Vaginal cuff brachytherapy for endometrial cancer: a review of major clinical trials with a focus on fractionation.

The use of vaginal cuff brachytherapy in the adjuvant management of endometrial cancer has increased over time. Recommendations from the American Brachytherapy Society, American Society of Radiation Oncology, and European Society for Medical Oncology help to guide the application of vaginal cuff brachytherapy. However, wide variation in practice remains regarding treatment techniques. This article reviews the use of vaginal cuff brachytherapy in the post-operative management of endometrial cancer. It covers risk stratification, treatment rationale, outcomes, and treatment planning recommendations with a specific focus on dose-fractionation regimens. The authors performed a thorough literature review of articles pertinent to the goals of this review. Also presented are early results of the Short Course Adjuvant Vaginal Cuff Brachytherapy in Early Endometrial Cancer Compared with Standard of Care (SAVE) trial of a two-fraction vaginal cuff brachytherapy regimen.Adjuvant vaginal cuff brachytherapy for early-stage endometrial cancer results in excellent disease control with minimal toxicity. The PORTEC-2 trial showed that vaginal cuff brachytherapy is non-inferior to external beam radiation for vaginal recurrence in patients at high-intermediate risk. Vaginal cuff brachytherapy may also be used as a boost following external beam radiation in combination with chemotherapy for high-risk histologies. Numerous techniques can be used for vaginal cuff brachytherapy, including various medical devices, dose-fractionation schedules, and treatment planning approaches. The early control results of the SAVE trial are promising and we are hopeful that this trial establishes two fraction regimens as a viable option for vaginal cuff brachytherapy.

Risk of secondary malignancies in ovarian cancer survivors: 52,680 patients analyzed with over 40 years of follow-up.

OBJECTIVE: Survivors of ovarian cancer are at risk of developing a secondary malignancy (SM). We sought to evaluate the risk of developing SM, stratified by treatment modality. METHODS: Standardized incidence ratios (SIR, observed-to-expected [O/E] ratio) were assessed in 52,680 patients diagnosed with ovarian cancer between 1975 and 2016 in the National Cancer Institute's Surveillance, Epidemiology, and End Results Program. RESULTS: Of the 52,680 patients, 3366 patients (6.4%) developed SM, which was more than the endemic rate (O/E 1.13; p < .05). Patients who received any radiation (RT) had an increased risk of overall SM compared to those who didn't (O/E 1.42 vs 1.11; p < .05), and specifically, in the bladder (O/E 2.81). Patients who received any chemotherapy (CT) had an increased risk of leukemia (O/E 3.06), and a similar risk of overall SM compared to those not treated with CT (O/E 1.11 vs 1.14; p < .05). The excess risk of developing a solid tumor SM was greatest at latencies of 10-20 years. Patients younger than 50 had the highest risk of developing SM. Non-White patients had a higher risk of SM compared to White patients. CONCLUSIONS: This is the largest study to examine the risk of SM in patients with ovarian cancer and has the longest follow-up. Risk of SM was increased after ovarian cancer and varied with treatment modality, race, latency, and age. These results may help inform SM screening protocols for women diagnosed with ovarian cancer.

The use and efficacy of chemotherapy and radiotherapy in children and adults with pilocytic astrocytoma.

PURPOSE: The aim of this study was to understand the use of chemotherapy (CMT) and radiotherapy (RT) in pilocytic astrocytoma (PA) and their impact on overall survival (OS). METHODS: Data from the National Cancer Database (NCDB) for patients with non-metastatic WHO grade I PA from 2004 to 2014 were analyzed. Pearson's chi-squared test and multivariate logistic regression analyses were performed to assess the distribution of demographic, clinical, and treatment factors. Inverse probability of treatment weighting (IPTW) was used to account for differences in baseline characteristics. Kaplan-Meier analyses and doubly-robust estimation with multivariate Cox proportional hazards modeling were used to analyze OS. RESULTS: Of 3865 patients analyzed, 294 received CMT (7.6%), 233 received RT (6.0%), and 42 (1.1%) received both. On multivariate analyses, decreasing extent of surgical resection was associated with receipt of both CMT and RT. Brainstem tumors were associated with RT, optic nerve tumors were associated with CMT. Cerebellar tumors were inversely associated with both CMT and RT. Younger age was associated with receipt of CMT; conversely, older age was associated with receipt of RT. After IPTW, receipt of CMT and/or RT were associated with an OS decrement compared with matched patients treated with surgery alone or observation (HR 3.29, p < 0.01). CONCLUSIONS: This is the largest study to date to examine patterns of care and resultant OS outcomes in PA. We identified patient characteristics associated with receipt of CMT and RT. After propensity score matching, receipt of CMT and/or RT was associated with decreased OS.

