Determination of anti-Mycobacterium tuberculosis IgM and IgG antibodies in individuals in contact with patients with active tuberculosis.
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1
Facultad de Medicina U.A.N.L., Inmunologia, Mexico
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2
Facultad de Medicina, U.A.N.L., Inmunología, Mexico
INTRODUCTION: Tuberculosis is a global health issue, and a third of the entire population is infected with the bacilli. In 2013, 8.9 millions of infected patients were reported and 1.5 million of these died. The cellular immune response by Th1 cells appears to be responsible for the resolution and protection against the disease, and the humoral immune response, although not much involved in this protection, is useful as a diagnostic tool. In general, the production of IgM antibodies takes place during the acute or latent phase of most infectious diseases and their serum levels decrease during the chronic phase. On the other hand, IgG antibodies increase during the active infection and their levels remain high even after the infection is resolved, becoming the immunological memory. The OBJECTIVE of this work was to determine the presence of anti-M. tuberculosis IgM and IgG in serum of individuals in contact with patients with pulmonary tuberculosis. METHODOLOGY: We obtained sera from 46 clinically healthy individuals, from 77 persons that were in contact with patients with tuberculosis for at least 6 hours a day, and from 28 patients with pulmonary tuberculosis diagnosed clinically, radiologically and with a positive culture. We used ELISA plates covered with antigens obtained from a purified extract of extracellular proteins of the H37 Rv strain, including ESAT6 and CFP10 (Patent Nº 285260 “Process for the detection of tuberculosis”). The antibodies present in the sera of healthy subjects, contacts, and patients were developed with anti-IgM and anti-IgG antibodies conjugated with peroxidase. All subjects were tested with the PPD cutaneous reaction to evaluate the efficacy of our ELISA method. RESULTS: IgM+/IgG- or IgM+/IgG+ indicates a tuberculosis infection; IgM-/IgG+ indicates immunological memory or that the TB infection was in the process of resolving; and IgM-/IgG- indicates no infection with Mycobacterium tuberculosis. We found that IgM was positive (+) in 2/46 (4.3%) of healthy patients, in 72/77 (93.5%) of contacts, and in 27/28 (96.4 %) of patients with TB. IgG was positive (+) in 26/46 (56.5%) of healthy patients, 31/77 (40.22%) of contacts, and 13/28 (46.4%) of patients with TB. The reaction to the PPD (48-72 hours) was positive (> 5mm) in 20/46 (43%) of healthy patients, 55/77 (71.4%) of contacts, and 28/28 (100%) of patients with TB. CONCLUSION: IgM and IgG positive sera from contacts of infected patients suggest they could be infected with M. tuberculosis. The presence of IgG but not IgM in a 56.5% of healthy individuals could be interpreted as immunological memory. The fact that 96.4% of sera from sick patients was positive for IgM indicates that the ELISA method that we used is useful for the diagnosis of latent and active tuberculosis. The PPD cutaneous reaction was less efficient in diagnosing a latent infection in contacts of sick patients compared to our ELISA method. This proofs that the ELISA method we use could be useful for the prompt detection of the M. tuberculosis infection, allowing for the control of the disease.
Keywords:
Tuberculosis, Pulmonary,
ELISA,
IgM,
Mycobacterium tuberculosis,
Individuals contacts
Conference:
IMMUNOCOLOMBIA2015 - 11th Congress of the Latin American Association of Immunology - 10o. Congreso de la Asociación Colombiana de Alergia, Asma e Inmunología, Medellin, Colombia, 13 Oct - 16 Oct, 2015.
Presentation Type:
Poster Presentation
Topic:
Infectious and parasitic diseases
Citation:
Arce Mendoza
AY,
Cantú Rodríguez
MP,
Ramírez Vega
JA,
Rosas Taraco
AG and
Limón Flores
AY
(2015). Determination of anti-Mycobacterium tuberculosis IgM and IgG antibodies in individuals in contact with patients with active tuberculosis..
Front. Immunol.
Conference Abstract:
IMMUNOCOLOMBIA2015 - 11th Congress of the Latin American Association of Immunology - 10o. Congreso de la Asociación Colombiana de Alergia, Asma e Inmunología.
doi: 10.3389/conf.fimmu.2015.05.00157
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Received:
30 May 2015;
Published Online:
14 Sep 2015.
*
Correspondence:
PhD. Alma Y Arce Mendoza, Facultad de Medicina U.A.N.L., Inmunologia, Monterrey, Nuevo León, 64460, Mexico, aya.mayola@yahoo.com