We report the efficient identification of four human histocompatibility leukocyte antigen (HLA)-A*0201–presented cytotoxic T lymphocyte (CTL) epitopes in the tumor-associated antigen PRAME using an improved “reverse immunology” strategy. Next to motif-based HLA-A*0201 binding prediction and actual binding and stability assays, analysis of in vitro proteasome-mediated digestions of polypeptides encompassing candidate epitopes was incorporated in the epitope prediction procedure. Proteasome cleavage pattern analysis, in particular determination of correct COOH-terminal cleavage of the putative epitope, allows a far more accurate and selective prediction of CTL epitopes. Only 4 of 19 high affinity HLA-A*0201 binding peptides (21%) were found to be efficiently generated by the proteasome in vitro. This approach avoids laborious CTL response inductions against high affinity binding peptides that are not processed and limits the number of peptides to be assayed for binding. CTL clones induced against the four identified epitopes (VLDGLDVLL, PRA100–108; SLYSFPEPEA, PRA142–151; ALYVDSLFFL, PRA300–309; and SLLQHLIGL, PRA425–433) lysed melanoma, renal cell carcinoma, lung carcinoma, and mammary carcinoma cell lines expressing PRAME and HLA-A*0201. This indicates that these epitopes are expressed on cancer cells of diverse histologic origin, making them attractive targets for immunotherapy of cancer.

In chronic myeloid leukemia (CML) the classical 9;22 translocation results in a BCR-ABL fusion gene, which encodes chimeric BCR-ABL fusion 210 kD oncoproteins (p210BCR-ABL). The two main p210BCR-ABL fusion variants in CML, b2a2 and b3a2 are examples of well characterized antigens expressed by malignant cells. The possibility of an immunotherapeutic approach involving the fusion part of p210BCR-ABL in CML has previously been illustrated by observed peptide binding to major histocompatibility complex (MHC) class I alleles and by demonstrating the immunogenicity of p210BCR-ABL breakpoint peptides. In this report we show that in vitro immunization of human T cells with a 17 amino acid (aa) peptide representing the p210BCR-ABL fusion region resulted in peptide specific CD4+ T-cell lines designated P4, P6, and P7. HLA DR4 (DRB1*0401) restricted T-cell line P4 and several subsequently derived clones recognized HLA-DRB1*0401 and p210b3a2-mRNA expressing blasts from an allogeneic patient with CML in blast crisis. Recognition appeared DR expression-dependent. No responses were observed with DR4 positive p210BCR-ABL negative cells or with p210b3a2 leukemic cells with absent or insufficient expression of DR4. These observations indicate that oncoprotein p210b3a2 can be degraded and processed for presentation by MHC class II molecules at the surface of leukemic cells. The BCR-ABL fusion region is in all likelihood presented as peptides by HLA DR and thus capable to act as a distinctive tumor antigen to peptide specific CD4+ T cells.

Reassessment of published observations in patients with multiple sclerosis (MS) suggests a microglial malfunction due to inappropriate (over)activity of the mitogen-activated protein kinase pathway ERK (MAPKERK). These observations regard biochemistry as well as epigenetics, and all indicate involvement of this pathway. Recent preclinical research on neurodegeneration already pointed towards a role of MAPK pathways, in particular MAPKERK. This is important as microglia with overactive MAPK have been identified to disturb local oligodendrocytes which can lead to locoregional demyelination, hallmark of MS. This constitutes a new concept on pathophysiology of MS, besides the prevailing view, i.e., autoimmunity. Acknowledged risk factors for MS, such as EBV infection, hypovitaminosis D, and smoking, all downregulate MAPKERK negative feedback phosphatases that normally regulate MAPKERK activity. Consequently, these factors may contribute to inappropriate MAPKERK overactivity, and thereby to neurodegeneration. Also, MAPKERK overactivity in microglia, as a factor in the pathophysiology of MS, could explain ongoing neurodegeneration in MS patients despite optimized immunosuppressive or immunomodulatory treatment. Currently, for these patients with progressive disease, no effective treatment exists. In such refractory MS, targeting the cause of overactive MAPKERK in microglia merits further investigation as this phenomenon may imply a novel treatment approach.

Thrombotic thrombocytopenic purpura (TTP) is a serious disorder of unknown etiology. Clinical findings are the result of vascular occlusions by platelet aggregates. Treatment with plasma exchange, often used in combination with corticosteroids, vincristine, aspirin, and dipyridamole, has reduced mortality to 20%. Relapses may occur even after long disease-free intervals. In this report we describe our experience with splenectomy in patients with relapsing TTP. Between July 1978 and March 1994, 16 patients with TTP were treated in our hospital. Five of the 13 patients surviving the first episode of TTP had relapses. Most relapses were treated as the first episode of TTP with plasma exchange with fresh-frozen plasma, followed by plasma infusions, corticosteroids, and vincristine. Sometimes aspirin and dipyridamole were added. Splenectomy was performed after five relapses in the first two patients and after two and three relapses in the other patients. Before splenectomy the disease-free interval varied from 3 weeks to 27 months and the incidence rate of relapses was 1.5 relapse/patient/year. None of the patients had relapses after splenectomy. The mean follow-up after splenectomy is 39 months with a range of 9-62 months. We conclude that patients with relapsing TTP can benefit from splenectomy, since it seems to increase disease-free intervals. Further investigation is necessary to understand the role of the spleen in the pathogenesis of TTP.

On June 14, 2010, the European Commission issued a conditional marketing authorization valid throughout the European Union for pazopanib for the treatment of advanced renal cell carcinoma. Pazopanib is an antineoplastic agent that inhibits multiple receptor tyrosine kinases. The recommended oral dose is 800 mg once daily. The benefit of pazopanib is an increased progression-free survival. In the pivotal trial VEG105192, the median progression-free survival was 9.2 months (95% confidence interval, 7.4-12.9) in the pazopanib arm compared with 4.2 months (95% confidence interval, 2.8-4.2) in the placebo arm. The most common side effects include diarrhea, hair color change, hypertension, nausea, fatigue, anorexia, vomiting, dysgeusia, elevated alanine aminotransferase, elevated aspartate aminotransferase, and abdominal pain. The objective of this article is to summarize the scientific review of the application that led to approval in the European Union.