Anti-cyclic citrullinated peptide antibodies and rheumatoid factor in leprosy patients with articular involvement

S.L.E Ribeiro,R.M.S Neves,E.I Sato,H.L.A Pereira,N.P Silva

doi:10.1590/s0100-879x2008001100010

S.L.E Ribeiro, R.M.S Neves + Show 3 more

Open Access

https://doi.org/10.1590/s0100-879x2008001100010

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Abstract

The objective of the present research was to evaluate the usefulness of anti-cyclic citrullinated peptide (anti-CCP) antibodies and the IgM rheumatoid factor (IgM RF) test for the differential diagnosis of leprosy with articular involvement and rheumatoid arthritis (RA). Anti-CCP antibodies and IgM RF were measured in the sera of 158 leprosy patients (76 with and 82 without articular involvement), 69 RA patients and 89 healthy controls. Leprosy diagnosis was performed according to Ridley and Jopling classification criteria and clinical and demographic characteristics of leprosy patients were collected by a standard questionnaire. Leprosy patients with any concomitant rheumatic disease were excluded. Serum samples were obtained from all participants and frozen at -20 degrees C. Measurement of anti-CCP antibodies and IgM RF were performed by ELISA, using a commercial second-generation kit, and the latex agglutination test, respectively. Anti-CCP antibodies and IgM RF were detected in low frequencies (2.6 and 1.3%, respectively) in leprosy patients and were not associated with articular involvement. Among healthy individuals both anti-CCP antibodies and IgM RF were each detected in 3.4% of the subjects. In contrast, in the RA group, anti-CCP antibodies were present in 81.2% and IgM RF in 62.3%. In the present study, both anti-CCP antibodies and IgM RF showed good positive predictive value for RA, helping to discriminate between RA and leprosy patients with articular involvement. However, anti-CCP antibodies were more specific for RA diagnosis in the population under study.

Highlights

Leprosy is a chronic granulomatous disease caused by Mycobacterium leprae, an obligate intracellular parasite that affects mainly skin and peripheral nerves [1]
Tuberculoid leprosy, the host is able to keep the disease under control due to an efficient T-cell-mediated immune response; while at the opposite pole, lepromatous leprosy, cell-mediated immunity is inefficient leading to excessive bacillary multiplication and dissemination [3]
Careful physical exams and histories as well as medical chart review and rheumatological examinations were performed for all patients by two rheumatologists (S.L.E.R. and H.L.A.P.), and leprosy patients with any concomitant rheumatic disease were excluded

Summary

Introduction

Leprosy is a chronic granulomatous disease caused by Mycobacterium leprae, an obligate intracellular parasite that affects mainly skin and peripheral nerves [1]. The number of new cases of leprosy is decreasing, the disease still constitutes a major public health problem in many developing countries [2]. The clinical spectrum of leprosy is characterized by two stable polar forms of disease. Between the two stable poles are unstable forms of leprosy, named borderline (or dimorphous) that may combine characteristics of the polar forms. Known as reactional episodes, may occur during the chronic course of leprosy, due to either alterations in cellular immunity (type 1 or reversal reaction) or excessive formation of immune complexes at the sites of antigen deposition (type 2 or erythema nodosum leprosum) [4]

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