Background: Human leukocyte antigen B27 (HLA-B27) is an major histocompatibility complex Class I cell surface antigen that shows strong association with spondylarthropathies. Although polymerase chain reaction (PCR) is the gold standard method for HLA-B27 detection, monoclonal antibodies, and flow cytometric analysis is also frequently used. We aimed to compare the efficiency of two commercially available monoclonal antibody clones and the DuraClone kit that uses simultaneously these clones.
Methods: Blood samples drawn from 63 patients were analyzed by flow cytometry and PCR. For flow cytometry analysis ABCm3 and FD705 clones were used for flow cytometry as well as the DuraClone Reagent Kit. Results of flow cytometric analysis were confirmed by PCR.
Results: Numbers of false-positive and equivocal samples were high when ABCm3 or FD705 clones were used separately: 34 out of 63 and 27 out of 63, respectively. Simultaneous use of the two antibody clones and pre-selection of CD3+ T cells, in the DuraClone kit, significantly decreased the number of these samples. Using the DuraClone kit, only 11 out of 63 samples were inconclusive. Influence of HLA-B7 expression was detectable in some cases when ABCm3 and FD705 were used separately.
Conclusions: Our results show that simultaneous use of HLA-B27 monoclonal antibodies and pre-selection of T cells significantly increased the specificity of the flow cytometric assay, however it did not reach the specificity of PCR. Nevertheless, based on our results, performing the PCR test exclusively in equivocal cases by DuraClone kit reduces the burden of PCR assays and the turn-around time.
Keywords: DuraClone; HLA-B27; flow cytometry.
© 2020 International Clinical Cytometry Society.