Immune infiltrates in liver metastases of colorectal cancer and response to chemotherapy

e15069

Background: Colorectal cancer (CRC) is a major cause of death from cancer. Patients with irresectable or metastasized CRC usually receive chemotherapy in combination with a monoclonal antibody, median overall survival time is around 20- 21 months with response rates of around 50%. Almost half of the patients experience treatment related side effects without benefit. K-ras mutation is the only (negative) predictive marker for response to therapy (for EGFR-targeting antibody treatment), no biomarkers are available that help to select patients most likely responding to chemotherapy. In primary colon cancer immune infiltrates in the tumor represent an important prognostic factor. High densities of tumor infiltrating lymphocytes (TIL) were shown to be correlated with an improved survival in patients with primary CRC. TILs therefore represent a valuable prognostic tool, a high density of immune cells being associated with good outcome independently of other established prognostic markers. Little is known about an association between these immune cells and the response to chemotherapy. Methods: Here the relation between infiltrates of immune cells in liver metastases of CRC and the response to chemotherapy (using immunohistochemical staining against CD8, GranB, FOXP3, CD45RO, etc.) was investigated. Samples from 33 patients with metastasized colorectal cancer (samples from 22 patients were used as training set and samples from 11 patients as validation set) were analyzed. Results: The evaluation of positively stained TIL in the invasive margin of the liver metastasis allowed to predict response to chemotherapy. This was also observed in the analysis of the time to progression, where higher numbers of positively stained cells were associated with longer intervals. The difference between the groups with either response or no response to chemotherapy in time to progression was statistically significant in the analyzed sets (Mann-Whitney- U, p<0.001, two-tailed, z=-3,961, n=33). In primary tumors no association between TIL densities and response to chemotherapy was observed. Conclusions: Our results suggest that the immune system has an important impact on the efficacy of chemotherapy and the presented data will have implications for the assessment of therapy options.

No significant financial relationships to disclose.

[Acceptance and safety of vaccines]

As a result of decreasing willingness to be vaccinated some diseases, which seemingly had been eradicated, may reappear. One example for this is the increase of measles cases in the United Kingdom since the 1990s after a decrease of immunization rate in response to a subsequently discredited publication suggesting a link between the triple measles, mumps and rubella vaccine and autism. As the incidence of vaccine preventable diseases decreases, vaccine safety dominates personal risk-benefit analysis. To deal with such concerns this review discusses pre- and post-licensing procedures controlling vaccine safety, taking HPV vaccination as well as vaccination against rotavirus as examples.

Abnormal crosstalk between pancreatic acini and macrophages during the clearance of apoptotic cells in chronic pancreatitis

In chronic pancreatitis (CP), both the progressive loss of acinar parenchyma and aggressive fibro-inflammatory reactions ultimately lead to irreversible organ destruction. Dying cells are normally removed by macrophages and elimination is associated with anti-inflammatory cytokine switch. We investigated whether defective clearance of damaged acini by macrophages such as compromised phagocytosis or altered cytokine reaction occurs in CP and thus represents a causative link between acinar loss and fibro-inflammation. In a checkerboard-like co-culture system, we assessed normal and CP macrophages for their phagocytic and cytokine responses to dying pancreatic acinar cells of normal or CP origin by FACS, confocal microscopy, QRT-PCR, and ELISA. In CP, phagocytosis of apoptotic acini by macrophages was not impaired; however, the associated cytokine responses were gradually perturbed. Most interestingly, only normal acini suppressed TGFbeta1 expression and accumulation specifically in normal macrophage cultures, while CP acini lost this ability. Both types of apoptotic acini induced pro-inflammatory cytokine bursts of varying strength in both types of macrophages; however, the most significant difference (more than 50-fold higher expression of IL-1beta, IL-6, and IL-8) was evident between CP/CP and normal/normal combinations, indicating that acinar and macrophage alterations synergistically lead to the ultimate CP-specific bias. In combination with in situ data comparing circulating inflammatory cells to pancreatic resident ones, our results indicate that cytokine expression in inflammatory cells undergoes spatiotemporal modulation, most likely through a successive interplay of acinar, stromal, and circulating factors. Thus, clearance of injured pancreatic acini by macrophages is associated with a unique cytokine reaction which may constitute a basis for progression of SAPE (sentinel acute pancreatitis event) to the irreversible fibro-inflammation in CP.