Search

Background Immunoglobulin M multiple myeloma and Waldenström macroglobulinemia are two different hematological diseases with the common finding of an immunoglobulin M monoclonal gammopathy of unknown significance. However, clinical characteristics of the two entities can overlap. Case presentation In this report, we describe two cases of immunoglobulin M neoplasm with the same histological bone marrow presentation but with different clinical behavior, cytogenetics, and biological assessment. On the basis of comprehensive diagnostic workup, these patients were considered to have different diseases and treated accordingly with different approaches. Patient 1 (Caucasian man) presented with increased serum protein and immunoglobulin M (7665 mg/L) with an M-spike electrophoresis of 4600 mg/L. His bone marrow biopsy revealed a small-cell immunoglobulin M multiple myeloma. The result of testing for the MYD88 L265P mutation was negative, while fluorescence in situ hybridization analysis showed translocation t(11,14). A diagnosis of immunoglobulin M-κ multiple myeloma was made. Patient 1 was a candidate for bortezomib plus thalidomide and dexamethasone, followed by autologous stem cell transplant consolidation. Patient 2 (Caucasian man) showed an M-spike by protein electrophoresis (300 mg/L, 4.9%), with serum immunoglobulin M level of 327 mg/L. His bone marrow biopsy revealed immunoglobulin M-κ multiple myeloma. Computed tomography showed many enlarged lymph nodes and splenomegaly. Patient 2’s clinical features were suggestive of Waldenström macroglobulinemia, in contrast to the bone marrow biopsy results. The result of testing for the MYD88 L265P mutation was positive. Patient 2 was diagnosed with Waldenström macroglobulinemia and received rituximab, cyclophosphamide, and dexamethasone. Conclusions A correct differential diagnosis between immunoglobulin M multiple myeloma and Waldenström macroglobulinemia is a critical point in the setting of a new immunoglobulin M monoclonal gammopathy onset. These patients should undergo a complete diagnostic workup with pathological, radiological, and serological examinations to establish the diagnosis and plan the most appropriate treatment in order to improve the prognosis.

Antibody-dependent cell-mediated cytotoxicity (ADCC) may contribute to the antitumor activity of cetuximab. However, the extent of this contribution is unclear. In this study, we investigated the impact of baseline ADCC on the outcome of patients with locally advanced squamous cell carcinoma treated with cetuximab and radiotherapy. We determined baseline ADCC in 28 patients treated with cetuximab and radiotherapy and in 15 patients treated with chemoradiation. We linked the values observed with complete response and with overall survival. We also considered the role of epidermal growth factor receptor (EGFR) expression and studied the combined effect of EGFR and ADCC. We observed a wide range of baseline values of ADCC. Complete response did not correlate with either ADCC or EGFR expression. However, when ADCC and EGFR were considered together using a mixed score, they significantly correlated with achieving a complete response (p = 0.04). High baseline ADCC significantly correlated with outcome compared to low (p = 0.03), but not in patients treated without cetuximab. Patients showing high baseline levels of both ADCC and EGFR3+ achieved the best outcome compared to the others (p = 0.02). In this study, patients treated with cetuximab and radiotherapy, showing high baseline of both ADCC and EGFR3+, have significant higher probability of achieving a complete response and a long overall survival compared to the others.

Background Advances in the understanding of tumor biology have led to the development of targeted therapies as monoclonal antibodies (MoAbs) in clinical oncology. Among their suggested mechanisms of action monoclonal antibodies (IgG1) selectively directed against tumor membrane receptors mediate of antibody–dependent cellular cytotoxicity (ADCC) by triggering Fc-γRIII on natural killer (NK) cells. Methods This study reviews the clinical context of ADCC measurement with a particular focus on EGFR targeting and describes an ex vivo ADCC method applied to MoAbs (cetuximab and panitumumab), against epidermal growth factor receptor (EGFR). The test performance was evaluated on different target cells lines (CAL166, A431, HNO91, CAL27), with different effector cells (peripheral blood mononuclear cells or natural killers -NK-) and in various experimental conditions, in order to establish a truly clinically applicable method. Results Using the experience available in the published literature, we optimized all variables involved in the experimental design: target cells type, numbers and ratio target cells and NK cells (effector cells) per well, time of exposure and repeatability. Conclusion ADCC measurement may be of clinical relevance in the context of treatment with MoAbs. This study describes a non-radioactive method which has proven satisfactory in terms of sensitivity, reproducibility, feasibility and cost effectiveness for the measurement of ADCC activity mediated by NK with an orientation towards the EGFR target.

