Determination of HLA-B27 by Enzyme Immunoassay and Flow Cytometry: Comparison with the Classic Microlymphocytotoxic Assay

Abstract

Additional key phrase: inflammatory rheumatic diseasesSerological typing of HLA-B27 is routinely done by the microlymphocytotoxicity test (MLCT).l This method is easy and allows a daily typing of a relatively large number of samples. Nevertheless, the interpretation requires some experience in the exclusion of false-positive typing results caused by cross-reactions. A significant disadvantage of the MLCT is the subjective microscopic evaluation of the percentage of killed and viable lymphocytes. In order to overcome the difficulties with the MLCT, other serological methods such as flow cytometry (FC)2 or enzyme immunoassay (EIA)3 have been developed. Recently molecular biological methods have also been introduced.v? The aim of our study was to compare the accuracy of FC and EIA with MLCT for HLA-B27 typing. MATERIALS AND METHODS PatientsEighty-one patients, 35 women and 46 men (aged between 19 and 89 years) with a suspected diagnosis of inflammatory disorders (ankylosing spondylitis, seronegative rheumatoid arthritis, reactive arthritis, psoriatic arthritis, psoriasis vulgaris and other unclassified rheumatic disorders) were included in the study. Determination of HLA-B27 was by MLCT, ElA and occasionally (if discrepant typing results were obtained) by Fe. In addition 20 healthy probands were typed for HLA-B27 by FC only in order to obtain appropriate values for

Durchflußzytometrie in der Klinischen Diagnostik. Positionspapier der Arbeitsgruppe Durchflußzytometrie und Quantitative Mikroskopie der Deutschen Gesellschaft für Klinische Chemie und Deutschen Gesellschaft für Laboratoriumsmedizin

“…Die durchflußzytometrische Analyse der HLA-B27 Expression stellt eine zuverlässige, ökonomische, anwendungsfreundliche und zeitsparende Alternative gegenüber dem konventionellen Mikrolymphozytentoxizitätstest und neueren serologischen Methoden dar [92][93][94]. Beim Einsatz der monoklonalen Antikörper ist zu bedenken, daß viele Antikörper eine Kreuzreaktivität mit HLA-B7 auf weisen.…”

“…Hierzu zählen neben der Auswahl der Antikörper vor allem die Inkubationszeit. Eine Standardisierung dieses Testes steht aus [92,93,95,96]. Positive Befunde sollten derzeit aber noch im Mikrozytotoxizitätstest oder mittels Molekularbiologie bestätigt werden.…”