The importance of nonrenal involvement in hemolytic-uremic syndrome.

Fifteen children with the clinical manifestations of hemolytic-uremic syndrome are reported. Prompt recognition of the syndrome and effective therapy for acute renal failure including early dialysis were instituted in each case. Analysis of the clinical course and histopathologic features in these patients indicated that early dialysis and effective management of acute renal failure may unmask evidence of nonrenal involvement; microthrombi may be found in a wide distribution of organs, including the brain and myocardium; and extent and severity of nonrenal involvement become an important determinant of ultimate prognosis.

Rapid subtyping of influenza A virus isolates by membrane fluorescence.

During the winter of 1977-1978 three influenza A virus serotypes (A/Vic/3/75, A/Texas/1/77 [both H3N2], and A/USSR/90/77 [H1N1]) circulated in Denver, offering us the opportunity to apply fluorescent antibody techniques to the specific identification of these viruses. Surface antigens of infected, unfixed primary monkey kidney cells were stained in suspension by an indirect immunofluorescence technique with anti-H3N2 and anti-H1N1 antisera. In tests of cells infected with known viruses, the members of the H3N2 family could not be distinguished from one another, but were easily distinguished from H1N1 strains. A total of 101 hemadsorption-positive clinical specimens were evaluated over a 6-month period. Forty-five of 48 influenza A H3N2 and 24 of 29 H1N1 specimens confirmed by hemagglutination inhibition were correctly identified by membrane fluorescence of cultured cells, with no misidentifications among influenza strains and with 1 false positive among 24 non-influenza isolates. The average time to identification by this technique was 4 days compared to 7 days by hemagglutination inhibition. Live cell membrane fluorescence is a simple, rapid, and accurate method for identifying and grouping influenza A viruses.

Cryopreservation of virus-infected cells for use in the fluorescent antibody to membrane antigen test.

Tissue culture cells infected with varicella-zoster, respiratory syncytial, para-influenza types 1, 2, and 3, and influenza A/Texas/1/77 and A/USSR/90/77 viruses were exposed to ultraviolet light and frozen in the presence of a final concentration of 20% glycerol. These cells were quick thawed at 37 degrees C and compared with freshly prepared, living infected tissue culture cells in assays of fluorescence antibodies to membrane antigens of the infecting agents in serum, nasal wash secretions, colostrum, and breast milk. Frozen cells performed as efficiently as fresh cells as targets and retained their activity for long periods of time. Cryopreservation combined with photoinactivation of infected target cells allows this useful antibody test to be performed in routine serology laboratories.

Viral vaccination via the mucosal routes.

Viral vaccines have been successfully administered by the mucosal route for two decades now. However, only in the last 10 years have the concepts involved in mucosal immunocompetence been well characterized. It is apparent that the bronchus-associated lymphoid tissue, the gut-associated lymphoid tissue, and the immunocompetent cells present in ocular tissue, conjunctiva, nasopharynx, genital tract, and secretions of the mammary glands represent the components of the common mucosal immune system. The predominant immunologic activity in the external mucosal surfaces is associated with secretory IgA and T lymphocytes, with variable contributions from other immunoglobulins and macrophages. Evidence presented in this review suggests that immunization via the mucosal routes of the respiratory and gastrointestinal tracts is the most effective means of inducing effective immunity in the mucosal surfaces as well as in the systemic tissues. Available experience with mucosal immunization with poliovirus, rubella virus, measles virus, and adenovirus vaccines in humans and with other viral vaccines in animals is briefly reviewed.

Toxic-shock syndrome associated with phage-group-I Staphylococci.

Seven children (aged 8--17 years) presented with a high fever, headache, confusion, conjunctival hyperaemia, a scarlatiniform rash, subcutaneous oedema, vomiting, watery diarrhoea, oliguria, and a propensity to acute renal failure, hepatic abnormalities, disseminated intravascular coagulation, and severe prolonged shock. One patient died, one had gangrene of the toes, and all have had fine desquamation of affected skin and peeling of palms and soles during convalescence. Five patients were studied prospectively. Staphylococcus aureus related to phage-group I was isolated from mucosal (nasopharyngeal, vaginal, tracheal), or sequestered (empyema, abscess) sites, but not from blood. This organism produces an exotoxin which causes a positive Nikolsky sign in the newborn mouse and which is biochemically, pathologically, and immunologically distinct from phage-group-II stapphylococcal exfoliatin.

