title: Evidence for an association between Chlamydia psittaci and ocular adnexal lymphomas.
abstract: BACKGROUND
  Ocular adnexal lymphomas may be antigen-driven disorders; however, the source of the putative antigen or antigens is still unknown. Hence, we assessed whether Chlamydiae infection is associated with the development of ocular adnexal lymphomas.
  
  
  METHODS
  The presence of Chlamydia psittaci, trachomatis, and pneumoniae DNA was investigated by polymerase chain reaction in 40 ocular adnexal lymphoma samples, 20 nonneoplastic orbital biopsies, 26 reactive lymphadenopathy samples, and peripheral blood mononuclear cells (PBMCs) from 21 lymphoma patients and 38 healthy individuals. Seven patients with chlamydia-positive PBMCs were treated with the antibiotic doxycycline, and objective response was assessed in four patients with measurable lymphoma lesions. Differences in Chlamydiae DNA detection between the case patients and the control subjects were analyzed using the Fisher exact test. All statistical tests were two-sided.
  
  
  RESULTS
  Thirty-two of the 40 (80%) ocular adnexal lymphoma samples carried C. psittaci DNA, whereas all lymphoma samples were negative for C. trachomatis and C. pneumoniae. In contrast, none of the 20 nonneoplastic orbital biopsies (0% versus 80%; P<.001) and only three of 26 (12%) reactive lymphadenopathy samples (12% versus 80%; P<.001) carried the C. psittaci DNA. Nine of 21 (43%) patients with chlamydia-positive lymphomas carried C. psittaci DNA in their PBMCs, whereas none (0%) of the healthy PBMC donors carried C. psittaci DNA in their PBMCs (43% versus 0%; P<.001). One month after doxycycline treatment, chlamydial DNA was no longer detectable in the PBMCs of all seven treated patients, and objective response was observed in two of the four evaluable patients.
  
  
  CONCLUSIONS
  Patients with ocular adnexal lymphoma had a high prevalence of C. psittaci infection in both tumor tissue and PBMCs. Persistent C. psittaci infection may contribute to the development of these lymphomas, as was also supported by the clinical responses observed in this study with C. psittaci-eradicating antibiotic therapy.
authors.affiliation: Department of Radiochemotherapy, San Raffaele H Scientific Institute, Milan, Italy. andres.ferreri@hsr.it
authors.forename: Andrés J M
authors.initials: AJ
authors.lastname: Ferreri
authors.forename: Massimo
authors.initials: M
authors.lastname: Guidoboni
authors.forename: Maurilio
authors.initials: M
authors.lastname: Ponzoni
authors.forename: Carlo
authors.initials: C
authors.lastname: De Conciliis
authors.forename: Stefania
authors.initials: S
authors.lastname: Dell'Oro
authors.forename: Katharina
authors.initials: K
authors.lastname: Fleischhauer
authors.forename: Laura
authors.initials: L
authors.lastname: Caggiari
authors.forename: Antonia A
authors.initials: AA
authors.lastname: Lettini
authors.forename: Elena
authors.initials: E
authors.lastname: Dal Cin
authors.forename: Rossella
authors.initials: R
authors.lastname: Ieri
authors.forename: Massimo
authors.initials: M
authors.lastname: Freschi
authors.forename: Eugenio
authors.initials: E
authors.lastname: Villa
authors.forename: Mauro
authors.initials: M
authors.lastname: Boiocchi
authors.forename: Riccardo
authors.initials: R
authors.lastname: Dolcetti
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D016022:Case-Control Studies; D002689:Chlamydia / Q000235:genetics / Q000302:isolation & purification*; D002690:Chlamydia Infections / Q000150:complications* / Q000188:drug therapy / Q000382:microbiology; D002692:Chlamydia trachomatis / Q000302:isolation & purification; D016993:Chlamydophila pneumoniae / Q000302:isolation & purification; D002691:Chlamydophila psittaci / Q000302:isolation & purification; D004269:DNA, Bacterial / Q000302:isolation & purification; D005134:Eye Neoplasms / Q000382:microbiology*; D005260:Female; D005784:Gene Amplification; D006801:Humans; D007150:Immunohistochemistry; D007963:Leukocytes, Mononuclear / Q000382:microbiology*; D008228:Lymphoma, Non-Hodgkin / Q000382:microbiology*; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial