Patients with pulmonary tuberculosis are frequently positive for anti–cyclic citrullinated peptide antibodies, but their sera also react with unmodified arginine‐containing peptide

Abstract

Objective. The anti-cyclic citrullinated peptide (anti-CCP) enzyme-linked immunosorbent assay (ELISA) has high sensitivity and specificity for rheumatoid arthritis (RA). However, detection of anti-CCP in patients with active pulmonary tuberculosis (TB) has recently been reported. To determine whether this activity was specific for the citrullinated residue, the specificity of anti-CCP-positive sera for CCP versus that for unmodified arginine-containing peptide (CAP) was examined in patients with TB and compared with that in patients with RA.Methods. Anti-CCP and anti-CAP in sera from patients with pulmonary TB (n ‫؍‬ 49), RA patients (n ‫؍‬ 36), and controls (n ‫؍‬ 18) were tested by ELISA. Sera were available at diagnosis from most TB patients. All TB patients were treated with a combination of 2-4 antibiotics for at least 6 months, and sera were collected over time.Results. Anti-CCP was found in 37% of TB patients and in 43% of RA patients. CAP reactivity was more common in TB than in RA. High anti-CCP:anti-CAP ratios (>2.0) were seen far more commonly in anti-CCP-positive RA patients than in anti-CCPpositive TB patients (94% versus 22%). Anti-CCP was inhibited by CCP peptide in sera from RA patients, but not in sera from TB patients. A slight increase in anti-CCP was common after initiating treatment for TB, although the anti-CCP level decreased after 1-2 months.Conclusion. Anti-CCP is frequently present in patients with active TB. However, many anti-CCPpositive TB sera also reacted with CAP, and anti-CCP: anti-CAP ratios in TB sera were low. Anti-CCP:anti-CAP ratios should be useful clinically for distinguishing CCP-specific reactivity seen in RA from reactivity with both CCP and CAP frequently seen in pulmonary TB.

The diagnostic utility of the anti-CCP antibody test is no better than rheumatoid factor in South Africans with early rheumatoid arthritis

“…The control group consisted of healthy subjects (n=30), systemic lupus erythematosus (SLE) patients (n=35) and systemic sclerosis (SSc) patients (n=28). In the SLE group, the presence of active tuberculosis (TB) was also noted because of recent reports of an association between aCCP and TB [13,14], coupled with the frequent occurrence of TB in our SLE patients [15].…”

Anti-CCP Antibody and Rheumatoid Factor Positivity in a Case of Tuberculosis Arthritis

“…Kakumanu et al (11) reported that anti-unmodified arginine-containing peptide (anti-CAP) levels were higher in patients with active TB infections compared to RA patients. While the anti-CAP/anti-CCP ratio was >2 in 94% of patients with RA, the same ratio was observed in only 22% of patients with TB.…”

“…While the anti-CAP/anti-CCP ratio was >2 in 94% of patients with RA, the same ratio was observed in only 22% of patients with TB. Thus, it was concluded that the anti-CCP/anti-CAP ratio could be used for differentiating TB arthritis from RA (11).…”

“…An increase in inflammatory markers may be misinterpreted as activation of RA and lead to alterations in disease-modifying drug choices, and even initiation of treatment by biological agents (11).…”

Rheumatoid factor and anti-cyclic citrullinated peptide (anti-CCP) antibodies with hepatitis B and hepatitis C infection: Review

“…14 The diagnosis of chronic HBV and HCV infections is based on the HBsAg and anti-HCV positivity persisting for more than 6 months. 2 Certain characteristics of chronic HBV and HCV infections are similar to those of rheumatic and renal diseases. Any of the symptoms of chronic HBV and HCV infections such as arthralgia, peripheral arthritis or laboratory findings like elevated acute phase reactants including C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) and positivity of RF are important markers for the diagnosis of inflammatory rheumatic diseases.…”