SYNOVIAL CHLAMYDIA-TRACHOMATIS IN PATIENTS WITH REACTIVE ARTHRITIS REITERS-SYNDROME ARE VIABLE BUT SHOW ABERRANT GENE-EXPRESSION

Objective, We used reverse transcription-polymerase chain reaction (RT -PCR) assays to assess expression of genes from Chlamydia trachomatis in synovial tissues of patients with reactive arthritis (ReA)/Reiter's syndrome (RS) to determine viability/metabolic activity of the bacter ium in joints of infected patients. Methods. Synovial biopsies were ob tained from 18 patients with ReA, RS, or other arthriticies; nucleic a cids from 16 samples were PCR positive for chlamydial chromosomal DNA, RT-PCR assays targeting primary transcripts from C. trachomatis rRNA operons, and mRNA from the bacterial ompI, hsp60, glyQS, and r-protein S5 and L5 genes, were used to characterize viability/metabolic activi ty. Host actin mRNA was assessed as control in each sample preparation . Results, RT-PCR of host cell actin mRNA in the 18 patient samples co nfirmed the quality of all RNA preparations. RNA from 14/16 PCR positi ve samples was positive by RT-PCR for chlamydial rRNA primary transcri pts. Each of these same 14 samples was also RT-PCR positive in assays targeting glyQS, r-protein S5 and L5,and hsp60 mRNA. However, none of the 14 samples showing chlamydial rRNA and mRNA was positive for ompl transcripts. Conclusion, Synovial chlamydia are viable/metabolically a ctive, since primary rRNA transcripts and mRNA from chlamydial genes s pecifying components of the bacterial protein synthetic system were pr esent in most patient samples assayed. Expression of ompl, encoding th e major outer membrane protein, is strongly attenuated in persistently infecting synovial chlamydia, while that of hsp60, specifying a highl y immunogenic heat shock protein of the organism, is not downregulated .