Afamitresgene autoleucel for advanced synovial sarcoma and myxoid round cell liposarcoma (SPEARHEAD-1): an international, open-label, phase 2 trial

BACKGROUND

Afamitresgene autoleucel (afami-cel) showed acceptable safety and promising efficacy in a phase 1 trial (NCT03132922). The aim of this study was to further evaluate the efficacy of afami-cel for the treatment of patients with HLA-A*02 and MAGE-A4-expressing advanced synovial sarcoma or myxoid round cell liposarcoma.

METHODS

SPEARHEAD-1 was an open-label, non-randomised, phase 2 trial done across 23 sites in Canada, the USA, and Europe. The trial included three cohorts, of which the main investigational cohort (cohort 1) is reported here. Cohort 1 included patients with HLA-A*02, aged 16-75 years, with metastatic or unresectable synovial sarcoma or myxoid round cell liposarcoma (confirmed by cytogenetics) expressing MAGE-A4, and who had received at least one previous line of anthracycline-containing or ifosfamide-containing chemotherapy. Patients received a single intravenous dose of afami-cel (transduced dose range 1·0 × 109-10·0 × 109 T cells) after lymphodepletion. The primary endpoint was overall response rate in cohort 1, assessed by a masked independent review committee using Response Evaluation Criteria in Solid Tumours (version 1.1) in the modified intention-to-treat population (all patients who received afami-cel). Adverse events, including those of special interest (cytokine release syndrome, prolonged cytopenia, and neurotoxicity), were monitored and are reported for the modified intention-to-treat population. This trial is registered at ClinicalTrials.gov, NCT04044768; recruitment is closed and follow-up is ongoing for cohorts 1 and 2, and recruitment is open for cohort 3.

FINDINGS

Between Dec 17, 2019, and July 27, 2021, 52 patients with cytogenetically confirmed synovial sarcoma (n=44) and myxoid round cell liposarcoma (n=8) were enrolled and received afami-cel in cohort 1. Patients were heavily pre-treated (median three [IQR two to four] previous lines of systemic therapy). Median follow-up time was 32·6 months (IQR 29·4-36·1). Overall response rate was 37% (19 of 52; 95% CI 24-51) overall, 39% (17 of 44; 24-55) for patients with synovial sarcoma, and 25% (two of eight; 3-65) for patients with myxoid round cell liposarcoma. Cytokine release syndrome occurred in 37 (71%) of 52 of patients (one grade 3 event). Cytopenias were the most common grade 3 or worse adverse events (lymphopenia in 50 [96%], neutropenia 44 [85%], leukopenia 42 [81%] of 52 patients). No treatment-related deaths occurred.

INTERPRETATION

Afami-cel treatment resulted in durable responses in heavily pre-treated patients with HLA-A*02 and MAGE-A4-expressing synovial sarcoma. This study shows that T-cell receptor therapy can be used to effectively target solid tumours and provides rationale to expand this approach to other solid malignancies.

FUNDING

Adaptimmune.

Autologous T cell therapy for MAGE-A4+ solid cancers in HLA-A*02+ patients: a phase 1 trial

Affinity-optimized T cell receptors can enhance the potency of adoptive T cell therapy. Afamitresgene autoleucel (afami-cel) is a human leukocyte antigen-restricted autologous T cell therapy targeting melanoma-associated antigen A4 (MAGE-A4), a cancer/testis antigen expressed at varying levels in multiple solid tumors. We conducted a multicenter, dose-escalation, phase 1 trial in patients with relapsed/refractory metastatic solid tumors expressing MAGE-A4, including synovial sarcoma (SS), ovarian cancer and head and neck cancer ( NCT03132922 ). The primary endpoint was safety, and the secondary efficacy endpoints included overall response rate (ORR) and duration of response. All patients (N = 38, nine tumor types) experienced Grade ≥3 hematologic toxicities; 55% of patients (90% Grade ≤2) experienced cytokine release syndrome. ORR (all partial response) was 24% (9/38), 7/16 (44%) for SS and 2/22 (9%) for all other cancers. Median duration of response was 25.6 weeks (95% confidence interval (CI): 12.286, not reached) and 28.1 weeks (95% CI: 12.286, not reached) overall and for SS, respectively. Exploratory analyses showed that afami-cel infiltrates tumors, has an interferon-γ-driven mechanism of action and triggers adaptive immune responses. In addition, afami-cel has an acceptable benefit-risk profile, with early and durable responses, especially in patients with metastatic SS. Although the small trial size limits conclusions that can be drawn, the results warrant further testing in larger studies.

Abstract LB001: Identifying MAGE-A4-positive tumors for SPEAR T-cell therapies in HLA-A*02-eligible patients

Autologous T-cells engineered with T-cell receptors (TCRs) targeting tumor antigens are promising therapies for metastatic solid cancers.1 Specific peptide enhanced affinity receptor (SPEAR) T-cell therapies are T-cells with engineered HLA-restricted TCRs that precisely target tumor cells with specific antigens, such as MAGE-A4 (a cancer testis antigen), presented on the surface by HLA molecules. In SPEAR T-cell clinical trials targeting MAGE-A4, a 2-step prescreen is done before enrolment. 1) Patients undergo HLA typing via a high-resolution (allelic, 4-digit) sequence-based assay, and those who are positive for the inclusion alleles (HLA-A*02:01P, 02:02P, 02:03P, 02:06P) and not positive for the exclusion allele A*02:05P are eligible. 2) Tumor MAGE-A4 testing is done via an immunohistochemical clinical trial assay (MAGE-A4+ cutoff: ≥30% tumor cell staining at ≥2+ intensity) in HLA-eligible patients. A screening protocol (NCT02636855) has been used in Phase 1 trials of first- and next-generation SPEAR T-cells targeting MAGE-A4 (NCT03132922, NCT04044859) with responses in multiple MAGE-A4+ tumors. As of November 19, 2021, 6,168 patients with 9 solid tumor types were screened at 32 sites across North America and Europe in this screening protocol; among which, 2,744 were HLA-eligible (eligibility rate: 45%, range per tumor type: 42%-55%). HLA-A*02:01 was the most frequent HLA-A*02 allele. Of these HLA-eligible patients, 1,549 had tumor tissues evaluable for MAGE-A4 expression; among which, 313 were MAGE-A4+ (MAGE-A4+ rate: 20%, range: 8%-54%) (Table). MAGE-A4 showed highest prevalence in synovial sarcoma and myxoid/round cell liposarcoma but was seen across all tumor types investigated. Our results will be discussed in the context of tumor histopathology, disease status, and demography. HLA and MAGE-A4 biomarker data will inform the therapeutic opportunities for SPEAR T-cells targeting MAGE-A4 in metastatic solid cancers. 1. D’Angelo et al. Cancer Discov. 2018;8:944.

HLA eligibility and MAGE-A4 prevalence in a screening protocol (NCT02636855) Indication Esophageal cancer Esophagogastric junction cancer Gastric cancer Head and neck squamous cell carcinoma Non-small cell lung cancer Melanoma Ovarian cancer Urothelial cancer Synovial sarcoma and myxoid/round cell liposarcoma HLA screened (N) 284 228 271 601 3189 668 539 270 118 HLA eligible (%) 46 45 43 42 43 50 49 43 55 MAGE-A4 evaluable (N) 104 91 73 200 457 245 225 93 61 MAGE-A4 positive (%) 22 25 8 22 14 16 24 32 54

Citation Format: Tianjiao Wang, Jean-Marc Navenot, Stavros Rafail, Mark Carroll, Ruoxi Wang, Cheryl McAlpine, Swethajit Biswas, Francine Brophy, Erica Elefant, Paige Bayer, Sandra McGuigan, Dennis Williams, George Blumenschein, Marcus Butler, Jeffrey M. Clarke, Justin F. Gainor, Ramaswamy Govindan, Victor Moreno, Janet Tu, David S. Hong. Identifying MAGE-A4-positive tumors for SPEAR T-cell therapies in HLA-A*02-eligible patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB001.

376 Radiation sub-study to characterize safety and tolerability of low-dose radiation in combination with afami-cel in patients with advanced cancers (NCT03132922)

Background

Autologous cell therapies with an engineered T-cell receptor targeting MAGE-A4 have shown responses in patients with synovial sarcoma1 with additional responses in myxoid/round cell liposarcoma (MRCLS), head and neck, lung, esophagogastric junction, and melanoma cancers.2 3 Low-dose radiation may control tumor growth locally and modulate stroma of solid tumors,4 potentially facilitating T-cell infiltration into tumors and antitumor activity.

Methods

Sub-study designed to assess safety, tolerability, and efficacy in up to 10 patients with low-dose radiation in combination with lymphodepleting chemotherapy, followed by afami-cel (an autologous TCR cell T-cell therapy targeting MAGE-A4). Eligible patients are HLA-A*02^+ with MAGE-A4 expressing tumors including urothelial, melanoma, head and neck, ovarian, non-small cell lung, esophageal, gastric, synovial sarcoma, and MRCLS cancers. Patients receive afami-cel by infusion following low-dose radiation and lymphodepleting chemotherapy. Radiation was 4.2–7 Gy per lesion or isocenter (maximum of 5). Lymphodepleting regimen was IV fludarabine 30 mg/m^2/day for 4 days (−7 to −4) and cyclophosphamide 600 mg/m^2/day for 3 days (−7 to −5). Afami-cel doses ranged from 1.2 x 10^9 to 10 x 10^9 transduced cells. Pts receive afami-cel infusion on Day 1.

Results

As of Dec 27, 2020, a total of 8 patients, including 4 patients (1 male) with melanoma (2), HNSCC (1), or ovarian (1) cancers received low-dose radiation and afami-cel. Most frequently reported AEs (4/4 pts) were leukopenia/decreased white blood cell count, lymphopenia/decreased lymphocyte count, and neutropenia/decreased neutrophil count; all of which were related to the lymphodepletion regimen. The most commonly (>1 patient) reported AEs considered related to T-cell infusion were cytokine release syndrome (2/4 pts) and fatigue (2/4 pts). Two patients had a total of 5 SAEs: adrenal insufficiency, hyperglycemia, neurotoxicity, pneumonia aspiration, and pneumothorax. The only SAE considered to be related to treatment was Grade 3 neurotoxicity. Best overall responses per RECIST 1.1: 1 partial response (melanoma, −42% in target lesions), 2 stable diseases (ovarian cancer, −23%; HNSCC, no change), and 1 patient did not have post-baseline scans yet. Translational analyses showed peripheral persistence and serum cytokine response profiles consistent with that of afami-cel monotherapy, whilst a relatively greater T cell infiltration in tumor biopsies was evident.

Conclusions

Afami-cel with low-dose radiation has had an acceptable safety profile. Most AEs were consistent with those typically experienced by cancer patients undergoing lymphodepletion cytotoxic chemotherapy and cellular therapy. Infused T-cells were observed in tumor biopsies at high frequency, and one patient exhibited a clinical partial response.

Trial Registration

NCT03132922

References

Van Tine BA, et al. CTOS 2020.

Hong DS, et al. ASCO 2020.

Hong DS, et al. SITC 2020.

De Selm C, et al. Mol Ther 2018;26(11):2542–2552.

Abstract IA-004: The impact of gut microbiota on the radiotherapy-induced antitumor immune response

Alterations in gut microbiota impact the pathophysiology of several diseases, including cancer. Radiotherapy (RT), an established curative and palliative cancer treatment, exerts potent immune modulatory effects, inducing tumor-associated antigen (TAA) cross-priming with antitumor CD8+ T cell elicitation and abscopal effects. We tested whether the gut microbiota modulates antitumor immune response following RT distal to the gut. Vancomycin, an antibiotic that acts mainly on gram-positive bacteria and is restricted to the gut, potentiated the RT-induced antitumor immune response and tumor growth inhibition. This synergy was dependent on TAA cross presentation to cytolytic CD8+ T cells and on IFN-γ. Notably, butyrate, a metabolite produced by the vancomycin-depleted gut bacteria, abrogated the vancomycin effect. In conclusion, depletion of vancomycin-sensitive bacteria enhances the antitumor activity of RT, which has important clinical ramifications.

Citation Format: Mireia Uribe-Herranz, Stavros Rafail, Silvia Beghi, Ioannis Verginadis, Clementina Mesaros, Costantinos Koumenis, Andrea Facciabene. The impact of gut microbiota on the radiotherapy-induced antitumor immune response [abstract]. In: Proceedings of the AACR Virtual Special Conference on Radiation Science and Medicine; 2021 Mar 2-3. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(8_Suppl):Abstract nr IA-004.

