Expression of phagocyte Fcg receptors during anti-tuberculous treatment
Abstract number: P1943
Garcia-Egido A.A., Escobar M.A., Gomez-Soto F.J., Fernandez F.J., Puerto J.L., Asencio C., Andrey J.L., Ruiz P., Rosety M., 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 149 HIV-negative patients with TB (107 men and 42 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 name:||18th European Congress of Clinical Microbiology and Infectious Diseases|
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