scholarly journals Interim Cell-Free Circulating Lymphoma DNA Analysis of the Phase 2 Accept Trial

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 24-25
Author(s):  
Anthony Cutts ◽  
Edward Wilson ◽  
Pek Sang Tang ◽  
Andrew Davies ◽  
Peter Johnson ◽  
...  

Introduction Plasma cell-free DNA (cfDNA) and circulating tumor DNA (ctDNA) genotyping in Diffuse Large B-cell Lymphoma (DLBCL) holds great promise for early detection and response prediction. DLBCL is a highly heterogenous disease with diverse tumor behaviour and outcomes, yet the delineation of poor- risk groups remains challenging. Genomically driven molecular risk stratification, using ultradeep next generation sequencing (NGS) provides a comprehensive view of the mutational landscape of lymphoma and enables ultrasensitive disease detection. Here, we present an interim analysis of ctDNA kinetics from ACCEPT, a phase Ib/II study of acalabrutinib with rituximab, cyclophosphamide, doxorubicin, vincristine and prednisolone (R-CHOP) for patients with previously untreated DLBCL. Methods Plasma samples were collected at four time points, at baseline and before the second, third and final cycles of chemotherapy. Extracted cell-free DNA (cfDNA) was quantified by fluorometry, prior to undergoing library preparation and next-generation sequencing using the CAncer Personalized Profiling by deep Sequencing (CAPP-Seq) methodology. The targeted sequencing panel covered 799 regions over 50 genes (>200Kb) known to be involved in lymphomagenesis. Analysis was carried out with a custom bioinformatics pipeline using error-corrected deduplication and a database of known artefacts to reduce background noise and improve sensitivity for low-level somatic variant detection. Patients were closely monitored through the study period by clinical examination and PET-CT scanning to provide objective endpoints against which the ctDNA response could be correlated. Results Fifteen patients had samples analysed for all four time points at the time of the interim analysis and were included in the study. Ten (66%) had late stage disease, nine (60%) poor risk disease (IPI > 2). Early vs late stage of disease at presentation showed a strong correlation with baseline levels of both total cfDNA (3,946 HGE/ml vs 21,613 HGE/ml) and ctDNA (842HGE/ml vs 6,380 HGE/ml). Twelve patients (80%) had trackable variants detected at baseline. The majority of these cleared after the first cycle of chemotherapy (Figure A; representative patient). Two cases (Figures B and C) had variants persistently detectable at high variant allele frequency (VAF) (0.059 and 0.068). These patients both had primary refractory disease. One patient from the first acalabrutinib dose escalation cohort and the second patient was found to be ineligible and withdrawn from the primary analysis because of continuous co-administration of omeprazole during therapy which inhibits acalabrutinib absorption. All others achieved a metabolic complete metabolic remission (mCR) after the final cycle of therapy. A third pattern of response noted was (Figure D) showing disappearance of detectable variants at baseline but progressive emergence of an acquired TP53 variant throughout follow-up that was not detected in the patient's germline sample. This high-risk patient with IPI of 5 and triple-hit DLBCL achieved a mCR and remains in remission in follow-up. Conclusion The clearance of ctDNA from the plasma of the responding patients in our study is consistent with the prior literature, as is the poor prognostic significance of persisting variants after the first cycle of chemotherapy. The rapid kinetics of the changes in ctDNA is noted and is potentially of advantage over other modalities of monitoring, such as PET-CT scan. Data on the entire cohort (n=30) and longer follow-up will be available at the time of the meeting. Figure 1 Disclosures Davies: Roche: Other: TRAVEL, ACCOMMODATIONS, EXPENSES; Roche, Celgene, Kite Pharma, Acerta, Karyopharma, Regeneron, Incyte: Consultancy; Roche, Acerta Pharma, AstraZeneca, Celgene, Gilead, ADC Therapeutics, Gilead: Research Funding; Celegene, Roche, Kite Pharma, Celegene: Honoraria. Johnson:Oncimmune: Consultancy; Bristol-Myers: Honoraria; Celgene: Honoraria; Genmab: Honoraria; Incyte: Honoraria; Kite Pharma: Honoraria; Kymera: Honoraria; MorphoSys: Honoraria; Novartis: Honoraria; Takeda: Honoraria; Boehringer Ingelheim: Consultancy; Epizyme: Consultancy, Research Funding; Janssen: Consultancy; Oncimmune: Consultancy; Epizyme: Consultancy, Research Funding; Janssen: Consultancy. Schuh:Illumina: Other: Consulting fees; Roche: Other: Consulting fees; Gilead: Other: Consulting fees; Abbvie: Other: Consulting fees.