Refusal of surgery and survival outcomes in endometrial cancer.

OBJECTIVES: The goal of this study was to determine the impact refusal of surgery has on overall survival in patients with endometrial cancer. METHODS: From January 2004 to December 2015, the National Cancer Database was queried for patients with pathologically proven endometrial cancer who were recommended surgery and refused. Inverse probability of treatment weighting was used to account for differences in baseline characteristics between patients who underwent surgery and those who refused. Kaplan-Meier analyses and doubly robust estimation with multivariate Cox proportional hazards modeling were used to analyze overall survival. RESULTS: Of the 300 675 patients identified, 534 patients (0.2%) were recommended surgical treatment but refused: 18% (95/534) were age ≤40 years. The 5-year overall survival for all patients who refused surgery was significantly decreased compared with patients who underwent surgery (29.2% vs 71.9%, P<0.01). This was demonstrated at ages 41-64 years (65.5% vs 91.0%, P<0.01) and ≥65 years (23.4% vs 75.3%, P<0.01). The 5-year overall survival did not meet statistical significance at age ≤40 years (90.1% vs 87.8% P<0.19). However, there were few patients in this cohort. On multivariate analysis, factors associated with refusal of surgery included: Medicaid insurance, Black race, Hispanic Race, Charlson Comorbidity Index scores of 2 or greater, stage II or III, and if patient received external beam radiation therapy alone. Factors associated with undergoing surgery included: age greater than 41, stage IB, and if the patient received brachytherapy. CONCLUSIONS: Refusal of surgery for endometrial cancer is uncommon and leads to decreased overall survival.

The Effect of Measured Radiotherapy Dose on Intrathecal Drug Delivery System Function.

OBJECTIVES: Radiation therapy (RT) and intrathecal drug delivery systems (IDDS) are often used concurrently to optimize pain management in patients with cancer. Concern remains among clinicians regarding the potential for IDDS malfunction in the setting of RT. Here we assessed the frequency of IDDS malfunction in a large cohort of patients treated with RT. MATERIALS AND METHODS: Cancer patients with IDDS and subsequent RT at our institution from 2011 to 2019 were eligible for this study. Patients were excluded in the rare event that their IDDS was managed by an outside clinic and follow-up documentation was unavailable. Eighty-eight patients aged 22-88 years old (43% female, 57% male) representing 106 separate courses of RT were retrospectively identified. Patients received varying levels of radiation for treatment of cancer and cumulative dose to the IDDS was calculated. IDDS interrogation was subsequently performed by a pain specialist. Malfunction was recorded as deviation from the expected drug volume and/or device errors reported upon interrogation as defined by the manufacturer. RESULTS: Total measured RT dose to the IDDS ranged from 0 to 18.0 Gy (median = 0.2 Gy) with median dose of 0.04 Gy/fraction (range, 0-3.2 Gy/fraction). Ten pumps received a total dose >2 Gy and three received ≥5 Gy. Eighty-two percentage of patients had follow-up with a pain specialist for IDDS interrogation and all patients underwent follow-up with a healthcare provider following RT. There were zero incidences of IDDS malfunction related to RT. No patient had clinical evidence of radiation related pump malfunction at subsequent encounters. CONCLUSIONS: We found no evidence that RT in patients with IDDS led to device failure or dysfunction. While radiation oncologists and pain specialists should coordinate patient care, it does not appear that RT dose impacts the function of the IDDS to warrant significant clinical concern.

