Vitamin E and carotenoids are fat-soluble microconstituents that may exert beneficial effects in humans, including protection against cancer, cardiovascular diseases, and age-related eye diseases. Their bioavailability is influenced by various factors including food matrix, formulation, and food processing. Since human studies are labor-intensive, time-consuming, and expensive, the in vitro model used in this study is increasingly being used to estimate bioaccessibility of these microconstituents. However, the ability of this model to predict bioavailability in a healthy human population has not yet been verified. The first aim of this study was to validate this model by comparing model-derived bioaccessibility data with (i) human-derived bioaccessibility data and (ii) published mean bioavailability data reported in studies involving healthy humans. The second aim was to use it to measure alpha- and gamma-tocopherol, beta-carotene, lycopene, and lutein bioaccessibility from their main dietary sources. Bioaccessibility as assessed with the in vitro model was well correlated with human-derived bioaccessibility values (r = 0.90, p < 0.05), as well as relative mean bioavailability values reported in healthy human groups (r = 0.98, p < 0.001). The bioaccessibility of carotenoids and vitamin E from the main dietary sources was highly variable, ranging from less than 0.1% (beta-carotene from raw tomato) to almost 100% (alpha-tocopherol from white bread). Bioaccessibility was dependent on (i) microconstituent species (lutein > beta-carotene and alpha-carotene > lycopene and alpha-tocopherol generally > gamma-tocopherol), (ii) food matrix, and (iii) food processing.

Objective: (R,R,R)-a-tocopherol is a fat-soluble antioxidant vitamin generally ingested with other dietary antioxidants. The objective of this study was to assess whether the main dietary antioxidant classes, that is carotenoids, polyphenols, vitamin C and g-tocopherol, affect the intestinal absorption of a-tocopherol. Methods, design and subjects: We evaluated first the effect of different combinations of antioxidants on (R,R,R)-a-tocopherol absorption by a human intestinal cell line (Caco-2 clone TC7). Then we compared the effect of two doses of a dietary antioxidant (lutein) on the postprandial chylomicron a-tocopherol responses to an a-tocopherol-rich meal. Eight healthy men ate two similar meals in a random order at a 1 month interval. The meals contained 24 mg a-tocopherol in sunflower oil plus either 18 or 36 mg lutein. Blood samples were collected during the postprandial periods to compare chylomicron a-tocopherol responses. Results: A mixture of polyphenols (gallic acid, caffeic acid, ( þ )-catechin and naringenin) and a mixture of carotenoids (lycopene, b-carotene and lutein) significantly impaired a-tocopherol absorption in Caco-2 cells (Po0.001 and Po0.0001, respectively). The inhibitory effect of g-tocopherol was close to significance (P ¼ 0.055). In contrast, vitamin C had no significant effect (P ¼ 0.158). Naringenin was the only polyphenol that significantly impaired a-tocopherol absorption. Postprandial atocopherol response was weakest at the highest dose of lutein (6167280 nmol/l h vs 10017287 nmol/l h). The observed extent of reduction (À38%, P ¼ 0.069) supported the inhibitory effect of carotenoids observed in the Caco-2 experiments. Conclusion: Naringenin, carotenoids and probably g-tocopherol can impair a-tocopherol absorption whereas vitamin C and phenolic acids have no effect.

1653 Poster Board I-679 Background The immune system is involved in AML control and Natural Killer (NK) cells are among the most promising effectors. The therapeutic potential of NK cells has been revealed by the Killer Immunoglobulin Receptor (KIR) mismatch allogeneic transplant model where the anti-leukemic effect of the graft, is due to unleashed NK cells towards AML blasts, as suggested by enhanced in vitro lytic activity of KIR-HLA mismatched donor NK cells against recipient blasts (Miller et al. 2005; Ruggeri et al. 2002). Receptors involved in the function of NK cells against AML blasts have been identified (Pende et al., 2005). Some of these receptors are altered in AML patients at diagnosis and might be involved in the immune escape of AML blasts (Costello et al., 2002). However, the status of NK cells during early stages of patient's chemotherapy (CT) treatment is unknown. The present study monitored status of NK cells during early stages following patient's remission after CT that may be critical for their long lasting clinical response, and results might provide new targets for immunotherapy. Methods We enrolled 20 elderly patients (60 to 80 years old) with non promyelocytic AML in first CR following induction and pre-consolidation CT with normal renal and hepatic functions. Patient peripheral NK, gd T and CD8 T cells were analyzed before consolidation CT and every other week after treatment for 8 weeks. 6-colors flow cytometry was performed to investigate the expression of MHC receptors (CD158a, b, e, i, CD85j and NKG2A), activating receptors (NKp30, NKp46, NKG2D, CD16, DNAM-1, 2B4) as well as their differentiation status (perforin and granzyme expression). Their function, as determined by cytotoxicity (51Cr release and CD107 expression) and cytokine production (intracellular staining of IFN-g), was analyzed using purified NK cells stimulated by K562, or in redirected assays using NKp30, NKp46 and CD16 mAbs. Results NK cell counts were depressed away from the induction and pre-consolidation CT as compared to NK cell counts of age-matched controls (ctl) (95±107 NK/μL vs 229±91 NK/μL respectively); they were further depressed during the first 2 weeks post-consolidation CT (55±57 NK/μL), but were back to pre-consolidation CT level at 4 weeks (105±102 NK/μL). In contrast, CD8 T cells and gd T cells counts were normal even at early times post-CT. Expression of 2B4 was depressed at all time points. In contrast, NKp30 expression was lower at diagnosis and close to ctl level post-consolidation CT (p=0.0003) and NKp46 expression increased after CT (p<0.0001). Sizes of NK cell subsets expressing CD158a or CD158b in patients post-induction and consolidation CT were smaller than those of ctl (% CD158a+: p=0.003; % CD158b+: p=0.014). In contrast the NKG2A or CD85j positive NK cell subsets were either unchanged or slightly increased respectively at all time points (p=0.0015 for CD85j+). Moreover, sizes of perforin or granzyme positive NK cell subsets were increased in treated AML patients (% Granzyme+: p= 0.0125 and % Perforin+: p=0.0268). In addition, we observed an important heterogeneity in the expression of the surface receptors among patients that is currently analyzed with respect to the duration of the CR. Finally, NK cell cytoxicity was comparable at all time points to the one of age-matched ctl. In contrast, IFN-g secretion was decreased, at all time points, against K562 or in redirected assays using CD16 mAb and almost abolished using redirected assay with NKp30 mAb. Conclusions This study demonstrates that in elderly AML patients in CR after CT (1) several alterations are detected at all time points, (2) NK cell number is lower and (3) IFN-g secretion is impaired. However NK cytotoxic function is comparable to age-matched controls. The likely basis of the complex pattern of modifications might rely on an interplay between the direct and indirect effects of chemotherapy, activation of immune system, NK cell differentiation and its interaction with AML blasts. Altogether this study indicates that new immunotherapeutic approaches might be used to increase NK cell numbers and functions (cytotoxicity and IFN-g secretion) at early times post-CT in elderly patients with AML. Disclosures Romagne: Innate Pharma: Employment.

