Browsing by Author "Lantos, PM"

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    Erythrocyte invasion profiles are associated with a common invasion ligand polymorphism in Senegalese isolates of Plasmodium falciparum.
    (Parasitology, 2009-01) Lantos, PM; Ahouidi, AD; Bei, AK; Jennings, CV; Sarr, O; Ndir, O; Wirth, DF; Mboup, S; Duraisingh, MT
    Plasmodium falciparum parasites use multiple ligand-receptor interactions to invade human erythrocytes. Variant expression levels of members of the PfRh and PfEBA ligand families are associated with the use of different erythrocyte receptors, defining invasion pathways. Here we analyse a major polymorphism, a large sequence deletion in the PfRh2b ligand, and erythrocyte invasion profiles in uncultured Senegalese isolates. Parasites vary considerably in their use of sialic acid-containing and protease-sensitive erythrocyte receptors for invasion. The erythrocyte selectivity index was not related to invasion pathway usage, while parasite multiplication rate was associated with enhanced use of a trypsin-resistant invasion pathway. PfRh2b protein was expressed in all parasite isolates, although the PfRh2b deletion was present in a subset (approximately 68%). Parasites with the PfRh2b deletion were found to preferentially utilize protease-resistant pathways for erythrocyte invasion. Sialic acid-independent invasion is reduced in parasites with the PfRh2b deletion, but only in isolates derived from blood group O patients. Our results suggest a significant role for PfRh2b sequence polymorphism in discriminating between alternative erythrocyte receptors for invasion and as a possible determinant of virulence.
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    Poor Positive Predictive Value of Lyme Disease Serologic Testing in an Area of Low Disease Incidence.
    (Clin Infect Dis, 2015-11-01) Lantos, PM; Branda, JA; Boggan, JC; Chudgar, SM; Wilson, EA; Ruffin, F; Fowler, VG; Auwaerter, PG; Nigrovic, LE
    BACKGROUND: Lyme disease is diagnosed by 2-tiered serologic testing in patients with a compatible clinical illness, but the significance of positive test results in low-prevalence regions has not been investigated. METHODS: We reviewed the medical records of patients who tested positive for Lyme disease with standardized 2-tiered serologic testing between 2005 and 2010 at a single hospital system in a region with little endemic Lyme disease. Based on clinical findings, we calculated the positive predictive value of Lyme disease serology. Next, we reviewed the outcome of serologic testing in patients with select clinical syndromes compatible with disseminated Lyme disease (arthritis, cranial neuropathy, or meningitis). RESULTS: During the 6-year study period 4723 patients were tested for Lyme disease, but only 76 (1.6%) had positive results by established laboratory criteria. Among 70 seropositive patients whose medical records were available for review, 12 (17%; 95% confidence interval, 9%-28%) were found to have Lyme disease (6 with documented travel to endemic regions). During the same time period, 297 patients with a clinical illness compatible with disseminated Lyme disease underwent 2-tiered serologic testing. Six of them (2%; 95% confidence interval, 0.7%-4.3%) were seropositive, 3 with documented travel and 1 who had an alternative diagnosis that explained the clinical findings. CONCLUSIONS: In this low-prevalence cohort, fewer than 20% of positive Lyme disease tests are obtained from patients with clinically likely Lyme disease. Positive Lyme disease test results may have little diagnostic value in this setting.
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    Response of the Infectious Diseases Society of America Lyme disease review panel to Johnson and Stricker
    (Clinical Infectious Diseases, 2010-11-01) Lantos, PM; Charini, WA; Medoff, G; Moro, MH; Mushatt, DM; Parsonnet, J; Sanders, JW; Baker, CJ