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 4359-4359
Author(s):  
Koji Sasaki ◽  
Rashmi Kanagal-Shamanna ◽  
Guillermo Montalban-Bravo ◽  
Rita Assi ◽  
Kiran Naqvi ◽  
...  

Abstract Introduction: Clearance of detected somatic mutations at complete response by next-generation sequencing is a prognostic marker for survival in patients with acute myeloid leukemia (AML). However, the impact of allelic burden and persistence of clonal hematopoiesis of indeterminate potential (CHIP)-associated mutations on survival remains unclear. The aim of this study is to evaluate the prognostic impact of allelic burden of CHIP mutations at diagnosis, and their persistence within 6 months of therapy. Methods: From February 1, 2012 to May 26, 2016, we reviewed 562 patients with newly diagnosed AML. Next-generation sequencing was performed on the bone marrow samples to detect the presence of CHIP-associated mutations defined as DNMT3A, TET2, ASXL1, JAK2 and TP53. Overall survival (OS) was defined as time period from the diagnosis of AML to the date of last follow-up or death. Univariate (UVA) and multivariate Cox proportional hazard regression (MVA) were performed to identify prognostic factors for OS with p value cutoff of 0.020 for the selection of variables for MVA. Landmark analysis at 6 months was performed for the evaluation of the impact of clearance of CHIP, FLT3-ITD, FLT3D835, and NPM1 mutations. Results: We identified 378 patients (74%) with AML with CHIP mutations; 134 patients (26%) with AML without CHIP mutations. The overall median follow-up of 23 months (range, 0.1-49.0). The median age at diagnosis was 70 years (range, 17-92) and 66 years (range, 20-87) in CHIP AML and non-CHIP AML, respectively (p =0.001). Of 371 patients and 127 patients evaluable for cytogenetic in CHIP AML and non-CHIP AML, 124 (33%) and 25 patients (20%) had complex karyotype, respectively (p= 0.004). Of 378 patients with CHIP AML, 183 patients (48%) had TET2 mutations; 113 (30%), TP53; 110 (29%), ASXL1; 109 (29%), DNMT3A; JAK2, 46 (12%). Of 378 patients, single CHIP mutations was observed in 225 patients (60%); double, 33 (9%); triple, 28 (7%); quadruple, 1 (0%). Concurrent FLT3-ITD mutations was detected in 47 patients (13%) and 12 patients (9%) in CHIP AML and non-CHIP AML, respectively (p= 0.287); FLT3-D835, 22 (6%) and 8 (6%), respectively (p= 0.932); NPM1 mutations, 62 (17%) and 13 (10%), respectively (p= 0.057). Of 183 patients with TET2-mutated AML, the median TET2 variant allele frequency (VAF) was 42.9% (range, 2.26-95.32); of 113 with TP53-mutated AML, the median TP53 VAF, 45.9% (range, 1.15-93.74); of 109 with ASXL1-mutated AML, the median ASXL1 VAF was 34.5% (range, 1.17-58.62); of 109 with DNMT3A-mutated AML, the median DNMT3A VAF was 41.8% (range, 1.02-91.66); of 46 with JAK2-mutated AML, the median JAK2 VAF was 54.4% (range, 1.49-98.52). Overall, the median OS was 12 months and 11 months in CHIP AML and non-CHIP AML, respectively (p= 0.564); 16 months and 5 months in TET2-mutated AML and non-TET2-mutated AML, respectively (p <0.001); 4 months and 13 months in TP53-mutated and non-TP53-mutated AML, respectively (p< 0.001); 17 months and 11 months in DNMT3A-mutated and non-DNMT3A-mutated AML, respectively (p= 0.072); 16 months and 11 months in ASXL1-mutated AML and non-ASXL1-mutated AML, respectively (p= 0.067); 11 months and 12 months in JAK2-murated and non-JAK2-mutated AML, respectively (p= 0.123). The presence and number of CHIP mutations were not a prognostic factor for OS by univariate analysis (p=0.565; hazard ratio [HR], 0.929; 95% confidence interval [CI], 0.722-1.194: p= 0.408; hazard ratio, 1.058; 95% confidence interval, 0.926-1.208, respectively). MVA Cox regression identified age (p< 0.001; HR, 1.036; 95% CI, 1.024-1.048), TP53 VAF (p= 0.007; HR, 1.009; 95% CI, 1.002-1.016), NPM1 VAF (p=0.006; HR, 0.980; 95% CI, 0.967-0.994), and complex karyotype (p<0.001; HR, 1.869; 95% CI, 1.332-2.622) as independent prognostic factors for OS. Of 33 patients with CHIP AML who were evaluated for the clearance of VAF by next generation sequencing , landmark analysis at 6 months showed median OS of not reached and 20.3 months in patients with and without CHIP-mutation clearance, respectively (p=0.310). Conclusion: The VAF of TP53 and NPM1 mutations by next generation sequencing can further stratify patients with newly diagnosed AML. Approximately, each increment of TP53 and NPM1 VAF by 1% is independently associated with 1% higher risk of death, and 2% lower risk of death, respectively. The presence of CHIP mutations except TP53 does not affect outcome. Disclosures Sasaki: Otsuka Pharmaceutical: Honoraria. Short:Takeda Oncology: Consultancy. Ravandi:Macrogenix: Honoraria, Research Funding; Seattle Genetics: Research Funding; Sunesis: Honoraria; Xencor: Research Funding; Jazz: Honoraria; Seattle Genetics: Research Funding; Abbvie: Research Funding; Macrogenix: Honoraria, Research Funding; Bristol-Myers Squibb: Research Funding; Orsenix: Honoraria; Abbvie: Research Funding; Jazz: Honoraria; Xencor: Research Funding; Orsenix: Honoraria; Sunesis: Honoraria; Amgen: Honoraria, Research Funding, Speakers Bureau; Bristol-Myers Squibb: Research Funding; Astellas Pharmaceuticals: Consultancy, Honoraria; Amgen: Honoraria, Research Funding, Speakers Bureau; Astellas Pharmaceuticals: Consultancy, Honoraria. Kadia:BMS: Research Funding; Abbvie: Consultancy; Takeda: Consultancy; Jazz: Consultancy, Research Funding; Takeda: Consultancy; Amgen: Consultancy, Research Funding; Celgene: Research Funding; Novartis: Consultancy; Amgen: Consultancy, Research Funding; BMS: Research Funding; Jazz: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Novartis: Consultancy; Abbvie: Consultancy; Celgene: Research Funding. DiNardo:Karyopharm: Honoraria; Agios: Consultancy; Celgene: Honoraria; Medimmune: Honoraria; Bayer: Honoraria; Abbvie: Honoraria. Cortes:Novartis: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Daiichi Sankyo: Consultancy, Research Funding; Astellas Pharma: Consultancy, Research Funding; Arog: Research Funding.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 2813-2813
Author(s):  
Maryam Sarraf Yazdy ◽  
Umair Jarral ◽  
Chao Yin ◽  
Frank Kuhr ◽  
Allison P. Jacob ◽  
...  

