Journal of Clinical Oncology, Vol 10, 954-959, Copyright © 1992 by American Society of Clinical Oncology
Constitutive production of tumor necrosis factor-alpha in hairy cell leukemia: possible role in the pathogenesis of the cytopenia(s) and effect of treatment with interferon-alpha
R Foa, A Guarini, P Francia di Celle, L Trentin, A Gillio Tos, G Bellone, A Carbone, C Attisano, M Massaia and D Raspadori
Dipartimento di Scienze Biomediche e Oncologia Umana, Consiglio Nazionale delle Richerche, Torino, Italy.
PURPOSE: In view of the pleomorphic role cytokines play in human
lymphoproliferative disorders, we investigated the possible involvement of
tumor necrosis factor-alpha (TNF) in hairy cell leukemia (HCL). PATIENTS
AND METHODS: The levels of TNF were measured in the serum of untreated
patients, and in the culture supernatants of unstimulated and stimulated
enriched hairy cells (HC). Furthermore, the presence of TNF mRNA
transcripts in HC was analyzed. The possibility that HC could inhibit the
in vitro growth of normal erythroid progenitors via the release of TNF was
also investigated. Finally, in an attempt to correlate the circulating
levels of TNF with the course of the disease, these were retested during
and after treatment with interferon-alpha (IFN). RESULTS: Significantly
increased levels of TNF were found in the sera of untreated HCL patients
compared with normal control sera were seen from patients with other
diseases (P less than .001), with values greater than 10 pg/mL in 21 of 42
samples tested. A significant decrease (P less than .01) of TNF levels was
recorded following IFN-2a administration in 16 cases with detectable
pretreatment serum levels of TNF. In two cases, an increase in TNF values
was associated with persistence or progression of disease. The likelihood
that the circulating levels of TNF were caused by the pathologic cells is
supported by the evidence that purified HC may release TNF spontaneously.
The values can be markedly increased following in vitro activation with the
phorbol ester 12-0-tetradecanoylphorbol-13 acetate (PMA), with B-cell
growth factor (BCGF), and, to a further extent, with the combination of PMA
and BCGF. Furthermore, the constitutive mRNA for TNF was found in seven of
eight HC samples analyzed. Although supernatants of enriched HC, were
capable of reducing the growth of normal bone marrow erythroid progenitors
by 50%, duplicate experiments using an anti-TNF antibody produced an almost
complete disappearance of the inhibitory effect. CONCLUSION: The results of
this study suggest that TNF plays an important role in the pathogenesis of
the cytopenia(s) characteristically associated with HCL.