In this pilot study, we investigated the ability of autologous dendritic cells pulsed ex vivo with tumor-specific idiotype protein to stimulate host antitumor immunity when infused as a vaccine. Four patients with follicular B-cell lymphoma received a series of three or four infusions of antigen-pulsed dendritic cells followed, in each instance, by subcutaneous injections of soluble antigen two weeks later. All patients developed measurable antitumor cellular immune responses. In addition, clinical responses have been measured with one patient experiencing complete tumor regression, a second patient having partial tumor regression, and a third patient resolving all evidence of disease as detected by a sensitive tumor-specific molecular analysis.

We studied concentration, phenotype, and function of peripheral blood (PB) dendritic cells (DCs) from patients with multiple myeloma (MM). The absolute number of circulating precursors of myeloid and plasmacytoid DCs was significantly lower in MM patients than in healthy subjects. After maturation, PBDCs from MM patients showed significantly lower expression of HLA-DR, CD40, and CD80 antigens and impaired induction of allogeneic T-cell proliferation compared with controls. Remarkably, they were not capable of presenting the patientspecific tumor idiotype to autologous T cells. Conversely, DCs generated in vitro from CD14 ؉ monocytes from the same

Purpose: To elucidate the mechanism by which trastuzumab, a humanized monoclonal antibody against HER2 with proven survival benefit in women with HER2-positive metastatic breast cancer, mediates its antitumor activity.Experimental Design: A pilot study including 11 patients with HER2-positive tumors treated in a neo-adjuvant setting with trastuzumab was performed. Trastuzumab was administered i.v. at a dose of 4 mg/kg followed by three weekly i.v. doses of 2 mg/kg. The primary tumor was surgically removed 7 days after the last treatment. Surgical samples, tumor biopsies, and lymphocytes from these patients were collected for biological studies.Result: Clinical data indicated one complete pathological remission and four partial remissions using RECIST (Response Evaluation Criteria in Solid Tumors). Trastuzumab was well tolerated and neither serious adverse events nor changes in cardiac function were observed during this short-term treatment and after surgery. The biological data showed that, independent of response, (a) all patients showed high levels of circulating trastuzumab; (b) saturating level of trastuzumab was present in all of the tumors; (c) no down-modulation of HER2 was observed in any tumors; (d) no changes in vessel diameter was observed in any tumors; (e) no changes in proliferation was observed in any tumors; and (f) a strong infiltration by lymphoid cells was observed in all cases. Patients with complete remission or partial remission were found to have a higher in situ infiltration of leukocytes and a higher capability to mediate in vitro antibody-dependent cellular cytotoxicity activity.Conclusions: The results of this pilot study argue against trastuzumab activity in patients through downmodulation of HER2 but in favor of antibody-dependent cellular cytotoxicity guiding efforts to optimize the use of trastuzumab in breast cancer patients.

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Clinical observations indicate that elderly people are prone to severe, often lethal infectious diseases induced by novel pathogens. Since the ability to mount primary immune responses relies on the availability of naive T cells, the circulating naive T-cell reservoir was evaluated throughout the human life span. Naive T cells were identified as CD95− T lymphocytes for their phenotypic and functional features. Indeed, the lack of CD95 marker is sufficient to identify a population of naive T cells, as defined by coincidence with previously characterized CD45RA+ CD62L+ T cells. Naive CD95− T cells, as expected, require a costimulatory signal, such as CD28, to optimally proliferate after anti-CD3 stimulation. Cytofluorimetric analysis of circulating T lymphocytes from 120 healthy subjects ranging in age from 18 to 105 years revealed that naive T cells decreased sharply with age. The younger subjects had a naive T-lymphocyte count of 825 ± 48 cells/μL, and the centenarians had a naive T-lymphocyte count of 177 ± 28 cells/μL. Surprisingly, the naive T-cell count was lower in CD8+than in CD4+ subsets at any age, and the oldest individuals were almost completely depleted of circulating naive CD8+ T cells (13 ± 4 cells/μL). Concomitantly, a progressive expansion of CD28− T cells occurs with age, which can be interpreted as a compensatory mechanism. These data provide new insights into age-related T-cell–mediated immunodeficiency and reveal some analogies of T-cell dynamics between advanced aging and human immunodeficiency virus (HIV) infection. In conclusion, the exhaustion of the naive CD8+ T-cell reservoir, which has never been reported before, suggests that this T-cell pool is a major target of the aging process and may define a parameter possibly related to the life span of humans.

