IgA and IgG antibody detection of mycobacterial antigens in pleural fluid and serum from pleural tuberculous patients

Abstract

Background A previous study demonstrated pleural fluid (PF) IgA immunodominance for the fused MT10.3:MPT64 protein in pleural tuberculosis (PLTB) cases. However, no clue on the role of IgA and IgG against this and other antigens in PF and serum concerning improved diagnosis is available. Thus, the aim of the present study was to validate PF IgA-MT10.3:MPT64 and evaluate PF and serum IgA and IgG reactivity against this protein, its peptides (F2) and single MPT64, MT10.3 and the PPE59 mycobacterial specific antigens. IgA and IgG ELISA were measured against the antigen in PLTB (n = 29) and other non-TB pleurisy (n = 39) patient samples. Results The immunodominance of PF IgA-MT10.3:MPT64 was confirmed in PLTB (86.2%) followed by PPE59 (62%), while serum IgA-F2 exhibited 51.7% sensitivity. PF and serum IgG-MT10.3:MPT64 led to 65.5 and 51.7% sensitivity, respectively. However, MT10.3 and MPT64 displayed overall lower sensitivity (≤34.5) for both antibodies. All results at 95% fixed specificity. Combinatory results indicated 93.1% sensitivity for PF IgA-MT10.3:MPT64/−PPE59 and IgA/IgG-MT10.3:MPT64 at 92.3% specificity, followed by IgA-MT10.3:MPT64/−MPT64 or /−F2 (89.6%) without jeopardizing specificity (94.9%). The combinatory results of the PF adenosine deaminase test (ADA) and IgA-MT10.3:MPT64/−F2 demonstrated the highest sensitivity (96.6%), with a specificity of 92.3%. Conclusions The PF IgA-MT10:MPT64 immune dominance was validated in PLTB, and its combinatory results with PPE59 or MPT64 or F2 antigens as well as with IgG, are reported herein for the first time, improving their potential to assist diagnosis. Combining PF-ADA and IgA-MT10.3:MPT64/−F2 results achieved better accuracy. Moreover, serum IgG, although less accurate, displays potential beyond microbiological tests.

Differential Diagnosis of Latent Tuberculosis Infection and Active Tuberculosis: A Key to a Successful Tuberculosis Control Strategy

“…Yan et al (2018) reported that the sensitivity and specificity of individual antigen-specific antibodies are relatively low in detecting patients with TB not infected with the bacteria, but the combination of six antigenspecific antibodies (LAM, 38KD, MPT32, EspC, MPT64, and Mtb81) increased sensitivity and specificity to 69.6% and 77.0%, respectively. Similarly, another study also demonstrated that the sensitivity (96.6%) and specificity (92.3%) of IgA/IgG of a fused MT10.3:MPT64 protein were significantly higher than those of single antigens in pleural TB cases (da Silva et al, 2019). These results suggest that combining multiple antigenspecific antibodies can significantly improve the sensitivity and specificity of a single antigen-specific antibody, which will help in the diagnosis of TB and LTBI, but the current data are insufficient and further research is needed.…”

Application value of tissue tuberculosis antigen combined with Xpert MTB/RIF detection in differential diagnoses of intestinal tuberculosis and Crohn’s disease

“…Increasing attention has been paid to the study of MTBC antigen following the development of immune technology in recent years [13,36] . At present, the main samples used for MTBC antigen diagnosis are body uid and bacterial culture medium [37,38] . Reports on the application of tuberculosis antigen in ITB tissues are very rare.…”

Application value of tissue tuberculosis antigen combined with Xpert MTB/RIF detection in differential diagnosis of intestinal tuberculosis and Crohn’s disease

“…Over recent years, following the development of immune technology, an increasing attention has been paid to the study of MTBC antigen [13,34] . At present, the main samples used for MTBC antigen diagnosis are body fluid and bacterial culture medium [35,36] . Reports on the application of tuberculosis antigen in ITB tissues are very rare.…”