The detection of the HLA-B27 antigen by immunomagnetic separation and enzyme-linked immunosorbent assay - comparison with a flow cytometric procedure

The HLA-B27 antigen is an important genetic marker in ankylosing spondyliti s (AS). Methods for the detection of B27 include the microlymphocytotoxicit y test and, more recently, flowcytometry (FC). Here, we describe a new meth od, IMS-ELISA, for measuring the B27-antigen. It combines immunomagnetic se paration (IMS), to obtain B27-positive cells from whole blood samples, with an enzyme-linked immunosorbent assay (ELISA) as a read-out. IMS-ELISA was tested on 367 samples obtained from five different hospitals in Taiwan. The sensitivity, specificity and accuracy of the method were compared with FC. Any conflicting data between IMS-ELISA and FC was confirmed by HLA-DNA typ ing via PCR-SSP (polymerase chain re action-sequence specific primers). Ove rall, the results for sensitivity, specificity and accuracy obtained by IMS -ELISA and FC did not show any significant difference (p > 0.05). However, when considering laboratory time, cost, ease of operation and the screening of large samples for HLA-B27, the IMS-ELISA was superior to the FC method. We conclude that IMS-ELISA may be used as a fast screening method for HLA B27 detection. (C) 2001 Elsevier Science B.V. All rights reserved.