IFN-γ and IL-12 synergize to convert in vivo generated Th17 into Th1/Th17 cells

Th1 and Th17 cells are distinct lineages of effector/memory cells, imprinted for re-expression of IFN-γ and IL-17, by upregulated expression of T-bet and retinoic acid-related orphan receptor γt (RORγt), respectively. Apparently, Th1 and Th17 cells share tasks in the control of inflammatory immune responses. Th cells coexpressing IFN-γ and IL-17 have been observed in vivo, but it remained elusive, how these cells had been generated and whether they represent a distinct lineage of Th differentiation. It has been shown that ex vivo isolated Th1 and Th17 cells are not interconvertable by TGF-β/IL-6 and IL-12, respectively. Here, we show that ex vivo isolated Th17 cells can be converted into Th1/Th17 cells by combined IFN-γ and IL-12 signaling. IFN-γ is required to upregulate expression of the IL-12Rβ2 chain, and IL-12 for Th1 polarization. These Th1/Th17 cells stably coexpress RORγt and T-bet at the single-cell level. Our results suggest a molecular pathway for the generation of Th1/Th17 cells in vivo, which combine the pro-inflammatory potential of Th1 and Th17 cells.     

Photoprovocation in cutaneous lupus erythematosus: a multicenter study evaluating a standardized protocol

Photosensitivity is an important and distinguishing sign in various subtypes of cutaneous lupus erythematosus (CLE); however, it remains poorly defined. The purpose of this study was to evaluate whether standardized photoprovocation is a reproducible method to assess photosensitivity in subjects with CLE. A total of 47 subjects with CLE (subacute cutaneous lupus erythematosus (SCLE), n=14; discoid lupus erythematosus (DLE), n=20; lupus erythematosus tumidus (LET), n=13) and 13 healthy volunteers underwent photoprovocation at seven European sites. Of these, 22 (47%) subjects (57% SCLE, 35% DLE, and 54% LET) and none of the healthy volunteers developed photoprovoked lesions according to clinical analysis. Of these 22 subjects, 19 (86%) developed lesions that were histopathologically confirmed as specific for lupus erythematosus (LE). In CLE subjects who developed UV-induced lesions, 86% had Fitzpatrick's phototypes I or II, and the mean minimal erythema dose (MED) was significantly lower compared with subjects without UV-induced lesions (P=0.004). No significant differences in photoprovocation results were observed between study sites. Safety parameters showed no clinically meaningful differences between CLE subjects and healthy volunteers after photoprovocation. In conclusion, a standardized, safe, and reproducible protocol for photoprovocation using UVA and UVB radiation induced skin lesions in approximately half of all CLE subjects and showed comparable results across multiple sites. This method may therefore be used for future diagnostic testing and clinical trials.     

Deutsche Leitlinie zur Diagnostik und Therapie der zirkumskripten Sklerodermie

Bei der zirkumskripten Sklerodermie handelt es sich um eine heterogene Gruppe von sklerotischen Erkrankungen der Haut mit je nach Subtyp, Schweregrad und Lokalisation möglicher Beteiligung von hautnahen Strukturen wie Fettgewebe, Muskulatur, Gelenke und Knochen. Dies ist eine Aktualisierung der bereits bestehenden deutschen Leitlinie der AWMF (Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Wissenschaften) mit dem Klassifizierungsgrad S2k. Die Leitlinie gibt einen Überblick zur Definition, Epidemiologie, Klassifikation, Pathogenese, Labordiagnostik, Histopathologie sowie klinischen Scores und apparativen Diagnostik der zirkumskripten Sklerodermie. Des Weiteren erfolgen konsensbasierte Empfehlungen zum Management der zirkumskripten Sklerodermie in Abhängigkeit vom klinischen Subtyp. Die Behandlungsempfehlungen sind in einem Therapiealgorithmus dargestellt. Eine finanzielle Unterstützung zur Erstellung der Leitlinie durch die pharmazeutische Industrie erfolgte nicht. Die Leitlinie ist bis Juli 2019 gültig.     

Erlotinib resistance in EGFR-amplified glioblastoma cells is associated with upregulation of EGFRvIII and PI3Kp110δ

Background

The treatment efficacy of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors like erlotinib has not met expectations for glioblastoma therapy, even for EGFR-overexpressing tumors. We determined possible mechanisms of therapy resistance using the unique BS153 glioblastoma cell line, which has retained amplification of the egfr gene and expression of EGFR variant (v)III.

Methods

Functional effects of erlotinib, gefitinib, and cetuximab on BS153 proliferation, migration, and EGFR-dependent signal transduction were systematically compared in vitro. The tumor-initiating capacity of parental and treatment-resistant BS153 was studied in Naval Medical Research Institute/Foxn1^nu mice. Potential mediators of resistance were knocked down using small interfering (si)RNA.