AIM: To investigate the prognostic role of invariant natural killer T (iNKT) cells and antibody-dependent cell-mediated cytotoxicity (ADCC) in wild type KRAS metastatic colorectal cancer (mCRC) patients treated with cetuximab. METHODS: Forty-one KRAS wt mCRC patients, treated with cetuximab and irinotecan-based chemotherapy in II and III lines were analyzed. Genotyping of single nucleotide polymorphism (SNP)s in the FCGR2A, FCGR3A and in the 3’ untranslated regions of KRAS and mutational analysis for KRAS, BRAF and NRAS genes was determined either by sequencing or allelic discrimination assays. Enriched NK cells were obtained from lymphoprep-peripheral blood mononuclear cell and iNKT cells were defined by co-expression of CD3, TCRVα24, TCRVβ11. ADCC was evaluated as ex vivo NK-dependent activity, measuring lactate dehydrogenase release. RESULTS: At basal, mCRC patients performing ADCC activity above the median level (71%) showed an improved overall survival (OS) compared to patients with ADCC below (median 16 vs 8 mo; P = 0.026). We did not find any significant correlation of iNKT cells with OS (P = 0.19), albeit we observed a trend to a longer survival after 10 mo in patients with iNKT above median basal level (0.382 cells/microliter). Correlation of OS and progression-free survival (PFS) with interesting SNPs involved in ADCC ability revealed not to be significant. Patients carrying alleles both with A in FCGR2A and TT in FCGR3A presented a trend of longer PFS (median 9 vs 5 mo; P = 0.064). Chemotherapy impacted both iNKT cells and ADCC activity. Their prognostic values get lost when we analysed them after 2 and 4 mo of treatment. CONCLUSION: Our results suggest a link between iNKT cells, basal ADCC activity, genotypes in FCGR2A and FCGR3A, and efficacy of cetuximab in KRAS wt mCRC patients.

OBJECTIVES Morphology and cytogenetics are currently used to define prognosis in myelodysplastic syndromes (MDS). However, these parameters have some limits. Flow cytometry has been recently included in the diagnostic panel for MDS, and its prognostic significance is under evaluation. METHODS Marrow aspirates from 424 MDS patients were analyzed by flow cytometry to evaluate the impact of bone marrow cell immunophenotype on overall survival (OS) and leukemia-free survival (LFS). The immature compartment of myeloblasts was analyzed by the quantitative expression of CD34 (

Chronic lymphocytic leukemia (CLL) has a variable clinical course. CD38 expression and IgV(H) gene mutational status are independent predictors of prognosis, but their relationships and the CD38 cutoff level are unknown. Using cytofluorography, we analyzed CD38 in 148 patients, in 108 of whom we were able to evaluate IgV(H) Mutations, make correlations with disease history, and assess cumulative survival. Three different patient groups were identified by the CD38 expression pattern: a group homogeneously CD38(-), a group homogeneously CD38(+), and a group characterized by a bimodal profile, because of the concomitant presence of variable proportions of 2 distinct populations, one CD38(+) and one CD38(-). In CD38 bimodal expression patients the CD38(+) subset was significantly more represented in the bone marrow than in the peripheral blood. For IgV(H) mutations, 11.4% of CD38-, 84.6% of CD38(+), and 68.0% of CD38 bimodal expression patients had no mutation. CD38 expression, 19V(H) mutational status, and traditional prognostic factors were concordant. The progression rate was 12.9% for CD38-, 75.0% for CD38(+), and 63.3% for CD38 bimodal expression patients. Only 25.8% of the CD38(-) patients but 63.3% of the bimodal and 75.0% of CD38(+) patients were treated The presence of a CD38(+) population, albeit small, correlated with the development of auioimmune manifestations. T I he CD38(-) group has hot yet reached the median survival, which is 183 months in the CD38(+) group and 156 months in the CD38 bimodal expression group, regardless of the size of the CD38(+) population. The presence of a distinct CD38(+) population within the leukemic clone, rather than a numerical cutoff definition, correlates with IgV(H) gene mutational status and, irrespective of its size, identifies CLL patients who will have progressive disease. (C) 2003 by The American Society of Hematology.