BACKGROUND FL is the most common indolent non-Hodgkin lymphoma (NHL). While very responsive to therapy, it has been considered incurable. Nonetheless, pts remaining in remission >24 months appear to have a survival comparable to an age-matched population without NHL (Casulo et al, J Clin Oncol, 33:2516, 2015), and some are free of disease for many years and die from unrelated events. METHODS Adult pts were accrued from the Lombardi Comprehensive Cancer Center Lymphoma clinic. Pts were required to have histologically confirmed FL or transformed FL that was previously treated resulting in a complete remission, and were required to be free of progression at any time > 24 months following completion of treatment without intervening therapy. Original diagnostic samples were retrieved and subjected to clonality assessment using Adaptive's next generation sequencing (NGS) MRD assay , a research version of clonoSEQ®; (Adaptive Biotechnologies, Seattle, WA) that leverages multiplex PCR followed by NGS to identify and track rearrangements of IgH, V-J, D-J and IgK/L loci as well as translocations in Bcl1/2 IgH. Lymph node biopsy from time of original diagnosis was assessed to identify trackable clonotypes, which were found in 37/43 patients. Peripheral blood was assayed upon entry onto the study and every 6 months thereafter by the NGS-MRD assay to monitor MRD. Samples are being collected every 6 months during follow-up, and the results are being correlated with clinical outcome. RESULTS Of the 60 eligible pts who signed consent 41% were females, with a median age at diagnosis of 56 yrs (21-75) and median age at treatment of 56 years (21-75). Twenty six had received one prior line of treatment (LOT), 4 had 2, 6 had 3, and 1 had 5. The most common immediately prior line of therapy included bendamustine and rituximab (BR, n=16); rituximab, cyclophosphamide, adriamycin, vincristine, prednisone (RCHOP, n=6); double-monoclonal antibody containing regimens(rituximab-galiximab; rituximab-epratuzumab (n=3)), radioimmunotherapy (n=3), and allogeneic bone marrow transplant (n=2). The media follow-up since the start and completion of most recent therapy was 62 months (range 25-183 and 32-193, respectively). Of the 60 pts for whom original biopsy slides were obtainable, the quality was inadequate to amplify the DNA in 18. In another 5 pts, the sample was polyclonal and a dominant rearrangement could not be identified. In 32 of the 37 pts (86.5%), samples were negative at enrollment to this study at a level of detection of 10-5. By prior LOT, samples were negative in 25 of 26 following 1st line; 1 of 4 following 2nd line; 5 of 6 following 3rd line; and in the one pt after 5th line. In all but 1 pt, the assay has remained negative on subsequent determinations as shown in the spider plot (Fig 1). The 5 positive patients had been followed for a median of 85 (56-118) months. Additional follow-up is underway to determine if positive pts will eventually relapse. CONCLUSIONS These data are the first to demonstrate that a high proportion of FL pts in a prolonged clinical remission have undetectable DNA by sensitive next generation sequencing, without evidence of clinical progression, and are potentially cured of their disease. Figure 1 Disclosures Yazdy: Bayer: Honoraria, Speakers Bureau; Genentech: Research Funding; Abbvie: Consultancy; Octapharma: Consultancy. Kuhr:Adaptive Biotechnologies: Employment, Other: shareholder. Jacob:Adaptive Biotechnologies: Employment, Other: shareholder. Cheson:Epizyme: Research Funding; TG Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Seattle Genetics: Research Funding; Bristol Myers Squibb: Research Funding; Portola: Research Funding; Kite: Research Funding; Gilead: Research Funding; Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmacyclics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Symbios: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Trillium: Research Funding; AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Morphosys: Membership on an entity's Board of Directors or advisory committees; Acerta: Consultancy, Research Funding.


Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 1920-1920
Author(s):  
Maximilian Mossner ◽  
Johann Christoph Jann ◽  
Evi Launiger-Lörsch ◽  
Daniel Nowak ◽  
Uwe Platzbecker ◽  
...  

Abstract Introduction: MDS with isolated deletion 5(q) accounts for approximately 5% of all MDS cases. A recent retrospective analysis has found a cumulative progression rate of 18% after 5 years in patients with MDS deletion 5(q) without an increased medullary blast count[1]. Retrospective analyses have indicated that mutations in TP53 have an adverse impact on the clinical course of affected patients and their response to Len treatment. Here we report on the results of the German multi-center, prospective Le-Mon-5 trial that investigated the safety and efficacy of lenalidomide (Len) in patients with MDS and isolated deletion 5(q). Methods: Le-Mon-5 is a trial of Len in patients with MDS with isolated 5q abnormality, a blast count of < 5% in the bone marrow, a platelet count > 50.000/µl and absolute neutrophil counts of > 500/µl in the peripheral blood. Patients were treated with the standard dose of 10 mg Len for 21 days q28 days. The primary endpoint was safety. Secondary endpoints included response according to IWG criteria (2000), time to response, duration of transfusion independency and incidence and time to AML-transformation, respectively. All patients gave written informed consent to the trial including additional molecular genetic analyses. Central cytologic, cytogenetic and histologic review was performed. Mutational analysis of TP53 was done by next generation sequencing (NGS). For generation of PCR amplicon libraries TP53 primer plate assays were used and technically validated within the IRON-II (Interlaboratory Robustness Of Next generation sequencing) study network. Amplicon sequencing of TP53 was performed on a Roche 454 GS Junior system. Mean coverage of sequenced exons was about 800-fold allowing an approximate detection sensitivity of 2% mutational burden. Results: A total of 91 patients were enrolled into the trial. Of those, 71 patients (male, n=13) were analyzed for TP53 mutations. Median age was 71 years (range 40-88 years). TP53 mutations prior to treatment initiation with Len were found in 7 patients (10%). There was no difference between the TP53 mutated (TP53mut) versus TP53 wildtype patients (TP53WT) with regard to age, IPSS risk, hemoglobin levels, absolute neutrophil counts and platelet counts at baseline. Transfusion independence was achieved in a significantly lower proportion of patients in the TP53mut group versus TP53WT group (43% vs. 62%, p=0.036). Moreover, median survival was significantly shorter in the TP53mut group as compared to TP53WT group (533 days vs. not reached, p=0.0002). No difference was seen with regard to cytologic and cytogenetic response. Data on evolution into AML are currently being collected. Of 2 patients we had follow-up samples available. Both patients showed no difference with regard to the mutation frequency after a follow-up of 4-17 months on Len treatment (27% and 51%, respectively), although one of the patients achieved a complete cytogenetic response during Len treatment. Conclusions: Using the NGS technique on a routine basis, we achieved high quality runs with a high mean coverage of analyzed exons of TP53. Presence of TP53 mutations adversely affected response to Len with regard to transfusion independence. Moreover, TP53mut patients had a shorter overall survival as compared to TP53WT patients underlining the prognostic relevance of TP53 mutations in this patient cohort. Therefore, mutation analysis of TP53 might guide treatment decisions in the future, e.g. consideration of combination regimens. Since the TP53 clone obviously prevails during Len treatment, careful monitoring for signs of transformation should be performed. Disclosures Platzbecker: Celgene Corp.: Honoraria, Research Funding. Götze:Celgene Corp, Novartis Pharma: Honoraria. Schlenk:Celgene Corp.: Research Funding, Speakers Bureau. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Bug:Celgene: Honoraria, Research Funding. Germing:Celgene Corp.: Honoraria, Research Funding. Nolte:Celgene Corp., Novartis Pharma: Honoraria, Research Funding.


