[Viral diarrheas]. / Diarrhées virales.

It is now well known that several viruses are responsible for acute diarrhoea or gastroenteritis in both children and adults. These viruses are difficult to identify since most of them cannot be isolated by stool cultures on cells. The reality of proven reinfection by some of these organisms is not always clearly understood, even though the existence of several serotypes in the same group (notably rotavirus) can be blamed, and this explains why vaccines are difficult to develop.

Dot ELISA for direct detection of BK virus in urine samples.

The dot ELISA technique was applied for direct detection of BK virus in clinical urine samples. The assay was performed on nitrocellulose paper dotted with the polyethylene glycol precipitated urine samples free of cellular debris. BK virus was detected with an anti-BK virus monoclonal antibody, and the complex was visualized by immunoperoxidase staining. Positive reaction appeared as well-defined dark blue spots. Of the 110 urine samples examined, 31 were positive in the dot ELISA and 79 proved negative. Comparing with the IIF results, the dot ELISA had a 88.46% of sensibility and 90.4% of specificity, and the results agreed completely in 99 samples. The simple dot ELISA technique can be recommended for detection of BK virus excretion in routinary diagnostic.

BK virus (BKV) detection in urine specimens of immunocompromised patients: comparison between the DNA-DNA hybridization assay, the immunofluorescence test and the dot enzyme immunoassay.

Three methods used for the detection of BK virus in urine specimens, the indirect immunofluorescence test, the dot enzyme immunoassay and the DNA-DNA hybridization assay, were compared by testing specimens from 49 immunocompromised patients. All three assays were effective in detecting BK virus. The technical advantage of each of them was discussed. The immunofluorescence test was found to be the simplest one to perform; the DNA-DNA hybridization assay displayed exquisite sensitivity; and the easy reading of the dot enzyme immunoassay did not require the specialized training inherent to immunofluorescence assays. The dot enzyme immunoassay might therefore be the most practical method for screening urine specimens of immunocompromised patients, especially when the sediment is poor in cells. Conversely, the indirect immunofluorescence test might be the method of choice for checking patients with haemorragic cystitis whose urine samples usually contain large amounts of cells.

Follow-up of subjects with isolated and persistent anti-core (anti-p24 or anti-p17) antibodies to HIV.

Systematic screening of blood donations by enzyme-linked immunosorbent assay (ELISA) for HIV antibodies carries a false-positive rate: the sera involved react in Western blot to core antigens (p24 or p17) but reactivity to envelope is absent. We studied 22 subjects with persistent and isolated anti-core reactivities; 75 HIV seropositive patients were controls. The epidemiological data and the follow-up and biological tests performed in these two populations argue that donors with persistent and isolated anti-core antibodies are not seroconverting for HIV. We conclude: (1) that verification of all anti-HIV ELISA-positive sera by Western blot is essential and that the presence of at least once anti-envelope (gp120 or gp41) antibody is indispensable for the diagnosis of HIV infection; (2) that the solitary anti-p24 or anti-p17 bands observed on Western blot are false-positive. There is no evidence that donors with such reactivities are HIV-infected.

DNA hybridization for detection of human cytomegalovirus in bronchoalveolar lavage and pharynx biopsy.

A simplified hybridization procedure was used for detection of cytomegalovirus (CMV) in human specimens. The probe was a 32P-labelled cloned DNA fragment of CMV strain AD169. This probe did not hybridize to DNA from uninfected cells or other herpesviruses (herpes simplex virus, Epstein-Barr virus). Specific hybridization was obtained with unselected bronchoalveolar lavage specimens, but the sensitivity of the test (33%) was lower than that of culture (80%) and immunofluorescence (60%) assays which are routinely performed in our laboratory. The detection procedure was also carried out with pharynx biopsy specimens which had been kept frozen at -70 degrees C. CMV DNA was detected in 14% of tumour specimens and only in 1.7% of control specimens (p less than 0.05). The indications of DNA hybridization for CMV diagnosis are discussed.

Evaluation of three assays on alveolar lavage fluid in the diagnosis of cytomegalovirus pneumonitis after bone marrow transplantation.

Cytologic examination, immunofluorescence assays, and cultures for virus were compared prospectively in the detection of cytomegalovirus (CMV) in cells obtained by 41 bronchoalveolar lavages (BALs) from 30 bone marrow transplant recipients with pneumonia. No evidence of CMV was found in 21 BALs. Viral inclusions, positive immunologic assays, and positive cultures were found in 14, 15, and 18 BALs, respectively. Cytological and immunologic results were closely related except in one BAL. In five BALs, a positive culture for virus was the sole criterion noted for diagnosis of CMV. The patients with both cytologically and immunologically positive results were more likely to die with or from respiratory failure (P less than .05), diffuse interstitial patterns (P less than .01), and severe acute graft-vs.-host disease (P less than .02) than were the patients without any criterion for diagnosis of CMV. The discrepancies with the previously reported data, the interpretation of the three diagnostic procedures, and the ability of BAL to diagnose CMV pneumonia are discussed.

A new human adenovirus of subgenus D: candidate adenovirus type 42.

A new serotype, candidate adenovirus type 42, a member of subgenus D, was isolated from the feces of a healthy child. It shared its hemagglutinin with adenovirus type 15, but had no relationship in neutralization to other human adenoviruses. It also had a distinct DNA restriction pattern.

A one-year virological survey of acute intussusception in childhood.

A prospective study was carried out during 1 year in order to correlate intussusceptions in childhood with a viral infection. A virus was incriminated in 50% of the 64 patients in this survey. Adenovirus infections remain predominant as compared to rotavirus infections.

Control of BK virus antibodies in contacts of patients under chronic hemodialysis or after renal transplantation (by an enzyme linked immunosorbent assay).

Elisa technique for IgG humoral BK virus antibodies titration is not time consuming, not expensive and brings results in accordance with those obtained by HI. It was observed among adults attending patients in chronic hemodialysis and renal transplantation centers an antibody level similar to observed titers in control subjects.

[Virus infections in man during immunodepression (author's transl)]. / Les infections virales au cours de l'immunodépression en pathologie humaine

The authors review virus infections observed in patients undergoing immunosuppressive treatment. The herpes virus, in particular the cytomegalovirus, are the most important cause. However, the role of the virus itself in an unfavourable course is variously assessed. The mechanism of the virus infection is discussed, whether primary infection, exogenous or endogenous re-infection. The latter seems to be the most frequent, at least in the case of the herpes viruses.