Follicular lymphomas (FLs) localize in lymphoid tissues and recapitulate the structure of normal secondary follicles. The chemokine/chemokine receptor pair CXCL13/CXCR5 is required for the architectural organization of B cells within lymphoid follicles. In this study, we showed that CXCL13 was secreted by FL cells. FL cells expressed CXCR5 and migrated in response to CXCL13. Furthermore, we observed a synergistic effect between CXCL13 and CXCL12 (SDF-1), a chemokine produced by stromal cells in lymphoid tissues. The production of CXCL13 by FL cells and CXCL12 by stromal cells probably directs and participates in the accumulation of FL cells within specific anatomic sites.

Several algorithms for early prediction of poor-mobilizing patients after chemotherapy and granulocyte colony-stimulating factor administration have been proposed. They generally define peripheral blood cut-off levels of CD34+ cells at a fixed day after starting chemotherapy, mostly with cyclophosphamide. To define an algorithm for early addition of plerixafor regardless of the chemotherapy regimen used, we retrospectively analyzed 280 chemomobilization attempts in 236 patients treated at our institution between 2002 and 2012. In multivariate analysis, CD34+ absolute count and CD34+ percentage upon total leukocyte count at day 1 (defined as the first day in which leukocytes reached a value > 1 × 109/L) were the only factors able to predict a total harvest ≥ 2 × 106 CD34+/kg. In patients with day 1 CD34+ lower than 20/μL, the CD34+ percentage was a more reliable predictor of stem cell harvest in the following days than CD34+ absolute count. Upon definition of the best CD34+ cut-off value for identification of poor-mobilizing patients, an algorithm was set up to guide plerixafor administration. It was prospectively validated in 20 patients in 2013 with encouraging results in terms of low incidences of both mobilization failure and plerixafor use. Large prospective trials that define the most cost-effective strategy for just-in-time rescue plerixafor are warranted.

Introduction Cetuximab is a IgG1 monoclonal antibody against epidermal growth factor receptor (EGFR) used for head and neck squamous cell carcinoma (HNSCC) treatment. In addition to EGFR targeting, cetuximab is able to develop an antibody-dependent cell-mediated cytotoxicity (ADCC), triggered by Fc receptors (Fcγ-R) on Natural Killer cells, macrophages and polymorphonucleated leukocytes. This prospective study examined the possible prognostic value of cetuximab-mediated ADCC response in a cohort of HNSCC patients. Patients and Methods There were 63 patients treated with curative intent with chemo-radiotherapy (CT-RT), associated (N = 39) or not (N = 24) with cetuximab. Peripheral blood samples were collected at start of therapy. Intrinsic ADCC was evaluated from ex vivo NK-dependent activity measuring LDH release through the Cytotox 96® non radioactive cytotoxicity assay, previously standardized in our laboratory (Crit Rev Oncol Hematol, 2015). EGFR tumoral expression was analyzed by immunohistochemistry. Results Median ADCC response at treatment start for all patients was 56.1% (range 5-99%). Analysing the whole population, patients with ADCC above the median value (high) showed a better OS as compared to patients with ADCC below the median (low), HR = 0.3827 (95% CI, 0.1464 to 1.000), p = 0.05 (Long-rank Mantel-Cox Test). A sub-group analysis confirmed a possible link between high ADCC and a better OS (CT-RT group, p = 0.223 and CT-RT+cetuximab group, p = 0.244). Importantly, considering CT-RT+cetuximab treatment and EGFR tumoral expression (N = 21), patients with EGFR 3+ status and high ADCC showed an improved OS as compared to patients with ADCC below median value, HR = 0.09031 (95% CI, 0.009983 to 0.8170), p = 0.032 (Long-rank Mantel-Cox Test). Median OS values for patients with high EGFR expression were 34.8 months (range 9.1-53.7) and 13.1 months (range 2.1-39.5) for patients with respectively high ADCC and low ADCC. Conclusion ADCC is shown to be a strong driver of cetuximab-based therapy outcome in HNSCC. High tumoral EGFR expression and high ADCC confer a particularly long overall survival. These data suggest an ADCC-based and EGFR expression-based precision therapy under cetuximab in HNSCC and open perspectives for NK boosting. Citation Format: Cristiana Lo Nigro, Laura Lattanzio, Daniela Vivenza, Martino Monteverde, Federica Tonissi, Giuliana Strola, Marco Merlano, Gerard Milano. Treatment outcome under cetuximab-based therapy and individual ADCC capability in head and neck cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1414.

