Possible Mechanism of Interferon Action in Hairy Cell Leukemia
Recently, we described that peripheral blood mononuclear cells (MNC) from patients with hairy cell leukemia (HCL) can be induced in vitro to produce higher levels of interferon-gamma (IFN-γ) but lower levels of IFN-α than in healthy controls . The reduced IFN-α production has been explained by the lack of monocytes in this disease. The increased production of IFN-γ suggests an increased release of cytokines by T cells. This assumption has been confirmed by Ford et al. , who described that a conditioned medium of T4-lymphocytes from patients with HCL contains a cytokine that stimulates the growth of activated, normal B cells. Kehrl et al.  demonstrated tumor necrosis factor alpha (TNF-α) to be a stimulator of activated normal B cells, and we (Digel et al. 1988) have shown recently that recombinant TNF-α stimulates the growth of purified B cells from patients with B-chronic lymphocytic leukemia (B-CLL). Based on these findings, we hypothesize that TNF is produced in B-cell disorders like HCL and that TNF may stimulate the growth of hairy cells (HC).
KeywordsCytotoxic Activity Hairy Cell Leukemia Hairy Cell Cytotoxic Factor Percoll Gradient Centrifugation
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