Toward Sézary Syndrome immunotherapy

Sézary syndrome (SS) is a leukemic form of cutaneous mature T-cell lymphoma characterized by circulating malignant CD4 T lymphocytes (Sezary cells). Patients with SS have a poor prognosis and current treatment options show high rates of relapse, morbidity or mortality. Thus, there is an unmet need for an efficient and safe treatment. Sézary cells have unique clonal potentially targetable epitopes, including their TCR, and TCR- and neoantigen-derived HLA-restricted peptides.

Our general aim is to design a patient-tailored two-pronged strategy against SS. The specific aims are 1) to target SS clonal TCR B cell epitopes using mAb and/or CAR T cells, 2) to target SS HLA-restricted T-cell epitopes using TCR peptide- and/or neoantigen-specific human T cells, and 3) to validate efficacy in vitro and in mouse models.

For the generation of mAb, apheresis-purified SS cells or SS TCR CDR3beta peptides were used for immunizations, and screening was done on SS vs non-SS CD4 cells as defined by flow cytometry using CD26 and/or PD-1. For in vitro expansion of SS peptide-specific T cells, SS patient-derived non-SS PBMC were stimulated in 96-well plates with IL-2 and pooled HLA class I+II SS peptides, 10 μM each, defined by SS WGS, WES and RNAseq-based predictions or peptidome studies. After one week, cells were exposed to autologous DC pre-loaded with peptide pools, and cytokine production was analyzed by flow cytometry.

We have obtained preliminary data on aims 1 and 2 studying two SS patients with monoclonal T cell lymphomas, including potential mouse antibodies against a clonal SS TCR using cell and peptide immunization and T-cell hits that seem to be specific of a SS TCR HLA class-I-restricted CDR3beta sequence.

Expression of adhesion molecules and RANTES in kidney transplant from nonheart-beating donors

The main difference between cadaveric kidneys from donors with a heartbeat (HBD) and kidneys from nonheart-beating donors (NHBD) is related to warm ischemia/reperfusion time which constitutes an acute inflammatory process. On the contrary, brain death induces in HBD expression of pro-inflammatory adhesion molecules, making it important to evaluate this kind of molecules in both types of donors. Human renal biopsies from NHBD, HBD and normal kidneys (ischemia time = 0) were taken and frozen just before transplant. A semi-quantitative RT-PCR method was used to determine intracellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), lymphocyte function associated antigen (LFA-1), LFA-3, CD40, CD40 ligand (CD40L) and RANTES (regulated upon activation, normal T-cell expressed and secreted) gene expression. We have detected an elevated relative gene expression of ICAM-1, VCAM-1 and RANTES in NHBD biopsies compared with normal kidneys. In the case of RANTES, the gene expression from NHBD biopsies was higher than observed in HBD biopsies. The rest of genes were not augmented in any group. Preliminary data about early outcome of transplants indicates a correlation between pretransplant RANTES high gene expression levels and early post-transplant acute rejection. The gene expression of pro-inflammatory molecules like adhesion molecules and RANTES is augmented in kidneys from cadaveric NBD just before transplant. The expression is higher probably because of the prolonged warm ischemia period. A larger clinical study is necessary to clarify the effects of these variable expressions on the transplant outcome.