2189 Background: Human Natural Killer (NK) cells are able to kill abnormal cells while preserving normal cells. Accumulating clinical and experimental data point toward a key role of these cells in the control and clearance of most if not all hematologic malignancies. Recent insights into NK have stimulated studies of innate immunity in haematological malignancies, as the role of NK cells in allogeneic transplantation. Better knowledge of the deficiencies of these effector cells can allow elaborating new protocols of immunotherapy in order to directly enhance their capacity to eliminate tumor cells. Hence, the mechanisms of recognition and killing of leukemic cells and their role in vivo have only been investigated very recently. Even though lysis of leukemic cells or leukemic cell lines by NK cells has been described in vitro, mechanisms underlying the interaction and destruction of these cells are not clearly defined. Some of these receptors are altered in AML patients at diagnosis and might be involved in the immune escape of AML blasts. However, the recovery of NK cells during consolidation chemotherapy treatment has not been studied. The present study monitored status of NK cells following patient's remission after chemotherapy in order to provide new targets for immunotherapy. Methods: We enrolled 29 elderly patients (mean: 70-years old) with non promyelocytic AML in first CR following induction and pre-consolidation chemotherapy. Patient peripheral NK cells were analyzed at diagnosis, before consolidation chemotherapy and every two weeks after treatment for 8 weeks. 6-colors flow cytometry was performed to investigate the expression of MHC receptors (CD158a, b, e, i, CD85j and NKG2A), activating receptors (NKp30, NKp46, NKG2D, CD16, DNAM-1, 2B4) as well as their differentiation status (perforin and granzyme expression). Their function, as determined by cytotoxicity (51Cr release and CD107 expression) and cytokine production (intracellular staining of IFN-g), was analyzed using purified NK cells stimulated by K562, or in redirected assays using NKp30, NKp46 and CD16 mAbs. The recovery of these receptors was then correlated with PFS and OS. Results: NK cell counts were depressed after induction and pre-consolidation chemotherapy as compared to NK cell counts of age-matched controls; they were further depressed during the first 2 weeks post-consolidation chemotherapy, but were back to pre-consolidation chemotherapy level at 4 weeks. NKp30 and NKp46 expression was lower at diagnosis as compared to controls but their levels restored progressively after induction and consolidation chemotherapy. NKG2D expression were depressed at pre-consolidation but increased after consolidation chemotherapy. For inhibitory receptors, CD158a or CD158b expressions were depressed at diagnosis, at post-induction and consolidation chemotherapy. In contrast, the NKG2A positive NK cell subsets increased progressively after consolidation chemotherapy. Moreover, sizes of perforin or granzyme positive NK cell subsets were increased in treated AML patients. K562 cytotoxicity was depressed after induction chemotherapy but increased after consolidation chemotherapy. In contrast, IFN-g secretion was decreased, at all time points. Finally, we try to correlate the recovery of these different receptors with OS and PFS. NKp30 and NKG2D recovery seems to be correlated with better PFS and OS. Conclusions: This study confirms that NK cells from AML patients displayed different phenotype and functional abnormalities at diagnosis. Chemotherapy seems to have different impact on the recovery of inhibitory or activatory NK receptors. The predominant data is that NK cells recovered rapidly after consolidation chemotherapy and seems to be more operational at that time. Immunotherapy of NK cells must be probably developed post consolidation chemotherapy when NK cells are ready and residual disease low. Antibodies to stimulate NK cells are actually evaluated in this setting. Disclosures: Anfossi: Innate Pharma: Employment. Andre:Innate Pharma: Employment. Breso:Innate Pharma: Employment. Perri:Innate Pharma: Employment. Romagne:Innate Pharma: Employment.