Comparison of serological responses in two different populations with pulmonary tuberculosis

Abstract

Observational studies on the humoural immune responses of the Warao indigenous people from Delta Amacuro, an isolated area, were compared with urban residents of the Venezuelan capital. Mycobacterium tuberculosisspecific reactivities (IgM, IgE, sIgA, IgG and IgG subclasses) Key words: tuberculosis -Warao -Creole -IgG subclasses -purified protein derivative -diagnosis Tuberculosis (TB) diagnosis needs to be improved, as it largely depends upon clinical examination and radiographic findings, mainly confirmed by sputum smear microscopy and bacterial culture (Murray et al. 1980). The latter requires a long cultivation period and diagnostic confirmation still relies on sputum smear examinations. Many alternative methodologies have been applied in TB diagnosis, such as western blot, microscopic observed direct sensitivity culture, PCR and cell-mediated immune response reactions (Moore et al. 2006, Negi et al. 2006. These methods require trained personnel and specific laboratory conditions, which hinder their implementation in many areas of high TB endemicity (mainly low-income countries) and field work application. On the other hand, there are other options that are currently under evaluation, including antibody detection by serology. While specific antibody detection by serology is under evaluation for a definitive demonstration that the humoural response can be used as a tool for the diagnosis of TB, future studies should be carried out in order to combine serological and cellular methods, such as T.SPOT-TB or Quantiferon Gold assay, which are considered to be approved tools. Regarding the immunodiagnosis of TB based on the T cell response to ESAT-6 and purified protein derivative (PPD) antigens, recently it has been reported that the IFN-γ assay using ESAT-6 as an antigenic stimulus has the potential to be used as a tool for the immunodiagnosis of early TB in children ( Van-Lume et al. 2008).The demand for a rapid, reliable, cost-effective and easy TB diagnostic tool focuses on antibody detection by serology (Bothamley 1995). It has been reported that the isotypic restriction of antibodies correlates with the biochemical nature of antigens; most antibodies against proteins are of IgG1 and IgG3 isotypes, while in those against carbohydrates IgG2 is over-represented (Chiang et al. 1997, Gupta et al. 2005. This is reflected in vivo where, for instance, antibody responses to viral proteins are mainly of the IgG1 and IgG3 subclasses. In contrast, bacteria carbohydrates usually induce type 2 T-independent responses, mainly of the IgG1 and IgG2 isotypes. Several ELISA tests have been attempted and results have presented a large variability in their accuracy depending on the antigen employed (one alone or a pool) (Chiang et al. 1997, Gupta et al. 2005, the immunoglobulin (Ig) class, the subclass measured (Radin et al. 1983, Daniel & Debane 1987, Pottumarthy et al. 2000, Conde et al. 2004, Imaz et al. 2004 and Mycobacterium tuberculosis strain variation (Alde et al. 1989, Zheng et al. 1994, Raja et al. 2002. This indicate...

Proteomic analysis of purified protein derivative of Mycobacterium tuberculosis

“…The role of PPD in serodiagnosis of TB, with sensitivity as high as 92%, was reported in Warao and Creole populations [10]. Several studies reported the use of PPD in serodiagnosis of tuberculosis infection with high sensitivity [11,12].…”

Evaluation of immunologic response of salivary sIg-A in pediatric tuberculosis patients to antigen Ag38-rec of Mycobacterium tuberculosis Indonesian strain

“…In consequence, a rapid, simple, and inexpensive method to confirm Mycobacterium tuberculosis (Mtb) infection is required to reduce the spread of the disease. One such promising method, a serodiagnostic approach focusing on the detection of specific TB antibodies in patients, has been extensively studied [3][4][5] . A non-invasive diagnostic method like this would be highly valued, particularly with regards to pediatric TB patients.…”

Immunologic evaluation and validation of methods using synthetic peptides derived from Mycobacterium tuberculosis for the diagnosis of tuberculosis infection

“…Serologic assays -The serum IgG levels that were reactive against rESAT-6, ESAT-6 peptides and the Ag85c and Ag85A peptides were determined by an ELISA as previously described (Araujo et al 2008). Briefly, serum was isolated from venous blood obtained from HC individuals and patients.…”

“…Several enzyme-linked immunosorbent assays (ELISA) have been attempted and result in large variability depending on whether antigen alone or a pool of antigens was used, the immunoglobulin (Ig) class or subclass measured and the Mycobacterium tuberculosis strain used (Chiang et al 1997, Turneer et al 1998, Pottumarthy et al 2000, Raja et al 2002, Conde et al 2004, Mabey et al 2004, Gupta et al 2005. This indicates that more optimal antigens have yet to be tested or that there is a differential antibody response as a result of ethnic genetic variation (Lyashchenko et al 1998, Demkow et al 2004, Araujo et al 2008. A successful serodiagnostic test for TB hinges on the capacity of the assay to detect the pauci and multibacillary forms of TB, paediatric TB cases and TB-infected patients coinfected with human immunodeficiency virus (HIV) (Mabey et al 2004, Tiwari et al 2007).…”