Combination of vasculature targeting, hypofractionated radiotherapy, and immune checkpoint inhibitor elicits potent antitumor immune response and blocks tumor progression

Background

Tumor endothelial marker 1 (TEM1) is a protein expressed in the tumor-associated endothelium and/or stroma of various types of cancer. We previously demonstrated that immunization with a plasmid-DNA vaccine targeting TEM1 reduced tumor progression in three murine cancer models. Radiation therapy (RT) is an established cancer modality used in more than 50% of patients with solid tumors. RT can induce tumor-associated vasculature injury, triggering immunogenic cell death and inhibition of the irradiated tumor and distant non-irradiated tumor growth (abscopal effect). Combination treatment of RT with TEM1 immunotherapy may complement and augment established immune checkpoint blockade.

Methods

Mice bearing bilateral subcutaneous CT26 colorectal or TC1 lung tumors were treated with a novel heterologous TEM1-based vaccine, in combination with RT, and anti-programmed death-ligand 1 (PD-L1) antibody or combinations of these therapies, tumor growth of irradiated and abscopal tumors was subsequently assessed. Analysis of tumor blood perfusion was evaluated by CD31 staining and Doppler ultrasound imaging. Immunophenotyping of peripheral and tumor-infiltrating immune cells as well as functional analysis was analyzed by flow cytometry, ELISpot assay and adoptive cell transfer (ACT) experiments.

Results

We demonstrate that addition of RT to heterologous TEM1 vaccination reduces progression of CT26 and TC1 irradiated and abscopal distant tumors as compared with either single treatment. Mechanistically, RT increased major histocompatibility complex class I molecule (MHCI) expression on endothelial cells and improved immune recognition of the endothelium by anti-TEM1 T cells with subsequent severe vascular damage as measured by reduced microvascular density and tumor blood perfusion. Heterologous TEM1 vaccine and RT combination therapy boosted tumor-associated antigen (TAA) cross-priming (ie, anti-gp70) and augmented programmed cell death protein 1 (PD-1)/PD-L1 signaling within CT26 tumor. Blocking the PD-1/PD-L1 axis in combination with dual therapy further increased the antitumor effect and gp70-specific immune responses. ACT experiments show that anti-gp70 T cells are required for the antitumor effects of the combination therapy.

Conclusion

Our findings describe novel cooperative mechanisms between heterologous TEM1 vaccination and RT, highlighting the pivotal role that TAA cross-priming plays for an effective antitumor strategy. Furthermore, we provide rationale for using heterologous TEM1 vaccination and RT as an add-on to immune checkpoint blockade as triple combination therapy into early-phase clinical trials.

Gut microbiota modulate dendritic cell antigen presentation and radiotherapy-induced antitumor immune response

Alterations in gut microbiota impact the pathophysiology of several diseases, including cancer. Radiotherapy (RT), an established curative and palliative cancer treatment, exerts potent immune modulatory effects, inducing tumor-associated antigen (TAA) cross-priming with antitumor CD8+ T cell elicitation and abscopal effects. We tested whether the gut microbiota modulates antitumor immune response following RT distal to the gut. Vancomycin, an antibiotic that acts mainly on gram-positive bacteria and is restricted to the gut, potentiated the RT-induced antitumor immune response and tumor growth inhibition. This synergy was dependent on TAA cross presentation to cytolytic CD8+ T cells and on IFN-γ. Notably, butyrate, a metabolite produced by the vancomycin-depleted gut bacteria, abrogated the vancomycin effect. In conclusion, depletion of vancomycin-sensitive bacteria enhances the antitumor activity of RT, which has important clinical ramifications.

Abstract IA25: Tumors alter gut microbiota to suppress immunity and foster progression

Immune dysfunction is commonly observed in patients with cancer contributing to tumor progression. While previous work established a connection between the gut microbiota and the immune system, the mechanisms by which microbiotas contribute to cancer-associated immune dysfunction are not well understood. Using multiple mouse cancer models, we demonstrated robust alterations of gut microbiota in tumor-bearing mice and a substantial change in antimicrobial peptides produced by the gut epithelium. We identified an overall reduction in IFN-γ T cells in tumor-bearing mice, which was rescued with antibiotics treatment or by co-housing tumor-bearing mice with healthy mice. Similar to mouse, we observed changes in gut microbiota and antimicrobial peptides levels of patients diagnosed with ovarian or lung cancer. We identify Firmicutes Ruminococcus members as key promoters of immune dysfunctions and tumor development. These findings identify a new mechanism of immune modulation utilized by tumors to undermine the immune responses and promote tumor progression.

Citation Format: Mireia Hribe-Herranz, Kyle Bittinger, Ceylan Tanes, Stavros Rafail, Stefano Pierini, Edgar Ben-Joseph, Janos Tanyi, Andrea Facciabene. Tumors alter gut microbiota to suppress immunity and foster progression [abstract]. In: Proceedings of the AACR Special Conference on the Microbiome, Viruses, and Cancer; 2020 Feb 21-24; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2020;80(8 Suppl):Abstract nr IA25.

An autologous humanized patient-derived-xenograft platform to evaluate immunotherapy in ovarian cancer

OBJECTIVE

The aim of this study was to "humanize" ovarian cancer patient-derived xenograft (PDX) models by autologous transfer of patient-matched tumor infiltrating lymphocytes (TILs) to evaluate immunotherapies.

METHODS

Orthotopic high-grade serous ovarian cancer (HGSOC) PDX models were established from three patient donors. Models were molecularly and histologically validated by immunohistochemistry. TILs were expanded from donor tumors using a rapid expansion protocol. Ex vivo TIL and tumor co-cultures were performed to validate TIL reactivity against patient-matched autologous tumor cells. Expression of TIL activation markers and cytokine secretion was quantitated by flow cytometry and ELISA. As proof of concept, the efficacy of anti-PD-1 monotherapy was tested in autologous TIL/tumor HGSOC PDX models.

RESULTS

Evaluation of T-cell activation in autologous TIL/tumor co-cultures resulted in an increase in HLA-dependent IFNγ production and T-cell activation. In response to increased IFNγ production, tumor cell expression of PD-L1 was increased. Addition of anti-PD-1 antibody to TIL/tumor co-cultures increased autologous tumor lysis in a CCNE1 amplified model. Orthotopic HGSOC PDX models from parallel patient-matched tumors maintained their original morphology and molecular marker profile. Autologous tumor-reactive TIL administration in patient-matched PDX models resulted in reduced tumor burden and increased survival, in groups that also received anti-PD-1 therapy.