2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S390-S390
Author(s):  
Priya Edward ◽  
William V La Via ◽  
Mehreen Arshad ◽  
Kiran Gajurel

Abstract Background Mycoplasma hominis is typically associated with genital infections in women and is a rare cause of musculoskeletal infections often in immunocompromised hosts. Diagnosis of invasive Mycoplasma hominis infections are difficult due to challenges in culturing these organisms. Molecular diagnostics require an index of suspicion which may not be present at the time of tissue sampling. Accurate, rapid diagnosis of Mycoplasma hominis infections are important for antibiotic management. Methods Two cases of invasive Mycoplasma hominis infections are presented in which the Karius test (KT) was used to make the diagnosis. The KT is a CLIA certified/CAP-accredited next-generation sequencing (NGS) plasma test that detects microbial cell-free DNA (mcfDNA). After mcfDNA is extracted and NGS performed, human reads are removed and remaining sequences are aligned to a curated database of &gt; 1400 organisms. Organisms present above a statistical threshold are reported. Case review was performed for clinical correlation. Results A young woman with lupus nephritis status post renal transplant developed persistent fever with progressive multifocal culture-negative osteoarticular infection despite empiric ceftriaxone. An adolescent female presented with an ascending pelvic infection progressing to purulent polymicrobial peritonitis (see table) requiring surgical debridement and cefipime, metronidazole and micafungin therapy; her course was complicated by progressive peritonitis/abscesses. Karius testing detected high-levels of Mycoplasma hominis mcfDNA in both cases – at 3251 molecules/microliter (MPM) in the first case and 3914 MPM in the second case. The normal range of Mycoplasma hominis mcfDNA in a cohort of 684 normal adults is 0 MPM. The patients rapidly improved with atypical coverage with doxycycline and levofloxaxin. Clinical findings in 2 patients with M. hominis infection detected by the Karius Test Conclusion Open-ended, plasma-based NGS for mcfDNA provides a rapid, non-invasive method to diagnose invasive Mycoplasma hominis infection. This case series highlights the potential to diagnose infections caused by fastidious pathogens to better inform antimicrobial therapy and achieve favorable outcomes. Disclosures William V. La Via, MD, Karius (Employee)


2018 ◽  
Vol 12 (11) ◽  
pp. 1197-1201
Author(s):  
Demosthenes E Ziogas ◽  
Ioannis D Kyrochristos ◽  
Efstathios G Lykoudis ◽  
Dimitrios H Roukos

F1000Research ◽  
2019 ◽  
Vol 8 ◽  
pp. 1194 ◽  
Author(s):  
Jose F. Camargo ◽  
Asim A. Ahmed ◽  
Martin S. Lindner ◽  
Michele I. Morris ◽  
Shweta Anjan ◽  
...  

