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Addition of methylated β-lactoglobulin (Met-BLG) in the medium of MDCK cell lines infected with influenza virus subtype H1N1 reduced hemagglutination activity (HA) in a concentration dependent manner. Antiviral activity of Met-BLG depended on its concentration, viral load, and duration of infection. Using 17 μg/ml of Met-BLG inhibited 50% of HA of H1N1 grown in MDCK cells at 1 MOI after 24 h incubation at 37°C and in 5% CO2. Extension of incubation time enhanced antiviral action since the same concentration of Met-BLG inhibited about 61% of viral activity after 48 h. This viral inhibition was accompanied by a protection of MDCK cells as observed by using neutral red or by direct microscope examination. Reduction of viral RNA replication upon the addition of Met-BLG (50 μg/ml) was observed by real time-PCR showing a reduction of viral log value of about 0·9. When viral stock solution was mixed with 25 μg/ml Met-BLG in absence of cell lines, the morphology and viability of virus particles were significantly affected as observed by electron microscopy, and the number of intact virus particles was reduced by roughly 65%.

A case of fatal Epstein-Barr virus infection in a previously healthy girl who was first found to have severe infectious mononucleosis with spontaneous recovery is reported. Because an abnormal immune response to the virus persisted, the disease relapsed, manifesting in cutaneous and pulmonary lesions associated with hemophagocytic syndrome responsible for death. Pathologic findings were characterized by polymorphous atypical lymphoid infiltrate, prominent necrosis, and histiocytic hyperplasia. Lymphoid cells displayed CD8 phenotype and clonal T-cell receptor gene rearrangement. Viral genome was detected in lesions by Southern blot and located in nuclei of lymphoid cells by in situ hybridization. Pathologic findings suggested fatal infectious mononucleosis; however, phenotype and genotype favored a malignant diagnosis. Clonality was demonstrated to have arisen during primary infection. Virologic examination indicated that Epstein-Barr virus was a causative agent. Such a process belongs to the recently recognized spectrum of Epstein-Barr virus-related T-cell lymphoproliferative disorders that might overlap fatal infectious mononucleosis in patients who are especially vulnerable to the virus.

Between September, 1987, and April, 1989, three techniques for the detection of respiratory syncytial virus (RSV) were compared: indirect immunofluorescence (IF) on the sample, indirect immunofluorescence after 72 h of MRC-5 cell culture (IF 72h), and detection of the cytopathic effect (CPE) by MRC-5 and HEp-2 cell culture. A study of 383 nasal aspirates from young children admitted to the Centre Hospitalier de Nantes (CHR) showing miscellaneous respiratory symptoms produced the following results: 143 samples (37%) were RSV positive by IF, 119 (31%) were positive by IF 72h, and 117 (31%) showed RSV-induced CPE. In comparison with tissue culture isolation (TC), the sensitivities of IF and IF 72h were 89% and 80% and their specificities 85% and 91%, respectively. During the winter of 1988-1989, of the 110 RSV-positive nasal aspirates (104 by IF, 89 by IF 72h, 83 by CPE detection), 109 were identified by IF and/or IF 72h. IF 72h affords rapid detection of RSV.