CONCLUSIONS

This study validates a novel, clinically relevant model system for in vivo testing of immunomodulating therapeutic strategies for ovarian cancer, and provides a unique platform for assessing patient-specific T-cell response to immunotherapy.

Abstract 4961: Gut microbiota modulates adoptive cell therapy via CD8α dendritic cells and IL-12

Adoptive T cell therapy (ACT) is a promising new modality for malignancies. Here, we report that adoptive T cell efficacy in tumor-bearing mice is significantly affected by differences in the native composition of the gut microbiome or treatment with antibiotics, or by heterologous fecal transfer. Depletion of bacteria with vancomycin decreased the rate of tumor growth in mice from The Jackson Laboratory receiving ACT, whereas treatment with neomycin and metronidazole had no effect, indicating the role of specific bacteria in host response. Vancomycin treatment induced an increase in systemic CD8α+ DCs, which sustained systemic adoptively transferred antitumor T cells in an IL-12-dependent manner. In subjects undergoing allogeneic hematopoietic cell transplantation, we found that oral vancomycin also increased IL-12 levels. Collectively, our findings demonstrate an important role played by the gut microbiota in the antitumor effectiveness of ACT and suggest potentially new avenues to improve response to ACT by altering the gut microbiota.

Citation Format: Mireia Uribe-Herranz, Kyle Bittinger, Stavros Rafail, Stefano Pierini, Sonia Guedan, Frederic Bushman, Carl June, Andrea Facciabene. Gut microbiota modulates adoptive cell therapy via CD8α dendritic cells and IL-12 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4961.

Abstract 666: Gut microbiota SCFA modulates DCs antigen presentation and impacts tumor response to radiotherapy

Alterations in gut microbiota modulate host physiologic functions, including immune responses, and they play a role in the pathophysiology of several diseases, including cancer. Radiotherapy (RT), an established curative and palliative cancer treatment, exerts potent immune modulatory effects, inducing tumor-associated antigen (TAA) cross-priming with antitumor CD8+ T cell elicitation and abscopal effects. Herein, we tested whether the gut microbiota modulates antitumor immune response following RT. Vancomycin, an antibiotic that acts mainly on gram-positive bacteria and is restricted to the gut, potentiated the RT-induced antitumor immune response and tumor growth inhibition. This synergy was dependent on tumor-associated antigen cross-presentation enanchement, cytolytic CD8+ T cells and on IFN-g. Notably, butyrate, a metabolite produced by the vancomycin-depleted gut bacteria, abrogated the vancomycin effect. In conclusion, gram-positive bacteria depletion by vancomycin enhances the antitumor activity of RT, which has important clinical ramifications.

Citation Format: Andrea Facciabene, Stavros Rafail, Luis Gil de Gomez, Stefano Pierini, Mireia Uribe-Herranz, Kyle Bittinger. Gut microbiota SCFA modulates DCs antigen presentation and impacts tumor response to radiotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 666.

Abstract 719: A tumor mitochondria vaccine protects against experimental renal cell carcinoma

Mitochondria provide energy for cells via oxidative phosphorylation. Reactive oxygen species, a byproduct of this mitochondrial respiration, can damage mitochondrial DNA (mtDNA), and somatic mtDNA mutations have been found in all colorectal, ovarian, breast, urinary bladder, kidney, lung, and pancreatic tumors studied. The resulting altered mitochondrial proteins or tumor-associated mitochondrial Ags (TAMAs) are potentially immunogenic, suggesting that they may be targetable Ags for cancer immunotherapy. In this article, we show that the RENCA tumor cell line harbors TAMAs that can drive an antitumor immune response. We generated a cellular tumor vaccine by pulsing dendritic cells with enriched mitochondrial proteins from RENCA cells. Our dendritic cell-based RENCA mitochondrial lysate vaccine elicited a cytotoxic T cell response in vivo and conferred durable protection against challenge with RENCA cells when used in a prophylactic or therapeutic setting. By sequencing mtDNA from RENCA cells, we identified two mutated molecules: COX1 and ND5. Peptide vaccines generated from mitochondrial-encoded COX1 but not from ND5 had therapeutic properties similar to RENCA mitochondrial protein preparation. Thus, TAMAs can elicit effective antitumor immune responses, potentially providing a new immunotherapeutic strategy to treat cancer.

Citation Format: Stefano Pierini, Andrea Facciabene, Mireia Uribe-Herranz, Stavros Rafail, Chongyun Fang, Janos Tanyi. A tumor mitochondria vaccine protects against experimental renal cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 719.

Abstract 3798: Gut microbiota modulates adoptive cell therapy via CD8α dendritic cells

Adoptive T-Cell therapy (ACT) is a promising new modality for malignancies. Here, we report that adoptive T-cell efficacy in tumor-bearing mice is significantly affected by differences in the native composition of the gut microbiome, treatment with antibiotics or by heterologous fecal transfer. Depletion of bacteria with vancomycin, decreased the rate of tumor growth in mice receiving ACT, whereas treatment with neomycin and metronidazole had no effect, indicating the role of specific bacteria in host response. Vancomycin treatment induced an increase in systemic CD8α+ dendritic cells, which mediated a sustained systemic expansion of adoptively transferred antitumor T cells in an IL-12-dependent manner. In subjects undergoing allogeneic hematopoietic cell transplantation, we found that oral vancomycin also increased IL-12 levels. Collectively, our findings demonstrate an important role played by the gut microbiota in the antitumor effectiveness of ACT and suggest new avenues to improve response to ACT by altering the gut microbiota.

Citation Format: Mireia Uribe-Herranz, Kyle Bittinger, Stavros Rafail, Sonia Guedan, Stefano Pierini, Ceylan Tanes, Saar A. Gill, Janos Tany, Mark A. Morgan, Frederic D. Bushman, Carl H. June, Andrea Facciabene. Gut microbiota modulates adoptive cell therapy via CD8α dendritic cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3798.