Dectin-2 regulates the effector phase of house dust mite-elicited pulmonary inflammation independently from its role in sensitization.

The myeloid C-type lectin receptor Dectin-2 directs the generation of Th2 and Th17 immune responses to the house dust mite Dermatophagoides farinae through the generation of cysteinyl leukotrienes and proinflammatory cytokines, respectively, but a role for Dectin-2 in effector phase responses has not been described. In this study, we demonstrate that administration of the Dectin-2 mAb solely at the time of D. farinae challenge abrogated eosinophilic and neutrophilic inflammation in the bronchoalveolar lavage fluid and Th1, Th2, and Th17 inflammation in the lung of previously sensitized mice. Furthermore, Dectin-2 null mice (Clec4n(-/-)) sensitized with the adoptive transfer of D. farinae-pulsed wild-type (WT) bone marrow-derived dendritic cells (DCs) also had less D. farinae-elicited pulmonary inflammation, supporting an effector function for Dectin-2. The protection from pulmonary inflammation seen with the Dectin-2 mAb or in Clec4n(-/-) mice was associated with little or no reduction in lung-draining lymph node cells or their cytokine production and with no reduction in serum IgE. WT and Clec4n(-/-) mice recipients, sensitized with D. farinae-pulsed WT bone marrow-derived DCs, had comparable levels of D. farinae-elicited IL-6, IL-23, TNF-α, and cysteinyl leukotrienes in the lung. By contrast, D. farinae-elicited CCL4 and CCL8 production from pulmonary CD11c(+)CD11b(+)Ly6C(+) and CD11c(+)CD11b(+)Ly6C(-)CD64(+) monocyte-derived DCs was reduced in Clec4n(-/-) recipients. Addition of CCL8 at the time of D. farinae challenge abrogated the protection from eosinophilic, neutrophilic, and Th2 pulmonary inflammation seen in Clec4n(-/-) recipients. Taken together, these results reveal that Dectin-2 regulates monocyte-derived DC function in the pulmonary microenvironment at D. farinae challenge to promote the local inflammatory response.

Cysteinyl leukotriene 2 receptor on dendritic cells negatively regulates ligand-dependent allergic pulmonary inflammation.

Cysteinyl leukotrienes (cys-LTs) can mediate Th2 immunity to the house dust mite, Dermatophagoides farinae, via the type 1 receptor CysLT(1)R on dendritic cells (DCs). However, the role of the homologous type 2 receptor CysLT(2)R in Th2 immunity is unknown. D. farinae sensitization and challenge of CysLT(2)R-deficient mice showed a marked augmentation of eosinophilic pulmonary inflammation, serum IgE, and Th2 cytokines. Wild-type (WT) mice sensitized by adoptive transfer of D. farinae-pulsed CysLT(2)R-deficient bone marrow-derived DCs (BMDCs) also had a marked increase in D. farinae-elicited eosinophilic lung inflammation and Th2 cytokines in restimulated hilar nodes. This response was absent in mice sensitized with D. farinae-pulsed BMDCs lacking leukotriene C(4) synthase (LTC(4)S), CysLT(1)R, or both CysLT(2)R/LTC(4)S, suggesting that CysLT(2)R negatively regulates LTC(4)S- and CysLT(1)R-dependent DC-mediated sensitization. CysLT(2)R-deficient BMDCs had increased CysLT(1)R-dependent LTD(4)-induced ERK phosphorylation, whereas N-methyl LTC(4) activation of CysLT(2)R on WT BMDCs reduced such signaling. Activation of endogenously expressed CysLT(1)R and CysLT(2)R occurred over an equimolar range of LTD(4) and N-methyl LTC(4), respectively. Although the baseline expression of cell surface CysLT(1)R was not increased on CysLT(2)R-deficient BMDCs, it was upregulated at 24 h by a pulse of D. farinae, compared with WT or CysLT(2)R/LTC(4)S-deficient BMDCs. Importantly, treatment with N-methyl LTC(4) reduced D. farinae-induced CysLT(1)R expression on WT BMDCs. Thus, CysLT(2)R negatively regulates the development of cys-LT-dependent Th2 pulmonary inflammation by inhibiting both CysLT(1)R signaling and D. farinae-induced LTC(4)S-dependent cell surface expression of CysLT(1)R on DCs. Furthermore, these studies highlight how the biologic activity of cys-LTs can be tightly regulated by competition between these endogenously expressed receptors.

