Frequent isolation of Propionibacterium acnes from sarcoidosis lymph nodes

Isolation of Propionibacterium acnes from biopsied lymph nodes of sarcoidosis patients and from the lymph nodes or other tissues of non-sarcoidosis patients was carried out, carefully avoiding contamination by skin-resident P. acnes. Out of 40 sarcoidosis lymph nodes examined, 31 nodes (77.5%) showed a positive culture of P. acnes, while 38 of 180 (21.1%) non-sarcoidosis tissues revealed positive results, the difference being significant (p less than 0.001). Among non-sarcoidosis tissues, the intra-thoracic lymph nodes demonstrated a positive culture in low percentages, while intra-abdominal lymph nodes indicated no positive culture. The possible role of this microorganism in the etiology of sarcoidosis is discussed.