#8-OR
HLA ANTIBODY IDENTIFICATION WITH SINGLE ANTIGEN BEADS COMPARED TO CONVENTIONAL METHODS.
Nadim R. El-Awar BA,MBA 1, Jar-How Lee PhD 1 and Paul I. Terasaki PhD 2. 1 Research II, One Lambda Inc., Los Angeles, CA, USA ; 2 Research, One Lambda Inc., Canoga Park, CA, USA and 3 Terasaki Foundation, Los Angeles, CA, USA .
Methods of serum analysis for HLA specificities have not changed substantially for 40 years. Large panel of cells and computer programs are used to identify the likely specificities present within a serum. With the recent development of beads having only a single antigen (SA) on each bead, it has become possible to more accurately identify the specificities. We compared the reactions of SA beads with the results of specificities reported by 63 laboratories to the UCLA serum exchange. 58 sera of the exchange were analyzed. As shown by one example. In the figure, on the left hand side is the % of laboratories that reported a specificity, and on the right hand side are the specificities identified by SA beads. In this serum, A2 was missed by 45% of the Labs. In addition A68, A69 and A80 were also missed. The overlay graphs show confirmation of A2 and A69 specificities by reaction of the recombinant lines having the single antigen. In order to check that the SA beads are giving the correct results, we compared the results with that of the multiple antigen beads (MA) carrying the same antigen. 7% of the MA beads were negative suggesting that 93% of SA bead reactions are true. Many low frequency specificities such as B37 and others were almost always missed. We conclude that especially the low freq. specificities are missed by conventional antibody testing methods.