High prevalence of Chlamydophila psittaci subclinical infection in Italian patients with Sjögren's syndrome and parotid gland marginal zone B-cell lymphoma of MALT-type.
OBJECTIVE
To assess Chlamydophila psittaci (Cp) subclinical infection in patients with Sjögren's syndrome (SS).


METHODS
Seventy-four SS patients (55.4 ±13.4 yrs; 94.6% females) were studied. Among them, 18 had salivary gland mucosa-associated lymphoid tissue (MALT) B-cell lymphoma, 20 myoepithelial sialoadenitis (MESA), and 36 no lymphoproliferative disorders (LPD). The presence of Cp DNA was assessed in peripheral blood of all patients by specific PCR protocols. Paired salivary gland samples were also investigated whenever available (34 cases), including lymphomatous and non-lymphomatous samples, as well as major and minor salivary gland tissues. As controls, 225 blood donors were analysed in the peripheral blood.


RESULTS
Overall, Cp DNA was detected in 11/74 (14.9%) SS patients vs. 1/225 (0.4%) controls (p<0.0001). Cp was detected at higher frequency in MALT lymphoma patients (6/18, 33.3%), as compared with MESA (3/20, 15%) or patients without LPD (2/36, 5.6%), (MALT lymphomas vs. others: p=0.02). A similar Cp prevalence was observed in blood vs. salivary gland tissues, however with a higher frequency in the major than in the minor salivary glands (5/18, 27.8%, vs. 1/17, 5.9%, p=0.18). Cp-positive patients were all rheumatoid factor positive (11/11, 100% vs. 40/63, 63.5% Cp-negative; p=0.014), while no difference was noticed for anti-SSA/SSB positivity.


CONCLUSIONS
In the light of accepted models of MALT B-cell lymphomagenesis and considering previous data implicating Cp infection in ocular adnexa MALT lymphoma, our results suggest that Cp infection could be involved also in a fraction of patients with SS developing lymphoma. The potential therapeutic implications of these findings appear worthwhile.
Institute of Clinical Pathology and Clinic of Rheumatology, University Hospital of Udine, Italy. fabris.martina@aoud.sanita.fvg.it.
Martina
M
Fabris
Riccardo
R
Dolcetti
Elisa
E
Pasini
Luca
L
Quartuccio
Elena
E
Pontarini
Sara
S
Salvin
Maurilio
M
Ponzoni
Cathryn Anne
CA
Scott
Salvatore
S
De Vita
D000328:Adult; D000368:Aged; D058345:Asymptomatic Infections; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D002691:Chlamydophila psittaci / Q000235:genetics / Q000302:isolation & purification*; D004269:DNA, Bacterial / Q000097:blood; D005260:Female; D006801:Humans; D007558:Italy / Q000453:epidemiology; D042583:Lymphangiogenesis; D018442:Lymphoma, B-Cell, Marginal Zone / Q000175:diagnosis / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D010307:Parotid Neoplasms / Q000175:diagnosis / Q000453:epidemiology*; D016133:Polymerase Chain Reaction; D015995:Prevalence; D009956:Psittacosis / Q000175:diagnosis / Q000453:epidemiology* / Q000382:microbiology; D012307:Risk Factors; D012859:Sjogren's Syndrome / Q000175:diagnosis / Q000453:epidemiology*
D015415:Biomarkers; D004269:DNA, Bacterial