SOLUBLE HLA-DR IS A POTENT PREDICTIVE INDICATOR OF DISEASE PROGRESSION IN SERUM FROM EARLY-STAGE MELANOMA PATIENTS Vera REBMANN 1 , Selma UGUREL 2 , Wolfgang TILGEN 2 , Uwe REINHOLD 2 and Hans GROSSE-WILDE 1 * 1 Institute of Immunology, University Hospital of Essen, Essen, Germany 2 Department of Dermatology, The Saarland University Hospital, Homburg/Saar, Germany Despite numerous therapeutic options, the prognosis of malignant melanoma, once metastasized, is still poor. Thus, the search for reliable methods to identify patients with high risk of disease progression as early as possible is of major importance. In our study, we analyzed the predictive value of soluble HLA-DR (sHLA-DR) in comparison to S100- in se- rum from 183 melanoma patients of different stages of dis- ease and with or without current therapy using immunosor- bent assays. sHLA-DR serum levels of 121 healthy individuals served as controls. We found significantly (p < 0.0005) re- duced sHLA-DR serum levels in melanoma patients (0.70  0.08 SEM g/ml) compared to controls (1.49  0.10 SEM g/ml). Reduced sHLA-DR and increased S100- levels were associated with advanced disease stages and tumor load. S100- was increased under cytostatic therapy (p < 0.0005), whereas sHLA-DR was not influenced by therapy modalities. Univariate analysis showed an association of sHLA-DR < 0.3 g/ml and S100- > 0.12 g/l with poor overall (p  0.021 and p  0.0009) and progression-free survival (p < 0.0005 and p  0.0025). Multivariate analysis revealed disease stage (p  0.0093) and tumor burden (p < 0.0005) as independent pre- dictive factors for overall survival, and sHLA-DR (p  0.0007) and tumor burden (p  0.0015) for progression-free survival. In contrast to S100-, sHLA-DR serum concentrations < 0.3 g/ml were strongly associated (p  0.0001) with poor pro- gression-free survival in a subgroup of 60 nonmetastasized patients. In conclusion, our results suggest sHLA-DR as a potent prognostic serum marker in melanoma patients su- perior to S100- in helping to identify early-stage patients at high risk of disease progression. © 2002 Wiley-Liss, Inc. Key words: melanoma; soluble HLA-DR; S100-; overall survival; progression-free survival; chemotherapy Since the incidence of malignant melanoma is still increasing, various efforts have been undertaken to improve the patients’ prognosis. After surgical removal of the primary tumor, clinically tumor-free patients are enrolled into follow-up examination pro- grams with the aim of the early detection of metastasis. Once metastasized, despite numerous therapeutic options like chemo- and/or immunotherapy the melanoma patients’ prognosis is still poor. Therefore, the search for reliable methods to identify patients with high risk of disease progression as early as possible is of major importance. The recently developed method of the diagnos- tic exstirpation of the sentinel lymph node is a promising but invasive and costly tool for the early detection of micrometastasis. 1 Since laboratory tests are easier to handle and less expensive, a variety of different serum factors have been investigated for their potential relevance as prognostic markers in malignant mela- noma. 2–5 To date, none of these markers have yet reached routine clinical use. The most promising one at present, S100-, has been demonstrated in several studies as a valid and reliable predictive marker for clinical progression 3 and response to therapy 6 in mel- anoma patients with advanced stages of disease. However, a major disadvantage of S100- is the poor prognostic impact of this marker in early-stage melanoma patients. 3,7,8 HLA antigens are one of the most important structures for the interaction of the host immune system with tumor cells. HLA molecules present antigens, e.g., tumor antigen-derived peptides to T-cell receptors, through which helper T cells and cytotoxic T cells (CTL) recognise these foreign antigens. HLA molecules also do exist in soluble forms (sHLA) in serum and other body fluids 9,10 and bind to the same physiologic ligands as the membrane-an- chored ones. Consequently, sHLA molecules can function as mod- ulators of the immune response. In vitro experiments demonstrate that sHLA class I (sHLA-I) and DR (sHLA-DR) molecules bind to the T-cell receptor and CD8 and CD4 co-receptors, 11–17 respec- tively, resulting, e.g., in the induction of apoptosis. Moreover, classical and nonclassical sHLA-I molecules bind to NK cell inhibitor receptors leading to an inactivation of NK cells. 18 –20 Clinical studies revealed a strong correlation of increased sHLA levels with an activated immune status of patients. This is reported for patients with viral infections, e.g., HBV, HIV and CMV infected patients, 21,22 for patients of solid allografts during acute graft rejections and for patients with acute graft vs. host disease after allogeneic stem cell transplantation. 23–26 Furthermore, in patients with autoimmune diseases, elevated sHLA levels are also associated with disease activity. 27–31 In cancer patients, however, only a few studies on sHLA have been reported. 32–34 Although these studies gave evidence for an association of advanced cancer disease and decreased sHLA lev- els, the prognostic significance of sHLA for disease progression or patients’ survival was not further evaluated. We therefore studied sHLA-DR levels in comparison to the established marker S100- in serum from malignant melanoma patients. Exclusively sHLA-DR appeared as a potent serum marker for the identification of patients at high risk of disease progression or relapse in early stages of melanoma. MATERIAL AND METHODS Patients and healthy controls A total of 183 patients with histologically confirmed malignant melanoma presenting between September 1997 and November 1998 at the Department of Dermatology, The Saarland University Hospital, Homburg/Saar, Germany, were enrolled in our study. The clinical staging was performed according to the American Joint Committee on Cancer (AJCC). Briefly, stages I and II in- cluded patients with primary melanoma, stage III included patients with regional lymph node and/or in-transit metastases and stage IV included patients with distant metastases. Patients were treated according to therapy protocols of the Dermatologic Cooperative Oncology Group (DeCOG) including cytostatic drugs (dacar- bacine, cisplatinum, temozolomide, vincristine) and immuno- modulatory agents [interferon(IFN)-] in different combinations and schedules. Follow-up was performed in at least 3-month intervals including physical examination, x-ray of the chest, ultra- *Correspondence to: Institute of Immunology, University Hospital of Essen, Virchowstr. 171, D-45122 Essen, Germany. Fax: +49-201-723-5906. E-mail: immunologie@uni-essen.de Received 17 December 2001; Revised 5 April 2002; Accepted 29 April 2002 DOI 10.1002/ijc.10524 Published online 19 June 2002 in Wiley InterScience (www.interscience. wiley.com). Int. J. Cancer: 100, 580 –585 (2002) © 2002 Wiley-Liss, Inc. Publication of the International Union Against Cancer