Search

Autoimmunerkrankungen sind eine klinisch heterogene Gruppe von Erkrankungen, die den Hausarzt oft vor differentialdiagnostische Herausforderungen stellen. Mit Ausnahme der rheumatoiden Arthritis, die mit einer Pravalenz von ca. 1 % der Bevolkerung zu den haufigen Autoimmunerkrankungen zahlt, sind systemische Autoimmunerkrankungen in der allgemeinmedizinischen Praxis so selten, dass der niedergelassene Arzt fur Allgemeinmedizin meist wenig Erfahrung mit den einzelnen Krankheitsbildern hat. Bei entsprechender klinischer Symptomatik und mit gezielten Fragestellungen konnen bestimmte Autoantikorper die Verdachtsdiagnose stutzen. Die osterreichische Gruppe der Europaischen Autoimmun Standardisierungsinitiative (EASI, European Autoimmunity Standardisation Initiative) hat es sich zum Ziel gesetzt, im vorliegenden und 2009 publizierten Leitfaden, dem Allgemeinmediziner einen Wegweiser durch den Dschungel der Biomarker fur Autoimmunerkrankungen zu bieten.

Autoimmune diseases are a clinically heterogeneous group of disorders that represent a challenge for the general practitioner in daily routine. Except for rheumatoid arthritis, which is one of the most frequent autoimmune diseases with a prevalence of approximately 1 % of the population, systemic autoimmune disorders are rare. Thus outside specialized wards it might be a challenge to diagnose the underlying autoimmune disease considering the often kaleidoscopic clinical manifestations. Together with careful anamnesis and suspicious clinical symptoms determination of specific autoantibodies can support the suspected diagnosis. The Austrian group of the European autoimmune standardization initiative (EASI) firstly published this guide 2009 with the aim to provide a map through the jungle of the biomarkers for autoimmune diseases for the general practitioner.

A flow cytometric method performing a five-part leukocyte differential based on three-color staining with anti-CD45-fluorescein isothiocyanate (FITC), anti-CD-14-phycoerythrin (PE)/Cy5, and a cocktail of PE-labeled anti-CD2, anti-CD16, and anti-HLA-DR antibodies was evaluated. Results obtained by using three different sample preparation procedures and two different flow cytometers were compared with those of a 1,000-cell manual differential for evaluation of accuracy. We observed excellent correlations with the manual differential for all leukocyte subclasses and even higher correlations between the different flow cytometric methods. Flow cytometric basophil results were identical to the manual counts, regardless of which sample preparation technique or flow cytometer was used. Therefore, we propose our flow cytometric method as the first acceptable automated reference method for basophil counting. The flow cytometric results for the other leukocyte subclasses were apparently influenced by the sample preparation, which could not be explained by cell loss during washing steps. Moreover, a small influence of the flow cytometer was also observed. Assessing the influence of sample storage, we found only minimal changes within 24 h. In establishing reference values, high precision of flow cytometric results facilitated detection of a significantly higher monocyte count for males (relative count: 7.08 +/- 1.73% vs. 6.44 +/- 1.33%, P < 0.05; absolute count: 0.536 +/- 0.181 x 10(9)/liter vs. 0.456 +/- 139 x 10(9)/liter, P < 0.01). Our data indicate that monoclonal antibody-based flow cytometry is a highly suitable reference method for the five-part differential: It also shows, however, that studies will have to put more emphasis on methodological issues to define a method that shows a high interlaboratory reproducibility.