Screening of potential transplant recipients for antibodies that can cause graft rejection is an essential part of the pre-transplant monitoring carried out by tissue typing laboratories. This is a time-consuming process and the rapid reporting of results is dependent on the maintenance of frozen cell panels. The usual procedure of screening against a panel of random cells takes up to 6 weeks. In this study we have used flow cytometric analysis of pooled chronic lymphatic leukaemia (CLL) cells to detect antibodies directed against HLA antigens. We show that FACS screening of pooled cells can accurately and rapidly detect these antibodies and that the method is suitable for routine use. An estimate of the degree of patient panel reactivity can be determined within a few hours. In addition, the technique is more sensitive than those conventionally used, an advantage that may be of importance in preventing graft damage.

Flow cytometric screening of sera using pooled chronic lymphocytic leukaemia (CLL) cells has previously been reported as a quick method for detecting HLA antibodies of the IgG class. In this study we investigated the sensitivity of this method in the detection of IgG and IgM alloantibodies, and its performance in serum screening when compared to conventional microlymphocytotoxic screening. Results indicate that flow cytometric screening is more sensitive in the measurement of IgG alloantibodies by up to five doubling dilutions, whereas the converse is true for IgM. IgM autoantibodies were found not to be detectable by flow cytometry. By testing a large number of sera by both methods in parallel, we have found that a significant proportion of sera exhibiting no activity of IgM activity alone on cytotoxic screening contain IgG antibodies detectable with a pool of CLL cells on the flow cytometer.

Flow cytometric screening of sera using pooled chronic lymphocytic leukaemia (CLL) cells has previously been reported as a quick method for detecting HLA antibodies of the IgG class. In this study we investigated the sensitivity of this method in the detection of IgG and IgM alloantibodies, and its performance in serum screening when compared to conventional microlymphocytotoxic screening. Results indicate that flow cytometric screening is more sensitive in the measurement of IgG alloantibodies by up to five doubling dilutions, whereas the converse is true for IgM. IgM autoantibodies were found not to be detectable by flow cytometry. By testing a large number of sera by both methods in parallel, we have found that a significant proportion of sera exhibiting no activity of IgM activity alone on cytotoxic screening contain IgG antibodies detectable with a pool of CLL cells on the flow cytometer.

No abstract

Screening of potential transplant recipients for antibodies that can cause graft rejection is an essential part of the pre-transplant monitoring carried out by tissue typing laboratories. This is a time-consuming process and the rapid reporting of results is dependent on the maintenance of frozen cell panels. The usual procedure of screening against a panel of random cells takes up to 6 weeks. In this study we have used flow cytometric analysis of pooled chronic lymphatic leukaemia (CLL) cells to detect antibodies directed against HLA antigens. We show that FACS screening of pooled cells can accurately and rapidly detect these antibodies and that the method is suitable for routine use. An estimate of the degree of patient panel reactivity can be determined within a few hours. In addition, the technique is more sensitive than those conventionally used, an advantage that may be of importance in preventing graft damage.