Murine liver plasmacytoid dendritic cells become potent immunostimulatory cells after Flt-3 ligand expansion

The liver has unique immunological properties. Although dendritic cells (DCs) are central mediators of immune regulation, little is known about liver DCs. Plasmacytoid DCs (pDCs) are a recently identified subtype of murine liver DC. We sought to define the function of freshly isolated murine liver pDCs. We found that normal liver pDCs were weak in stimulating T cells, yet they possessed a proinflammatory cytokine profile with high tumor necrosis factor-alpha and low IL-10 secretion. To facilitate the investigation of murine liver pDCs, we expanded them in vivo with fms-like tyrosine kinase 3 ligand (Flt3L). After Toll-like receptor-9 ligation, expanded liver pDCs secreted high levels of IFN-alpha and were able to stimulate NK cells, NKT cells, and antigen-specific CD8+ T cells in vitro. In addition, Flt3L expansion alone generated pDCs capable of activating antigen-specific CD8+ T cells in vivo. Conclusion: Unstimulated liver pDCs exist in a latent state with the potential to become potent activators of the innate and adaptive immune systems through their interactions with other immune effectors. Our findings have implications for understanding the role of the liver in tolerance and immunity.     

Left renal vein reconstruction after right nephrectomy and inadvertent left renal vein ligation: a case report and review of the literature.

Left renal vein ligation has been used as a technical aid to gain exposure to the perirenal aorta and to control bleeding in abdominal aortic operations. Left renal vein ligation is considered to be well tolerated in patients with 2 functioning kidneys, but has rarely been described in the setting of concomitant right nephrectomy and presents a management challenge. Some reports suggest recovery of renal function may be possible after left renal vein ligation during right nephrectomy, but other suggest that a delay in revascularizing the left renal venous drainage may result in irreversible nephropathy. This article reports the inadvertent division of the left renal vein during right nephrectomy. Renal failure ensued postoperatively. The left renal vein was reconstructed, and renal function was recovered. The inability to reliably predict which patients will have adverse outcome after left renal vein ligation in the setting of a right nephrectomy may necessitate preemptive intervention.     

Extent of Microinvasion in Ductal Carcinoma In Situ is not Associated with Sentinel Lymph Node Metastases

Background

Ductal carcinoma in situ with microinvasion (DCISM) is a rare diagnosis with a good prognosis. Although nodal metastases are uncommon, sentinel lymph node biopsy (SLNB) remains standard care. Volume of disease in invasive breast cancer is associated with SLNB positivity, and, thus we hypothesized that in a large cohort of patients with DCISM, multiple foci of microinvasion might be associated with a higher risk of positive SLNB.

Methods

Records from a prospective institutional database were reviewed to identify patients with DCISM who underwent SLNB between June 1997 and December 2010. Pathology reports were reviewed for number of microinvasive foci and categorized as 1 focus or ≥2 foci. Demographic, pathologic, treatment, and outcome data were obtained and analyzed.

Results

Of 414 patients, 235 (57 %) had 1 focus of microinvasion and 179 (43 %) had ≥2 foci. SLNB macrometastases were found in 1.4 %, and micrometastases were found in 6.3 %; neither were significantly different between patients with 1 focus versus ≥2 foci (p = 1.0). Patients with positive SLNB or ≥2 foci of microinvasion were more likely to receive chemotherapy. At median 4.9 years (range 0–16.2 years) follow-up, 18 patients, all in the SLNB negative group, had recurred for an overall 5-year recurrence-free proportion of 95.9 %.

Conclusions

Even with large numbers, there was no higher risk of nodal involvement with ≥2 foci of microinvasion compared with 1 focus. Number of microinvasive foci and results of SLNB appear to be used in decision making for systemic therapy. Prognosis is excellent.     

ASO Author Reflections: Clinical Importance of Histologic Subtype for Metaplastic Breast Cancer

Annals of Surgical Oncology -     

Dendritic cells are required for effective cross-presentation in the murine liver

The liver harbors a diversity of cell types that have been reported to stimulate T cells. Although most hepatic dendritic cells are immature, a small population of CD11c(high) conventional dendritic cells (cDCs) exists that expresses high levels of costimulatory molecules. We sought to determine the relative contribution of cDCs to cross-presentation by the liver. In vitro, liver nonparenchymal cells (NPCs) depleted of cDCs induced only minimal proliferation and activation of antigen-specific CD8(+) T cells when loaded with soluble protein antigen. Using a transgenic mouse with the CD11c promoter driving expression of the human diphtheria toxin receptor, we found that selective depletion of cDCs in vivo reduced the number and activation of antigen-specific CD8(+) T cells in the liver after intravenous administration of soluble protein antigen. Adoptive transfer of DCs, but not CD40 stimulation, restored the hepatic T-cell response. Conclusion: Our findings indicate that the ability of the liver to effectively cross-present soluble protein to antigen-specific CD8(+) T cells depends primarily on cDCs. Despite costimulation, other resident liver antigen-presenting cells cannot compensate for the absence of cDCs.     