Gut microbiota modulates adoptive cell therapy via CD8α dendritic cells and IL-12

Adoptive T cell therapy (ACT) is a promising new modality for malignancies. Here, we report that adoptive T cell efficacy in tumor-bearing mice is significantly affected by differences in the native composition of the gut microbiome or treatment with antibiotics, or by heterologous fecal transfer. Depletion of bacteria with vancomycin decreased the rate of tumor growth in mice from The Jackson Laboratory receiving ACT, whereas treatment with neomycin and metronidazole had no effect, indicating the role of specific bacteria in host response. Vancomycin treatment induced an increase in systemic CD8α+ DCs, which sustained systemic adoptively transferred antitumor T cells in an IL-12-dependent manner. In subjects undergoing allogeneic hematopoietic cell transplantation, we found that oral vancomycin also increased IL-12 levels. Collectively, our findings demonstrate an important role played by the gut microbiota in the antitumor effectiveness of ACT and suggest potentially new avenues to improve response to ACT by altering the gut microbiota.

Abstract LB-178: The impact of the gut microbiome on the antitumor effects of radiotherapy

The sheer enormity of the microbial biomass in the human intestinal tract, the co-evolution between humans and the microbiota, and the established function of the gut microbes in regulating normal host physiologic functions, are all consistent with the idea that alterations in gut microbial ecology play a role in the pathophysiology of several conditions including cancer. Radiotherapy (RT) is an established curative and palliative cancer treatment regimen, with approximately half of cancer patients with solid tumors receiving RT some time during their disease. Mounting evidence also suggests that high-dose (hypofractionated) radiation exerts potent immune modulatory effects, prompting immunological active tumor cell death inducing tumor associated antigen (TAA) cross priming with elicitation of anti-tumor CD8+ T cells, and abscopal effects. Although there have been groundbreaking responses to immunotherapy in certain malignancies such as lung cancer and melanomas, so far, immunotherapy is effective only in a portion of patients19. This raises the issue of whether there are additional important regulators of T cell function that are relevant to tumor control and could be harnessed to enhance radiotherapy. In support of this hypothesis, we have generated preliminary results demonstrating that: a) Treatment with vancomycin, an antibiotic with action in the gut mostly against Gram+ bacteria, significantly increased the presence of overall tumor infiltrating T cells or cytotoxic CD8+ cells in tumors from mice treated with RT/vancomycin combination compared to RT alone; b) vancomycin caused a significant enhancement of the tumor inhibitory effect of targeted radiation. c) Vancomycin enhanced the ability of RT to increase the expression of IFN-g in CD8+ infiltrating T cells and antigen presentation in the tumor draining lymph nodes and d) the observed synergy between vancomycin and RT in eliciting an anti-tumor immune response and inhibiting tumor growth was abrogated in IFN-g KO animals or by CD8+ cell depletion.

Citation Format: Andrea Facciabene, Stavros Rafail, Mireia Uribe-Herranz, Stefano Pierini, Kile Bittinger, Iannis Verginadis, Costas Koumenis, Amit Maity. The impact of the gut microbiome on the antitumor effects of radiotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr LB-178. doi:10.1158/1538-7445.AM2017-LB-178

Targeting the ATR/CHK1 Axis with PARP Inhibition Results in Tumor Regression in BRCA-Mutant Ovarian Cancer Models

Purpose: PARP inhibition (PARPi) has modest clinical activity in recurrent BRCA-mutant (BRCA^MUT) high-grade serous ovarian cancers (HGSOC). We hypothesized that PARPi increases dependence on ATR/CHK1 such that combination PARPi with ATR/CHK1 blockade results in increased cell death and tumor regression.Experimental Design: Effects of PARPi (olaparib), CHK1 inhibition (CHK1i;MK8776), or ATR inhibition (ATRi;AZD6738) alone or in combination on survival, colony formation, cell cycle, genome instability, and apoptosis were evaluated in BRCA1/2^MUT HGSOC cells. Tumor growth in vivo was evaluated using a BRCA2^MUT patient-derived xenograft (PDX) model.Results: PARPi monotherapy resulted in a decrease in BRCA^MUT cell survival, colony formation and suppressed but did not eliminate tumor growth at the maximum tolerated dose (MTD) in a BRCA2^MUT PDX. PARPi treatment increased pATR and pCHK1, indicating activation of the ATR-CHK1 fork protection pathway is relied upon for genome stability under PARPi. Indeed, combination of ATRi or CHK1i with PARPi synergistically decreased survival and colony formation compared with single-agent treatments in BRCA^MUT cells. Notably, PARPi led to G₂ phase accumulation, and the addition of ATRi or CHK1i released cells from G₂ causing premature mitotic entry with increased chromosomal aberrations and apoptosis. Moreover, the combinations of PARPi with ATRi or CHK1i were synergistic in causing tumor suppression in a BRCA2^MUT PDX with the PARPi-ATRi combination inducing tumor regression and in most cases, complete remission.Conclusions: PARPi causes increased reliance on ATR/CHK1 for genome stability, and combination PARPi with ATR/CHK1i is more effective than PARPi alone in reducing tumor burden in BRCA^MUT models. Clin Cancer Res; 23(12); 3097-108. ©2016 AACR.

The dual role of complement in cancer and its implication in anti-tumor therapy

Chronic inflammation has been linked to the initiation of carcinogenesis, as well as the advancement of established tumors. The polarization of the tumor inflammatory microenvironment can contribute to either the control, or the progression of the disease. The emerging participation of members of the complement cascade in several hallmarks of cancer, renders it a potential target for anti-tumor treatment. Moreover, the presence of complement regulatory proteins (CRPs) in most types of tumor cells is known to impede anti-tumor therapies. This review focuses on our current knowledge of complement's potential involvement in shaping the inflammatory tumor microenvironment and its role on the regulation of angiogenesis and hypoxia. Furthermore, we discuss approaches using complement-based therapies as an adjuvant in tumor immunotherapy.

