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Expression of phagocyte Fcg receptors during anti-tuberculous treatment

Abstract number: 1733_1507

Escobar M.A., Garcia-Egido A.A., Gomez-Soto F.M., Fernandez F.J., Puerto J.L., Ruiz P., Rivera C., Gomez F.

Receptors for IgG (FcgRs) on phagocytic cells are important in host defence against infection.

Objectives: We have studied the expression of FcgRs by peripheral blood monocytes (M), M cultured for 72 hours (M/Mø), and granulocytes (G) in patients with active Tuberculosis (TB), during anti-TB therapy (anti-TB-Rx) and, after completition of anti-TB-Rx.

Methods: The expression of the three type of FcgRs, FcgRI, FcgRII and FcgRIII, on M, M/Mø and G were analysed by flow cytometry in 103 HIV-negative patients with TB (77 men and 26 women), at diagnosis, and monthly thereafter until completition of anti-TB-Rx. FcgRs expression was assessed on resting M, M/Mø and G, and on these cells after stimulation by culture with IFNg.

Results: The expression of FcgRI and FcgRIII by M, M/Mø and G was enhanced in patients with active TB by: 42±4% and 22±2% for M, respectively (p < 0.001), 56±6% and 41±4% for M/Mø, respectively (p < 0.001) and, 119±9% and 37±3% for G, respectively (p < 0.001). The expression of FcgRIIA by M, M/Mø and G was decreased by -31±1% (p = 0.02), -46±3% (p < 0.001), and -23±1% (p = 0.002), respectively. These alterations of FcgRs expression normalised from the 8th week until the end of effective anti-TB-Rx. The expression of FcgRI, FcgRIIA and FcgRIII by M, M/Mø or G from patients with active TB was significantly increased by culture in the presence of IFNg (p < 0.001), returning to normal after 8 wks of anti-TB-Rx. Setting a cut-off value =25% of the mean fluorescence intensity over controls for FcgRs surface expression and, assuming a prevalence range of active TB between 25 and 80% among patients undergoing confirmatory tests, results in a range of sensitivity, specificity, positive and, negative predictive values of: 57–96%, 48–97%, 34–74%, and 59–98%, respectively for M-FcgRIIA, 48–73%, 51–96%, 38–74% and 68–97%, respectively for M-FcgRIII, 31–58%, 64–93%, 37–79% and 69–95%, respectively for G-FcgRI and, 52–71%, 88–98%, 49–77% and 81–93%, respectively for G-FcgRIIB.

Conclusions: Mø and G from patients with active TB exhibit an altered expression of FcgRs that disappear after effective anti-TB-Rx. Thus, Mø and G FcgRs expression may help in predicting the response to anti-TB therapy.

Session Details

Date: 31/03/2007
Time: 00:00-00:00
Session name: European Society of Clinical Microbiology and Infectious Diseases
Subject:
Location: ICC, Munich, Germany
Presentation type:
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