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Biomedical subjects

C Casavant

Publications and source records attributed to C Casavant.

6 recordsLinked to original sources

Risk of seroconversion for acquired immunodeficiency syndrome (AIDS) in San Francisco health workers.

The occupational risk of acquiring acquired immunodeficiency syndrome (AIDS) virus infection in health workers exposed to AIDS patients and specimens was assessed by a serologic study at San Francisco General Hospital and collaborating research laboratories. A total of 101 medical workers without risk factors for AIDS were examined for antibodies to two isolates of the AIDS retrovirus (AIDS-associated retrovirus 2[ARV-2] and human T cell lymphotropic virus III). Most had heavy, long-term exposure to AIDS patients and 29 had been exposed by needlestick or mucocutaneous accident. None of the 101 had antibodies to ARV-2 by immunofluorescence or to HTLV-III by enzyme-linked immunosorbent assay and Western Blot.

Acquired Immunodeficiency Syndrome↗

AIDS-associated retroviruses (ARV) can productively infect other cells besides human T helper cells.

We have examined the host range of AIDS-associated retroviruses (ARV) that are known to infect human T cells of the helper subset. We have observed that the virus cannot infect fibroblast and epithelial cell lines of many different animal species. It is infectious and replicates efficiently in peripheral mononuclear cells (PMC) of chimpanzee and at low levels in baboon and rhesus monkey PMC. Most importantly, it has been found to replicate in established lines of human B cells, monocytes, and promyelocytes. This ability to infect these other cell types appears to be associated, in most cases, with the presence of the Leu 3 T helper cell antigen on the cell surface. Other mechanisms for virus infection, however, may be involved. The results suggest that ARV will be found in other cells of AIDS patients, besides T cells, and that these cells could be the reservoir for continual virus spread in the host. Variations in the replicative ability of ARV isolates in human cells have also been noted; they could reflect potentially important pathogenic differences among these human retroviruses.

Animals↗

Cytomegalovirus infection and abnormal T-lymphocyte subset ratios in homosexual men.

T-helper:T-suppressor cell ratios of 1 or less were found in 2 of 42 homosexual men without antibodies to cytomegalovirus but in 33 of 67 homosexual men with antibodies (p less than 0.001). Of 34 men without antibody who were followed prospectively, 12 became seropositive for cytomegalovirus and all 12 developed helper: suppressor ratios of less than 1.0. These ratios remained at 1 or less for an average of 9.6 months but persisted for 15 months or more in 3 men. None of the men in the prospective study developed antibodies to the acquired-immunodeficiency-syndrome-associated retrovirus. These results indicate that in the homosexual men studied, abnormally low T-lymphocyte helper: suppressor ratios occurred almost exclusively in those who were infected with cytomegalovirus, and in those prospectively followed low ratios did not reflect contact with the syndrome-associated retrovirus. Abnormal ratios were rarely seen in men who had never been exposed to cytomegalovirus. Thus, cytomegalovirus infection may be an important cofactor in the immunologic disorders leading to the acquired immunodeficiency syndrome.

Antibodies, Viral↗

Acquired immune dysfunction in homosexual men: immunologic profiles.

Homosexual men with Kaposi sarcoma, lymphadenopathy syndrome, opportunistic infection, and nonhomosexual traditional Kaposi sarcoma were evaluated for B cell, T cell, and complement immunity and compared to normal controls and homosexual controls. No significant immunologic abnormalities were found in the traditional Kaposi group. All homosexual groups, including the homosexual controls, had a significant decrease in the helper/suppressor cell ratio. Functional abnormalities of T-cell immunity were observed in the homosexual Kaposi sarcoma, lymphadenopathy syndrome, and opportunistic infection groups. Significant elevations of IgG, IgM, IgA, and IgE were found in the lymphadenopathy group, while only IgG and IgA were elevated in the Kaposi sarcoma group. C3, C4, and immune complexes were normal, while total hemolytic complement activity was increased in the Kaposi sarcoma and lymphadenopathy syndrome groups.

Acquired Immunodeficiency Syndrome↗

Outbreak of Burkitt's-like lymphoma in homosexual men.

Four cases of Burkitt's-like lymphoma (undifferentiated, monoclonal, B-cell tumours) in homosexual men were seen in a 9-month period in San Francisco. One tumour contained both Epstein-Barr-virus nuclear antigen (EBNA) and cytomegalovirus (CMV) antigen. Another tumour contained EBNA, and a third contained no viral antigen, but EBNA and CMV antigens were detected in the overlying epithelium. This outbreak widens the array of neoplasms affecting immunosuppressed homosexual men and provides further evidence of an oncogenic role for EBV and CMV.

Adult↗