Variations of the Lymphocytotoxicity Test an Evaluation of Sensitivity and Specificity

Detecting and monitoring human leukocyte antigen–specific antibodies

“…The development and commercial availability of solid phase antibody screening assays has greatly reduced the utility of cell-based assays for antibody screening so that cell-based assays are best used for crossmatch testing. Cell-based tests differ in their sensitivity [21,41,42] but are comparable in specificity, with both assays subject to interference by non-HLA-specific antibodies that bind to lymphocytes. For antibodies strong enough to yield a positive cytotoxicity crossmatch (CDCXM), simple doubling dilutions can be used to establish titer although, once positive, the titer may not be important unless the patient is to undergo desensitization.…”

“…This is usually determined by the type of negative crossmatch required. Various modifications of the cytotoxicity assay yield differing degrees of sensitivity and the flow cytometric crossmatch is more sensitive than any of the various cytotoxicity crossmatches [21,41,42]. Furthermore the threshold of what is considered positive varies among laboratories.…”

Simultaneous detection of antibody binding and cytotoxicity in flow cytometry crossmatch for renal transplantation

“…The higher number of cells analyzed ($5,000 T cells) in the cytotoxic FCXM than that in the AHG-CDC ($3,000 lymphocytes) appears to improve the accuracy of the qualitative interpretation. In addition, doubling both the serum/cell ratio and the complement incubation time, as proposed by Zachary et al (10), also appears to promote complement-mediated cytotoxicity. Regarding the dead-cell %, a few discordant results were observed in the HLA allosera at a low or borderline level.…”

“…Therefore, a new method is required to be developed, which enables the simultaneous detection of Ab binding and cytotoxicity to the lymphocytes in a single FCXM assay. This study was intended to confirm that Ab binding and cytotoxicity to the lymphocytes can be detected simultaneously in a single FCXM assay, using already known techniques to improve the sensitivity of the National Institutes of Health (NIH)-CDC (10). This new FCXM was named the cytotoxic FCXM.…”

Luminex and antibody detection in kidney transplantation

“…Nevertheless, CDC has the advantage of reflecting the situation in vivo, because HLA antigens, used as antibody target, are in their native configuration on cell membrane. Over the years, changes have been introduced to increase CDC sensitivity, such as antihuman globulin (AHG) addition and prolonged incubation times [18]. Therefore, the CDC reactivity pattern is a useful indicator of increased risk of hyperacute or acute rejection, and a positive CDC test is still considered a contraindication to transplantation in many centers.…”