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Natural resistance-associated macrophage protein 1 polymorphisms are associated with microscopy-positive tuberculosis

Christian Søborg1, Aase B Andersen, Hans O Madsen

  • 1Department of Clinical Immunology, Tissue Typing Laboratory, Rigshospitalet, Denmark. cs@rh.dk

The Journal of Infectious Diseases
|August 27, 2002
PubMed

Insights

Variant alleles in the natural resistance-associated macrophage protein 1 (NRAMP1) gene increase mycobacterial replication. This suggests NRAMP1 variants may confer a higher risk of severe tuberculosis disease, particularly microscopy-positive cases.

Area of Science:

  • Genetics
  • Immunology
  • Infectious Diseases

Background:

  • The natural resistance-associated macrophage protein 1 (NRAMP1) gene plays a role in the body's defense against mycobacterial infections.
  • Understanding genetic factors influencing tuberculosis (TB) severity is crucial for disease management.

Purpose of the Study:

  • To investigate the association between NRAMP1 gene polymorphisms and tuberculosis in HIV-negative individuals.
  • To determine if specific NRAMP1 genotypes correlate with increased risk or severity of tuberculosis.

Main Methods:

  • Polymerase chain reaction (PCR) was used to analyze NRAMP1 genotypes at four specific loci (INT4, N543D, 3'UTR, 5'(CA)(n)).
  • Genotypes were compared between 104 tuberculosis patients and 176 healthy controls in Denmark.

Main Results:

  • No significant difference in overall genotype frequency was observed between tuberculosis patients and controls.
  • Carriage of NRAMP1 variant alleles at the INT4 and 5'(CA)(n) loci was significantly associated with an increased risk of microscopy-positive tuberculosis.
  • NRAMP1 alleles were not linked to the development of lung cavities or extrapulmonary tuberculosis.

Conclusions:

  • Variant alleles in the NRAMP1 gene are associated with increased mycobacterial replication, not initial susceptibility to tuberculosis.
  • These findings suggest that NRAMP1 variants may contribute to a higher risk of severe disease presentation in tuberculosis.

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