The clinical significance of soluble human leukocyte antitgen class-I, ICTP, and RANKL molecules in multiple myeloma patients Philipp Schütt a , Vera Rebmann b , Dieter Brandhorst a , Johannes Wiefelspütz a , Peter Ebeling a , Bertram Opalka a , Siegfried Seeber a , Mohammad R. Nowrousian a , Thomas Moritz a , Hans Grosse-Wilde b, * a Department of Internal Medicine (Cancer Research), West German Cancer Center, University of Duisburg-Essen Medical School, Hufelandstrasse 55, Essen, Germany b Institute of Immunology, West German Cancer Center, University of Duisburg-Essen Medical School, Hufelandstrasse 55, Essen, Germany Received 28 June 2007; received in revised form 18 January 2008; accepted 22 January 2008 Summary Because of the variable clinical course of multiple myeloma, the identification of prognostic parameters is of clinical interest. Therefore, we analyzed the clinical signifi- cance of serum levels of soluble human leukocyte antigen class I molecules (sHLA-I), carboxy-terminal telopeptide of type-I collagen (ICTP), and receptor activator of nuclear factor B ligand (RANKL). Compared with controls, sHLA-I were threefold (p  0.001) elevated in multiple myeloma. Increased levels of ICTP and RANKL were demonstrated in 50 and 43% of patients, respectively. sHLA-I correlated significantly with stage of disease. Serial determination of sHLA-I in 11 patients revealed significantly higher sHLA-I levels (median [range] g/l) during active disease than during remission (700 [250 –2090] versus 380 [130 –920]). ICTP demonstrated an association with stages of disease and the presence of osteolytic lesions, whereas there were no differences with respect to active/remittent disease. Importantly, levels of sHLA-I  1000 g/l and ICTP  5 g/l were significantly associated with a poor overall survival. For RANKL, no significant associations were observed with disease stages, disease status, osteolytic lesions, and survival. In conclusion, sHLA-I and ICTP serum levels seem to be of prognostic significance in multiple myeloma and might be helpful to identify patients of poor prognosis. © 2008 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved. KEYWORDS Multiple myeloma; Soluble HLA; ICTP; RANKL * Corresponding author. Fax: +49 201 723 5906. E-mail address: immunology@uni-essen.de (H. Grosse-Wilde). Human Immunology (2008) 69, 79 – 87 0198-8859/$ -see front matter © 2008 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved. doi:10.1016/j.humimm.2008.01.006