Abstract: Objective To investigate the possible role of mycobacterial infection in the pathogenesis of sarcoidosis.Methods DNA fragments of mycobacterial 16S rRNA gene and the complex-specific insertion sequence IS6110 of M.tuberculosis were detected by polymerase chain reaction(PCR)in formalin-fixed,paraffin-embeded skin biopsy specimens from12patients with sarcoidosis.Results Mycobacterial common sequence16S rRNA gene was found in6patients,among which5were further confirmed as M.tuberculosis,the other one was atypical mycobacteria.The IS6110DNA fragment amplified by PCR was confirmed by DNA sequencing.Conclusion The above findings suggest an aetiological role of mycobacterial infection,especially M.tuberculosis,in some patients with sarcoidosis.

Key words: Sarcoidosis, Mycobacterium, Polymerase chain reaction