Secondary malignancies in non-Hodgkin lymphoma survivors: 40 years of follow-up assessed by treatment modality.

BACKGROUND: Survivors of non-Hodgkin lymphoma (NHL) have increased secondary malignancy (SM) risk. We quantified this risk by patient and treatment factors. METHODS: Standardized incidence ratios (SIR, observed-to-expected [O/E] ratio) were assessed in 142,637 NHL patients diagnosed from 1975 to 2016 in the National Cancer Institute's Surveillance, Epidemiology, and End Results Program. Comparisons were made between subgroups in terms of their SIRs relative to respective endemic populations. RESULTS: In total, 15,979 patients developed SM, more than the endemic rate (O/E 1.29; p < 0.05). Compared with white patients, relative to respective endemic populations, ethnic minorities had a higher risk of SM (white O/E 1.27, 95% CI 1.25-1.29; black O/E 1.40, 95% CI 1.31-1.48; other O/E 1.59, 95% CI 1.49-1.70). Relative to respective endemic populations, patients who received radiotherapy had similar SM rates to those who did not (O/E 1.29 each), but irradiated patients had increased breast cancer (p < 0.05). Patients who received chemotherapy had higher SM rates than those who did not (O/E 1.33 vs. 1.24, p < 0.05) including more leukemia, Kaposi sarcoma, kidney, pancreas, rectal, head and neck, and colon cancers (p < 0.05). CONCLUSIONS: This is the largest study to examine SM risk in NHL patients with the longest follow-up. Treatment with radiotherapy did not increase overall SM risk, while chemotherapy was associated with a higher overall risk. However, certain subsites were associated with a higher risk of SM, and they varied by treatment, age group, race and time since treatment. These findings are helpful for informing screening and long-term follow-up in NHL survivors.

International medical tourism of US cancer patients for alternative cancer treatments: Financial, demographic, and clinical profiles of online crowdfunding campaigns.

BACKGROUND: Previous research has found that individuals may travel outside their home countries in pursuit of alternative cancer therapies (ACT). The goal of this study is to compare individuals in the United States who propose plans for travel abroad for ACT, compared with individuals who seek ACT domestically. METHODS: Clinical and treatment data were extracted from campaign descriptions of 615 GoFundMe® campaigns fundraising for individuals in the United States seeking ACT between 2011 and 2019. We examined treatment modalities, treatment location, fundraising metrics, and online engagement within campaign profiles. Clinical and demographic differences between those who proposed international travel and those who sought ACT domestically were examined using two-sided Fisher's exact tests. Differences in financial and social engagement data were examined using two-sided Mann-Whitney tests. RESULTS: Of the total 615 campaigns, 237 (38.5%) mentioned plans to travel internationally for ACT, with the majority (81.9%) pursuing travel to Mexico. Campaigns that proposed international treatment requested more money ($35,000 vs. $22,650, p < 0.001), raised more money ($7833 vs. $5035, p < 0.001), had more donors (57 vs. 45, p = 0.02), and were shared more times (377 vs. 290.5, p = 0.008) compared to campaigns that did not. The median financial shortfall was greater for campaigns pursuing treatments internationally (-$22,640 vs. -$13,436, p < 0.003). CONCLUSIONS: Campaigns proposing international travel for ACT requested and received more money, were shared more online, and had more donors. However, there was significantly more unmet financial need among this group, highlighting potential financial toxicity on patients and families.

