title: The antibody response to Propionibacterium acnes is an independent predictor of serum prostate-specific antigen levels in biopsy-negative men.
abstract: OBJECTIVE
  To investigate whether the serum titres of Propionibacterium acnes antibodies in patients undergoing prostate biopsy are associated with prostate cancer or markers of prostate disease, including serum prostate-specific antigen (PSA) levels.
  
  
  METHODS
  The cell wall-associated proteins from P. acnes types IA, IB and II were extracted and characterized by Western blotting and immunoblotting. We developed an enzyme-linked immunosorbent assay (ELISA) based on extracted proteins to determine the anti-P. acnes antibody titres in the sera of 68 patients undergoing prostate biopsy. Correlations between these titres and multiple markers of prostate disease were investigated.
  
  
  RESULTS
  In patients with biopsies negative for cancer, a high anti-P. acnes antibody titre was associated with high serum PSA levels (>or=10.0 ng/mL, P = 0.04), and multiple linear regression analysis identified antibody titre as the predominant independent predictor of serum PSA level (P = 0.03). The titre was positively correlated with patient age, prostate volume and aggressive inflammation, suggesting an involvement with benign prostatic hyperplasia (BPH). However in patients with histologically detected cancer, the volume of cancer in the biopsy cores was the predominant independent predictor of serum PSA (P = 0.01).
  
  
  CONCLUSIONS
  These results support our hypothesis that P. acnes might be involved in the development of inflammation-related prostate diseases, in particular with BPH. Our ELISA might be valuable for identifying P. acnes infection of the prostate gland in patients with elevated serum PSA levels but a negative biopsy, and might identify men at risk of developing clinical BPH. However, an investigation with more patients is needed to confirm these preliminary findings.
authors.affiliation: Tissugen Pty Ltd and Faculty of Medicine, University of Western Australia, Perth, Western Australia.
authors.forename: Beverley A
authors.initials: BA
authors.lastname: Shannon
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Cohen
authors.forename: Kerryn L
authors.initials: KL
authors.lastname: Garrett
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000907:Antibodies, Bacterial / Q000097:blood / Q000276:immunology*; D015153:Blotting, Western; D004797:Enzyme-Linked Immunosorbent Assay; D016908:Gram-Positive Bacterial Infections / Q000097:blood / Q000276:immunology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011425:Propionibacterium acnes / Q000276:immunology* / Q000302:isolation & purification; D017430:Prostate-Specific Antigen / Q000097:blood*; D011470:Prostatic Hyperplasia / Q000097:blood / Q000276:immunology* / Q000382:microbiology; D011471:Prostatic Neoplasms / Q000097:blood / Q000276:immunology* / Q000382:microbiology; D012044:Regression Analysis
chemical_list: D000907:Antibodies, Bacterial; D017430:Prostate-Specific Antigen