Dados do Trabalho

Título

Diagnostic Performance of Chimeric Recombinant Antigens of Trypanosoma cruzi for Identifying Chagas Disease in Samples from Rio Grande do Sul

Introdução

Chagas disease (CD), caused by the protozoan Trypanosoma cruzi, is a significant neglected tropical disease with severe, life-threatening consequences. Laboratory diagnosis of chronic CD is challenging due to the lack of standardized reference tests. The performance of commercial immunoassays varies, influenced by the antigenic preparations used for detecting anti-T. cruzi antibodies and the diversity of parasite strains in different geographical regions. A promising approach to these diagnostic challenges involves chimeric recombinant protein-based antigenic matrices, such as IBMP-8.1, IBMP-8.2, IBMP-8.3, and IBMP-8.4.

Objetivo (s)

This study aims to evaluate the diagnostic performance of four IBMP chimeric T. cruzi antigens in detecting anti-T. cruzi antibodies in individuals from Canguçu, an endemic city near Pelotas, Rio Grande do Sul.

Material e Métodos

A total of 333 serum samples were analyzed for anti-T. cruzi antibodies using indirect ELISA with the chimeric antigens. Indirect ELISA results served as the reference test, and latent class analysis (LCA) was used to classify samples as T. cruzi-positive or T. cruzi-negative. The performance of each antigen was evaluated in terms of sensitivity, specificity, accuracy, and diagnostic odds ratio (DOR).

Resultados e Conclusão

LCA classified 44 (13.2%) samples as T. cruzi-positive and 289 as T. cruzi-negative. The IBMP-8.3 antigen exhibited the highest sensitivity (100%), followed by IBMP-8.4 (97.7%) and IBMP-8.1 (95.6%). IBMP-8.2 showed a sensitivity of 84.1%, with seven false-negative results, although this difference was not statistically significant compared to the other antigens. Specificity values were high for all antigens, ranging from 99.3% for IBMP-8.1 and 99.7% for IBMP-8.3 to 100% for both IBMP-8.2 and IBMP-8.4. Accuracy was 99.7% for IBMP-8.3 and IBMP-8.4, while IBMP-8.1 and IBMP-8.2 exhibited accuracies of 98.8% and 97.9%, respectively. Notably, IBMP-8.3 and IBMP-8.4 showed the highest DOR values (> 1,230,000), while IBMP-8.2 and IBMP-8.1 had DOR values exceeding 152,000 and 3,100, respectively. These findings indicate that all four IBMP T. cruzi-chimeric proteins are effective for diagnosing chronic CD in Rio Grande do Sul. This supports previous research conducted in various endemic and non-endemic regions, demonstrating that these antigens can be reliably used regardless of geographical regions or local strain diversity.

Palavras Chave

Trypanosoma cruzi; Serological diagnosis; chimeric recombinant antigens; ELISA