Improved overall survival over time in advanced stage mycosis fungoides: a cross-sectional study.

Mycosis Fungoides (MF) is a rare T-cell lymphoma and evidence on treatment practices, and outcomes are limited. We evaluated changes in practice patterns and corresponding effects on overall survival (OS) in MF using a cross-sectional study of patients diagnosed with MF from 2004 to 2016 in the National Cancer Database. Outcomes evaluated included patterns of care and OS across treatment eras. We found factors associated with chemotherapy use included male gender, treatment from 2004 to 2010 and stage III-IV disease. Factors associated with radiotherapy receipt included stage I-II disease, nonacademic treatment centers, male gender, non-black race, and Medicare status. Immunotherapy use was associated with treatment from 2004 to 2010 and stage III-IV disease. After propensity score matching, there was no OS difference among patients with stage I-II disease between 2004-2010 and 2011-2016. However, amongst patients with stage III-IV disease, OS was significantly improved in those treated from 2011 to 2016.

The Effect of Maximum Tumor Diameter by MRI on Disease Control in Intermediate and High-risk Prostate Cancer Patients Treated With Brachytherapy Boost.

BACKGROUND: Larger maximum tumor diameter (MTD) has been associated with worse prostate cancer (PCa) outcomes. However, the impact of MTD in PCa treated with external beam radiotherapy and brachytherapy boost (EBRT+BB) remains unknown. MATERIALS AND METHODS: Patients with PCa treated with EBRT+BB were identified from an institutional database. Clinical data including MTD, age, androgen deprivation therapy (ADT) use, prostate specific antigen (PSA), International Society of Urologic Pathology (ISUP) group, clinical T-stage, and presence of adverse pathology on imaging were retrospectively collected. Multivariable and univariable cox proportional hazards models for biochemical failure (BF) and distant metastasis (DM) were produced with MTD grouped by receiver operating characteristic (ROC) cut-point. Cumulative hazard functions for BF and DM were compared with log-rank test and stratified by ISUP group. RESULTS: Of 191 patients treated with EBRT+BB, 113 had MTD measurements available. Larger MTD was associated with increased ADT use and seminal vesicle involvement. ROC optimization identified MTD of 24 mm as the optimal cut-point for both BF and DM. MTD was independently associated with both BF (HR 8.61, P = .048, 95% CI 1.02-72.97) and DM (HR 8.55, P = .05, 95% CI 1.00-73.19). In patients with ISUP group 4 to 5 disease, MTD > 24 mm was independently associated with increased risk of DM (HR 10.13, P = .04, 95% CI 1.13-91.12). CONCLUSIONS: This is the first study to evaluate MTD in the setting of EBRT+BB. These results demonstrate that MTD is independently associated with BF and metastasis. This suggests a possible role for MTD in risk assessment models and clinical decision-making for men receiving EBRT+BB.

Second Primary Malignancies in Diffuse Large B-cell Lymphoma Survivors with 40 Years of Follow Up: Influence of Chemotherapy and Radiation Therapy.

Purpose: Previous studies have shown an increased risk of second primary malignancies (SPMs) in survivors of diffuse large B-cell lymphoma (DLBCL). Survivors live longer due to the intensification of and improvements in therapy; thus, we aimed to characterize SPM patterns in patients with DLBCL by treatment modality. Methods and Materials: Standardized incidence ratio and absolute excess risk of SPMs were assessed in patients with primary DLBCL from 1975 to 2016 in the National Cancer Institute's Surveillance, Epidemiology, and End Results Program. A subgroup analyses based on, sex, race, age at the time of diagnosis, latency, and treatment modality were performed. Propensity score-adjusted cumulative incidence curves were generated, stratified by treatment and accounting for death as a competing risk. Results: In total, 45,946 patients with DLBCL were identified with a mean follow up of 70 months. Overall, 9.2% of patients developed an SPM with a standardized incidence ratio of 1.23 (95% confidence interval, 1.20-1.27). There was no difference in SPM risk between men and women or Black and White patients. Patients age <25 years were particularly susceptible to the development of SPMs, with a risk 2.5 times greater than patients aged 50 to 74 years. Temporal patterns showed increasing risk of solid malignancies and decreasing risk of hematologic malignancies over time, with bladder cancer posing the greatest absolute excess risk of any cancer type after 15 years. Patients treated with radiation therapy (RT), chemotherapy (CT), and chemoradiation therapy (CRT) all had an increased risk of SPM development compared with the general population. The cumulative incidence of SPMs was the lowest in patients treated with RT and the highest when treated with CRT. In the modern treatment era, the cumulative incidence of SPM for patients treated with CT versus CRT was not significantly different. Conclusions: In this large population-based study, we demonstrate unique SPM risk patterns based on age, latency, and treatment modality that have important implications for the treatment and screening of patients diagnosed with DLBCL.

