Pleural tuberculosis (PL-TB) remains difficult to diagnose. An enzyme-linked immunosorbent assay (ELISA) was developed based on a construction containing the fusion of the Rv3019c (MT10.3) and Rv1980c (MPT64) gene sequences, and its performance was evaluated in an area where TB is endemic. A total of 92 pleural fluid (PF) samples at serial dilutions of 1:50 to 1:800 were included in the ELISA IgA MT10.
4%). Our findings demonstrated the promising use of this test as an adjunct in PL-TB diagnoses, particularly in cases with lower bacterial loads and false-negative results in the reference tests, since the new test includes such important features as quick and easy application, high sensitivity and, perhaps most importantly, affordability, which is so crucial for its widespread use in developing countries.Tuberculosis (TB) is the leading cause of preventable morbidity and mortality from infectious agents worldwide. A global plan has been outlined to eradicate the disease by 2050 (37). To reach this goal, both political commitments and increments in interdisciplinary research are needed; because the specific diagnostics, drugs, and vaccines available for this purpose have been insufficient in eradicating the disease, the development of more effective tools and strategies is urgently needed (7).In Brazil, the TB prevalence rate is approximately 60 per 100,000 inhabitants (44). Generally speaking, the incidence of pleural tuberculosis (PL-TB) is closely related to the local disease prevalence. Moreover, PL-TB is the major cause of pleural effusions, responsible for approximately 50% of all related diagnoses in Brazil (25, 32).TB diagnoses have traditionally relied on the identification of acid-fast bacilli (AFB) and the culture of clinical specimens. However, low sensitivities (5 and 47%, respectively) are achieved with PL-TB. Besides, the final culture results may take as long as 4 to 6 weeks to complete, delaying the initiation of specific therapy.The histopathological examination of pleural biopsy specimens comprises the standard PL-TB reference test. Nevertheless, its sensitivity is highly variable (39 to 84%), it is expensive and time-consuming, and its proper administration requires skilled personnel. It is clear that there is an overriding need for the development of a simple, fast, effective, and affordable yet robust tool that would be readily available throughout the national public health care sector to aid in the diagnosis of PL-TB, with special emphasis on developing countries (12,15,30). What is most frequently used is an enzyme-linked immunosorbent assay (ELISA) together with commercial and inhouse antibody tests, which have been developed using antigens in a cocktail-like format. The downside is that lower reactivity has been described for this format compared with the rates obtained after testing these components individually (9,13,22). In our previous studies, when the single proteins MPT64 and MT10.3 were tested individually for each patient, the combined results achieved a 76% sensitivity rate in...