Immunological findings in patients with myelodysplastic syndrome

Activation of monocytes and granulocytes in vitro by cytokines, in vivo administration of cytokines, as well as in vivo cytokine production due to infectious and inflammatory diseases causes changes of the surface expression density of certain membrane molecules. In recent studies we attempted to determine the feasibility of using flow cytometric immunophenotyping as a tool to develop a sensitive parameter for detecting infections at an early stage of disease when clinical parameters are still negative. Since infections are an important factor determining the clinical course of myelodysplastic syndromes (MDS), early detection of infection might be beneficial for these immunocompromised patients. We indeed found activation-associated immunophenotypic changes of cell surface antigens on monocytes and granulocytes of clinically infection free MDS patients suggesting enhanced immune activity in these patients, most likely due to latent or beginning infections. In particular, analyses of the expression density of receptors for IgG (Fc gamma Rs), complement receptors, and certain activation-associated surface molecules such as the CD67 and the M5 molecule seem to be of clinical relevance. We will also discuss findings concerning changes of cytokine levels and functional alterations of immunologic parameters in MDS patients.