Dominant tolerance is mediated by regulatory T cells (Treg) that control harmful autoimmune T cells in the periphery. In this study, we investigate the implication of Treg in modulating infiltrating T lymphocytes in human metastatic melanoma. We found that CD4+CD25high T cells are overrepresented in metastatic lymph nodes (LNs) with a 2-fold increased frequency compared with both tumor-free LNs and autologous PBMCs. These cells express the Foxp3 transcription factor, display an activated phenotype, and display a polyclonal TCR Vβ chain repertoire. They inhibit in vitro the proliferation and cytokine production of infiltrating CD4+CD25− and CD8+ T cells (IL-2, IFN-γ) through a cell-contact-dependent mechanism, thus behaving as Treg. In some cases, the presence of Treg type 1/Th3-like lymphocytes could also be demonstrated. Thus, Treg are a major component of the immunosuppressive microenvironment of metastatic melanoma LNs. This could explain the poor clinical response of cancer patients under immunotherapeutic protocols, and provides a new basis for future immunotherapeutic strategies counteracting in vivo Treg to reinforce local antitumor immune responses.

The WHIM syndrome is a rare immunodeficiency disorder characterized by warts, hypogammaglobulinemia, infections, and myelokathexis. Dominant heterozygous mutations of the gene encoding CXCR4, a G-protein-coupled receptor with a unique ligand, CXCL12, have been associated with this pathology. We studied patients belonging to 3 different pedigrees. Two siblings inherited a CXCR4 mutation encoding a novel C-terminally truncated receptor. Two unrelated patients were found to bear a wild-type CXCR4 open reading frame. Circulating lymphocytes and neutrophils from all patients displayed similar functional alterations of CXCR4-mediated responses featured by a marked enhancement of G-protein-dependent responses. This phenomenon relies on the refractoriness of CXCR4 to be both desensitized and internalized in response to CXCL12. Therefore, the aberrant dysfunction of the CXCR4-mediated signaling constitutes a common biologic trait of WHIM syndromes with different causative genetic anomalies. Responses to other chemokines, namely CCL4, CCL5, and CCL21, were preserved, suggesting that, in clinical forms associated with a wild-type CXCR4 open reading frame, the genetic anomaly might target an effector with some degree of selectivity for the CXCL12/ CXCR4 axis. We propose that the sus- IntroductionThe CXC chemokine stromal cell-derived factor 1 (SDF-1/ CXCL12) 1,2 is the sole natural ligand for CXCR4, 3,4 a broadly expressed G-protein-coupled receptor (GPCR). 5 The unique, nonpromiscuous interaction between CXCL12 and CXCR4 is critically involved in the organogenesis of a number of phylogenetically distant animal species. [6][7][8][9][10][11] In addition, B-cell lymphopoiesis and bone marrow (BM) myelopoiesis are regulated by the CXCL12/ CXCR4 axis during embryogenesis. [12][13][14] In postnatal life, the CXCL12/CXCR4 couple controls the BM homing of CD34 ϩ cells and lymphocyte trafficking. [15][16][17][18] Besides the regulation of homeostatic processes, CXCR4 has been implicated in the development of infectious 3,19 and inflammatory diseases as well as tumor metastasis. [20][21][22][23] Recently, inherited heterozygous autosomal dominant mutations of the CXCR4 gene, which result in the truncation of the carboxyl-terminus (C-tail) of the receptor, were found to be associated with the WHIM syndrome. 24 This rare immunodeficiency disease is characterized by disseminated human papillomavirus (HPV)-induced warts, hypogammaglobulinemia, recurrent bacterial infections, and myelokathexis, a form of neutropenia associated with abnormal retention of mature neutrophils in the BM. [25][26][27] Patients with WHIM also exhibit a marked T-cell lymphopenia. The disorder is clinically and genetically heterogeneous, 28 since hypogammaglobulinemia and verrucosis were absent in some cases, 29 and individuals with isolated myelokathexis were found to be wild type for the CXCR4 gene. 24 However, the altered mechanism accounting for the pathogenesis of the WHIM syndrome not associated to CXCR4 mutations remains unknown. Here, we provide original...

BACKGROUND This study addressed the question of whether limited surgery for primary malignant melanoma with a 2‐cm margin is as good as a 5‐cm margin. An update of a 16‐year follow‐up is provided. METHODS Nine European Centers, over a period of 5 years, prospectively randomized 337 patients with melanoma measuring less than 2.1 mm in thickness to undergo a local excision with either a 2‐cm or a 5‐cm margin. Three hundred twenty‐six patients were eligible for statistical analysis. Excluded from the trial were patients older than 70 years; those with melanomas from the toe, nail, or finger; and those with acral‐lentiginous melanoma. A separate randomization was performed to independently test an adjuvant treatment with a nonspecific immunostimulant, isoprinosine, compared with observation. The median follow‐up time was 192 months (16 years) for the estimation of survival and disease recurrences. RESULTS There were 22 tumor recurrences in the 2‐cm arm and 33 in the 5‐cm arm. The median time to disease recurrence was 43 months and 37.6 months, respectively. The 10‐year disease‐free survival rates were 85% for the group with a 2‐cm margin and 83% for the group with a 5‐cm margin. There was no difference in the 10‐year overall survival rates (87% vs. 86%). Isoprinosine did not demonstrate any activity in this setting. CONCLUSIONS The authors concluded that for melanoma less than 2.1‐mm thick, a margin of excision of 2 cm is sufficient. A larger margin of 5 cm does not appear to have any impact on either the rate or the time to disease recurrence or on survival. Cancer 2003;97:1941–6. © 2003 American Cancer Society. DOI 10.1002/cncr.11272

The p16 gene expresses two alternative transcripts (p16a and p16b) involved in tumor suppression via the retinoblastoma (Rb) or p53 pathways. Disruption of these pathways can occur through inactivation of p16 or p53, or activating mutations of cyclin dependant kinase 4 gene (Cdk4). We searched for p16, Cdk4 and p53 gene mutations in 20 squamous cell carcinomas (SSCs), 1 actinic keratosis (AK), and 28 basal cell carcinomas (BCCs), using PCR-SSCP. A deletion and methylation analysis of p16 was also performed. Six dierent mutations (12%) were detected in exon 2 of p16 (common to p16a and p16b), in ®ve out of 21 squamous lesions (24%) (one AK and four SCCs) and one out of 28 BCCs (3.5%). These included four (66%) ultraviolet (UV)-type mutations (two tandems CC : GG to TT : AA transitions and two C : G to T : A transitions at dipyrimidic site) and two transversions. P53 mutations were present in 18 samples (37%), mostly of UV type. Of these, only two (one BCC and one AK) harboured simultaneously mutations of p16, but with no consequence on p16b transcript. Our data demonstrate for the ®rst time the presence of p16 UV induced mutations in non melanoma skin cancer, particularly in the most aggressive SCC type, and support that p16 and p53 are involved in two independent pathways in skin carcinogenesis.

Our results suggest that antiviral therapy with protease inhibitors are clinically efficient in HIV-associated Kaposi's sarcoma and that there exists a correlation between clinical response and negation of HHV-8 viraemia.