Background: Cell-free DNA (cfDNA) sequencing has emerged as an effective laboratory method for rapid and noninvasive diagnosis in prenatal screening testing, organ transplant rejection screening, and oncology liquid biopsies but clinical experience for use of this technology in diagnostic evaluation of infections in immunocompromised hosts is limited.  Methods: We conducted an exploratory study using next-generation sequencing (NGS) for detection of microbial cfDNA in a cohort of ten immunocompromised patients with febrile neutropenia, pneumonia or intra-abdominal infection.  Results: Pathogen identification by cfDNA NGS demonstrated positive agreement with conventional diagnostic laboratory methods in 7 (70%) cases, including patients with proven/probable invasive aspergillosis, Pneumocystis jirovecii pneumonia, Stenotrophomonas maltophilia bacteremia, Cytomegalovirus and Adenovirus viremia. NGS results were discordant in 3 (30%) cases including two patients with culture negative sepsis who had undergone hematopoietic stem cell transplant in whom cfDNA testing identified the etiological agent of sepsis; and one kidney transplant recipient with invasive aspergillosis who had received >6 months of antifungal therapy prior to NGS testing. Conclusion: These observations support the clinical utility of measurement of microbial cfDNA sequencing from peripheral blood for rapid noninvasive diagnosis of infections in immunocompromised hosts. Larger studies are needed.


2017 ◽  
Vol 12 (1) ◽  
pp. S787-S788
Author(s):  
Umberto Malapelle ◽  
Clara Mayo ◽  
Danilo Rocco ◽  
Monica Garzon ◽  
Pasquale Pisapia ◽  
...  

Author(s):  
Rachel D Downey ◽  
Susan M Russo ◽  
Sarmistha B Hauger ◽  
Donald K Murphey ◽  
Grace Marx ◽  
...  

Abstract Diagnosis and treatment of culture negative endocarditis remains a challenge. This report describes a rare cause of endocarditis in humans, Bartonella vinsonii, identified through next generation sequencing of plasma microbial cell-free DNA with confirmation of cardiac valve tissue infection through immunohistochemical staining and polymerase chain reaction.


2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S725-S725
Author(s):  
Fernando H Centeno ◽  
Asim A Ahmed ◽  
David K Hong ◽  
Sudeb Dalai ◽  
Laila Woc-Colburn

Abstract Background Rickettsia typhi typically causes a nonspecific syndrome characterized by fever, rash, and headache but can rarely progress to severe disease. R. typhi is transmitted by the rat flea and there has been an increased incidence in Houston, TX. Establishing the diagnosis can be challenging and is often made by serological studies. Prompt therapy with doxycycline is important especially in severe disease. Methods Karius Test results from the prior 2 years (Redwood City, CA) were reviewed for detections of R. typhi. The Karius Test is a CLIA-certified/CAP-accredited next-generation sequencing (NGS) plasma test that detects microbial cell free DNA (mcfDNA). After mcfDNA is extracted and NGS performed, human sequences are removed and remaining sequences are aligned to a curated pathogen database of >1,000 organisms. Organisms present above a statistical threshold are reported. Chart review was conducted on the cases of R. typhi identified by the Karius Test. Results The Karius Test detected R. typhi in 6 adult patients, 4 women and 2 men, from a medical center in Houston, TX. In 2 patients, R. typhi mcfDNA was present in the raw sequencing data but at an abundance below validated statistical thresholds. R. typhi mcfDNA was not found in negative controls run simultaneously with the samples. All patients presented with fever, 4 presented with headache, 3 presented with gastrointestinal symptoms, 3 developed rash, one presented with hypotension. Laboratory data were available for 5 patients. Four patients developed thrombocytopenia, 5 had anemia, 4 patients had WBC < 5, 4 had transaminase elevation and 3 developed hyponatremia. 3 out of 5 had R. typhi serologies sent; all 3 were positive (including two of the patients with R. typhi mcfDNA levels below threshold). In the two other patients the Karius test was the means of establishing the diagnosis. 3 out of 5 patients where data were available were treated with doxycyline. Conclusion The Karius test was able to detect R. typhi in a cluster of 6 patients in one medical center in Houston, TX. NGS for mcfDNA offers a rapid means of detecting R. typhi infection. Accurate, rapid diagnosis of R. typhi has important public health implications given its vector-borne mechanism of transmission. Disclosures All authors: No reported disclosures.


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