A Tumor Mitochondria Vaccine Protects against Experimental Renal Cell Carcinoma

Mitochondria provide energy for cells via oxidative phosphorylation. Reactive oxygen species, a byproduct of this mitochondrial respiration, can damage mitochondrial DNA (mtDNA), and somatic mtDNA mutations have been found in all colorectal, ovarian, breast, urinary bladder, kidney, lung, and pancreatic tumors studied. The resulting altered mitochondrial proteins or tumor-associated mitochondrial Ags (TAMAs) are potentially immunogenic, suggesting that they may be targetable Ags for cancer immunotherapy. In this article, we show that the RENCA tumor cell line harbors TAMAs that can drive an antitumor immune response. We generated a cellular tumor vaccine by pulsing dendritic cells with enriched mitochondrial proteins from RENCA cells. Our dendritic cell-based RENCA mitochondrial lysate vaccine elicited a cytotoxic T cell response in vivo and conferred durable protection against challenge with RENCA cells when used in a prophylactic or therapeutic setting. By sequencing mtDNA from RENCA cells, we identified two mutated molecules: COX1 and ND5. Peptide vaccines generated from mitochondrial-encoded COX1 but not from ND5 had therapeutic properties similar to RENCA mitochondrial protein preparation. Thus, TAMAs can elicit effective antitumor immune responses, potentially providing a new immunotherapeutic strategy to treat cancer.

Complement deficiency promotes cutaneous wound healing in mice

Wound healing is a complex homeostatic response to injury that engages numerous cellular activities, processes, and cell-to-cell interactions. The complement system, an intricate network of proteins with important roles in immune surveillance and homeostasis, has been implicated in many physiological processes; however, its role in wound healing remains largely unexplored. In this study, we employ a murine model of excisional cutaneous wound healing and show that C3(-/-) mice exhibit accelerated early stages of wound healing. Reconstitution of C3(-/-) mice with serum from C3(+/+) mice or purified human C3 abrogated the accelerated wound-healing phenotype. Wound histology of C3(-/-) mice revealed a reduction in inflammatory infiltrate compared with C3(+/+) mice. C3 deficiency also resulted in increased accumulation of mast cells and advanced angiogenesis. We further show that mice deficient in the downstream complement effector C5 exhibit a similar wound-healing phenotype, which is recapitulated in C5aR1(-/-) mice, but not C3aR(-/-) or C5aR2(-/-) mice. Taken together, these data suggest that C5a signaling through C5aR may in part play a pivotal role in recruitment and activation of inflammatory cells to the wound environment, which in turn could delay the early stages of cutaneous wound healing. These findings also suggest a previously underappreciated role for complement in wound healing, and may have therapeutic implications for conditions of delayed wound healing.

Inhibition of biomaterial-induced complement activation attenuates the inflammatory host response to implantation

Although complement is a known contributor to biomaterial-induced complications, pathological implications and therapeutic options remain to be explored. Here we investigated the involvement of complement in the inflammatory response to polypropylene meshes commonly used for hernia repair. In vitro assays revealed deposition of complement activation fragments on the mesh after incubation in plasma. Moreover, significant mesh-induced complement and granulocyte activation was observed in plasma and leukocyte preparations, respectively. Pretreatment of plasma with the complement inhibitor compstatin reduced opsonization >2-fold, and compstatin and a C5a receptor antagonist (C5aRa) impaired granulocyte activation by 50 and 67%, respectively. We established a clinically relevant mouse model of implantation and could confirm deposition of C3 activation fragments on mesh implants in vivo using immunofluorescence. In meshes extracted after subcutaneous or peritoneal implantation, the amount of immune cell infiltrate in mice deficient in key complement components (C3, C5aR), or treated with C5aRa, was approximately half of that observed in wild-type littermates or mice treated with inactive C5aRa, respectively. Our data suggest that implantation of a widely used surgical mesh triggers the formation of an inflammatory cell microenvironment at the implant site through complement activation, and indicates a path for the therapeutic modulation of implant-related complications.

Anaphylatoxin C5a creates a favorable microenvironment for lung cancer progression

The complement system contributes to various immune and inflammatory diseases, including cancer. In this study, we investigated the capacity of lung cancer cells to activate complement and characterized the consequences of complement activation on tumor progression. We focused our study on the production and role of the anaphylatoxin C5a, a potent immune mediator generated after complement activation. We first measured the capacity of lung cancer cell lines to deposit C5 and release C5a. C5 deposition, after incubation with normal human serum, was higher in lung cancer cell lines than in nonmalignant bronchial epithelial cells. Notably, lung malignant cells produced complement C5a even in the absence of serum. We also found a significant increase of C5a in plasma from patients with non-small cell lung cancer, suggesting that the local production of C5a is followed by its systemic diffusion. The contribution of C5a to lung cancer growth in vivo was evaluated in the Lewis lung cancer model. Syngeneic tumors of 3LL cells grew slower in mice treated with an antagonist of the C5a receptor. C5a did not modify 3LL cell proliferation in vitro but induced endothelial cell chemotaxis and blood-vessels formation. C5a also contributed to the immunosuppressive microenvironment required for tumor growth. In particular, blockade of C5a receptor significantly reduced myeloid-derived suppressor cells and immunomodulators ARG1, CTLA-4, IL-6, IL-10, LAG3, and PDL1 (B7H1). In conclusion, lung cancer cells have the capacity to generate C5a, a molecule that creates a favorable tumor microenvironment for lung cancer progression.

A complement-IL-4 regulatory circuit controls liver regeneration

The involvement of IL-4 in liver regeneration has not yet been recognized. In this article, we show that IL-4, produced by NKT cells that accumulate in regenerating livers after partial hepatectomy, contributes to this process by regulating the activation of complement after liver resection in mice. The mechanism of this regulation was associated with the maintenance of an appropriate level of IgM in mouse blood, because IgM deposited in liver parenchyma most likely initiated complement activation during liver regeneration. By controlling complement activation, IL-4 regulated the induction of IL-6, thereby influencing a key pathway involved in regenerating liver cell proliferation and survival. Furthermore, the secretion of IL-4 was controlled by complement through the recruitment of NKT cells to regenerating livers. Our study thus reveals the existence of a regulatory feedback mechanism involving complement and IL-4 that controls liver regeneration.

Endothelin-1 signaling promotes fibrosis in vitro in a bronchopulmonary dysplasia model by activating the extrinsic coagulation cascade

Neonatal respiratory distress syndrome can progress to bronchopulmonary dysplasia (BPD), a serious pulmonary fibrotic disorder. Given the involvement of the extrinsic coagulation cascade in animal models of lung fibrosis, we examined its role in BPD. We observed a higher number of neutrophils expressing tissue factor (TF) in bronchoalveolar lavage fluid (BALF) from infants with BPD than from those with uncomplicated respiratory distress syndrome together with a parallel decrease in TF and connective tissue growth factor (CTGF) in BALF supernatants during the disease course. The involvement of coagulation in the fibrotic process associated with BPD was further evaluated by treating primary human colonic myofibroblasts with BALF supernatants from infants with BPD. These human colonic myofibroblasts demonstrated an enhanced C5a- and thrombin-dependent migration. Moreover, they expressed TF in an endothelin-1-dependent manner, with subsequent activation of the extrinsic coagulation cascade and CTGF production mediated by protease-activator receptor-1 signaling. These data provide a novel mechanism for the development of BPD and indicate that endothelin-1 signaling contributes to fibrosis by upregulating a TF/thrombin amplification loop responsible for CTGF production, and offer novel and specific therapeutic targets for pulmonary fibrotic disease.