Morphology and cytogenetics are currently used to define prognosis in myelodysplastic syndromes (MDS). However, these parameters have some limits. Flow cytometry has been recently included in the diagnostic panel for MDS, and its prognostic significance is under evaluation.Marrow aspirates from 424 MDS patients were analyzed by flow cytometry to evaluate the impact of bone marrow cell immunophenotype on overall survival (OS) and leukemia-free survival (LFS). The immature compartment of myeloblasts was analyzed by the quantitative expression of CD34 (3% vs. ≥3%), CD117, and CD11b(-) /CD66b(-) (5% vs. ≥5%); myeloid maturation was analyzed by the expression of CD11b(+) /CD66b(++) (15% vs. ≥15%) and CD11b(+) /CD66b(+) (25% vs. ≥25%).In univariate analysis, the expression of immaturity markers (CD34(+) , CD117(+) , and CD11b(-) /CD66b(-) ) was associated with shorter LFS and OS (P 0.0001); higher expression of differentiation markers (CD11b(+) /CD66b(++) and CD11b(+) /CD66b(+) ) was associated with longer LFS (P 0.0001 and P = 0.0002, respectively) and OS (P 0.0001). In multivariate analysis, expression of CD34(+) (P = 0.007), CD117(+) (P = 0.013), and CD11b(+) /CD66b(++) (P = 0.023) retained independent prognostic value for OS, while only the expression of CD34(+) was a prognostic factor for LFS (P = 0.0003). Two different risk groups were defined according to the presence of 0-1 or ≥2 of these factors with significant different LFS and OS (P 0.0001). This score showed prognostic value in predicting survival even in subanalysis according to IPSS and WHO subgroups.Flow cytometric analysis in MDS may provide meaningful prognostic information. Blast percentage expressed as CD117(+) or CD34(+) cells and the quantitative assessment of myeloid maturation showed prognostic value for survival.

Introduction: Immunomodulation by anticancer agents is currently of major interest. We prospectively examined in 163 advanced cancer patients the impact of chemotherapy, combined or not with cetuximab, on relevant immune cell profile. Patients and Methods: 72 metastatic colorectal cancer patients received FOLFIRI, associated (N = 60) or not (N = 12) with cetuximab (Cetux), and 91 head&neck squamous cell carcinoma patients received 5FU+platinum-based chemotherapy, associated (N = 69) or not (N = 22) with Cetux. Median follow-up was 12.9 months (96 deaths). Phenotyping (Beckman coulter flow cytometer) of peripheral-blood lymphocytes was performed at baseline and after 2-month treatment. T cells were defined as CD3+ (irrespective of CD56), NK cells as CD3- CD56+, NKT cells as CD3+ CD56+, and invariant CD1d-restricted natural killer T (invNKT) cells were characterized by coexpression of T-cell antigen receptor-Vα24 and -Vβ11 along with CD3+ and CD56+. Results: Analysis of cell count evolution at 2-month showed that 5FU+platinum negatively significantly modulated both T, NK, NKT and invNKT cells, with a median decrease of 45% to 69% relative to baseline, whereas FOLFIRI had no significant impact. In combination with Cetux, the decrease observed with 5FU+platinum was significantly attenuated for T cells, and a similar trend was observed in NKT cells (Table). In contrast, the combination of Cetux with FOLFIRI induced a significant decrease in NK cells. Overall survival was not related to the evolution of any immune cell type, either in Chemo or Chemo-Cetux groups. Conclusion: Present results on the differential modulation of peripheral immune cells by cetuximab-chemotherapy draw attention and may be of importance in the context of future combinations with immunotherapy. Intra-patient cell count change (%) at 2 months relative to baseline: 5FU-Platinum group5FU-Platinum + Cetux groupInter-group stat**MedianStat*% of patients with decreaseMedianStat*% of patients with decreaseT cells-66p Citation Format: Cristiana Lo Nigro, Martino Monteverde, Marie-Christine Etienne-Grimaldi, Giuliana Strola, Laura Lattanzio, Daniela Vivenza, Federica Tonissi, Annalisa Ghiglia, Marco Merlano, Gerard Milano. Variable impact of chemotherapy +/- cetuximab on immune modulation in a prospective cohort of 163 cancer patients. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1327. doi:10.1158/1538-7445.AM2015-1327

