Combining chemotherapy and autologous peptide-pulsed dendritic cells provides survival benefit in stage IV melanoma patients.

BACKGROUND AND OBJECTIVES: We examined retrospectively whether the combination of standard dacarbazine (DTIC) and/or fotemustine chemotherapy and autologous peptide-loaded dendritic cell (DC) vaccination may improve survival of stage IV melanoma patients. Furthermore, a small cohort of long-term survivors was studied in more detail. PATIENTS AND METHODS: Between 1998 and 2008, 41 patients were vaccinated at least three times with DCs while receiving chemotherapy and compared to all other 168 patients in our database who only received chemotherapy (1993-2008). RESULTS: Median life expectancy of patients receiving additional DC-vaccination was 18 months, compared to eleven months for patients under standard chemotherapy alone. In contrast to patients with other haplotypes, the HLA-A1/A1 subset of DC-treated patients showed significantly lower median survival (12 vs. 25 months). Autoantibodies were frequently detected in serum of both vaccinated and non-vaccinated patients, and there was no correlation between titers, loss or appearance of autoantibodies and survival. Additionally, phenotyping of DCs and PBMCs also did not reveal any conspicuous correlation with survival. CONCLUSIONS: Combining standard chemotherapy and DC vaccination appears superior to chemotherapy alone. The impact of HLA haplotypes on survival emphasizes the importance of a careful selection of patients with specific, well-defined HLA haplotypes for future vaccination trials using peptide-pulsed DCs, possibly combined with checkpoint inhibitors.

Langerhans cells in hypospadias: an analysis of Langerin (CD207) and HLA-DR on epidermal sheets and full thickness skin sections.

BACKGROUND: Hypospadias are among the most common genital malformations. Langerhans Cells (LCs) play a pivotal role in HIV and HPV infection. The migration of LC precursors to skin coincides with the embryonic period of hypospadias development and genetic alterations leading to the formation of hypospadias impact the development of ectodermally derived tissues. We hypothesized that this might be associated with a difference in frequency or morphology of epidermal and dermal LCs in hypospadias patients. METHODS: A total of 43 patients from two centers were prospectively included into this study after parental consent and ethics approval. Epidermal and dermal sheets were prepared from skin samples of 26 patients with hypospadias, 13 patients without penile malformations and 4 patients with penile malformations other than hypospadias. Immunofluorescence staining of sheets was performed with anti-HLA-DR-FITC and anti-CD207/Langerin-A594 antibodies. Skin sections from 11 patients without penile malformation and 11 patients with hypospadias were stained for Langerin. Frequencies as well as morphology and distribution of epidermal and dermal LCs on sheets and sections were microscopically evaluated. Cell counts were compared by unpaired t-tests. RESULTS: There was no difference in frequency of epidermal LCs, Neither on sheets (873 ± 61 vs. 940 ± 84LCs/mm2, p = 0.522) nor on sections (32 ± 3 vs. 30 ± 2LCs/mm2, p = 0.697). Likewise, the frequency of dermal LCs (5,9 ± 0,9 vs. 7.5 ± 1.3LCs/mm2, p = 0.329) was comparable between patients with hypospadias and without penile malformation. No differences became apparent in subgroup analyses, comparing distal to proximal hypospadias (p = 0.949), younger and older boys (p = 0.818) or considering topical dihydrotestosterone treatment prior to surgery (p = 0.08). The morphology of the LCs was not different comparing hypospadias patients with boys without penile malformations. CONCLUSIONS: LCs are present in similar frequencies and with a comparable morphology and distribution in patients with hypospadias as compared to children without penile malformations. This suggests that patients with hypospadias are not different from patients with normal penile development considering this particular compartment of their skin immunity.

Impaired gp100-Specific CD8(+) T-Cell Responses in the Presence of Myeloid-Derived Suppressor Cells in a Spontaneous Mouse Melanoma Model.

Murine tumor models that closely reflect human diseases are important tools to investigate carcinogenesis and tumor immunity. The transgenic (tg) mouse strain tg(Grm1)EPv develops spontaneous melanoma due to ectopic overexpression of the metabotropic glutamate receptor 1 (Grm1) in melanocytes. In the present study, we characterized the immune status and functional properties of immune cells in tumor-bearing mice. Melanoma development was accompanied by a reduction in the percentages of CD4(+) T cells including regulatory T cells (Tregs) in CD45(+) leukocytes present in tumor tissue and draining lymph nodes (LNs). In contrast, the percentages of CD8(+) T cells were unchanged, and these cells showed an activated phenotype in tumor mice. Endogenous melanoma-associated antigen glycoprotein 100 (gp100)-specific CD8(+) T cells were not deleted during tumor development, as revealed by pentamer staining in the skin and draining LNs. They, however, were unresponsive to ex vivo gp100-peptide stimulation in late-stage tumor mice. Interestingly, immunosuppressive myeloid-derived suppressor cells (MDSCs) were recruited to tumor tissue with a preferential accumulation of granulocytic MDSC (grMDSCs) over monocytic MDSC (moMDSCs). Both subsets produced Arginase-1, inducible nitric oxide synthase (iNOS), and transforming growth factor-ß and suppressed T-cell proliferation in vitro. In this work, we describe the immune status of a spontaneous melanoma mouse model that provides an interesting tool to develop future immunotherapeutical strategies.

Human skin dendritic cells can be targeted in situ by intradermal injection of antibodies against lectin receptors.