Results

Erlotinib and gefitinib inhibited proliferation and migration of BS153 in a dose-dependent manner, whereas cetuximab had no effect. BS153 developed resistance to erlotinib (BS153^resE) but not to gefitinib. Resistance was associated with strong upregulation of EGFRvIII and subsequent activation of the phosphatidylinositol-3-OH kinase (PI3K) pathway in BS153^resE and an increased expression of the regulatory 110-kDa delta subunit of PI3K (p110δ). Knockdown of EGFRvIII in BS153^resE largely restored sensitivity to erlotinib. Targeting PI3K pharmacologically caused a significant decrease in cell viability, and specifically targeting p110δ by siRNA partially restored erlotinib sensitivity in BS153^resE. In vivo, BS153 formed highly invasive tumors with an unusual growth pattern, displaying numerous satellites distant from the initial injection site. Erlotinib resistance led to delayed onset of tumor growth as well as prolonged overall survival of mice without changing tumor morphology.

Conclusions

EGFRvIII can mediate resistance to erlotinib in EGFR-amplified glioblastoma via an increase in PI3Kp110δ. Interfering with PI3Kp110δ can restore sensitivity toward the tyrosine kinase inhibitor.     

Anuläres Erythem bei Sjögren-Syndrom

Annular erythema has been recognised as a cutaneous manifestation of Sjögren’s syndrome in the Asian literature and has been assumed to represent a distinct clinical entity. Since there are common pathophysiologic mechanisms, mainly the presence of anti-Ro/SSA or anti-La/SSB antibodies, it is difficult to separate the annular erythema from subacute cutaneous lupus erythematosus. Histological examination may reveal dermal mucin deposition resembling lupus erythematosus tumidus. We present a Chinese patient with widespread annular erythema, keratoconjunctivitis sicca, and anti-Ro/SSA antibodies. Clinical, histopathological, and immunogenetic findings are discussed reviewing the current literature, and the differences between annular erythema associated with Sjögren’s syndrome and cutaneous lupus erythematosus are emphasized.     

A high proportion of bone marrow T cells with regulatory phenotype (CD4+CD25hiFoxP3+) in Ewing sarcoma patients is associated with metastatic disease

Immunosuppressive CD4+CD25^hiFoxP3+ T cells (T_reg cells) have been found at increased densities within the tumor microenvironment in many malignancies and interfere with protective antitumor immune responses. Osseous Ewing sarcomas (ESs) are thought to derive from a bone marrow (BM) mesenchymal cell of origin, and microscopic marrow involvement defines a subpopulation of patients at a high risk of relapse. We hypothesized that BM‐resident T cells may contribute to a permissive milieu for immune escape of ESs. Using 6‐color‐flow cytometry, we investigated the pattern of immune cell subset distribution including NK cells, γδ T cells, central and effector memory CD8+ and CD4+ T cells as well as T cells with regulatory phenotype (T_reg cells) in BM obtained at diagnosis from 45 primary or relapsed ES patients treated within standardized protocols. Although patients at relapse had an inverted CD4:CD8 T‐cell ratio, neither CD8+ effector/memory T‐cell subsets nor T_reg cells significantly differed from patients at diagnosis. No significant associations of innate and effector/memory T‐cell subpopulations with known risk factors were found, including age, gender, tumor site, primary metastases and histological tumor response. By contrast, T_reg cells were found at significantly higher frequencies in patients with primary metastatic disease compared with localized ESs (5.0 vs. 3.3%, p = 0.01). Thus, increased BM T_reg cells in patients with metastasized ES may reflect an immune escape mechanism that contributes to the development of metastatic disease. Immunotherapeutic strategies will have to adequately consider the regulatory milieu within areas of Ewing tumor‐immune interactions. © 2009 UICC     

Triple angiokinase inhibition, tumour hypoxia and radiation response of FaDu human squamous cell carcinomas

Background and purpose

To test the effect of BIBF 1120, a novel small molecule inhibitor of multiple angiogenic receptor tyrosine kinases, on the hypoxia and radiation response of tumours.

Materials and methods

Poorly differentiated human squamous cell carcinoma FaDu growing in nude mice was treated with BIBF 1120 and investigated by functional histology. To test the effect of BIBF 1120 on the radiobiological hypoxic fraction (rHF), the number and intrinsic radiation sensitivity of tumour stem cells and the outcome after fractionated irradiation, a series of local tumour control assays were performed.

Results

BIBF 1120 significantly reduced the vessel area, vessel area with a perfusion signal and tumour growth rate but did not affect tumour hypoxia or the number and intrinsic radiation sensitivity of tumour stem cells. Concurrent BIBF 1120 had no effect on local tumour control after fractionated irradiation.

Conclusion

Triple angiokinase inhibition resulted in a clear-cut decrease of angiogenesis, vessel area with a perfusion signal and tumour growth but did not change tumour hypoxia or radiation response of tumour stem cells. Further experiments into mechanisms of interaction between anti-angiogenic strategies and irradiation appear to be necessary to better define and exploit the potential of this strategy to improve local tumour control after fractionated radiotherapy.