High Prevalence of <i>Mycobacterium tuberculosis</i> DNA in Biopsies from Sarcoidosis Patients from Catalonia, Spain

Abstract

Background: Sarcoidosis is a systemic granulomatous disease of unknown etiology. The presence of mycobacterial nucleic acid components in patients with sarcoidosis has been demonstrated with varying degrees of success. Objectives: The aim of this study was to estimate the presence of Mycobacterium tuberculosis DNA in tissues from sarcoidosis patients, in Catalonia, Spain, as well as to assess the long-term clinical course in these patients. Methods: Fifty-eight paraffin-embedded tissue biopsies corresponding to cases of sarcoidosis (n = 23), lung neoplasm (n = 23), and lung tuberculosis (n = 12) available in 1996 were analyzed in a retrospective study by means of a nested polymerase chain reaction using primers corresponding to the insertion element IS6110 of M. tuberculosis complex. For greater sensitivity, Southern blot hybridization was performed. Clinical data were recorded prior to and after PCR analysis (follow-up reported until 2002). Results:M. tuberculosis DNA was present in 9 out of 23 sarcoidosis biopsies (39%), in 1 out of 23 control patients (4%) (p < 0.01), and in all tissue samples from the 12 control patients with tuberculosis. To date, none of these sarcoidosis patients has developed tuberculosis over a mean (±SD) follow-up period of 11 (±3.4) years. Conclusion: In our setting, M. tuberculosis DNA is present in tissue biopsies of significantly more sarcoidosis patients than controls. However, these results do not demonstrate causality, although they may suggest a link between M. tuberculosis infection and sarcoidosis in some cases. Follow-up of these patients suggests that M. tuberculosis-DNA-positive sarcoidosis patients are not at greater risk of developing tuberculosis than M. tuberculosis-DNA-negative patients.

Molecular evidence for the role of mycobacteria in sarcoidosis: a meta-analysis

“…Interestingly, the presence of mycobacteria also seems to influence disease outcome, with mycobacterial nucleic acidnegative patients showing better outcomes [58]. In one study it was reported that all patients with mycobacteria-positive samples did not respond to the typical immunosuppressive treatment for sarcoidosis but the remaining mycobacterianegative patients reacted positively to the same therapy [46].…”

Evidence for Mycobacteria in Sarcoidosis

“…Remission occurred in 10 of 14 cases of MTB-negative disease but in only three of nine MTB-positive patients with sarcoidosis. None of these patients developed clinical tuberculosis despite positive DNA findings (84).…”

“…Molecular detection of MTB has been linked to poor prognosis in sarcoidosis (84,85). Grosser and colleagues found that in patients with sarcoidosis with MTB-reactive PCR results from biopsies, blood samples, or BAL, the disease was more likely to be chronic (85).…”

Sarcoidose ovárica e pulmonar – um diagnóstico a considerar

“…1,2,5,6 A evolução e a gravidade da doença é muito variável, ocorrendo resolução espontânea dentro de 12 a 36 meses na maioria dos casos, sendo a complicação mais frequente a fibrose pulmonar.…”