Abstract

The interleukin (IL)-7 receptor (IL-7R) is expressed on human pre-B but not mature B-cells. We hypothesised that aberrant expression of IL-7R contributes to B-cell oncogenesis. Surface expression of IL-7R components CD127 and CD132, and intracellular Ki-67 and Bcl-2 were examined by flow cytometry on peripheral blood or bone marrow mononuclear cells (PBMC; BMMC) from patients with B-cell derived neoplasms, chronic human immunodeficiency virus type-1 (HIV-1) infection alone, or healthy volunteers. Plasma IL-7, IL-2, IL-4, IL-6, IL-10, IL-21, TNF-alpha, IFN-gamma and BAFF were measured by enzyme-linked immuno-sorbent assay or bead array. The effects of exogenous IL-7 on PBMC and BMMC were examined. CD127 expression was elevated in pre-B-cell acute lymphoblastic leukemia (pre-B-ALL) and in some cases of Non-Hodgkin's Lymphoma (B-NHL). Plasma IL-7 levels were higher in pre-B-ALL, B-cell chronic lymphocytic leukemia (B-CLL) and HIV-1 associated B-NHL (HIV-B-NHL) compared with control groups. CD127+ pre-B-ALL cells had higher expression of Ki-67, Bcl-2 and CD132 than CD127- counterparts. Unlike T-lineage cells, CD127+ pre-B-ALL cells did not down-regulate CD127 in response to exogenous IL-7. Patients with B-cell derived neoplasms had elevated circulating IL-10 and decreased BAFF. These findings support a role for the IL-7/IL-7R system in B-cell oncogenesis.

2009 Elsevier Ltd. All rights reserved.