Origin of the soluble interleukin-2 receptor in the serum of patients with hairy cell leukemia.
High levels of soluble IL-2 receptor (sIL-2R) are detectable in the serum of HCL patients. To determine the cell source of this molecule, we evaluated the presence of sIL-2R in the supernatants obtained from in vitro cultures of leukemic (hairy cell, HC) and non-leukemic lymphocytes from six untreated HCL patients and from an additional four patients under therapy with rIFN-alpha 2. We demonstrated that cultured HCs at resting conditions were able to spontaneously release the sIL-2R, whereas control enriched B cells did not. This phenomenon was present only when culturing HCs recovered from patients observed at the time of diagnosis but was not observed during treatment with rIFN-alpha 2. Following activation in vitro with a series of different stimulatory agents including BCGF, phorbol myristate acetate, and anti-human IgM antibody, cultured HCs increased their capability to shed the IL-2R molecules. On the other hand, the release of sIL-2R from enriched T cell populations from HCL patients did not significantly differ from the value obtained in controls. Taken together, these findings provide evidence that leukemic B cells represent the main source of sIL-2R in HCL patients and further emphasize the importance of evaluating this parameter as a relevant marker for monitoring the effectiveness of rIFN-alpha 2 therapy.
Semenzato
G
G
Padua University School of Medicine, Department of Clinical Medicine, Italy.
Trentin
L
L
Zambello
R
R
Agostini
C
C
Bulian
P
P
Siviero
F
F
Ambrosetti
A
A
Vinante
F
F
Prior
M
M
Chilosi
M
M
D000328:Adult; D000368:Aged; D001402:B-Lymphocytes / Q000187:drug effects / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000097:blood; D002454:Cell Differentiation / Q000187:drug effects; D005260:Female; D006801:Humans; D000077190:Interferon alpha-2; D016898:Interferon-alpha / Q000627:therapeutic use; D007943:Leukemia, Hairy Cell / Q000097:blood* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000097:blood / Q000378:metabolism*; D015375:Receptors, Interleukin-2 / Q000097:blood / Q000378:metabolism*; D011994:Recombinant Proteins; D014407:Tumor Cells, Cultured
D014408:Biomarkers, Tumor; D000077190:Interferon alpha-2; D016898:Interferon-alpha; D009363:Neoplasm Proteins; D015375:Receptors, Interleukin-2; D011994:Recombinant Proteins