Expression of RHAMM/CD168 and other tumor-associated antigens in patients with B-cell chronic lymphocytic leukemia

Abstract

Antigen targeted immunotherapies might represent a novel treatment for B-cell chronic lymphocytic leukemia (B-CLL). We screened the mRNA expression of tumor-associated antigens (TAAs) from the literature (fibromodulin, survivin, OFA-iLRP, BAGE, G250, MAGE1, PRAME, proteinase, syntaxin, hTERT, WT-1) and TAAs defined previously by serological analysis of cDNA expression libraries from leukemic cells (PINCH, HSJ2, MAZ, MPP11, RHAMM/CD168, NY-Ren60). Peripheral blood mononuclear cells from 43 B-CLL patients and 20 healthy volunteers (HVs) were examined by conventional and quantitative RT-PCR. mRNA of RHAMM/CD168, fibromodulin, syntaxin and NY-Ren60 was expressed in 55-90%, and mRNA of HSJ2, MAZ and OFAiLRP was expressed in 90-100% of the patients. No expression of WT-1, hTERT, BAGE, G250, MAGE1 or survivin was observed. Low (2-20%) expression frequencies of MPP11, PINCH, PRAME and proteinase were detected. RHAMM/CD168, fibromodulin, PRAME and MPP11 showed expression in B-CLL patients, but not in HVs. Because of the exquisite tissue expression of RHAMM/CD168 and its high expression frequency in CLL patients, mixed lymphocyte peptide culture (MLPC), enzyme-linked immunosorbent spot (ELISPOT) and flow cytometry were performed for antigen specific T-cells. In MLPC, RHAMM specific responses by CD8+HLA-A2/R3tetramer+CCR7-CD45RAhigh effector T-cells were detected. RHAMM/CD168 might be a possible target for future immunotherapies in both ZAP-70(+) and ZAP-70(-) B-CLL patients.