Production of hemo- and immunoregulatory cytokines by erythroblast antigen(+ )and glycophorin A(+ )cells from human bone marrow

BACKGROUND: Erythroid nuclear cells (ENC) of the bone marrow (BM) have not previously been considered as important producers of wide spectrum of haemo- and immunoregulatory cytokines. The aim of the current work was to confirm the production of the main hemo- and immunoregulatory cytokines in human ENC from BM. RESULTS: We used native human BM ENC in our experiments. We for the first time have shown, that the unstimulated erythroblasts (Gl A(+ )or AG-EB(+)) produced a wide spectrum of immunoregulatory cytokines. Human BM ENC produce cytokines such as interleukn (IL)-1β, IL-2, IL-4, IL-6, interferon (IFN)-γ, transforming growth factor (TGF)-β1, tumor necrosis factor (TNF)-α and IL-10. They can be sub-divided into glycophorin A positive (Gl A(+)) and erythroblast antigen positive (AG-EB(+)) cells. To study potential differences in cytokine expression between these subsets, ENC were isolated and purified using specific antibodies to Gl A and AG-EB and the separated cells were cultivated for 24 hours. The cytokine contents of the supernatant were measured by electrochemiluminescence immunoassay. Quantitative differences in TGF-β1 and TNF-α production were found between Gl A(+ )and AG-EB(+ )BM ENC. Furthermore, in vitro addition of erythropoietin (EPO) reduced IFN-γ and IL-2 production specifically by the AG-EB(+ )ENC. Thus, Gl A(+ )and AG-EB(+ )ENC produce IL-1β, IL-2, IL-4, IL-6, IFN-γ, TGF-β1 and TNF-α. Gl A(+ )ENC also produce IL-10. CONCLUSION: Cytokine production by erythroid nuclear cells suggests that these cells might be involved in regulating the proliferation and differentiation of hematopoietic and immunocompetent cells in human BM

Inhibition of p38 mitogen-activated protein kinase unmasks a CD30-triggered apoptotic pathway in anaplastic large cell lymphoma cells

CD30, a non-death domain-containing member of the tumor necrosis factor receptor superfamily, triggers apoptosis in anaplastic large cell lymphoma cells. The CD30 signaling pathways that lead to the induction of apoptosis are poorly defined. Here, we show that the induction of apoptosis by CD30 requires concurrent inhibition of p38 mitogen-activated protein kinase, which itself is activated by engagement of CD30 with CD30 ligand. Treatment of anaplastic large cell lymphoma cells with CD30 ligand and pharmacologic inhibitors of p38 mitogen-activated protein kinase, but not with CD30 ligand or inhibitors alone, triggered the activation of caspase-8 and the induction of apoptosis. Caspase-8 activation occurred within a few hours (2.5-4 h) after receptor triggering, was unaffected by the neutralization of ligands for the death domain-containing receptors TNFR1, Fas, DR3, DR4, or DR5, but was abolished by the expression of a dominant-negative form of the adaptor protein FADD. Importantly, we show that expression of the caspase-8 inhibitor c-FLIPS is strongly induced by the CD30 ligand, and that this is dependent on the activation of p38 mitogen-activated protein kinase. Thus, we provide evidence that the induction of apoptosis by CD30 in anaplastic large cell lymphoma cells is normally circumvented by the activation of p38 mitogen-activated protein kinase. These findings have implications for CD30-targeted immunotherapy of anaplastic large cell lymphom