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Regulatory T cells (Treg cells) are increased in context of malignancies and their expansion can be correlated with higher disease burden and decreased survival. Initially, interleukin 2 (IL-2) has been used as T-cell growth factor in clinical vaccination trials. In murine models, however, a role of IL-2 in development, differentiation, homeostasis, and function of Treg cells was established. In IL-2 treated cancer patients a further Treg-cell expansion was described, yet, the mechanism of expansion is still elusive. Here we report that functional Treg cells of a naïve phenotype - as determined by CCR7 and CD45RA expression - are significantly expanded in colorectal cancer patients. Treatment of 15 UICC stage IV colorectal cancer patients with IL-2 in a phase I/II peptide vaccination trial further enlarges the already increased naïve Treg-cell pool. Higher frequencies of T-cell receptor excision circles in naïve Treg cells indicate IL-2 dependent thymic generation of naïve Treg cells as a mechanism leading to increased frequencies of Treg cells post IL-2 treatment in cancer patients. This finding could be confirmed in naïve murine Treg cells after IL-2 administration. These results point to a more complex regulation of Treg cells in context of IL-2 administration. Future strategies therefore might aim at combining IL-2 therapy with novel strategies to circumvent expansion and differentiation of naïve Treg cells. [ABSTRACT FROM AUTHOR]

Today, many patients with lymphoma are cured by polychemotherapy and irradiation. However, residual masses are frequently observed after treatment and discrimination between vital tumor and inactive fibrotic tissue by computed tomography or magnetic resonance tomography is often not possible. [sup 18]F-Fluorodeoxyglucose (FDG) positron emission tomography (PET) is a metabolic imaging modality that is able to detect active lymphoma lesions. The application of PET may play a crucial role in identifying patients with residual disease and contribute valuable prognostic information. To assess the prognostic implications of PET in the post-therapeutic setting, we performed a MedLine Search and reviewed the current available studies on this important issue together with our own data. [ABSTRACT FROM AUTHOR]

Regulatory T cells (T(reg) cells) are increased in context of malignancies and their expansion can be correlated with higher disease burden and decreased survival. Initially, interleukin 2 (IL-2) has been used as T-cell growth factor in clinical vaccination trials. In murine models, however, a role of IL-2 in development, differentiation, homeostasis, and function of T(reg) cells was established. In IL-2 treated cancer patients a further T(reg)-cell expansion was described, yet, the mechanism of expansion is still elusive. Here we report that functional T(reg) cells of a naïve phenotype--as determined by CCR7 and CD45RA expression--are significantly expanded in colorectal cancer patients. Treatment of 15 UICC stage IV colorectal cancer patients with IL-2 in a phase I/II peptide vaccination trial further enlarges the already increased naïve T(reg)-cell pool. Higher frequencies of T-cell receptor excision circles in naïve T(reg) cells indicate IL-2 dependent thymic generation of naïve T(reg) cells as a mechanism leading to increased frequencies of T(reg) cells post IL-2 treatment in cancer patients. This finding could be confirmed in naïve murine T(reg) cells after IL-2 administration. These results point to a more complex regulation of T(reg) cells in context of IL-2 administration. Future strategies therefore might aim at combining IL-2 therapy with novel strategies to circumvent expansion and differentiation of naïve T(reg) cells.

In solid tumors, leukemias, and lymphomas, increased frequencies of functional CD4+CD25(high) regulatory T cells (T(reg) cells) have been previously demonstrated. In healthy individuals, T(reg) cells consist not only of memory but also of naive T cells, which can undergo peripheral expansion and are characterized by a relative enrichment for autoreactive T-cell receptors. Here, we demonstrate in patients with premalignant monoclonal gammopathy of undetermined significance and patients with multiple myeloma that functional FoxP3(+) T(reg) cells of naive, central, and effector memory phenotype as determined by CCR7 and CD45RA expression are significantly expanded. Low frequencies of T-cell receptor excision circles in naive T(reg) cells in both healthy controls and multiple myeloma patients point to peripheral expansion as the prominent mechanism of increased frequencies of naive T(reg) cells in these cancer patients. These findings strongly suggest that the increase of functional T(reg) cells in cancer patients is a response to the process of malignant transformation.

High-dose methotrexate (HDMTX) is a component of many cancer treatment regimens. Despite careful management, delayed renal clearance, followed by extremely high serum levels with potentially life-threatening toxicity can occur. In the present study, we report our results of carboxypeptidase-G2 (CPDG2) rescue in 8 patients with delayed methotrexate elimination and renal impairment after HDMTX therapy for lymphoma or osteosarcoma. A dose of 50 U/kg CPDG2 was administered. MTX plasma levels decreased rapidly and recovery of renal function was observed in all patients. No patient developed severe WHO grade 4 MTX toxicity. CPDG2 provides an alternative route of MTX elimination by converting it to inactive and non-toxic metabolites. CPDG2 rescue was well tolerated, safe and very effective in preventing severe or life-threatening MTX toxicity.