Temporal Trends and Predictors in Diagnosing Pathologic Node-Positive Prostate Cancer in Clinically Node-Negative Patients.

INTRODUCTION: Managing pathologically node positive (pN+) prostate cancer (PCa) is controversial. We describe temporal patterns and predictors of pN+ PCa in men with initially surgically managed clinically node negative (cN-) PCa. MATERIALS AND METHODS: This observational retrospective analysis of nonmetastatic, cN- PCa uses the National Cancer Database. Multivariable logistic regression was used to identify covariates associated with pN+ disease. Cox proportional hazards modeling and Kaplan-Meier analysis were used to evaluate survival patients undergoing radical prostatectomy with or without pelvic lymph node dissection (PLND). RESULTS: The rates of radical prostatectomy in men with grade group (GG) 4 and GG5 increased from 47.6% to 53.1% and from 42.5% to 49.5%, respectively. The annual rate increased from 2.02% in 2010 to 5.12% in 2017 (P < .001). The annual rates of PLND increased from 54.3% to 71.7%. The most significant predictor of pN+ PCa was ISUP GG4 (odds ratio [OR] 12.5, P< .001) and GG 5 (OR 26.2, P < .001). Rates of pN+ identification increased from 5.5% to 9.4% in men with GG4 and from 13.4% to 19.5% in men with GG5 (P< .001). In GG4 and GG5, patients undergoing PLND had superior survival to those managed without PLND (P < .01). CONCLUSION: Among patients with cN- PCa, the diagnosis of pN+ PCa has become more common over time. GG4 and GG5 are the strongest independent predictors of pN+ disease. Because incidental pN+ results in upstaging these data are useful for informing discussions before radical prostatectomy.

Refusal of Radiation Results in Inferior Survival in Endometrial Cancer.

OBJECTIVE: We sought to understand factors associated with refusal of adjuvant radiotherapy in endometrial cancer and its impact on outcomes. METHODS: Data from the National Cancer Database for patients who underwent surgery for nonmetastatic endometrial cancer between 2004 and 2015 were pooled. The Pearson χ test and multivariate logistic regression analyses were used to assess demographic, clinical, and treatment factors. Inverse probability of treatment weighting was used to account for differences in baseline characteristics. Kaplan-Meier analyses and doubly-robust estimation with multivariate Cox proportional hazards modeling were used to analyze overall survival (OS). RESULTS: We identified 4739 of 80,803 patients (5.9%) who refused radiotherapy. Factors associated with refusal were: no insurance (relative risk [RR]=1.66, P<0.01), Medicare (RR=1.42, P<0.01), living >50 miles from treatment (RR=1.34, P<0.01), Charlson-Deyo Comorbidity Scores of 1 (RR=1.16, P<0.01) or ≥2 RR=1.38, P<0.01), age above 60 years (RR=1.28, P<0.01), International Federation of Gynecology and Obstetrics (FIGO) stages IIIA (RR=1.63, P<0.01) and IIIC (RR=1.65, P<0.01) disease, papillary (RR=1.69, P<0.01) and clear cell histology (RR=1.64, P<0.01). Factors associated with radiation therapy receipt included: Hispanic race (RR=0.61, P<0.01), income >$63,000 (RR=0.89, P=0.044), undergoing chemotherapy (RR=0.17, P<0.01), FIGO stages IB (RR=0.81, P<0.01) and II (RR=0.70, P<0.01) disease, and lymphadenectomy (RR=0.79, P<0.01). After weighting, 5-year OS was significantly lower with refusal (74.3% vs. 79.7%, P<0.01). This survival decrement was maintained across FIGO stages. CONCLUSIONS: We identified characteristics associated with radiation refusal, including socioeconomic barriers, advanced disease stage, and histology. Refusal of radiotherapy conferred decreased OS across FIGO stages.

