RESUMEN
OBJETIVO: Este estudo avaliou a presença de anticorpos antipeptídeos citrulinados cíclicos (anti-CCP), fator reumatoide (FR) e imunocomplexos circulantes (ICC) em pacientes sudaneses infectados por Leishmania donovani. PACIENTES E MÉTODOS: Os soros foram coletados de pacientes infectados por Leishmania (n = 116) e de sudaneses saudáveis (n = 93). Dezenove pacientes sudaneses com artrite reumatoide (AR) e anti-CCP+ foram incluídos como controles positivos. Os níveis de ICC e anti-CCP foram medidos por ELISA. Para avaliar a reatividade citrulina-específica foi usada a placa-controle com peptídeos-controle cíclicos contendo arginina em vez de citrulina. RESULTADOS: Entre os pacientes infectados por Leishmania e os pacientes com AR e anti-CCP+, a maioria (86%) era positiva para FR, enquanto a frequência de positividade para ICC foi maior entre pacientes com leishmaniose visceral (LV) (LV 38%; AR e anti-CCP+ 24%). Quando foi analisada a reatividade anti-CCP, 12% dos pacientes com LV foram positivos. Os níveis de anti-CCP entre os pacientes com LV correlacionaram-se bem com os níveis de ICC encontrados (r = 0,65; P < 0,0001). No grupo de AR não foi encontrada associação entre ICC e anti-CCP. A possibilidade de que a positividade para anti-CCP se deva a reações cruzadas com ICC foi descartada experimentalmente. Ao contrário do que foi visto no soro dos sudaneses com AR, a reatividade anti-CCP não se restringiu à citrulina, mas houve reação igual com os peptídeos-controle com arginina. CONCLUSÃO: O fato de a reatividade CCP não se ter restringido à citrulina comprova tratar-se mais de um efeito de inflamação extensa e ativação imune do que de um sinal de características patogênicas compartilhadas com artrite anti-CCP. Nossos achados ressaltam a importância de se interpretar um teste CCP positivo com cuidado ao se avaliar condições não reumáticas ou em áreas onde tais infecções predominam.
OBJECTIVE: The present study evaluated the presence of anti-cyclic citrullinated peptides antibodies (anti-CCP), rheumatoid factor (RF), and circulating immune complexes (CIC) in Sudanese patients infected with the Leishmania donovani parasite. PATIENTS AND METHODS: Sera were collected from Leishmania infected patients (n = 116) and healthy Sudanese (n = 93). Nineteen Sudanese anti-CCP+ RA patients were included as positive controls. Levels of CIC and anti-CCP were measured by ELISA. Control plate with cyclic control peptides containing arginine instead of citrulline was used to evaluate citrulline specifi c reactivity. RESULTS: Among Leishmania-infected patients and anti-CCP+ RA patients, most were RF positive (86%), while the frequency of CIC positivity was higher among visceral leishmaniasis (VL) patients (VL 38%; anti-CCP+ RA 24%). When anti-CCP reactivity was analysed, 12% of VL patients were found to be positive. The levels of anti-CCP among VL patients correlated well with the CIC levels found (r = 0.65, P < 0.0001). In RA group, no association was found between CIC and anti-CCP. The possibility that anti-CCP positivity was due to cross reactions with CIC was experimentally ruled out. Contrary to what was seen in Sudanese RA sera, the CCP reactivity was not restricted to citrulline but reacted equally well with the arginine control peptide. CONCLUSION: The finding that CCP reactivity was not restricted to citrulline argues that this is more an effect of extensive inflammation and immune activation than a sign of shared pathogenic characteristics with anti-CCP arthritis. Our fi ndings stress the importance to interpret a positive CCP test carefully when evaluated in non-rheumatic conditions or in areas where such infections predominate.
Asunto(s)
Adolescente , Adulto , Niño , Femenino , Humanos , Masculino , Adulto Joven , Complejo Antígeno-Anticuerpo/sangre , Autoanticuerpos/sangre , Leishmania donovani , Leishmaniasis Visceral/sangre , Leishmaniasis Visceral/inmunología , Péptidos Cíclicos/inmunología , Factor Reumatoide/inmunología , SudánRESUMEN
OBJECTIVE: The present study evaluated the presence of anti-cyclic citrullinated peptides antibodies (anti-CCP), rheumatoid factor (RF), and circulating immune complexes (CIC) in Sudanese patients infected with the Leishmania donovani parasite. PATIENTS AND METHODS: Sera were collected from Leishmania infected patients (n = 116) and healthy Sudanese (n = 93). Nineteen Sudanese anti-CCP+ RA patients were included as positive controls. Levels of CIC and anti-CCP were measured by ELISA. Control plate with cyclic control peptides containing arginine instead of citrulline was used to evaluate citrulline specifi c reactivity. RESULTS: Among Leishmania-infected patients and anti-CCP+ RA patients, most were RF positive (86%), while the frequency of CIC positivity was higher among visceral leishmaniasis (VL) patients (VL 38%; anti-CCP+ RA 24%). When anti-CCP reactivity was analysed, 12% of VL patients were found to be positive. The levels of anti-CCP among VL patients correlated well with the CIC levels found (r = 0.65, P < 0.0001). In RA group, no association was found between CIC and anti-CCP. The possibility that anti-CCP positivity was due to cross reactions with CIC was experimentally ruled out. Contrary to what was seen in Sudanese RA sera, the CCP reactivity was not restricted to citrulline but reacted equally well with the arginine control peptide. CONCLUSION: The finding that CCP reactivity was not restricted to citrulline argues that this is more an effect of extensive inflammation and immune activation than a sign of shared pathogenic characteristics with anti-CCP arthritis. Our fi ndings stress the importance to interpret a positive CCP test carefully when evaluated in non-rheumatic conditions or in areas where such infections predominate.