Fax +41 61 306 12 34 E-Mail karger@karger.ch www.karger.com Clinical Investigations Respiration 2006;73:20–26 DOI: 10.1159/000087688 High Prevalence of Mycobacterium tuberculosis DNA in Biopsies from Sarcoidosis Patients from Catalonia, Spain E. Fité a M.T. Fernández-Figueras b R. Prats a M. Vaquero b J. Morera a a Servei de Pneumologia, and b Departament de Patologia, Hospital Universitari Germans Trias i Pujol, Universitat Autonoma de Barcelona, Badalona, Spain oped tuberculosis over a mean ( 8 SD) follow-up period of 11 ( 8 3.4) years. Conclusion: In our setting, M. tuber- culosis 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 sar- coidosis in some cases. Follow-up of these patients sug- gests that M. tuberculosis- DNA-positive sarcoidosis pa- tients are not at greater risk of developing tuberculosis than M. tuberculosis- DNA-negative patients. Copyright © 2006 S. Karger AG, Basel Introduction Sarcoidosis is a systemic granulomatous disease of un- known etiology, although ample evidence supports an an- tigen-driven immunopathogenic process. It has been sug- gested that one or more microbes behaving in a noninfec- tious fashion in a genetically predisposed individual trigger the sarcoidosis granulomatous response [1, 2]. Ex- perience of organ transplantation has lent credence to the old hypothesis that sarcoidosis is a transmissible disease supported by the animal passage experiments of Mitchell and Rees [3] . In patients with sarcoidosis undergoing transplantation, the frequency of recurrence of sarcoid- osis in the transplanted organ or of exacerbation of the disease at a distant site has been well reported, and do- Key Words Sarcoidosis  Mycobacteria  Polymerase chain reaction  Tuberculosis Abstract Background: Sarcoidosis is a systemic granulomatous disease of unknown etiology. The presence of mycobac- terial nucleic acid components in patients with sarcoid- osis has been demonstrated with varying degrees of suc- cess. Objectives: The aim of this study was to estimate the presence of Mycobacterium tuberculosis DNA in tis- sues 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 devel- Received: May 6, 2004 Accepted after revision: January 26, 2005 Published online: August 17, 2005 Dra Enriqueta Fité Servei de Pneumologia Hospital Universitari Germans Trias i Pujol Carretera del Canyet s/n, ES–08916 Badalona (Spain) Tel. +34 93 465 12 00, Fax +34 93 497 88 43, E-Mail 9033efr@comb.es © 2006 S. Karger AG, Basel 0025–7931/06/0731–0020$23.50/0 Accessible online at: www.karger.com/res For editorial comment see p. 14