Clinical relevance of soluble HLA-1 and β2-microglobulin levels in non-Hodgkin's lymphoma and Hodgkin's disease

Plasma levels of beta-2 microglobulin (beta 2M), a subunit of the human leukocyte antigen-class I (HLA-I) molecule, correlate negatively with outcome in non-Hodgkin's lymphoma (NHL) and Hodgkin's disease (HD). We examined the clinical relevance of soluble HLA-I (sHLA-I) levels in NHL and HD. Sera from consecutive NHL (n = 65) and HD (n = 37) patients were analyzed in a blinded manner. NHL and HD patients had significantly higher levels of sHLA-I and beta 2M than control subjects. In NHL patients, sHLA-I levels correlated with clinical behavior in a fashion similar to that of beta 2M. However, multivariate analysis incorporating beta 2M, sHLA-I, and international prognostic index (IPI) indicated that NHL patients with elevated (> 312.6 mu g/100 mL) sHLA-I levels had significantly shorter survival, independent of IPI score as well as beta 2M. In HD patients, beta 2M but not sHLA-I levels were associated with clinical behavior. These findings not only establish the role of sHLA-I as an independent tumor marker in NHL that can be used to stratify patients, but also suggest that beta 2M and sHLA-I may reflect different biological processes in HD and NHL. Further studies are needed to assess whether the immumonodulatory properties of sHLA-I may be responsible for its divergence from beta 2M as an indicator of clinical behavior in HD. (c) 2006 Elsevier Ltd. All rights reserved.