Axillary Dissection Can Be Avoided in the Majority of Clinically Node-Negative Patients Undergoing Breast-Conserving Therapy

Background

The extent to which ACOSOG Z0011 findings are applicable to patients undergoing breast-conserving therapy (BCT) is uncertain. We prospectively assessed how often axillary dissection (ALND) was avoided in an unselected, consecutive patient cohort meeting Z0011 eligibility criteria and whether subgroups requiring ALND could be identified preoperatively.

Methods

Patients with cT1,2cN0 breast cancer undergoing BCT were managed without ALND for metastases in <3 sentinel nodes (SNs) and no gross extracapsular extension (ECE). Patients with and without indications for ALND were compared using Fisher’s exact and Wilcoxon rank sum tests.

Results

From August 2010 to November 2012, 2,157 invasive cancer patients had BCT. A total of 380 had histologic nodal metastasis; 93 did not meet Z0011 criteria. Of 287 with ≥1 H&E-positive SN (209 macrometastases), 242 (84 %) had indications for SN only. ALND was indicated in 45 for ≥3 positive SNs (n = 29) or ECE (n = 16). The median number of SNs removed in the SN group was 3 versus 5 in the ALND group (p < 0.0001). Age, hormone receptor and HER2 status, and grade did not differ between groups; tumors were larger in the ALND group (p < 0.0001). Of ALND patients, 72 % had additional positive nodes (median = 1; range 1–19). No axillary recurrences have occurred (median follow-up, 13 months).

Conclusions

ALND was avoided in 84 % of a consecutive series of patients having BCT, suggesting that most patients meeting ACOSOG Z0011 eligibility have a low axillary tumor burden. Age, ER, and HER2 status were not predictive of ALND, and the criteria used for ALND (≥3 SNs, ECE) reliably identified patients at high risk for residual axillary disease.     

Conventional DCs reduce liver ischemia/reperfusion injury in mice via IL-10 secretion

TLRs are recognized as promoters of tissue damage, even in the absence of pathogens. TLR binding to damage-associated molecular patterns (DAMPs) released by injured host cells unleashes an inflammatory cascade that amplifies tissue destruction. However, whether TLRs possess the reciprocal ability to curtail the extent of sterile inflammation is uncertain. Here, we investigated this possibility in mice by studying the role of conventional DCs (cDCs) in liver ischemia/reperfusion (I/R) injury, a model of sterile inflammation. Targeted depletion of mouse cDCs increased liver injury after I/R, as assessed by serum alanine aminotransferase and histologic analysis. In vitro, we identified hepatocyte DNA as an endogenous ligand to TLR9 that promoted cDCs to secrete IL-10. In vivo, cDC production of IL-10 required TLR9 and reduced liver injury. In addition, we found that inflammatory monocytes recruited to the liver via chemokine receptor 2 were downstream targets of cDC IL-10. IL-10 from cDCs reduced production of TNF, IL-6, and ROS by inflammatory monocytes. Our results implicate inflammatory monocytes as mediators of liver I/R injury and reveal that cDCs respond to DAMPS during sterile inflammation, providing the host with protection from progressive tissue damage.     

Combined stimulation with interleukin-18 and CpG induces murine natural killer dendritic cells to produce IFN-gamma and inhibit tumor growth

Natural killer dendritic cells (NKDC) are a novel subtype of dendritic cells with natural killer (NK) cell properties. IFN-gamma is a pleiotropic cytokine that plays an important role in the innate immune response to tumors. Based on our previous finding that the combination of Toll-like receptor 9 ligand CpG and interleukin (IL)-4 stimulates NKDC to produce IFN-gamma, we hypothesized that NKDC are the major IFN-gamma-producing dendritic cell subtype and may play a significant role in the host antitumor response. We found that under several conditions in vitro and in vivo NKDC accounted for the majority of IFN-gamma production by murine spleen CD11c(+) cells. IL-18 alone induced NKDC to secrete IFN-gamma, and the combination of IL-18 and CpG resulted in a synergistic increase in IFN-gamma production, both in vitro and in vivo. NK cells made 26-fold less IFN-gamma under the same conditions in vitro, whereas dendritic cells produced a negligible amount. The mechanism of IFN-gamma secretion by NKDC depended on IL-12. NKDC selectively proliferated in vitro and in vivo in response to the combination of IL-18 and CpG. Systemic treatment with IL-18 and CpG reduced the number of B16F10 melanoma lung metastases. The mechanism depended on NK1.1(+) cells, as their depletion abrogated the effect. IL-18 and CpG activated NKDC provided greater tumor protection than NK cells in IFN-gamma(-/-) mice. Thus, NKDC are the major dendritic cell subtype to produce IFN-gamma. The combined use of IL-18 and CpG is a viable strategy to potentiate the antitumor function of NKDC.