-filaggrin antibody titer was correlated with visual analogue scale of pain, tender joint count, Ritchie articular index or C-reactive protein, but not with anti-nuclear antibody or rheumatoid factor. These results suggest that anti-filaggrin antibody recognizes the uncitrullinated filaggrin as an antigen and its titer correlates with clinical parameters, explaining the variable sensitivity of anti-filaggrin antibody test.

Prevalence nd Clinical Features of Psoriatic Arthritis in Korea / 대한류마티스학회지

No abstract available.

A Case of Systemic Lupus Erythematosus Associated with Myasthenia Gravis / 대한내과학회지

Myasthenia gravis(MG) is an autoimmune disorder characterized by the presence of anti-acetylcholine receptor antibody and weakness of voluntary muscles. The pathogenesis of MG is decreased numbers of acetylcholine receptors at postsynaptic membranes of neuromuscular junctions. It has been reported that MG often coexists with other autoimmune disorders. This is a case report of systemic lupus erythematosus coexisting with MG in a 23 year old female patient presenting with dysarthria, dysphagia, and limb weakness. We report the case with relevant literature review.

The Study on the Clinical Features of Gouty Arthritis / 대한내과학회지

OBJECTIVES: The aim of this study is to enhance understanding the clinical features, pathogenesis, diagnosis and treatment of gouty arthritis in Korea by analyzing the clinical manifestations of the patients with urate crystal-proven gouty arthritis. METHODS: 78 cases who had been diagnosed as gouty arthritis by confirming the urate crystals in synovial fluids or tophi in Seoul National University Hospital between January 1, 1989 and July 31, 1995 were analysed for their histories, symptoms, signs, laboratory data, and X-ray findings. RESULTS: 1) Male to female ratio was 18.5:1. The mean age of onset is 49.3 +/- 14.5 years(range 11-83 years); the mean duration of disease 6.5 +/- 7.0 years(range 0-30 years); the mean duration of gouty attack 7.2 +/- 5.5 days(range 1-30 days). 2) The frequent precipitating factors of gouty arthritis were hospitalization(37%) and alcohol drinking(15%). The most frequent accompanying disease was hypertension(24%). Obesity, diabetes, chronic renal failure, hyperlipidemia, ischemic heart diseases, or cerebrovascular diseases were also accompanied by gouty arthritis. 3) The patterns of joint involvement were devided into 3 groups: monoarthritis; 42%, oligoarthritis; 35%, polyarthritis; 23%, The most frequent site of the first gouty attack was the 1st toe(65%). The most frequently involved joint at gouty attack was also the 1st toe(68%). While only lower extremities were involved in most cases with monoarthritis and oligoarthritis(91% and 78%, respectively), both lower and upper extremities were involved in most cases with polyarthritis(78%). 4) Hyperuricemia was found in 74% of the cases at gouty attack. But serum uric acid level was normal in 26%. With respect to pathogenesis of hyperuricemia, 14% of the cases had uric acid overproduction and 86% had uric acid underexcretion. 5) Bony changes in radiologic findings were found in 47% of the cases and tophi in 33%. Bony changes and tophi was significantly related to the younger age of gouty onset and higher serum uric acid level at gouty attack. 6) Acute gouty arthritis responded well to colchicine and NSAIDs. There was no difference in efficacy and the frequency of side effects between them. CONCLUSION: The clinical features of the gouty arthritis in Korea showed no difference from those in foreign studies except higher prevalence of oligo-/polyarthritis and tophi. To be remarkable, 26% of the patients with gouty arthritis did not have hyperuricemia at gouty attack. This finding indicates that urate crystals should be confirmed by synovial fluid examination for diagnosis of gouty arthritis.

Autoantibody Profile using Double Immunodiffusion, Elisa, Western Blot and Its Clinical Association in Patients with Ssystemi Lupus Erythematosus / 대한류마티스학회지

OBJECTIVE: To investigate the autoantibody profile and its clinical association in patients with systemic lupus erythematosus. METHODS: The frequency and clinical correlation of autoantibodies were studied in 73 patients with systemic lupus erythematosus who have been followed in Seoul National University Hospital. Double immunodiffusion, ELISA and immunoblot were used for the detection of autoantibodies. RESULTS: The frequency of each autoantibody measured by double immunodif fusion was as follows; anti-Ro 53.4%, anti-La 11.0%, anti-Sm 20.5%, anti-U1 RNP 20.5%. The frequency of each autoantibody by ELISA was as follows; anti-Ro 69.9%, anti-La 27.4%, anti-Sm 54.8%, anti-Ul RNP 68.5%, anti-dsDNA 72.6%, anti-cardiolipin 47.2% (IgG 43.1?0, igM 15. 3%). The frequency of each autoantibody by immunoblot was as follows; anti-Ro 15.1?0, anti-La 42. 5%, anti-Sm 46. 6%, anti-U1 RNP 42. 5%. anti-ribosomal P(P0) 27.4%. Anti-Ro was associated with decreased frequency of nephrotic syndrome. Anti-U1 RNP was associated with increased frequency of malar rash, Raynaud phenomenon and decreased frequency of nephritis. Patients with both anti-Ro and anti La had more frequent serositis than those with anti-l~o only. Patients with both anti-Sm and anti-U1 RNP had less frequent thrombocytopenia than those with anti-U1 RNP only. And patients with anti-Sm and anti-dsDNA had more frequent arthritis than those with only one of both antibodies. There was a positive correlation of autoantibody titers between anti-Ro and anti-La, anti-Sm and anti-U1 RNP, anti-dsDNA and anti-cardiolipin(IgG). Taking the result of immunoblot as a standard, both of double immunodiffusion and ELISA showed low sensitivity but high specficity for anti La. As for anti-Sm and anti-U1 RNP, double immunodiffusion showed low sensitivity but high specificity, whereas ELISA showed high sensitivity but low specificity. CONCLUSIONS: In our study, some autoantibodies (anti-Ro, anti-U1 RNP) were associated with certain clinical manifestations while others not. Immunoblot being used as a standard method, ELISA showed higher sensitivity but lower specificity for anti-La, anti-Sm and anti-U1 RNP compared with immunodiffusion. It is recommended that in interpretating the laboratory findings of these autoantibodies these parameters of each method should be considered.