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Biomedical subjects

C D Severson

Publications and source records attributed to C D Severson.

7 recordsLinked to original sources
PubMed1977

Microgranulocytotoxicity.

The microcytotoxicity assay technique has been extensively refined to permit the use of granulocytes as target cells in an effort to identify neutrophil-specific antigens. Virtually every aspect of the test required revision to obtain clear, reproducible results. The most radical modification was the adoption of double-fluorescent vital staining to detect cytotoxicity. The reactions detected with this new assay did not correlate with defined human histocompatibility systems (e.g., HLA, ABH, NA, NB, NC), nor were the target antigens detected on lymphocytes or platelets. Cytotoxicity was highly specific and was produced by the immunoglobulin fraction of alloantisera only in the presence of complement, thus implicating an antigen-antibody phenomenon rather than variable viability of the ephemeral PMN's in vitro. These specificities may have an impact on some aspects of human transplantation (especially of bone marrow) as well as playing a role in some febrile transfusion reactions. Of perhaps greater import is the suggested role of the antigens in immunoneutropenias and therefore in the response of myelosuppressed patients to adjunctive leukocyte transfusion therapy.

Antigen-Antibody Reactions↗
PubMed1976

Antileukocyte antibody in postpartum and renal transplant subjects. A comparison of capillary agglutination and lymphocytotoxicity reactions.

Sera were obtained from 48 gravida II prenatal and 211 multiparous nonpregnant females and examined for leukocyte antibodies comparing a standard lymphocytotoxicity (CY) test with capillary agglutination (CA). Antibody was detected in 41% of the samples in both groups but only CA tests were positive with approximately one-half of the prenatal and three-fourths of the multiparous specimens. Although, CA reactions, when accompanied by positive CY responses, usually correlated with HLA, no correlation with HLA, 5b, or the neutrophil antigens was determined for 35 of the 48 sera reacting only by CA. As a model to test the specificity of CA positive-CY negative antisera, four extensively studied sera were further analyzed in 16 families. Independent segregation from the HLA complex and ABO and Rh antigens was confirmed and two of the sera appeared to detect separate clusters of reactions in conjunction with some of the other reagents. Pre- and postgraft samples obtained from 23 living related and 75 cadaveric renal transplanted patients were investigated and compared for graft function and prospective tissue typing. Although direct crossmatches were negative prior to surgery, 17.9% of the pretransplant samples from living related and 28.0% from cadaveric recipients contained detectable antibody when tested against a cell panel. Similar to the prenatal and multiparous groups, the majority of these responses were detected by CA. Following engraftment, antibody first became evident in 11 of 19 (58%) living related and in 23 of 53 (48.2%) cadaveric hosts. There was a striking association between the development of CA and CY antibody and failure, as contrasted to 100% 9-month or greater survival in 10 of 10 living related and 15 of 15 cadaveric transplants in whom only CA antibodies arose postoperatively. In total, these studies indicate that CA reacts with HLA antigens in common with CY tests. In addition, CA may detect HLA when CY is negative but many other reactions appear to be directed at non-HLA specificities. The relevance of CA-only responses to clinical transplantation remains uncertain, but we may speculate that they have an enhancing effect on the course of renal transplantation and are associated with important histocompatibility determinants.

Agglutination Tests↗