Sarcoidosis: Role of non-tuberculosis mycobacteria and Mycobacterium tuberculosis

Abstract

Sarcoidosis is a granulomatous inflammatory disease that is induced by unknown antigen(s) in a genetically susceptible host. Although the direct link between Mycobacterium tuberculosis (MTB) infection and sarcoidosis can be excluded on the basis of current knowledge, non-infectious mechanisms may explain the causative role of mycobacterial antigens. Ever since sarcoidosis was first described, its relationship with tuberculosis (TB) has been under-investigated. Whereas some researchers consider sarcoidosis and TB as two examples of the same disease process, others have rejected mycobacteria as playing any causative role in sarcoidosis. Whether they are linked causally or not, clinical evidence makes a differential diagnosis between the two conditions very challenging, particularly in countries with high burden of TB. The present study analyzes the relationship between sarcoidosis and TB and its implications in clinical practice. The coincidence of TB and sarcoidosis and the higher incidence of mycobacterial DNA in biological samples of sarcoid patients have been reported by many authors. In addition, new evidence of a similarity in MTB phenotype in sarcoidosis is provided. Overall, these observations suggest that TB and sarcoidosis may not only share the same etiology, but may even be different aspects of one disease.

Etiology and Immunopathogenesis of Sarcoidosis: Novel Insights

“…In clinical, radiological, as well as immunological features, there is similarity between sarcoidosis and tuberculosis, 78 leading to the suggestion of mycobacteria as etiologic agent in sarcoidosis. 83 Several studies have described a role of mycobacteria in the involvement of sarcoidosis. Gupta and colleagues wrote a meta-analysis of 31 studies published between 1980 and 2006 that have used molecular techniques to determine the histological as well as the cellular presence of mycobacteria in sarcoidosis.…”

Sarcoidosis y amiloidosis secundaria, una rara asociación

“…En el paciente descrito se identificó antecedente de tuberculosis pulmonar con tratamiento previo, aunque fueron negativos los estudios para Mycobacterium tuberculosis. Es importante descartar esta enfermedad ya que se ha descrito una asociación importante entre la exposición a antígenos de micobacterias residuales como potenciales causantes de sarcoidosis (11,12).…”

Síndrome de Löfgren: presentación inusual de sarcoidosis

“…Información reciente sugiere que la sarcoidosis y la TB pueden potencialmente ser extremos opuestos de una misma enfermedad, que comparten características clínicas e inmunológicas; por tanto, se debe realizar un diagnóstico preciso para diferenciar estas dos entidades. En nuestro medio, dada la alta prevalencia de TB, su diferenciación se convierte en un reto diagnóstico (12,13).…”