MUC1 is a glycoprotein overexpressed in tumors as a hypoglycosylated form. A vaccine composed of a 100-amino acid peptide corresponding to five 20-amino acid long repeats, and SB-AS2 adjuvant, was tested in a phase I study for safety, toxicity, and ability to elicit or boost MUC1-specific immune responses. Patients with resected or locally advanced pancreatic cancer without prior chemotherapy or radiotherapy were eligible. Escalating doses of the peptide (100, 300, 1,000, and 3,000 mug) were admixed with SB-AS2 and administered intramuscularly every 3 weeks for three doses, in cohorts of four patients. Sixteen patients were enrolled. Common adverse effects were grade 1 flu-like symptoms, tenderness, and erythema at the injection site. Delayed-type hypersensitivity (DTH) sites showed few or no T cells prevaccination (Pre V), but increased T-cell infiltration postvaccination (Post V). There was an increase in the percentage of CD8(+) T cells in the peripheral blood Post V. An increase in total MUC1-specific antibody was seen in some patients, and several patients developed IgG antibody. Two of 15 resected pancreatic cancer patients are alive and disease free at follow-up of 32 and 61 months. MUC1 100mer peptide with SB-AS2 adjuvant is a safe vaccine that induces low but detectable mucin-specific humoral and T-cell responses in some patients. No difference was seen between different peptide doses. Further evaluation is warranted to examine the effect on disease-free survival and overall survival, especially in early disease and in the absence of immunosuppressive standard therapy.

Epstein Barr virus (EBV) positive mucocutaneous ulcers (EBVMCU) form part of a spectrum of EBV-associated lymphoproliferative disease. They have been reported in the setting of immunosenescence and iatrogenic immunosuppression, affecting the oropharyngeal mucosa, skin and gastrointestinal tract (GIT). Case reports and series to date suggest a benign natural history responding to conservative management, particularly in the GIT. We report an unusual case of EBVMCU in the colon, arising in the setting of immunosuppression in the treatment of Crohn's disease, with progression to Hodgkin lymphoma 18 mo after cessation of infliximab. The patient presented with multiple areas of segmental colonic ulceration, histologically showing a polymorphous infiltrate with EBV positive Reed-Sternberg-like cells. A diagnosis of EBVMCU was made. The ulcers failed to regress upon cessation of infliximab and methotrexate for 18 mo. Following commencement of prednisolone for her Crohn's disease, the patient developed widespread Hodgkin lymphoma which ultimately presented as a life-threatening lower GIT bleed requiring emergency colectomy. This is the first report of progression of EBVMCU to Hodgkin lymphoma, in the setting of ongoing iatrogenic immunosuppression and inflammatory bowel disease.

Acetylation of the histone variant H2A.Z (H2A.Zac) occurs at active promoters and is associated with oncogene activation in prostate cancer, but its role in enhancer function is still poorly understood. Here we show that H2A.Zac containing nucleosomes are commonly redistributed to neo-enhancers in cancer resulting in a concomitant gain of chromatin accessibility and ectopic gene expression. Notably incorporation of acetylated H2A.Z nucleosomes is a pre-requisite for activation of Androgen receptor (AR) associated enhancers. H2A.Zac nucleosome occupancy is rapidly remodeled to flank the AR sites to initiate the formation of nucleosome-free regions and the production of AR-enhancer RNAs upon androgen treatment. Remarkably higher levels of global H2A.Zac correlate with poorer prognosis. Altogether these data demonstrate the novel contribution of H2A.Zac in activation of newly formed enhancers in prostate cancer.

CD83 is a member of the Ig gene superfamily, first identified in activated lymphocytes. Since then, CD83 has become an important marker for defining activated human dendritic cells (DC). Several potential CD83 mRNA isoforms have been described, including a soluble form detected in human serum, which may have an immunosuppressive function. To further understand the biology of CD83, we examined its expression in different human immune cell types before and after activation using a panel of mouse and human anti-human CD83 mAb. The mouse anti-human CD83 mAbs, HB15a and HB15e, and the human anti-human CD83 mAb, 3C12C, were selected to examine cytoplasmic and surface CD83 expression, based on their different binding characteristics. Glycosylation of CD83, the CD83 mRNA isoforms, and soluble CD83 released differed among blood DC, monocytes, and monocyte-derived DC, and other immune cell types. A small T cell population expressing surface CD83 was identified upon T cell stimulation and during allogeneic MLR. This subpopulation appeared specifically during viral Ag challenge. We did not observe human CD83 on unstimulated human natural regulatory T cells (Treg), in contrast to reports describing expression of CD83 on mouse Treg. CD83 expression was increased on CD4, CD8 T, and Treg cells in association with clinical acute graft-versus-host disease in allogeneic hematopoietic cell transplant recipients. The differential expression and function of CD83 on human immune cells reveal potential new roles for this molecule as a target of therapeutic manipulation in transplantation, inflammation, and autoimmune diseases.

