The T1799A point mutation is present in posterior uveal melanoma

An activating mutation in exon 15 of the BRAF gene is present in a high proportion of cutaneous pigmented lesions. Until recently this mutation had however only been identified in one case of posterior uveal melanoma. Despite this apparent lack of the BRAF mutation, inappropriate downstream activation of the Ras/Raf/MAPK pathway has been described in posterior uveal melanoma. Based on the already recognised morphological and cytogenetic heterogeneity in uveal melanoma, we hypothesised that the BRAF mutation may be present in uveal melanoma but only in some of the tumour cells. In this study, we analysed 20 ciliary body and 30 choroidal melanomas using a nested PCR-based technique resulting in the amplification of a nested product only if the mutation was present. This sensitive technique can identify mutated DNA in the presence of wild-type DNA. The mutation was identified in 4 of 20 (20%) ciliary body and 11 of 30 (40%) choroidal melanomas. Further analysis of separate areas within the same choroidal melanoma demonstrated that the mutation was not present in the entire tumour. In conclusion, the T1799A BRAF mutation is present in a proportion of posterior uveal melanomas but within these tumours the distribution of the mutation is heterogeneous

Stromal fibroblasts support dendritic cells to maintain IL-23/Th17 responses after exposure to ionizing radiation

Dendritic cell function is modulated by stromal cells, including fibroblasts. Although poorly understood, the signals delivered through this crosstalk substantially alter dendritic cell biology. This is well illustrated with release of TNF-0/IL-113 from activated dendritic cells, promoting PGE2 secretion from stromal fibroblasts. This instructs dendritic cells to up-regulate IL-23, a key Th17-polarizing cytokine. We previously showed that ionizing radiation inhibited IL-23 production by human dendritic cells in vitro. In the present study, we investigated the hypothesis that dendritic cell-fibroblast crosstalk over¬comes the suppressive effect of ionizing radiation to support appropriately polarized Th17 responses. Radia¬tion (1–6 Gy) markedly suppressed IL-23 secretion by activated dendritic cells (P < 0.0001) without adversely impacting their viability and consequently, inhibited the generation of Th17 responses. Cytokine suppression by ionizing radiation was selective, as there was no effect on IL-10, -6, -10, and -27 or TNF-a and only a modest (11%) decrease in IL-12p70 secretion. Coculture with fibroblasts augmented IL-23 secretion by irradiated dendritic cells and increased Th17 responses. Impor¬tantly, in contrast to dendritic cells, irradiated fibroblasts maintained their capacity to respond to TNF-0/IL-10 and produce PGE2, thus providing the key intermediary signals for successful dendritic cell-fibroblasts crosstalk. In summary, stromal fibroblasts support Th17-polarizing cytokine production by dendritic cells that would other¬wise be suppressed in an irradiated microenvironment. This has potential ramifications for understanding the immune response to local radiotherapy. These findings underscore the need to account for the impact of microenvironmental factors, including stromal cells, in understanding the control of immunity. J. Leukoc. Biol. 100: 000–000; 2016

Dense deposit disease

Dense deposit disease (DDD) is an orphan disease that primarily affects children and young adults without sexual predilection. Studies of its pathophysiology have shown conclusively that it is caused by fluid-phase dysregulation of the alternative pathway of complement, however the role played by genetics and autoantibodies like C3 nephritic factors must be more thoroughly defined if we are to make an impact in the clinical management of this disease. There are currently no mechanism-directed therapies to offer affected patients, half of whom progress to end stage renal failure disease within 10 years of diagnosis. Transplant recipients face the dim prospect of disease recurrence in their allografts, half of which ultimately fail. More detailed genetic and complement studies of DDD patients may make it possible to identify protective factors prognostic for naïve kidney and transplant survival, or conversely risk factors associated with progression to renal failure and allograft loss. The pathophysiology of DDD suggests that a number of different treatments warrant consideration. As advances are made in these areas, there will be a need to increase healthcare provider awareness of DDD by making resources available to clinicians to optimize care for DDD patients

Conjunctival melanoma and melanocytic intra-epithelial neoplasia

The rarity of conjunctival melanoma has impeded progress in the management of patients with this cancer; however, much progress has occurred in recent years. Primary acquired melanosis is now differentiated histologically into hypermelanosis and conjunctival melanocytic intra-epithelial neoplasia, for which an objective reproducible scoring system has been developed. Mapping and clinical staging of conjunctival disease has improved. Adjunctive radiotherapy and topical chemotherapy have made tumour control more successful, with reduced morbidity. Genetic analyses have identified BRAF and other mutations, which may predict responsiveness to new chemotherapeutic agents, for example Vemurafenib, should metastatic disease develop. Multicentre studies are under way to enhance survival prediction by integrating clinical stage of disease with histological grade of malignancy and genetic abnormalities. Such improved prognostication would not only be more relevant to individual patients, but would also provide greater opportunities for basic science research