Regulation of the autophagic machinery in human neutrophils

The induction of the autophagy machinery, a process for the catabolism of cytosolic proteins and organelles, constitutes a crucial mechanism in innate immunity. However, the involvement of autophagy in human neutrophils and the possible inducers of this process have not been completely elucidated. In this study, the induction of autophagy was examined in human neutrophils treated with various activators and detected by the formation of acidified autophagosomes through monodansylcadaverine staining and via LC-3B conversion screened by immunoblotting and immunofluorescence confocal microscopy. In addition, the expression of the ATG genes was assessed by real-time RT-PCR. We provide evidence that autophagy is implicated in human neutrophils in both a phagocytosis-independent (rapamycin, TLR agonists, PMA) and phagocytosis (Escherichia coli)-dependent initiation manner. ROS activation is a positive mechanism for autophagy induction in the case of PMA, TLR activation and phagocytosis. Furthermore, LC3B gene expression was uniformly upregulated, indicating a transcriptional level of regulation for the autophagic machinery. This study provides a stepping stone toward further investigation of autophagy in neutrophil-driven inflammatory disorders.

Primary myeloid sarcoma of the jejunum and greater omentum causing small intestine obstruction

Myeloid sarcoma, which is highly associated with acute myeloid leukemia, is defined as an extramedullary discrete tumor mass, consisted by immature myeloid cells or myeloblasts. Myeloid sarcoma usually involves the skin, lymph node, bone, soft tissue and testis, while involvement of the gastrointestinal tract is rather uncommon. The diagnosis depends on histological features and immunohistochemical results. We present a rare case of myeloid sarcoma, with synchronous involvement of the jejunum and the greater omentum, manifesting with small bowel obstruction.

Leptin enhances the recruitment of endothelial progenitor cells into neointimal lesions after vascular injury by promoting integrin-mediated adhesion

The adipocytokine leptin modulates vascular remodeling and neointima formation. Because endothelial progenitor cells (EPCs) participate in vascular repair, we analyzed the effects of leptin on human EPC function in vitro and in vivo. After 7 days in culture, EPCs expressed the leptin receptor and responded to leptin stimulation with increased STAT3 phosphorylation. Incubation of EPCs with leptin (at concentrations between 1 and 100 ng/mL) increased the number of EPCs adhering to vitronectin and fibronectin in a receptor-specific manner. It also enhanced the capacity of EPCs to incorporate into a monolayer of human endothelial cells and the adherence of these cells to activated platelets. Leptin upregulated alphavbeta5 and alpha4 integrin expression in EPCs, and the effects of leptin on EPC function could be prevented, at least in part, by RGD peptides and function-blocking antibodies. Intravenous injection of fluorescently labeled human EPCs into athymic nude mice shortly after vascular injury revealed that preincubation of EPCs with leptin augmented their accumulation within intimal lesions, accelerating reendothelialization and decreasing neointima formation in an alphavbeta5 and alpha4 integrin-dependent manner. Our findings suggest that leptin specifically modulates the adhesive properties and the homing potential of EPCs and may thus enhance their capacity to promote vascular regeneration in vivo.

Leptin induces the expression of functional tissue factor in human neutrophils and peripheral blood mononuclear cells through JAK2-dependent mechanisms and TNFalpha involvement

INTRODUCTION

Leptin is an adipocyte-derived cytokine primarily involved in the regulation of body weight and energy balance. In vivo studies suggest that leptin promotes platelet aggregation and thrombosis. Neutrophils are involved in the crosstalk between inflammation and thrombosis in clinical disorders. Leptin is also involved in the regulation of inflammation.

AIM

We examined the in vitro effects of leptin on the expression of tissue factor (TF), the primary initiator of coagulation, in healthy neutrophils.

MATERIALS AND METHODS/RESULTS

The effects on TF expression were assayed functionally using a modified prothrombin time (mPT), as well as at mRNA and protein levels. The same experiments were performed in parallel with PBMC. Leptin induced functional TF and increased TF mRNA and protein expression in both cell types, as determined by mPT, real-time RT-PCR, western blot, flow cytometry, immunocytochemistry. Inhibition studies revealed that the effect of leptin on TF expression is mediated, at least in part, by JAK2 and PI3K. Our findings, after neutralising TNFalpha in supernatants of leptin-treated cells, also suggest the involvement of TNFalpha in the leptin-induced TF expression in leukocytes.

CONCLUSIONS

This study indicates a novel link between inflammation, obesity and thrombosis by showing that leptin is able to trigger the extrinsic coagulation cascade. This work suggests a possible mechanism of the thrombotic effects of hyperleptinemic-associated clinical disorders.

MEFV alterations and population genetics analysis in a large cohort of Greek patients with familial Mediterranean fever

Familial Mediterranean fever (FMF) is a disease characterized by recurrent, self-limiting bouts of fever and serositis and caused by altered pyrin due to mutated MEFV gene. FMF is common in the Mediterranean Basin populations, although with varying genetic patterns. The spectrum and clinical significance of MEFV alterations in Greece has yet not been elucidated. The aim of this study was to analyze the spectrum of MEFV alterations in FMF patients and healthy individuals in Greece. A cohort of 152 Greek FMF patients along with 140 Greek healthy controls was enrolled. Non-isotopic RNase cleavage assay (NIRCA) and sequencing allowed mutational and haplotypic analysis of the entire coding sequence of MEFV. The ARLEQUIN 2.0, DNASP 4.0 and PHYLIP software were used for population genetics analysis. Among patients, 127 (83.6%) carried at least one known mutation. The most common mutations identified were M694V (38.1%), M680I (19.7%), V726A (12.2%), E148Q (10.9%) and E230K (6.1%). The total carrier rate among healthy individuals was 0.7%. The presence of R202Q homozygosity in 12 of the remaining 25 MEFV negative FMF patients might be considered as disease related in Greeks. Population genetics analysis revealed that Greeks rely closer to the eastern rather than western populations of the Mediterranean Basin.

