1.2000
#19
HIDDEN ANTI-HLA ANTIBODIES AND B-CELL X-MATCH RESULTS.
Helmut K.G. Machulla, Ph.D., Wolfgang W. Altermann, M.D., Katarina Wittig, Anja Wahle, Astrid Schaaf and Barbara Seliger, Prof.. Halle Germany, Medical School of MLU, D-06097, Interbranch HLA Lab, Dept. GHATT, Inst. of Med. Immunol..

Terasaki (2003) summarized data on the high risk of anti-HLA antibodies (Abs) for graft outcome. The present study shows a chance to reveal hidden Abs in order to improve the interpretation of BC x-match results. 892 sera of patients of the German tx centers GDR, GHA, GJE, GLP were screened by extended CDC with an in-house panel of 30 BCLL cells (BCLLC). All positive sera were checked with an in-house panel of 60 PBLs. In addition, all positive and 111/662 non cytotoxic sera were checked with Luminex-LABScreen (OL Inc. /CA., USA). The results are shown in the table in the bottom. 230/892 sera (25.3%) had IgG and/or IgM anti-HLA cl. I and/or II Abs cytotoxic with the BCLL cells and/or the PBLs. However, 138/230 (60%) were found only by use of the BCLLC panel (= hidden Abs), but not by the PBLs. 63/138 (45.6%) belong to the IgM class (sensitive to DTT). Even if they would not have any importance for graft outcome they could affect the BC x-match result. By combination of LABScreen with CDC all hidden IgG Abs were found to be weak anti-HLA cl. I or II Abs that are detectable only in a BC x-match. Hence, positive results of BC x-matches can be caused by Abs deleterious for an organ graft . However, rarely occurring non cytotoxic Abs (2/111; 1.8%) stay a further problem.

Table: Hidden anti-HLA Abs affect the BC x-match result
Luminex-LABScreencl.I+ cl.II+cl.I+ cl.II-cl.I- cl.II+cl.I- cl.II+n% PRA ofx-match result to expect
extented CDCIgGIgGIgGIgMPBL / BCLLC
BCLLC+ PBL+341723992>0 / >0PBL/TC+ SpC/BC+
BCLLC+ PBL-28232463138=0 / >0PBL/TC- SpC/BC+
SpC = Spleen Cells, PBL = Peripheral Blood Lymphocytes, TC = T Cells, BC = B Cells, BCLLC = B Cells of Chronic Lymphoid Leukemia