Chlamydia infection and lymphomas: association beyond ocular adnexal lymphomas highlighted by multiple detection methods.
OBJECTIVE
Chlamydia psittaci (Cp) has been associated to ocular adnexal lymphomas (OAL) with variable geographic distribution. Herein, we used multiple Chlamydia detection tools to identify Cp elementary bodies-containing cell and to assess Cp prevalence in both nodal and extranodal lymphomas.


METHODS
TETR-PCR, immunohistochemistry, immunofluorescence, electron microscopy, and laser-capture microdissection were done in 35 OALs to define their effect in Chlamydia detection and, moreover, to identify the Cp cellular carrier. Cp prevalence was screened by TETR-PCR in 205 extraorbital lymphomas and 135 nonneoplastic controls.


RESULTS
Twenty-six (74%) OALs were associated with Cp infection: immunohistochemistry, immunofluorescence, and laser-capture microdissection-assisted PCR showed that monocytes/macrophages were the Cp carriers; electron microscopy showed the presence of intact Cp elementary bodies into these cells. Immunohistochemistry and TETR-PCR showed a 70% concordance rate (P = 0.001). Cp DNA was equally prevalent in non-OAL, nodal, and extranodal lymphomas: among the latter, it was more common in diffuse large B-cell lymphomas of the skin (P = 0.03) and Waldeyer's ring.


CONCLUSIONS
This multiparametric approach shows, for the first time, that monocytes/macrophages are the carriers of Cp, Cp seems preferentially associated with lymphomas arising in organs primarily exposed to antigens. The clinical implications of these findings deserve to be prospectively investigated.
Ponzoni
Maurilio
M
Pathology Unit, San Raffaele Scientific Institute, Milano, Italy. ponzoni.maurilio@hsr.it
Ferreri
Andrés J M
AJ
Guidoboni
Massimo
M
Lettini
Antonia A
AA
Cangi
Maria Giulia
MG
Pasini
Elisa
E
Sacchi
Luciano
L
Pecciarini
Lorenza
L
Grassi
Stefano
S
Dal Cin
Elena
E
Stefano
Rosalba
R
Magnino
Simone
S
Dolcetti
Riccardo
R
Doglioni
Claudio
C
D002690:Chlamydia Infections / Q000453:epidemiology*; D002691:Chlamydophila psittaci / Q000235:genetics / Q000302:isolation & purification; D004269:DNA, Bacterial / Q000032:analysis; D005134:Eye Neoplasms / Q000453:epidemiology* / Q000382:microbiology; D006801:Humans; D008223:Lymphoma / Q000453:epidemiology* / Q000382:microbiology; D008264:Macrophages / Q000382:microbiology; D009000:Monocytes / Q000382:microbiology; D016133:Polymerase Chain Reaction; D009956:Psittacosis / Q000453:epidemiology
D004269:DNA, Bacterial