Immunotherapy has shown great promise in the fight against cancer, as evidenced by the clinical efficacy of chimeric antigen receptor T cells in hematologic malignancies and checkpoint blockade in certain solid tumors. However, a considerable number of patients fail to respond to these therapies. Induction of myeloid-derived suppressor cells (MDSCs) by growing tumors has been shown to be one important factor limiting the efficacy of cancer immunotherapy. Recently, several chemotherapeutic agents used in conventional cancer chemotherapy have been found to reduce MDSC numbers in tumor tissues as well as in the peripheral lymphoid organs, and combining these agents with immunotherapy improved survival of tumor-bearing hosts. In this review, we will highlight the effects of chemotherapeutic agents on MDSC accumulation, and examine the various factors likely to influence these effects.

The increase of interleukin-4 (IL-4) level in tumor environment and the up-regulation of IL-4 receptor (IL-4R) on tumor cells have been long observed. However, their significance for tumor development has not been investigated. Here, we found that endogenous IL-4 promotes tumor growth because neutralizing IL-4 by 11B11 monoclonal antibody (mAb) significantly delayed the growth of MCA205 fibrosarcoma.

Adoptive immunotherapy using cytokine-induced killer (CIK) cells is a promising cancer treatment, but its efficacy is restricted by various factors, including the accumulation of myeloid-derived suppressor cells (MDSCs). In this study, we determine whether chemotherapeutic drugs that reduce MDSC levels enhance the efficacy of CIK cell therapy in the treatment of solid tumors. Fifty-three patients were included in this study; 17 were diagnosed with metastatic renal cell carcinoma (MRCC), 10 with advanced pancreatic cancer (PC), and 26 with metastatic melanoma (MM). These patients were divided into two groups: CIK cell therapy alone and CIK cell therapy combined with chemotherapy. Combining CIK cell therapy and chemotherapy increased 1-year survival rates and median survival times in MRCC and PC patients, but not in MM patients. The disease control rate did not differ between treatment groups for MRCC or MM patients, but was higher in PC patients receiving combined treatment than CIK cell treatment alone. These data suggest that addition of MDSC-decreasing chemotherapy to CIK cell therapy improves survival in MRCC and PC patients.

BackgroundThere is no standard neoadjuvant therapy for locally advanced esophageal cancer in China. The role of neoadjuvant chemotherapy plus immunotherapy for locally advanced esophageal cancer is still being explored.MethodsThis open-label, randomized phase II study was conducted at a single center between July 2019 and September 2020; 30 patients with locally advanced esophageal squamous cell carcinoma (ESCC) (T3, T4, or lymph-node positive) were enrolled. Patients were randomized according to the enrollment order at a 1:1 ratio to receive chemotherapy on day 1 and toripalimab on day 3 (experimental group) or chemotherapy and toripalimab on day 1 (control group). The chemotherapeutic regimen was paclitaxel and cisplatin. Surgery was performed 4 to 6 weeks after the second cycle of chemoimmunotherapy. The primary endpoint was pathological complete response (pCR) rate, and the secondary endpoint was safety and disease-free survival.ResultsThirty patients completed at least one cycle of chemoimmunotherapy; 11 in the experimental group and 13 in the control group received surgery. R0 resection was performed in all these 24 patients. Four patients (36%) in the experimental group and one (7%) in the control group achieved pCR. The experimental group showed a statistically non-significant higher pCR rate (p = 0.079). PD-L1 combined positive score (CPS) examination was performed in 14 patients; one in the control group had a PD-L1 CPS of 10, and pCR was achieved; the remaining 13 all had ≤1, and 11 of the 13 patients received surgery in which two (in the experimental group) achieved pCR. Two patients endured ≥grade 3 adverse events, and one suffered from grade 3 immune-related enteritis after one cycle of chemoimmunotherapy and dropped off the study. Another patient died from severe pulmonary infection and troponin elevation after surgery.ConclusionsAlthough the primary endpoint was not met, the initial results of this study showed that delaying toripalimab to day 3 in chemoimmunotherapy might achieve a higher pCR rate than that on the same day, and further large-sample clinical trials are needed to verify this.Clinical Trial RegistrationClinicalTrials.gov, identifier NCT 03985670.