A novel C5a receptor-tissue factor cross-talk in neutrophils links innate immunity to coagulation pathways

Neutrophils and complement are key sentinels of innate immunity and mediators of acute inflammation. Recent studies have suggested that inflammatory processes modulate thrombogenic pathways. To date, the potential cross-talk between innate immunity and thrombosis and the precise molecular pathway by which complement and neutrophils trigger the coagulation process have remained elusive. In this study, we demonstrate that antiphospholipid Ab-induced complement activation and downstream signaling via C5a receptors in neutrophils leads to the induction of tissue factor (TF), a key initiating component of the blood coagulation cascade. TF expression by neutrophils was associated with an enhanced procoagulant activity, as verified by a modified prothrombin time assay inhibited by anti-TF mAb. Inhibition studies using the complement inhibitor compstatin revealed that complement activation is triggered by antiphospholipid syndrome (APS) IgG and leads to the induction of a TF-dependent coagulant activity. Blockade studies using a selective C5a receptor antagonist and stimulation of neutrophils with recombinant human C5a demonstrated that C5a, and its receptor C5aR, mediate the expression of TF in neutrophils and thereby significantly enhance the procoagulant activity of neutrophils exposed to APS serum. These results identify a novel cross-talk between the complement and coagulation cascades that can potentially be exploited therapeutically in the treatment of APS and other complement-associated thrombotic diseases.

Increased frequency of mutations in the gene responsible for familial Mediterranean fever (MEFV) in a cohort of patients with ulcerative colitis: evidence for a potential disease-modifying effect?

The MEFV gene, responsible for familial Mediterranean fever (FMF), is involved in inflammatory reactions through altered leukocyte apoptosis, secretion of interleukin (IL)-1beta, and activation of the NF-kappa B pathway. Ulcerative Colitis (UC) and FMF are both characterized by a recurrent pattern of presentation with periods of remission and flares associated with neutrophilic infiltration at the site of injury. The aim of this study was to investigate the possible correlation between UC and MEFV gene alterations. Twenty-five consecutive, first-diagnosed and untreated UC patients, 28 control patients with rheumatoid arthritis, and 65 normal individuals were analyzed. Nonisotopic RNase Cleavage Assay (NIRCA) was applied as a first-step mutational screening method of exons 10 and 2 of MEFV gene; direct sequencing was subsequently performed to confirm the results. MEFV mutations were identified in 7 (3 M694V/0, 2 M680I/0, 1 E148Q/E148Q, and 1 A744S/0) out of 25 UC patients versus 1 (M694V/0) out of 28 rheumatoid arthritis patients (P = .0199) and 1 (M694V/0) out of 65 healthy controls (P = .0004). Four out of 7 patients with MEFV mutations had inflammatory arthritis, a clinical finding that was not observed in the 18 UC patients with unmutated MEFV (P = .0028). Patients with UC almost universally carried the T A C G MEFV exon 2 haplotype in contrast with normal individuals (P < .0001) and FMF patients (P = .0310). In conclusion the increased frequency of mutations of MEFV in UC patients, especially in those with episodic arthritis, suggests a possible modifying effect of MEFV in the disease process and its localization within the joint. The difference in distribution of MEFV exon 2 haplotypes between UC patients and both FMF patients and normal individuals, suggests that UC patients constitute a genetically distinct population. Larger, longitudinal studies are needed to confirm these initial findings.

Diagnostic usefulness of bone marrow aspiration material for the amplification of IS6110 insertion element in extrapulmonary tuberculosis: comparison of two PCR techniques

SETTING

In many cases of extra-pulmonary tuberculosis (EPTB), with the exception of paucibacillary analysed specimens, the suspected site of mycobacterial infection is relatively inaccessible or unknown, making laboratory confirmation of TB laborious and problematic.

OBJECTIVE

Two different polymerase chain reaction (PCR) based methods were compared to investigate the validity of bone marrow aspiration material as an easily accessible alternative sample for molecular analysis in EPTB.

DESIGN

We amplified the same sequence of IS6110 of Mycobacterium tuberculosis complex in 19 confirmed cases of EPTB using two different nested PCR techniques: one in-house 'classic' PCR and another based on LightCycler technology.

RESULTS

Both methods demonstrated the same reliability when performed in samples of infected tissue. However, the LightCycler protocol was superior to the in-house system when applied in bone marrow aspiration material, revealing positivity in 18/19 compared to 13/19 samples of 'classic' PCR.

CONCLUSION

The application of an optimised LightCycler nested amplification protocol in bone marrow aspirates may promote diagnostic accuracy in difficult and/or urgent cases of EPTB.

Non-isotopic RNase cleavage assay for mutation detection in MEFV, the gene responsible for familial Mediterranean fever, in a cohort of Greek patients

BACKGROUND

The MEFV gene is responsible for familial Mediterranean fever (FMF). Several disease associated mutations have been identified. The range of genetic variation in MEFV in Greek patients has not been determined.

OBJECTIVE

To describe a method that facilitates the routine screening of the entire coding sequence of MEFV (excluding exon 1).

METHODS

The non-isotopic RNase cleavage assay (NIRCA) was optimised and used as a first step screening method to screen exons 2 to 10 of MEFV. Exons 2 and 10 were analysed separately at DNA level, while exons 3 to 9 were analysed together at cDNA level. The sample group consisted of 26 FMF patients diagnosed using established clinical criteria, six asymptomatic relatives, 12 patients with atypical clinical manifestations, nine patients suffering from various inflammatory diseases, and three normal individuals. All were analysed by NIRCA for mutations in the MEFV gene and direct sequencing was applied subsequently to confirm the results.

RESULTS

MEFV mutations were identified in 25 of 26 typical FMF patients and in two of 12 patients with atypical manifestations. NIRCA results were in concordance with sequencing findings in all sequences analysed, suggesting that the method is highly reliable in this disease. Sixteen alterations of MEFV were identified (eight missense mutations and eight single nucleotide polymorphisms).

CONCLUSIONS

NIRCA can be used for rapid screening of the coding sequence of the MEFV gene in patients suspected of suffering from FMF.