Antibodies to citrullinated peptides in tuberculosis
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Rheumatoid arthritis (RA) is an autoimmune disease characterized by symmetric polyarthritis, rheumatoid factor (RF) positivity, and bone erosions. Recently, research has been conducted on anti-citrullinated peptide antibodies (ACPAs) to which there are greater sensitivity and specificity than RF. However, these antibodies have also been described in infectious diseases, particularly tuberculosis (TB), placing the high specificity of the test in doubt. The aim of this research was to study the prevalence of ACPAs in TB, RA, and healthy controls. Patients with bacteriologically confirmed pulmonary tuberculosis, RA (ACR criteria), in addition to healthy controls were included. ACPAs were researched by: anti-cyclic citrullinated peptide (CCP), anti-modified citrullinated vimentin (MCV), and RF by ELISA. The study was conducted in 50 TB patients, 50 with RA, and 20 controls. Anti-CCP antibodies were found in 39 (78 %) of the RA patients (median titer, 128 U), whereas anti-MCV antibodies were found in 25 (50 %). Of the patients with TB, two (4 %) had positivity for anti-CCP and anti-MCV and no patient in the control group tested positive for these antibodies. Sensitivity of anti-CCP for RA was 78 % (confidence interval (CI), 63 to 88 %) and specificity was 97 % (CI, 89 to 99 %) while the sensitivity of anti-MCV was 50 % (CI, 35–64 %) and specificity was 97 % (CI, 89 to 99 %). RF was positive in 40 samples (80 %) of RA, in 30 (60 %) of TB, and in 1 (5 %) of the controls. Our findings showed high sensitivity of anti-CCP and high specificity of both anti-CCP and anti-MCV antibodies for RA, even in a population with high incidence of tuberculosis. The higher frequency of positivity of ACPA in TB observed in previous studies may be attributed to methodological factors.
KeywordsACPA Anti-CCP Anti-MCV Rheumatoid arthritis Rheumatoid factor Tuberculosis
M.S. receives a scholarship from the Conselho Nacional de Desenvolvimento Científico e Tecnológico. We are indebted to the pneumologists of Hospital Otávio Mangabeira, where the TB patients came from.
- 2.Marques Neto J, Gonçalves E, Langen L, Cunha M, Radominski S, Oliveira S et al (1993) Estudo multicêntrico da prevalência da artrite reumatóide do adulto em amostras da população brasileira. Rev Bras Reumatol 33:169–173Google Scholar
- 12.Kakumanu P, Yamagata H, Sobel ES, Reeves WH, Chan EK, Satoh M (2008) Patients with pulmonary tuberculosis are frequently positive for anti-cyclic citrullinated peptide antibodies, but their sera also react with unmodified arginine-containing peptide. Arthritis Rheum 58(6):1576–1581PubMedCrossRefGoogle Scholar
- 14.Silva A, Matos A, Lima A, Lima E, Gaspar A, Braga J et al (2006) Valor diagnóstico do anticorpo antipeptídeo citrulinado cíclico na artrite reumatóide. Rev Bras Reumatol 46:174–180Google Scholar
- 16.Santiago M, Baron M, Miyachi K, Fritzler MJ, Bu-Hakima M, Leclercq S et al (2008) A comparison of the frequency of antibodies to cyclic citrullinated peptides using a third generation anti-CCP assay (CCP3) in systemic sclerosis, primary biliary cirrhosis and rheumatoid arthritis. Clin Rheumatol 27(1):77–83PubMedCrossRefGoogle Scholar