Autoimmune Diseases and Molecular Mimicry in Tuberculosis

Area of Science:

• Immunology
• Microbiology
• Molecular Biology

Background:

• Autoimmune diseases are increasingly comorbid with tuberculosis (TB).
• Molecular mimicry between Mycobacterium tuberculosis (Mtb) antigens and human autoantigens is a proposed mechanism driving autoimmunity in TB patients.
• Understanding this mimicry is crucial for diagnosing and treating TB-associated autoimmune conditions.

Purpose of the Study:

• To investigate the existence of molecular mimicry between Mtb antigens and human autoantigens.
• To identify specific shared sequences (epitopes) between Mtb and human proteins that may trigger autoimmune responses.
• To evaluate the serological evidence of autoimmunity in TB patients.

Main Methods:

• Analysis of antibody levels in 19 pulmonary tuberculosis patients using ELISA.
• Bioinformatic identification of 29 similar pentapeptides between key Mtb and human autoantigens using the "Alignmentaj" program.
• Evaluation of the immunoreactivity of shared pentapeptides against Mtb antigens using the IEDB database.

Main Results:

• High prevalence of antibodies to modified citrullinated vimentin (anti-MCV) detected in 57% of TB patients.
• Elevated levels of antibodies to C3 complement fragments (47%) and rheumatoid factors (21%) observed, even without diagnosed rheumatic diseases.
• Bioinformatic analysis confirmed shared pentapeptides within immunoreactive epitopes of Mtb antigens, correlating with autoantibody levels.

Conclusions:

• The study provides evidence for molecular mimicry between Mtb proteins and human autoantigens.
• Sequence similarity and cross-reactivity support the role of antigen mimicry in the development of autoimmunity in TB patients.
• These findings highlight a potential mechanism linking TB infection to autoimmune pathology.