The utility of bronchoalveolar lavage beta-D-glucan testing for the diagnosis of invasive fungal infections.

OBJECTIVES: To investigate the utility of beta-D-glucan (BDG) testing in bronchoalveolar lavage (BAL) fluid for the diagnosis of invasive fungal infection (IFI), as compared to BAL galactomannan (GM). METHODS: We retrospectively reviewed medical records of 132 consecutive patients at the National Institutes of Health (NIH) in whom BAL BDG testing was performed for diagnosis of pneumonia. Using the European Organization for Research and Treatment of Cancer/Mycoses Study Group guidelines, we determined which patients had proven or probable IFI, and assessed the diagnostic performance of BAL BDG testing, relative to BAL GM. We also determined the reproducibility of the BDG assay in BAL via repeat testing of patient samples. RESULTS: Ten patients had Pneumocystis pneumonia, and 34 patients had proven/probable IFI, including 14 with invasive aspergillosis (IA). BAL BDG was 100% sensitive for Pneumocystis. Although BAL BDG had similar sensitivity to BAL GM for the diagnosis of IA and IFI, it exhibited inferior specificity. Repeat testing demonstrated poor reproducibility of the BDG assay in BAL but not in serum. CONCLUSIONS: BDG testing exhibits poor specificity and reproducibility in BAL. Identification of the BAL-specific factors that may interfere with the performance of the assay could improve the clinical usefulness of BAL BDG testing.

Half- vs full-dose trivalent inactivated influenza vaccine (2004-2005): age, dose, and sex effects on immune responses.

BACKGROUND: Optimal public health strategies for managing influenza vaccine shortages are not yet defined. Our objective was to determine the effects of age, sex, and dose on the immunogenicity of intramuscular trivalent inactivated vaccine (TIV). METHODS: Healthy adults aged 18 to 64 years, stratified by age (18-49 and 50-64 years) and sex, were randomized to receive full- or half-dose TIV. Hemagglutination inhibition titers against vaccine antigens were measured before and 21 days after immunization. A primary outcome of noninferiority was defined as a difference of less than 20% in the upper 95% confidence interval (CI) of the proportion of subjects with strain-specific hemagglutination inhibition antibody titers of 1:40 or higher after vaccination. Secondary outcomes included geometric mean titers, after vaccination side effects, and occurrences of influenza-like illnesses. RESULTS: Among previously immunized subjects (N = 1114) receiving half- vs full-dose TIV (age, 18-49 years, n = 284 [half] and n = 274 [full]; and age 50-64 years, n = 276 [half] and n = 280 [full]), CIs for proportions of subjects with hemagglutination inhibition antibody titers of 1:40 or higher excluded substantial reduction for all antigens in the 18- to 49-year age group and for B/Shanghai/361/2002 (B) and A/Fujian/411/2002 (A/H3N2) in the 50- to 64-year age group. Geometric mean titer in the female 18- to 49-year age group exceeded male responses for all strains: responses to half-dose TIV that were comparable with male full-dose responses for A/New Caledonia/20/99 (A/H1N1) antigen, 25.4 (95% CI, 20.9-30.9) vs 25.6 (95% CI, 21.3-30.9); A/H3N2 antigen, 60.8 (95% CI, 50.8-72.7) vs 44.1 (95% CI, 37.6-51.8); and B antigen, 64.4 (95% CI, 53.9-76.9) vs 60.7 (95% CI, 51.4-71.7) (findings were similar for the 50- to 64-year age group). Some injection site and systemic reactions (myalgias and/or arthralgias [P < .05], headache [P < .001], and impact of fatigue [P < .05]) were significantly lower in men. The relative risk of medical visits and hospitalizations for influenza-like illnesses were similar in the half- and full-dose groups regardless of age. CONCLUSIONS: Antibody responses to intramuscular half-dose TIV in healthy, previously immunized adults were not substantially inferior to the full-dose vaccine, particularly for ages 18 to 49 years. Significantly higher geometric mean titer responses in women were identified for all ages, regardless of dose or influenza strain. Half-dose vaccination may be an effective strategy for healthy adults younger than 50 years in the setting of an influenza vaccine shortage.

Borrelia burgdorferi OspC protein required exclusively in a crucial early stage of mammalian infection.

This study demonstrates a strict temporal requirement for a virulence determinant of the Lyme disease spirochete Borrelia burgdorferi during a unique point in its natural infection cycle, which alternates between ticks and small mammals. OspC is a major surface protein produced by B. burgdorferi when infected ticks feed but whose synthesis decreases after transmission to a mammalian host. We have previously shown that spirochetes lacking OspC are competent to replicate in and migrate to the salivary glands of the tick vector but do not infect mice. Here we assessed the timing of the requirement for OspC by using an ospC mutant complemented with an unstable copy of the ospC gene and show that B. burgdorferi's requirement for OspC is specific to the mammal and limited to a critical early stage of mammalian infection. By using this unique system, we found that most bacterial reisolates from mice persistently infected with the initially complemented ospC mutant strain no longer carried the wild-type copy of ospC. Such spirochetes were acquired by feeding ticks and migrated to the tick salivary glands during subsequent feeding. Despite normal behavior in ticks, these ospC mutant spirochetes did not infect naive mice. ospC mutant spirochetes from persistently infected mice also failed to infect naive mice by tissue transplantation. We conclude that OspC is indispensable for establishing infection by B. burgdorferi in mammals but is not required at any other point of the mouse-tick infection cycle.