Objective. The mechanisms regulating the trafficking of leukemic myeloid blasts are poorly understood. A differential expression of chemokines and chemokine receptors might account for some aspects of the pattern of invasion and accumulation of leukemic cells. We aimed at defining the pattern of chemokine and chemokine receptor expression of acute myeloid leukemia (AML) blasts in comparison with their putative normal cell counterparts. Patients and Methods. Twenty-five cases of AML were analyzed by flow cytometry for the expression of several chemokine receptors and by RT-PCR for the expression of relevant chemokines. For selected chemokines, the production was confirmed by ELISA. AML blasts were also assessed for their migration capacity in response to autologous supernatants and recombinant chemokines. Results. Undifferentiated AML (M0-M1 and some M2) express only CXCR4 on their surface and produce mainly inflammatory chemokines, resembling normal CD34(+) progenitors. More differentiated AML (M4-M5 and some M2) have a more diversified receptor repertoire and, besides CXCR4, express the receptors for inflammatory chemokines and produce both constitutive and inflammatory chemokines, resembling resting and activated monocytes. In particular, M4-M5 blasts produce MCP-1 and MIP-3alpha and also express their specific receptors (CCR2 and, to a lesser extent, CCR6) and migrate in vitro in response to MCP-1 and MIP-3alpha and to their own supernatant. A significant correlation between extramedullary involvement and coexpression of MCP-1/CCR2 was found. Conclusions. These data suggest that chemokines and their receptors segregate within the different FAB subtypes and, by allowing cross-talk among members of the malignant clone, might help to explain some aspects of the pattern of invasion in AML with monocytic differentiation. (C) 2003 International Society for Experimental Hematology. Published by Elsevier Inc.

The natural history of B-chronic lymphocytic leukemia (CLL) is not entirely explained by intrinsic defects of the neoplastic cell, but is also favored by microenvironmental signals. As CLL cells retain the capacity to respond to CD40 ligand (CD40L) and as CD4(+) T cells are always present in involved tissues, we asked whether malignant CLL cells might produce T cell-attracting chemokines. We studied the chemokine expression of CD19(+)/CD5(+) malignant B cells from peripheral blood (PB), lymph nodes (LN) or bone marrow (BM) of 32 patients and found a major difference. LN- and BM-, but not PB-derived cells, expressed a readily detectable reverse transcription-PCR band for CCL22 and one for CCL17 of variable intensity. CD40 ligation of PB cells induced the mRNA expression of both CCL22 and CCL17. CCL22 was also released in the culture supernatants. These supernatants induced the migration of activated CD4(+), CD40L(+) T cells expressing the CCL22 receptor, CCR4. T cell migration was abrogated by anti-CCL22 antibodies. Immunohistochemistry and cytofluorography studies revealed that a proportion of CD4(+) T cells in CLL LN and BM expressed CD40L. Our data demonstrate that malignant CLL cells chemo-attract CD4(+) T cells that in turn induce a strong chemokine production by the leukemic clone, suggesting a vicious circle, leading to the progressive accumulation of the neoplastic cells.

Follicular lymphomas (FLs) localize in lymphoid tissues and recapitulate the structure of normal secondary follicles. The chemokine/chemokine receptor pair CXCL13/ CXCR5 is required for the architectural organization of B cells within lymphoid follicles. In this study, we showed that CXCL13 was secreted by FL cells. FL cells expressed CXCR5 and migrated in response to CXCL13. Furthermore, we observed a synergistic effect between CXCL13 and CXCL12 (SDF-1), a chemokine produced by stromal cells in lymphoid tissues. The production of CXCL13 by FL cells and CXCL12 by stromal cells probably directs and participates in the accumulation of FL cells within specific anatomic sites.

In B-cell chronic lymphocytic leukemia (B-CLL), defective apoptosis causes the accumulation of mature CD5(+) B cells in lymphoid organs, bone marrow (BM), and peripheral blood (PB). These cells are the progeny of a proliferating pool that feeds the accumulating compartment. The authors sought to determine which molecular mechanisms govern the proliferating pool, how they relate to apoptosis, and what the role is of the microenvironment. To begin to resolve these problems, the expression and modulation of the family of inhibitor of apoptosis proteins (IAPs) were investigated, with consideration given to the possibility that physiological stimuli, such as CD40 ligand (CD40L), available to B cells in the microenvironment, might modulate IAP expression. The in vitro data on mononuclear cells from PB or BM of 30 patients demonstrate that B-CLL cells on CD40 stimulation express Survivin and that Survivin is the only IAP whose expression is induced by CD40L. Through immunohistochemistry, in vivo Survivin expression in lymph node (LN) and BM biopsies was evaluated. In reactive LN, Survivin was detected only in highly proliferating germinal center cells. In LN from patients with B-CLL. Survivin was detected only in pseudofollicles. Pseudofollicle Survivin(+) cells were actively proliferating and, in contrast to Survivin+ B cells found in normal GC, were Bcl-2(+). In B-CLL BM biopsies, CD5(+), Survivin+ cells were observed in clusters interspersed with T cells. These findings establish that Survivin controls the B-CLL proliferative pool interfacing apoptosis and that its expression may be modulated by microenvironmental stimuli. (Blood. 2001;97:2777-2783) (C) 2001 by The American Society of Hematology.