The determination of histological subtype from a diagnostic biopsy is difficult due to sampling error, but an adequate specimen obtained from surgical biopsy increases the accuracy of subtype classification compared with radiological-guided biopsies.

Human plasmacytoid dendritic cells (pDCs) were considered to be a phenotypically and functionally homogeneous cell population; however, recent analyses indicate potential heterogeneity. This is of major interest, given their importance in the induction of anti-viral responses and their role in creating immunologically permissive environments for human malignancies. For this reason, we investigated the possible presence of human pDC subsets in blood and bone marrow, using unbiased cell phenotype clustering and functional studies. This defined two major functionally distinct human pDC subsets, distinguished by differential expression of CD2. The CD2(hi) and CD2(lo) pDCs represent discontinuous subsets, each with hallmark pDC functionality, including interferon-alpha production. The rarer CD2(hi) pDC subset demonstrated a significant survival advantage over CD2(lo) pDC during stress and upon exposure to glucocorticoids (GCs), which was associated with higher expression of the anti-apoptotic molecule BCL2. The differential sensitivity of these two human pDC subsets to GCs is demonstrated in vivo by a relative increase in CD2(hi) pDC in multiple myeloma patients treated with GCs. Hence, the selective apoptosis of CD2(lo) pDC during stress represents a novel mechanism for the control of innate responses.

Chemotherapy and hematopoietic stem cell transplantation are effective treatments for most Hodgkin lymphoma patients, however there remains a need for better tumor-specific target therapy in Hodgkin lymphoma patients with refractory or relapsed disease. Herein, we demonstrate that membrane CD83 is a diagnostic and therapeutic target, highly expressed in Hodgkin lymphoma cell lines and Hodgkin and Reed-Sternberg cells in 29/35 (82.9%) Hodgkin lymphoma patient lymph node biopsies. CD83 from Hodgkin lymphoma tumor cells was able to trogocytose to surrounding T cells and, interestingly, the trogocytosing CD83+T cells expressed significantly more programmed death-1 compared to CD83−T cells. Hodgkin lymphoma tumor cells secreted soluble CD83 that inhibited T-cell proliferation, and anti-CD83 antibody partially reversed the inhibitory effect. High levels of soluble CD83 were detected in Hodgkin lymphoma patient sera, which returned to normal in patients who had good clinical responses to chemotherapy confirmed by positron emission tomography scans. We generated a human anti-human CD83 antibody, 3C12C, and its toxin monomethyl auristatin E conjugate, that killed CD83 positive Hodgkin lymphoma cells but not CD83 negative cells. The 3C12C antibody was tested in dose escalation studies in non-human primates. No toxicity was observed, but there was evidence of CD83 positive target cell depletion. These data establish CD83 as a potential biomarker and therapeutic target in Hodgkin lymphoma.

HLDA10 is the Tenth Human Leukocyte Differentiation Antigen (HLDA) Workshop. The HLDA Workshops provide a mechanism to allocate cluster of differentiation (CD) nomenclature by engaging in interlaboratory studies. As the host laboratory, we invited researchers from national and international academic and commercial institutions to submit monoclonal antibodies (mAbs) to human leukocyte surface membrane molecules, particularly those that recognised molecules on human myeloid cell populations and dendritic cells (DCs). These mAbs were tested for activity and then distributed as a blinded panel to 15 international laboratories to test on different leukocyte populations. These populations included blood DCs, skin-derived DCs, tonsil leukocytes, monocyte-derived DCs, CD34-derived DCs, macrophage populations and diagnostic acute myeloid leukaemia and lymphoma samples. Each laboratory was provided with enough mAb to perform five repeat experiments. Here, we summarise the reactivity of different mAb to 68 different cell-surface molecules expressed by human myeloid and DC populations. Submitted mAbs to some of the molecules were further validated to collate data required to designate a formal CD number. This collaborative process provides the broader scientific community with an invaluable data set validating mAbs to leukocyte-surface molecules.