Identification of mycobacterial DNA in cutaneous lesions of sarcoidosis

Abstract

Sarcoidosis is a multisystemic granulomatous disease of uncertain etiology. Recently, mycobacterial DNA especially Mycobacterium tuberculosis and Mycobacterium avium complex were detected in lung tissue and bronchial lavage fluid from patients with sarcoidosis by polymerase chain reaction (PCR) assays in 30% to 50% cases. Moreover, cell wall-defective form (CWDF) acid-fast bacteria have been isolated from skin lesions of patients with sarcoidosis which were later confirmed as M. avium complex by PCR assays. CWDF acid-fast bacteria were also found to grow from the blood of 95% patients with active sarcoidosis demonstrating a mycobacterial origin similar to M. tuberculosis. In view of these reports, we investigated 20 cases of cutaneous sarcoidosis using PCR/restriction enzyme pattern analysis (PCR/REPA) to detect mycobacterial DNA from paraffin-embedded skin biopsy samples. The method involves restriction enzyme analysis of nested PCR products obtained with primers encoding for the 65-KDa protein common to all mycobacteria. Using three restriction enzymes, the mycobacterial DNA from PCR product was differentiated to the species level. All the 20 cases had clinical and histologic evidence of sarcoidosis. Special stains for fungi (PAS) and mycobacteria (Fite) were negative and no foreign body was identified on polaroscopic examination in any of the cases. The cell lysates of M. tuberculosis, Mycobacterium bovis, Mycobacterium avium-intracellulare, Mycobacterium kansasii and Mycobacterium marinum from Centers for Disease Control (CDC) were used as standard control for PCR/REPA. Eight cases of foreign body granuloma, seven normal skin samples from the margin of surgical excisions and 5 cases of dermatitis were used as negative controls, and 4 cases of cutaneous tuberculosis were used as positive controls. Mycobacterial DNA was detected by PCR in 16 of the 20 cases of sarcoidosis. PCR/REPA subtyped 8 of these to M. tuberculosis complex (2 cases), M. avium-intracellulare (4 cases), M. kansasii (2 cases) while the other 8 cases were non-tuberculous mycobacteria. All four cases of cutaneous tuberculosis were positive by PCR and had a typical M. tuberculosis PCR/REPA pattern. Mycobacterial DNA was not detected in any of the negative controls. Our results demonstrated that mycobacterial DNA is present in 80% of cutaneous lesions of sarcoidosis and these mycobacteria may play a role in the pathogenesis of sarcoidosis.

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

“…In this population, nested PCR demonstrated the presence of DNA from mycobacterial complex in tissue biopsies of 39% of sarcoidosis cases, who are significantly more likely to contain mycobacterial DNA than matched controls. Our findings are consistent with results from authors who detected M. tuberculosis DNAin approximately 20–71% of their cases using a similar analytical method and sequence [12, 14,16,17,18,19, 25,28,29,30]. Other authors, however, have detected mycobacterial DNA positivity in only a minority of cases [13, 22, 24, 26, 32] or in none [15, 20, 21, 23, 27, 31].…”

“…However, these results differ from a series of Greek patients with sarcoidosis, in which propionibacterium-positive sarcoidosis patients were found to be a subgroup (43%) of the mycobacterial-positive sarcoidosis subjects (71%) [14]. In general, the results of studies using PCR methodologies vary greatly, with mycobacterial nucleic components being detected in frequencies ranging from 0 to 70% of affected sarcoidosis tissues (table 3) [12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32]. Such variability might be explained by the techniques used and thus, the sensitivity and specificity may be implicated [8].…”

“…Other authors, however, have detected mycobacterial DNA positivity in only a minority of cases [13, 22, 24, 26, 32] or in none [15, 20, 21, 23, 27, 31]. In addition, as shown in table 2, there is evidence that appropriate procedures can detect mycobacteria other than M. tuberculosis complex [16,17,18, 21]. To evaluate the possible relationship between the incidence of TB and the frequency of M. tuberculosis DNA observed in patients with sarcoidosis in our setting, the contemporary incidence of TB in general populations of different regions and countries in which studies of sarcoidosis have been made should be taken into account.…”

Comorbidity of Leishmania major with cutaneous sarcoidosis

“…[13] Nowadays and with the advent of modern microbiological techniques, a great number of cases that were previously considered as sarcoidosis are understood to be associated with different infectious diseases. [23456789] However, Leishmania genus has rarely been investigated in these conditions. [81415]…”

“…[1] Several reports support the co-existence or even possible role of micro-organisms such as mycobacteria, especially cell-wall deficient forms like M. tuberculosis, atypical mycobacteria and M. leprae,[23456] Rickettsia helvetica ,[7] Leishmania infantum ,[8] and Brucella melitensis [9] in development of sarcoidosis; However, the exact etiology of sarcoidosis still remains unknown.…”