Immune monitoring and TCR sequencing of CD4 T cells in a long term responsive patient with metastasized pancreatic ductal carcinoma treated with individualized, neoepitope-derived multipeptide vaccines : a case report

Abstract Background Cancer vaccines can effectively establish clinically relevant tumor immunity. Novel sequencing approaches rapidly identify the mutational fingerprint of tumors, thus allowing to generate personalized tumor vaccines within a few weeks from diagnosis. Here, we report the case of a 62-year-old patient receiving a four-peptide-vaccine targeting the two sole mutations of his pancreatic tumor, identified via exome sequencing. Methods Vaccination started during chemotherapy in second complete remission and continued monthly thereafter. We tracked IFN-γ+ T cell responses against vaccine peptides in peripheral blood after 12, 17 and 34 vaccinations by analyzing T-cell receptor (TCR) repertoire diversity and epitope-binding regions of peptide-reactive T-cell lines and clones. By restricting analysis to sorted IFN-γ-producing T cells we could assure epitope-specificity, functionality, and TH1 polarization. Results A peptide-specific T-cell response against three of the four vaccine peptides could be detected sequentially. Molecular TCR analysis revealed a broad vaccine-reactive TCR repertoire with clones of discernible specificity. Four identical or convergent TCR sequences could be identified at more than one time-point, indicating timely persistence of vaccine-reactive T cells. One dominant TCR expressing a dual TCRVα chain could be found in three T-cell clones. The observed T-cell responses possibly contributed to clinical outcome: The patient is alive 6 years after initial diagnosis and in complete remission for 4 years now. Conclusions Therapeutic vaccination with a neoantigen-derived four-peptide vaccine resulted in a diverse and long-lasting immune response against these targets which was associated with prolonged clinical remission. These data warrant confirmation in a larger proof-of concept clinical trial

Associations of anterior accessory or thigh posterior tributary and great saphenous reflux patterns in early stages of chronic venous valvular insufficiency

Varicose veins are a common disorder. Extensive ultrasound (US) mapping of lower extremity chronic venous valvular insufficiency includes the great saphenous vein (GSV), anterior accessory saphenous vein (AASV) and thigh posterior tributary to GSV such as the posterior accessory saphenous vein (PTSV, PASV). The aim of this study was to determine associations between GSV-AASV-PTSV (including PASV) reflux in a specific sample population of Southern Brazilian women, mostly euro descendents, with telangiectasias, reticular veins, varices and/or intermittent edema. US performed in 1016 extremities of 513 women, 43±18 (18-81) years old were included. Women with previous venous thrombosis, surgery, suspicion of pelvic congestion syndrome, and men were excluded. Small saphenous vein and related thigh veins were excluded from analysis. GSV-AASV-PTSV reflux patterns were analyzed; prevalence was compared using χ2 statistics. Reflux prevalence in AASV and/or thigh PTSV was 5.8% (59/1016): 1.3% at PTSV (n=13) and 4.5% at AASV (n=46), significantly lower than GSV reflux: 72% (n=727) (P<0.001). AASV and/or PTSV reflux was associated with GSV reflux (81%, n=48/59); common pattern was diffuse reflux, starting at AASV/PTSV saphenous junctions (56%, n=33/59; otherwise, short, non-diffuse reflux was noted in part of the AASV/PTSV evaluated. Isolated AASV or PTSV reflux was rare (1%, n=11/1016): 9 at the AASV, and 2 at the PTSV. US mapping of AASV/PTSV in early stages of disease, in women without pelvic congestion syndrome, increased reflux detection by 1%, and improved definition of reflux patterns in about 6% of the extremities