Metastatic renal cell carcinoma (MRCC) is one of the malignancies that are sensitive to immunotherapy. However, the underlying immune inhibitory factors such as myeloid-derived suppressor cells (MDSCs) might restrain the efficacy of immunotherapy. The present study investigates the clinical efficacy of cytokine-induced killer (CIK) cell therapy in patients with MRCC and explores whether the levels of peripheral MDSCs are associated with the prognosis of patients receiving this therapy. Twenty-nine patients with measurable MRCC were treated with an adoptive transfer of autologous CIK cells, followed by 5 consecutive days of interleukin-2 administration. The tumor response and 1-year survival were observed. The proportion of MDSCs in the peripheral blood was detected, and the correlation of MDSCs with prognosis was analyzed. Of 29 evaluable patients, no complete responses were seen; 4 patients exhibited a partial response (13.8%), 18 patients displayed stable disease (62.1%), and 7 patients showed progressive disease (24.1%). Twenty patients (69.0%) were alive 14.8-41.4 months at the time of the last follow-up (median follow-up=20.2 mo). The 1-year survival was 82.8% (24/29). Peripheral blood MDSCs were elevated in almost all MRCC patients and decreased after CIK-cell infusion. Subgroup analysis indicated that patients with a relatively low proportion of MDSCs exhibited prolonged survival. In conclusion, our data suggest that transfusion of autologous CIK cells can induce regression of MRCC, and MDSCs can serve as a potential marker for the prognosis of patients receiving a CIK-based therapy.

Although adjuvants are important components of vaccines, few studies have been conducted to establish the criteria on adjuvant selection and to investigate mechanisms of adjuvant actions during vaccination. Here we found that complete Freund adjuvant (CFA) induced a CD11b cell population in a B-cell independent manner. This cell population exhibited strong ability to inhibit T-cell-mediated rejection of tumor transplants. In vitro studies indicated that these cells induced T-cell apoptosis and down-regulated interferon-gamma production. Nitric oxide (NO) played important roles to achieve these effects. Plenty of NO was produced by these CFA-induced CD11b cells. The addition of N-nitro-L-arginine-methyl ester, an inhibitor of NO synthase, rescued T cells from apoptosis and partially abrogated the detrimental effects of CFA in cancer vaccines. Incomplete Freund adjuvant, one of the adjuvants still being used in clinical trials, also induced a similar cell population. Our results reveal a previously unknown mechanism in which the myeloid cell population induced by Freund adjuvant impairs antitumor immunity, and highlight the importance of adjuvant selection during tumor vaccination.

Immune checkpoint inhibitors (ICIs) including anti-cytotoxic T-lymphocyte-associated protein 4 (anti-CTLA4) and anti-programmed death cell protein 1 (anti-PD1) have extended patient survival benefit and revolutionized cancer treatment. As ICIs rely on immune regeneration to eliminate tumor cells, they can also lead to an imbalance of immune reactions often called immune-related adverse events (irAEs). Rare irAEs such as ocular or cardiac toxicity or vasculitis are seen in less than 1% of patients receiving ICIs. Immune-related cystitis remains a rare occurrence. Herein, we describe a patient with extensive-stage small cell lung cancer (SCLC) and a history of syphilis with a complete response to second-line treatment using nivolumab plus paclitaxel who complained of urinary irritation symptoms. At biopsy, we found infiltration of CD3 + and CD8 + lymphocytes in the urothelium. Although there are reports describing immune-related cystitis in cancer patients, our case has comprehensive pathological confirmation and a differentiation diagnosis. In this report, we review other cases to elucidate clinical characteristics and discuss suitable management of this rare irAE.

BackgroundAdvanced pancreatic cancer (PC) has very poor prognosis with present treatments, thus necessitating continued efforts to find improved therapeutic approaches. Both preclinical and preliminary clinical data indicate that cytokine-induced killer (CIK) cells are an effective tool against various types of solid tumors. Here, we conducted a study to determine whether CIK cell-based therapy (CBT) can improve the outcomes of advanced PC.MethodsEighty-two patients with advanced PC, whose predicted survival time was longer than 3 months, were analyzed retrospectively. Of all the patients, 57 individuals were receiving chemotherapy, while the remaining 25 individuals were treated with CBT.ResultsThe overall survival analysis was based on 48 deaths in the 57 patients in the chemotherapy group (84.2 %) and 18 deaths in the 25 patients in the CBT group (72.0 %). In the CBT group, the median overall survival time was 13.5 months, as compared to 6.6 months in the chemotherapy group (hazard ratio for death, 0.39; 95 % confidence interval, 0.23 to 0.65; p < 0.001). The survival rate was 88.9 % in the CBT group versus 54.2 % in the chemotherapy group at 6 months, 61.1 % versus 12.5 % at 12 months, and 38.9 % versus 4.2 % at 18 months. The disease control rate was 68.0 % in the CBT group and 29.8 % in the chemotherapy group (p < 0.001).ConclusionsThese results from this retrospective analysis appeared to imply that CBT might prolong survival in these high-risk PC patients. Prospective study is needed to corroborate this observation.Electronic supplementary materialThe online version of this article (doi:10.1186/s13045-016-0237-6) contains supplementary material, which is available to authorized users.