Background ADCC may play a role in antitumor activity of IgG1 mAb by inducing immune cell-mediated tumor lysis. We evaluated ADCC ability before and under cetuximab treatment and impact on survival in locally advanced Head and Neck (LAHNSCC) or metastatic colorectal cancer (mCRC). Methods 82 patients (60 men, 22 women; median age 64, range 39-87), 39 LAHNSCC and 43 mCRC, treated with chemotherapy (irinotecan or folfiri) plus cetuximab, were prospectively enrolled. ADCC ex-vivo was measured before treatment and every 2 months (1 to 7 measurements/patient, 44 patients with ≥2 measurements). 400 000 purified Natural Killer cells (CD3- CD56+) from patients were incubated with 10 000 target cells (CAL166 cell line expressing EGFR) and 10 µg/ml cetuximab. Cytotoxicity was measured by LDH-release assay. ADCC was expressed as % of lysed target cells. Polymorphisms of Fcg receptors FcgR2a (131Arg > His) and FcgR3a (158Phe > Val) were analyzed by Allelic Discrimination assay. Results The feasibility rate of ADCC measurements was 85-90%. Basal ADCC ranged between 30% and 100% (mean 62%, median 66%) and was not influenced by gender. A trend for an increased basal ADCC was observed in younger patients: median was 66% in the 22 patients Conclusions A new generation of mAb is currently being developed with the aim to amplify ADCC. Present data illustrate the feasibility of ADCC measurement in mAb-treated patients and reveal an initial drop in ADCC under treatment that may reflect the variable chemotherapy-induced impact on host immunity. Disclosure All authors have declared no conflicts of interest.

2600 Background: ADCC plays a role in antitumor activity of IgG1 mAb by inducing immune cell-mediated lysis of tumor cells. We evaluated ADCC ability before and under cetuximab-based treatment and examined its impact on treatment outcome. Methods: 29 patients (17 men, 12 women, median age 72, range 51-84) with metastatic wild-type KRAS CRC treated with chemotherapy (irinotecan or Folfiri) plus cetuximab were prospectively enrolled. ADCC ex-vivo was measured before starting treatment and every 2 months during treatment (1 to 7 measurements/patient, 12 patients with >2 measurements). 400 000 purified Natural Killer cells (CD3- CD56+) from patients were incubated with 10 000 target cells (CAL166 cancer cell line expressing EGFR) and 10 µg/ml cetuximab (triplicates). Cytotoxicity was measured by the LDH-release assay. ADCC was expressed as the % of lyzed target cells. Gene polymorphisms of Fcγ receptors FCGR2a (131Arg>His) and FCGR3a (158Phe>Val) were analyzed (Allelic Discrimination assay). Results: The feasibility rate of ADCC measurement was 88%. ADCC basal values ranged between 30% and 100% (mean 62%, median 66%). Basal ADCC was not influenced by patient gender. A tendency for an increased ADCC basal value was observed in younger patients: median was 76% in the 6 patients ≤ 60 vs 56% in the 23 patients over 60 years-old (p = 0.031). FCGR2A and FCGR3A gene polymorphisms were not linked to basal ADCC. The evolution of individual ADCC ability before treatment and 2 months later revealed a significant drop in ADCC following treatment initiation (intra-patient comparison, n=18, p=0.006), with an absolute median drop of 19%. This decrease was not sustained over time and intra-patient comparison between basal value and 4-month measurement was not significant. 25 patients were assessable for survival (11 deaths). Basal ADCC values were not related to survival. Conclusions: A new generation of mAb is currently being developed with the aim to amplify ADCC. Present data illustrate the feasibility of ADCC measurement in mAb-treated patients and reveal an initial drop in ADCC under treatment that may reflect the variable chemotherapy-induced impact on host immunity.