Browsing by Author "Denti, Paolo"

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    Effects of pregnancy and isoniazid preventive therapy on mycobacterium tuberculosis interferon gamma response assays in women with HIV
    (Oxford University Press, 2020-07) Weinberg, Adriana; Aaron, Lisa; Montepiedra, Grace; Sterling, Timothy R.; Browning, Renee; Mmbaga, Blandina; Vhembo, Tichaona; Naik, Shilpa; Kabugho, Enid; Masheto, Gaerolwe; Pahwa, Savita; Mathad, Jyoti S.; LaCourse, Sylvia M.; McCarthy, Katie; Bradford, Sarah; Theron, Gerhard; Costello, Diane; Zimmer, Bonnie; Pierre, Marie F.; Gausi, Kamunkhwala; Denti, Paolo; Haas, David W.; Gupta, Amita
    Background Pregnancy is accompanied by immune suppression. We hypothesized that Mycobacterium tuberculosis-specific inflammatory responses used to identify latent tuberculosis infection (LTBI) lose positivity during pregnancy. We also hypothesized that isoniazid preventive therapy (IPT) may revert LTBI diagnoses because of its sterilizing activity. Methods 944 women with human immunodeficiency virus infection (HIV) participating in a randomized, double-blind, placebo-controlled study comparing 28 weeks of IPT antepartum versus postpartum, were tested by QuantiFERON-gold-in-tube (QGIT) antepartum and by QGIT and tuberculin skin test (TST) at delivery and postpartum. Serial QGIT positivity was assessed by logistic regression using generalized estimating equations. Results From entry to delivery, 68 (24%) of 284 QGIT-positive women reverted to QGIT-negative or indeterminate. Of these, 42 (62%) recovered QGIT positivity postpartum. The loss of QGIT positivity during pregnancy was explained by decreased interferon gamma (IFNγ) production in response to TB antigen and/or mitogen. At delivery, LTBI was identified by QGIT in 205 women and by TST in 113 women. Corresponding numbers postpartum were 229 and 122 women. QGIT and TST kappa agreement coefficients were 0.4 and 0.5, respectively. Among QGIT-positive women antepartum or at delivery, 34 (12%) reverted to QGIT-negative after IPT. There were no differences between women who initiated IPT antepartum or postpartum. Conclusions Decreased IFNγ responses in pregnancy reduced QGIT positivity, suggesting that this test cannot reliably rule out LTBI during pregnancy. TST was less affected by pregnancy, but had lower positivity compared to QGIT at all time points. IPT was associated with loss of QGIT positivity, the potential clinical consequences of which need to be investigated.
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    Pharmacokinetics and drug-drug interactions of abacavir and lamuvudine co-administered with antituberculosis drugs in HIV-positive children treated for multidrug-resistant tuberculosis
    (Frontiers Media S.A, 2021-10-08) Van der Laan, Louvina E.; Garcia-Prats, Anthony J.; Schaaf, H. Simon; Winckler, Jana L.; Draper, Heather; Norman, Jennifer; Wiesner, Lubbe; McIlleron, Helen; Denti, Paolo; Hesseling, Anneke C.
    Given the high prevalence of multidrug-resistant (MDR)-TB in high HIV burden settings, it is important to identify potential drug-drug interactions between MDR-TB treatment and widely used nucleoside reverse transcriptase inhibitors (NRTIs) in HIV-positive children. Population pharmacokinetic models were developed for lamivudine (n = 54) and abacavir (n = 50) in 54 HIV-positive children established on NRTIs; 27 with MDR-TB (combinations of high-dose isoniazid, pyrazinamide, ethambutol, ethionamide, terizidone, fluoroquinolones, and amikacin), and 27 controls without TB. Two-compartment models with first-order elimination and transit compartment absorption described both lamivudine and abacavir pharmacokinetics, respectively. Allometric scaling with body weight adjusted for the effect of body size. Clearance was predicted to reach half its mature value ∼2 (lamivudine) and ∼3 (abacavir) months after birth, with completion of maturation for both drugs at ∼2 years. No significant difference was found in key pharmacokinetic parameters of lamivudine and abacavir when co-administered with routine drugs used for MDR-TB in HIV-positive children.