Impaired response to alloantigens in HIV positive hemophilic patients.

The alloantigen responses of hemophilic patients was evaluated using a unidirectional mixed lymphocyte culture (MLC). The results of this study indicate that both the ability of peripheral blood mononuclear cells (PBMC) to proliferate in response to alloantigens and the capacity to stimulate the MLC are impaired in hemophilic patients infected with the human immune deficiency virus (HIV). These defects cannot be overcome by addition of exogenous interleukin-2 (IL-2) and are not related to the absence of IL-2 receptors (IL-2R). Lack of response was evident in PBMC from HIV+ patients with a high proportion of IL-2R+ cells. The number of IL-2 cells was similar in HIV+ and HIV- individuals, and higher than that of normal controls. Impaired MLC proliferation was not related to the occurrence of clinical symptoms. Apparently, MLC is a useful procedure for distinguishing the cell mediated immunity defects associated with HIV infection and unrelated to replacement therapy in hemophilia patients.

Anti-class II antibodies in AIDS patients and AIDS-risk groups.

The specificity of anti-lymphocyte antibodies was evaluated in AIDS patients and in individuals at risk of AIDS [R-AIDS: male homosexuals (Ho) and haemophiliacs (He)]. Antibodies capable of inducing antibody-dependent cell-mediated cytotoxicity (ADCC) against non-T cells and lymphoblastoid cell lines (P3HR-1K and Raji) were detected in AIDS patients and in R-AIDS with positive or negative human immune deficiency virus (HIV) serology. Anti-class II antigen specificity was revealed by experiments in which class II antigens on target cells were blocked with monoclonal anti-class II antibody (DA6,231) and the cytotoxic reaction induced by patient's sera was abolished. In contrast, ADCC was not impaired by preincubating the target cells with anti-class I monoclonal antibody (W6/32). Prevalence of antibodies to non-T cells was confirmed by standard C-mediated microlymphocytotoxicity. However, with this technique anti-T lymphocyte cytotoxicity was also observed in three AIDS patients with haemophilia. R-AIDS peripheral blood mononuclear cells (PBMC) were also cytotoxic against autologous non-T cells, and lysis was slightly increased by sensitization of the target cells with autologous serum. In addition to ADCC and C-mediated cytotoxicity, the specificity of anti-lymphocyte antibodies was assayed by their ability to interfere the binding of fluorescein-labelled anti-class II (HLA-DR) and anti-class I (W6/32) monoclonal antibodies to PBMC, non-T cells, P3HR-1K and Raji. Anti-class II specificity was confirmed, and antibody titres tended to be higher in Ho than in He R-AIDS, using non-T cells and Raji as targets. Higher titres of anti-class II antibodies in the Ho group could play a role in the different susceptibility of HIV-infected Ho when compared to HIV (+) He to develop AIDS.

Detection of an atypical rotavirus associated with diarrhoea in Chaco, Argentina.

Recently some unusual human and animal rotaviruses have been described which, although indistinguishable from standard rotaviruses by electron microscopy (EM), fail to react with antibody directed against the rotavirus group antigen. The genome of these viruses is composed of 11 double-stranded (ds) RNA segments; these RNA segments display different patterns when analysed by means of polyacrylamide gel electrophoresis (PAGE). The electrophoretic profile of the ds RNA segments of those human, antigenically different, viruses reported up to now appear to fit into two different patterns. Faecal samples from children with diarrhoea from different geographical areas of Argentina were evaluated for the presence of rotaviruses, using EM, ELISA and PAGE. During this survey a rotavirus-like agent was detected in the faeces of a child with diarrhoea from Chaco province, North-East Argentine. The pattern of the ds RNA segment of this virus on PAGE analysis appeared to be related to one of the atypical rotaviruses. This is the first description of such a virus strain in Argentina.

Rotavirus infection in children hospitalized for diarrhoea in Argentina.

An epidemiological survey was undertaken to establish the importance of rotavirus as a cause of admission of children to hospital in Buenos Aires, Argentina. Between August 1978 and January 1980 rotavirus infection was detected in 62 (34%) of 180 infants and children admitted to hospital with acute gastro-enteritis. In identification of the virus, electron microscopy (EM) was found to be as sensitive as counterimmunoelectrophoresis (CIE). There was agreement between EM and CIE diagnosis in 90.5% cases. Adenovirus and coronavirus were detected by electron microscopy less often. A serological response to rotavirus was revealed by complement fixation test in 38 (72%) of 53 infected patients. Rotaviruses were detected throughout the year, but peak incidence occurred during the cooler months, May to August. Infection was commoner among children under six months of age. Diarrhoea was generally mild in these children and respiratory illness showed no significant association with rotavirus gastroenteritis. These results indicate that rotaviruses may be a major cause of infantile acute gastroenteritis in Buenos Aires, Argentina especially during the winter.

Rotavirus in Buenos Aires, Argentina.

Rotavirus was studied over a 1-year period in 141 hospitalized children suffering from gastroenteritis and in 120 control children. Electron microscopy and discontinuous counterimmunoelectrophoresis techniques were employed with equal success. Rotavirus was detected with high frequency in children suffering from diarrhea (45 cases; 32%) and in only 2 cases (1.6%) of the control group. A marked seasonal distribution, with 80% in July (winter) and a decrease (0%) in December (summer), was observed. The frequency of infection with rotavirus was highest in infants between 0 and 6 months of age. Seroconversion, studied by complement fixation, was obtained in 34 of 42 (80%) virus-positive children, and antibody without conversion was observed in 8 (19%). Of 58 virus-negative children, 51 (96.2%) were negative for antibody and only 2 (3.7%) developed antibody.