Knockdown of Inner Arm Protein IC138 in Trypanosoma brucei Causes Defective Motility and Flagellar Detachment.

Motility in the protozoan parasite Trypanosoma brucei is conferred by a single flagellum, attached alongside the cell, which moves the cell forward using a beat that is generated from tip-to-base. We are interested in characterizing components that regulate flagellar beating, in this study we extend the characterization of TbIC138, the ortholog of a dynein intermediate chain that regulates axonemal inner arm dynein f/I1. TbIC138 was tagged In situ-and shown to fractionate with the inner arm components of the flagellum. RNAi knockdown of TbIC138 resulted in significantly reduced protein levels, mild growth defect and significant motility defects. These cells tended to cluster, exhibited slow and abnormal motility and some cells had partially or fully detached flagella. Slight but significant increases were observed in the incidence of mis-localized or missing kinetoplasts. To document development of the TbIC138 knockdown phenotype over time, we performed a detailed analysis of flagellar detachment and motility changes over 108 hours following induction of RNAi. Abnormal motility, such as slow twitching or irregular beating, was observed early, and became progressively more severe such that by 72 hours-post-induction, approximately 80% of the cells were immotile. Progressively more cells exhibited flagellar detachment over time, but this phenotype was not as prevalent as immotility, affecting less than 60% of the population. Detached flagella had abnormal beating, but abnormal beating was also observed in cells with no flagellar detachment, suggesting that TbIC138 has a direct, or primary, effect on the flagellar beat, whereas detachment is a secondary phenotype of TbIC138 knockdown. Our results are consistent with the role of TbIC138 as a regulator of motility, and has a phenotype amenable to more extensive structure-function analyses to further elucidate its role in the control of flagellar beat in T. brucei.

Dectin-2 mediates Th2 immunity through the generation of cysteinyl leukotrienes.

The innate signaling pathways for Th2 immunity activated by inhaled antigens are not well defined. We previously identified Dectin-2 as a receptor for glycans in allergen extracts from the house dust mite Dermatophagoides farinae (Df) that mediates cysteinyl leukotriene (cys-LT) generation from pulmonary CD11c+ cells and from GM-CSF-cultured bone marrow cells (BMCs(GM-CSF)). Using lentiviral knockdown of Dectin-2 in BMCs(GM-CSF) and adoptive transfer of Df-pulsed BMCs(GM-CSF) to sensitize naive mice, we now report that Dectin-2 is critical for the development of Df-elicited eosinophilic and neutrophilic pulmonary inflammation and Th2 cytokine generation in the lungs and restimulated lymph nodes. Sensitization with Df-pulsed BMCs(GM-CSF) from LTC(4) synthase (LTC(4)S)-deficient mice or type 1 cys-LT receptor (CysLT1R)-deficient mice demonstrated that both proteins were required for Df-elicited eosinophilic pulmonary inflammation and Th2 cytokine generation in the lungs and restimulated lymph nodes. Direct sensitization and challenge of Ltc4s-/- and Cysltr1-/- mice confirmed that cys-LTs mediate these parameters of Df-elicited Th2 pulmonary inflammation. Thus, the Dectin-2-cys-LT pathway is critical for the induction of Th2 immunity to a major allergen, in part through CysLT1R. These findings identify a previously unrecognized link between a myeloid C-type lectin receptor and Th2 immunity.