Behavior of respiratory syncytial virus in piglet tracheal organ culture.

Piglet tracheal organ cultures were infected with respiratory syncytial virus (RSV) and observed for 21 days. Light and immunofluorescence microscopy demonstrated destruction of the ciliated epithelial cells and the presence of viral antigens in the epithelium. Virus was shed in high titer for 12--19 days. Ciliostasis could be quantitated, and it was shown that several strains of RSV grew and damaged tracheal organ cultures in a similar fashion. A temperature-sensitive mutant of RSV, ts-1, was examined at permissive (33 C) and restrictive (37 C) temperatures. This mutant, although somewhat attenuated at 37 C, was still found to cause damage to the ciliated epithelium and to replicate at both temperatures. THIS BEHAVIOR IS SIMILAR TO THAT AFTER INOCULATION OF TS-1 INTO VOLUNTEERS. This in vitro model may prove useful in the study of RSV disease and in the evaluation of candidate live virus vaccines.

Activation of complement by cells infected with respiratory syncytial virus.

The ability of respiratory syncytial virus (RSV)-infected HE(p)-2 cells in culture to activate complement was investigated. After incubation of cells with various complement sources and buffer, binding of C3b to surfaces of infected cells was demonstrated by immunofluorescence with a double-staining technique. Nonsyncytial and syncytial (i.e., fused, multinucleated) cells were separately enumerated. Also, lysis of RSV-infected cells was assessed by lactic dehydrogenase release. In this system only RSV-infected cells stained for C3b, and they did so only after incubation with functionally active complement. Blocking of classical pathway activation with ethylenediaminetetraacetic acid diminished the number of infected nonsyncytial cells positively stained for C3b, but had no effect on staining of syncytial cells. Blocking of alternative pathway activation with either zymosan incubation or heat treatment decreased the number of both syncytial and nonsyncytial cells stained for C3b. Decreasing immunoglobulin concentration of the serum used as the complement source also decreased numbers of both cell types stained for C3b. Eliminating specific anti-RSV antibody diminished numbers of both cell types stained for C3b, but staining was not eliminated. Lastly, incubation with functionally active complement markedly increased lactic dehydrogenase release from infected cells. This study demonstrated that RSV-infected nonsyncytial and syncytial cells are able to activate complement by both classical and alternative pathways. Activation of complement by syncytial cells appears to be less dependent on the classical pathway than is activation by nonsyncytial cells, and activation by syncytial cells may require immunoglobulin but not specific antibody. These experiments suggest the possibility of complement activation during respiratory tract infection by RSV. Implications of this are discussed.

Detection of respiratory syncytial virus in nasal secretions from infants by enzyme-linked immunosorbent assay.

An enzyme-linked immunosorbent assay (ELISA) was developed for detection of respiratory syncytial virus (RSV) in nasal secretions from infants with respiratory disease. RSV was detected in 23 of 29 secretions positive for RSV by tissue culture and in one of 36 samples negative for RSV by tissue culture. The ELISA was a simple rapid, and surprisingly sensitive test for identification of RSV infection in infants.

Bronchomammary axis in the immune response to respiratory syncytial virus.

The products of lactation from 26 nursing mothers were sequentially examined over several months for the presence or appearance of antibodies directed against respiratory syncytial virus. Antiviral IgM and IgG were rarely identified in either colostrum or milk. RSV-specific IgA was found in 75% (18/24) of specimens of colostrum; 40% (6/15) and 59% (4/7) of milk samples obtained at three and six months still contained specific IgA antibody. The latter increase was felt to represent boosting of exposed individuals when the virus was present in the community. Infection with the virus was documented in two mothers. Both had specific IgG, IgM, and IgA antibody responses in serum and nasopharyngeal secretions, but response in milk was limited to IgA. These data confirm that antibody to a specific respiratory tract pathogen is present in the products of lactation, that the specific activity is mainly of the IgA class, and that booster responses in milk are exclusively of the IgA class. Since RSV appears to replicate only in the respiratory tract, it is suggested that viral specific antibody activity observed in the mammary gland may be derived from the bronchopulmonary lymphoid tissue.