Fig. 5.

IL-32 expression and NK activity. (A) IL-32 expression in peripheral blood CD56⁺ cells (n = 60). Shown are steady-state relative levels of expression of mRNA determined by quantitative RT-PCR. CMML, chronic myelomonocytic leukemia. MDS patients are shown by disease category [RCMD, refractory cytopenia with multilineage dysplasia; RAEB-1, refractory anemia with excess blasts type 1 (5–9% blasts); RAEB-2, refractory anemia with excess blasts, type 2 (10–19% blasts)]. Baseline expression of IL-32 in CD56⁺ cells from peripheral blood of patients with CMML was significantly lower than in CD56⁺ cells from healthy subjects (P = 0.001). Conversely, in patients with MDS, baseline expression of IL-32 tended to be higher than in healthy controls, although the difference did not reach statistical significance (P = 0.48). (B) Cytolytic function of NK cells. CD56⁺ cells were obtained from the peripheral blood of healthy subjects (n = 7) and patients with CMML or MDS (n = 13) and assayed at three different effector/target ratios (1:1; 5:1, and 10:1) against K562 cells. CD56⁺ cells were untreated or cultured for 24 h with 500 units/ml IL-2. Lytic activity was measured after 4 h of incubation of the effector cells (CD56⁺ cells) with target cells (K562). Lytic units were calculated from triplicate. Black dots show individual results, horizontal bars the mean percentage of lysis. (C) Expression of IL-32 in incubated peripheral blood CD56⁺ cells from healthy subjects (n = 7) and patients with MDS or CMML (because no difference was noted between MDS and CMML cells, results are lumped; n = 26). IL-32 levels were determined in unmodified cells (control) and cells that had been cultured with 500 units/ml IL-2 for 18 h. P values are for MDS/CMML patients in comparison with healthy subjects.