Ectopic expression of murine CD163 enables cell-culture isolation of lactate dehydrogenase-elevating virus 63 years after its discovery

IMPORTANCE

Mouse models of viral infection play an especially large role in virology. In 1960, a mouse virus, lactate dehydrogenase-elevating virus (LDV), was discovered and found to have the peculiar ability to evade clearance by the immune system, enabling it to persistently infect an individual mouse for its entire lifespan without causing overt disease. However, researchers were unable to grow LDV in culture, ultimately resulting in the demise of this system as a model of failed immunity. We solve this problem by identifying the cell-surface molecule CD163 as the critical missing component in cell-culture systems, enabling the growth of LDV in immortalized cell lines for the first time. This advance creates abundant opportunities for further characterizing LDV in order to study both failed immunity and the family of viruses to which LDV belongs, Arteriviridae (aka, arteriviruses).

Viscerotropic disease following yellow fever vaccination in Peru

Five suspected cases of yellow fever vaccine-associated viscerotropic disease (YEL-AVD) clustered in space and time following a vaccination campaign in Ica, Peru in 2007. All five people received the same lot of 17DD live attenuated yellow fever vaccine before their illness; four of the five died of confirmed YEL-AVD. The surviving case was classified as probable YEL-AVD. Intensive investigation yielded no abnormalities of the implicated vaccine lot and no common risk factors. This is the first described space-time cluster of yellow fever viscerotropic disease involving more than two cases. Mass yellow fever vaccination should be avoided in areas that present extremely low risk of yellow fever.

Fatal multiorgan failure due to yellow fever vaccine-associated viscerotropic disease

Yellow fever vaccine-associated viscerotropic disease (YEL-AVD) is a rare complication of yellow fever (YF) vaccination. A previously healthy 22-year-old female died following YF vaccination despite aggressive measures. Serial viral load titers, cytokine levels and host genetic factors were evaluated in an attempt to understand this unusual and lethal outcome. The patient's high-titer vaccine viremia and possibly related minor genetic anomalies provide clues to exploring the etiology of YEL-AVD.

Analysis of the structure and folding of the 3' genomic RNA of flaviviruses

The structure of the 3' genomic RNA of flaviviruses has been analyzed by thermal melting, and by chemical and enzymatic probing of model RNAs. The 3' RNA had more transitions than could be assigned to individual stem-loops and a transition in the 40-45 degrees C range was assigned to tertiary structure unfolding. In support of this assignment, mutants designed to destabilize the proposed pseudoknot tertiary structure lose the 40-45 degrees C transition. Enzyme cleavage of the RNA and chemical probing as a function of temperature also support a pseudoknot tertiary structure for the 3' flavivirus RNA.

Clinical utility of open lung biopsy for undiagnosed pulmonary infiltrates

Open lung biopsy (OLB) is often performed as the definitive diagnostic procedure in patients with undiagnosed pulmonary infiltrates, but controversy exists as to the clinical utility of this practice. A retrospective review of 50 consecutive patients who underwent OLB for undiagnosed pulmonary infiltrates was done to assess the diagnostic value as well as the frequency with which these results affected therapy and mortality. Histologic tissue diagnoses were obtained in all patients. Specific pathologic diagnoses were obtained in 56% of patients, nonspecific in 44%. Lobar or lateralized infiltrates were more likely to yield a specific diagnosis (87%) than diffuse, bilateral infiltrates (42%). Thirty-four patients (68%) had previously had a nondiagnostic transbronchial biopsy; 58% of these patients had a specific diagnosis established by OLB. Twelve patients (24%) were in acute respiratory failure at the time of OLB; this group had a 50% mortality rate as compared with only 2.6% for patients not in acute respiratory failure (p less than 0.01). Therapy was altered (new specific or nonspecific treatment initiated or therapy withdrawn) in 78% of patients undergoing OLB. Thirty-day in-hospital survival was significantly higher in patients for whom either specific or nonspecific therapy was indicated and initiated versus those in whom no therapy was initiated or all therapy was withdrawn (mortality: 5.5% versus 35.7%; p = 0.01). Mortality was not related to the presence of immunosuppression or to the finding of a specific diagnosis. The overall mortality rate of 14% in this series compares favorably with mortality rates found in similar series, reflecting differences in patient populations and possibly the timing of intervention. OLB remains a clinically valuable diagnostic tool in selected patients.

Comparative therapeutic efficacy of recombinant interferons-alpha, -beta, and -gamma against alphatogavirus, bunyavirus, flavivirus, and herpesvirus infections

Recombinant (r) preparations of interferons (IFN)-alpha, -beta, and -gamma were shown to protect mice against experimental virus infections with herpes simplex virus type 2 (HSV-2), and with three RNA-containing viruses from different families: Banzi, a flavivirus; Semliki Forest virus (SFV), an alphatogavirus; and Caraparu, a bunyavirus. The antiviral effects of the three different types of IFN were different with each virus. HSV-2 was the most sensitive virus, followed by SFV. Against Banzi virus, IFN-gamma was only effective when given both before and after infection. Against Caraparu virus, only IFN-gamma had a significant effect. These results suggest that IFN therapy might be valuable in human infections with these viruses, but that the correct choice of IFN and dose regimen is likely to be important.