Skin dendritic cells (DC) express C-type lectin receptors for the recognition of pathogens. Langerhans cells (LC) express the receptor Langerin/CD207, whereas DEC-205/CD205 is mainly expressed by dermal DC, but can also be detected at low levels on LC. In this study, we tested an ex vivo approach for targeting DC in situ with monoclonal antibodies (mAb) against Langerin and DEC-205. The targeting mAb was injected intradermally into human skin biopsies or added to the medium during skin explant culture. Corresponding to the expression patterns of these lectin receptors on skin DC, Langerin mAb was detected merely in LC in the epidermis and DEC-205 mainly in dermal DC in human skin explants, regardless of the application route. Migratory skin DC bound and carried targeting mAb from skin explants according to their lectin receptor expression profiles. In contrast to the very selective transport of Langerin mAb by LC, DEC-205 mAb was more widely distributed on all CD1a(+) skin DC subsets but almost absent in CD14(+) dermal DC. As effective vaccination requires the addition of adjuvant, we co-administered the toll-like receptor (TLR)-3 ligand poly I:C with the mAb. This adjuvant enhanced binding of DEC-205 mAb to all skin DC subsets, whereas Langerin targeting efficacy remained unchanged. Our findings demonstrate that LC can be preferentially targeted by Langerin mAb. In contrast, DEC-205 mAb can be bound by all CD1a(+) skin DC subsets. The efficacy of DEC-205 mAb targeting strategy can be boosted by addition of poly I:C underlining the potential of this combination for immunotherapeutical interventions.

Effect of the dual endothelin receptor antagonist bosentan on Raynaud's phenomenon secondary to systemic sclerosis: a double-blind prospective, randomized, placebo-controlled pilot study.

OBJECTIVE: To investigate the efficacy of the endothelin receptor antagonist, bosentan, in patients with RP secondary to SSc without pre-existing digital ulcers. METHODS: Single-centre, randomized, prospective, double-blinded comparison of bosentan and placebo. Patients received either 62.5 mg bosentan twice daily for 4 weeks, followed by 125 mg twice daily for 12 weeks or matching doses of placebo. RESULTS: Of the 17 patients enrolled, 16 completed the study and 1 withdrew from the study due to the reversible development of peripheral oedema. Compared with placebo, bosentan did not improve the frequency, duration, pain or severity of RP attacks. However, in contrast to placebo, bosentan significantly improved the functional scores. With respect to baseline, the scleroderma HAQ disability index changes were in favour of bosentan at Weeks 12 (P = 0.03) and 20 (P = 0.01), and the United Kingdom functional score changes at Weeks 8 (P = 0.038) and 16 (P = 0.039). CONCLUSIONS: Bosentan is not effective in SSc-related RP without pre-existing digital ulcers, but it might benefit functional impairment in those patients. TRIAL REGISTRATION: European Union Drug Regulating Authorities Clinical Trials, https://eudract.emea.europa.eu, EudraCT-Nr 2004-002686-21.

Monocyte-derived dendritic cells release neopterin.

Increased neopterin concentrations in body fluids are found in diseases associated with activated, cell-mediated immunity including infections, autoimmune diseases, and certain malignancies. Monocytes/macrophages are known to secrete large amounts of neopterin upon stimulation with interferon-gamma (IFN-gamma). Ontogenetically, the major part of dendritic cells (DC) belongs to the myeloid lineage. Therefore, we investigated whether cultured monocyte-derived DC can elaborate neopterin. Cells were treated with cytokines in the presence or absence of monocyte-conditioned medium as a maturation stimulus. DC secreted an average 3.5 nmol/l neopterin. In response to IFN-gamma, cells significantly increased their output of neopterin. In distinction to monocytes/macrophages, neopterin production in DC was highly sensitive to IFN-alpha and IFN-beta. Further, lipopolysaccharides (LPS) enhanced neopterin synthesis, whereas tumor necrosis factor alpha, interleukin (IL)-1beta, IL-2, IL-10, and IL-18 were ineffective. Simultaneously, tryptophan degradation by induction of indoleamine (2,3)-dioxygenase (IDO) was tested in stimulated cells. Our results showed that IFN-gamma as well as LPS are inducers of IDO in DC.

Dendritic cells contribute to the development of atopy by an insufficiency in IL-12 production.

BACKGROUND: IL-12 is a crucial factor in the development and course of allergic diseases. By virtue of their IL-12 production, dendritic cells (DCs) are potent inducers of T(H)1 responses. However, distinct subsets of DCs have also been shown to induce T(H)2 differentiation. OBJECTIVE: We hypothesized that DCs from atopic and nonatopic individuals might differ in their propensity to skew T-cell responses to either the T(H)1 type or the T(H)2 type. To this end, we investigated the cytokine patterns produced by DCs from atopic and nonatopic individuals, and we attempted to clarify whether this could be due to different DC lineages or, alternatively, to different microenvironmental factors. METHODS: DCs were generated from lymphocyte-depleted PBMCs from atopic and nonatopic donors and fully matured with monocyte-conditioned medium. Production of IL-4, IL-5, IL-10, IL-12, and IL-13 in response to CD40 ligation was measured with ELISA. DC subsets were identified in PBMCs from freshly drawn blood by 3-color flow cytometry. RESULTS: Compared with DCs from healthy donors, monocyte-derived DCs from atopic patients produced less bioactive IL-12 and IL-10. DC production of IL-4, IL-13, and IL-5 was not detected. Relatively more CD123(+) DCs, corresponding to T(H)2-inducing "DC2s," were found in PBMCs from atopic patients. CONCLUSION: The data suggest that in addition to the described abnormalities in the patients' T-cell populations, DCs might also critically contribute to the atopic/allergic T(H)1 outcome in the patient and thus to the disease.