Absence of Ribosomal RNA of Mycobacterium tuberculosis Complex in Sarcoidosis

Abstract

To determine whether Mycobacterium tuberculosis ribosomal RNA (rRNA) is present in fresh tissue specimens from patients with sarcoidosis. Design: A prospective study. Setting: A university-based hospital. Patients: Thirty-five patients diagnosed as having sarcoidosis at the University Hospital of Bellvitge, Barcelona, Spain, were included in the study. Fresh tissue samples with granulomatous inflammation were prospectively collected between 1997 and 2001 from all patients. For each sample tested, approximately 1 negative control was included. Main Outcome Measures: Mycobacterium tuberculosis rRNA was detected using an isothermal enzymatic amplification system of target rRNA of M tuberculosis complex via DNA intermediates. Smears for acid-fast staining and mycobacteriological cultures were also obtained. Results: A total of 78 biopsy specimens (57 skin, 10 lymph node, 3 lacrimal gland, 2 spleen, 2 lung, 2 muscle, 1 bone, and 1 nerve) collected from 74 patients (35 patients with sarcoidosis and 39 control patients) were included in the study. Stains for acid-fast bacilli and mycobacterial cultures were negative for organisms in all cases. Mycobacterium tuberculosis rRNA was not detected in the specimens from any patients with sarcoidosis or in those from control patients whose cultures were negative for organisms. Ribosomal RNA was detected in 6 tissue specimens from patients with cultures that were positive for M tuberculosis and that were processed in parallel to the samples included in the study. Conclusions: Although previous studies have reported that mycobacterial antigens may play a role in granuloma formation in some patients with sarcoidosis, our results suggest that M tuberculosis cannot be considered to be the etiologic agent of the disease.

Is there any association between Sarcoidosis and infectious agents?: a systematic review and meta-analysis

“…Both Mycobacterium tuberculosis complex (MTBC) and nontuberculous mycobacteria (NTM) were investigated in most of the 36 relevant studies, although some used primers to detect only M. tuberculosis [26, 28–33, 38, 39, 41, 42, 51, 52, 55], and others detected only nontuberculous mycobacteria [44, 50]. …”

The granulomatous reaction pattern

“…123,124 The term 'immune restoration disease' has been used for this circumstance. 133 Based on these results the authors concluded that this organism cannot be considered as the etiological agent of the disease. 125 The etiology of sarcoidosis remains controversial although an infectious origin has long been suspected.…”

Sarcoidosis and molecular mimicry—important etiopathogenetic aspects: current state and future directions

“…As an example of arguments in favor of a possible role for M. tuberculosis, it has been found that the enzyme catalase-peroxidase (mKatG) is not only found in tissues affected by sarcoidosis, but is also a target of the immune response in patients with sarcoidosis [23].However, previous studies attempting to detect mycobacterial nucleic acids in lesions of sarcoidosis have been controversial [22,24].…”

“…Confirmation of diagnosis is done by histopathology. Skin offers advantages compared to other affected organs since it is easily accessible [24].…”