Radiofrequency thermal ablation (RFA) destroys tumoral tissue generating a local necrosis followed by marked inflammatory response with a dense T-cell infiltrate. In this study, we tested whether hepatocellular carcinoma thermal ablation can induce or enhance T-cell responses specific for hepatocellular carcinoma-associated antigens. Peripheral blood mononuclear cells derived from 20 patients with hepatocellular carcinoma were stimulated before and a month after RFA treatment with autologous hepatocellular carcinoma-derived protein lysates obtained before and immediately after RFA treatment. The effect of thermal ablation on memory T-cell responses to recall antigens [tetanus toxoid, protein purified derivative (PPD), Escherichia coli] was also assessed. T-cell reactivity was analyzed in an IFN-; enzymelinked immunospot assay and by intracellular IFN-; staining. Treatment was followed by a significant increase of patients responsive either to tumor antigens derived from both the untreated hepatocellular carcinoma tissue (P < 0.05) and the necrotic tumor (P < 0.01) and by a higher frequency of circulating tumor-specific T cells. T-cell responses to recall antigens were also significantly augmented. Phenotypic analysis of circulating T and natural killer cells showed an increased expression of activation and cytotoxic surface markers. However, tumor-specific T-cell responses were not associated with protection from hepatocellular carcinoma relapse. Evidence of tumor immune escape was provided in one patient by the evidence that a new nodule of hepatocellular carcinoma recurrence was not recognized by T cells obtained at the time of RFA. In conclusion, RFA treatment generates the local conditions for activating the tumorspecific T-cell response. Although this effect is not sufficient for controlling hepatocellular carcinoma, it may represent the basis for the development of an adjuvant immunotherapy in patients undergoing RFA for primary and secondary liver

Preliminary results from a pilot trial on trastuzumab's mechanism of action against operable breast tumors overexpressing Her2 suggested a role for antibody-dependent cell cytotoxicity (ADCC). To examine factors affecting ADCC intensity and variability, we extended this study to the phenotypic and functional analysis of circulating mononuclear cells in 18 patients. ADCC was induced by trastuzumab therapy in 15 of 18 patients (83%). Inability to develop ADCC in three patients did not depend on inadequate levels of trastuzumab because further increase in its concentration in vitro was ineffective. Rather, susceptibility to develop ADCC was fairly predicted by test with trastuzumab before therapy and was correlated to the number of lymphocytes coexpressing CD16 and CD56. Phenotypic analysis at the end of ADCC evaluating down-regulation of CD16, and up-regulation of CD69 and CD107a, confirmed that natural killer (NK) cells and CD56 + T cells were involved in productive engagement of trastuzumab. Also, the killing efficiency of CD16 + lymphocytes was influenced by 158 V/F polymorphism of Fc;RIII (CD16), whereas variations of CD247 on NK cells were consistent with trends between ADCC before and after therapy. Complete pathologic response was observed in one patient showing ADCC of outstanding intensity, whereas four cases of partial response showed intermediate ADCC; none of the three patients unable to mount ADCC had significant tumor regression. These data indicate that quantity and lytic efficiency of CD16 + lymphocytes are major factors for ADCC induction by trastuzumab, and confirm that breast cancer responses to short-term trastuzumab monotherapy may depend on involvement of the ADCC mechanism. [Cancer Res 2007;67(24):11991-9]

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