Neoadjuvant rituximab modulates the tumor immune environment in patients with high risk prostate cancer.

BACKGROUND: Immunotherapeutic regulation of the tumor microenvironment in prostate cancer patients is not understood. Most antibody immunotherapies have not succeeded in prostate cancer. We showed previously that high-risk PCa patients have a higher density of tumor infiltrating B-cells in prostatectomy specimens. In mouse models, anti-CD20 antibody ablation of B-cells delayed PCa regrowth post-treatment. We sought to determine whether neoadjuvant anti-CD20 immunotherapy with rituximab could reduce CD20+ B cell infiltration of prostate tumors in patients. METHODS: An open label, single arm clinical trial enrolled eight high-risk PCa patients to receive one cycle of neoadjuvant rituximab prior to prostatectomy. Eleven clinical specimens with similar characteristics were selected as controls. Treated and control samples were concurrently stained for CD20 and digitally scanned in a blinded fashion. A new method of digital image quantification of lymphocytes was applied to prostatectomy sections of treated and control cases. CD20 density was quantified by a deconvolution algorithm in pathologist-marked tumor and adjacent regions. Statistical significance was assessed by one sided Welch's t-test, at 0.05 level using a gatekeeper strategy. Secondary outcomes included CD3+ T-cell and PD-L1 densities. RESULTS: Mean CD20 density in the tumor regions of the treated group was significantly lower than the control group (p = 0.02). Mean CD3 density in the tumors was significantly decreased in the treated group (p = 0.01). CD20, CD3 and PD-L1 staining primarily occurred in tertiary lymphoid structures (TLS). Neoadjuvant rituximab was well-tolerated and decreased B-cell and T-cell density within high-risk PCa tumors compared to controls. CONCLUSIONS: This is the first study to treat patients prior to surgical prostate removal with an immunotherapy that targets B-cells. Rituximab treatment reduced tumor infiltrating B and T-cell density especially in TLSs, thus, demonstrating inter-dependence between B- and T-cells in prostate cancer and that Rituximab can modify the immune environment in prostate tumors. Future studies will determine who may benefit from using rituximab to improve their immune response against prostate cancer. Trial registration NCT01804712, March 5th, 2013 https://clinicaltrials.gov/ct2/show/NCT01804712?cond=NCT01804712&draw=2&rank=1.

Effects of subtotal fasting on plasmatic coagulation, fibrinolytic status and platelet activation: a controlled pilot study in healthy subjects.

BACKGROUND AND AIM: There is considerable controversy as to whether fasting can be recommended to patients with cardiovascular disease. The objective of this study was to determine whether a well-known method of 1-week subtotal fasting affects hemostasis in healthy subjects. METHODS AND RESULTS: Analyses were carried out before, four times during and 3 days after fasting in 12 fasting subjects (< 300 kcal/day, only from carbohydrates) (group 1), and 8 control subjects (group 2). Plasmatic coagulation (prothrombin time, partial thromboplastin time, p < or = 0.001) and fibrinolysis (plasminogen, plasmin-antiplasmin-complex, p < 0.05) increased during fasting but remained within the normal limits. While the platelet count was similar in both groups, platelet sensitivity to stimulators was reduced in group 1 (P-selectin and activated GP IIb/IIIa on ADP-stimulated platelets, p < or = 0.01). Furthermore, soluble P-selectin (p < or = 0.01) and C-reactive protein were decreased in comparison to group 2 (p < or = 0.05). CONCLUSIONS: Hemostasis and inflammation parameters during 1-week subtotal fasting do not imply an increase in cardiovascular risk.

Adhesion of monocytes to medical steel as used for vascular stents is mediated by the integrin receptor Mac-1 (CD11b/CD18; alphaM beta2) and can be inhibited by semiconductor coating.

Implantation of stents into stenosed arteries helps to restore normal blood flow in ischemic organs. However, limited biocompatibility of the applied medical steel can cause acute thrombosis and long-term restenosis. Adhesion of monocytes to stent metal may participate in those acute and long-term complications of stent placement. Based on described prominent electrochemical properties of the interaction between the monocyte integrin receptor Mac-1 and its various ligands, we hypothesized, that this receptor is a central mediator of monocyte adhesion to stent metal and that semiconductor coating of medical steel reduces monocyte adhesion. Adhesion of monocytes on L-316 stainless steel was directly evaluated by light microscopy. Mac-1 could be identified as mediator of monocyte adhesion, since cell adhesion could be blocked by anti-Mac-1-antibodies, including the cross-reacting anti-GPIIb/IIIa antibody fragment abciximab. To further prove the central role of Mac-1, two CHO cell lines were generated expressing recombinant Mac-1 either as wild type, resulting in a low affinity receptor, or mutant with a GFFKR deletion of the alpha(M) subunit, resulting in a high affinity receptor. Indeed, adhesion was specific for Mac-1 and dependent on the affinity state of this integrin. Finally, we could demonstrate that Mac-1-mediated adhesion of monocytes to stents can be significantly inhibited by silicon carbide coating of the stent metal. In conclusion, the integrin Mac-1 and its affinity state could be identified as major mediators of monocyte adhesion on medical steel. As therapeutic strategies, the blockade of Mac-1 by antibodies or silicon carbide coating of steel inhibits monocyte adhesion on stents.