position article Allergo J Int (2018) 27:147–151 https://doi.org/10.1007/s40629-018-0070-2 Non-celiac gluten/wheat sensitivity (NCGS)—a currently undeﬁned disorder without validated diagnostic criteria and of unknown prevalence Position statement of the task force on food allergy of the German Society of Allergology and Clinical Immunology (DGAKI) Imke Reese · Christiane Schäfer · Jörg Kleine-Tebbe · Birgit Ahrens · Oliver Bachmann · Barbara Ballmer-Weber · Kirsten Beyer · Stephan C. Bischoff · Katharina Blümchen · Sabine Dölle · Paul Enck · Axel Enninger · Isidor Huttegger · Sonja Lämmel · Lars Lange · Ute Lepp · Vera Mahler · Hubert Mönnikes · Johann Ockenga · Barbara Otto · Sabine Schnadt · Zsolt Szepfalusi · Regina Treudler · Anja Wassmann-Otto · Torsten Zuberbier · Thomas Werfel · Margitta Worm Received: 16 February 2018 / Accepted: 19 March 2018 / Published online: 28 May 2018 © The Author(s) 2018 Abstract Within the last decade, non-celiac gluten/ to a lack of diagnostic criteria, a thorough differential wheat sensitivity (NCGS) has been increasingly dis- diagnostic work-up is recommended when NCGS is cussed not only in the media but also among medical suspected. This includes a careful patient history specialties. The existence and the possible triggers together with a food-intake and symptom diary, if of NCGS are controversial. Three international ex- necessary an allergy diagnostic workup and a reli- pert meetings which proposed recommendations for able exclusion of celiac disease. We recommend such NCGS were not independently organized and only a structured procedure since a medically proven di- partially transparent regarding potential conﬂicts agnosis is required before considering the avoidance of interest of the participants. The present posi- of gluten. tion statement reﬂects the following aspects about NCGS from an allergist’s and nutritionist’s point of Keywords Gluten-free · Self-diagnosis · Nocebo view: (A) Validated diagnostic criteria and/or reli- effects · Placebo effects · Irritable bowel syndrome able biomarkers are still required. Currently, this Abbreviations condition is frequently self-diagnosed, of unknown ATI Amylase-trypsin inhibitors prevalence and non-validated etiology. (B) Gluten has DBPCFC Double-blind, placebo-controlled food not been reliably identiﬁed as an elicitor of NCGS challenge because of high nocebo and placebo effects. Dou- DGAKI German Society of Allergology and Clini- ble-blind, placebo-controlled provocation tests are of cal Immunology limited value for the diagnosis of NCGS and should IBS Irritable bowel syndrome be performed in a modiﬁed manner (changed rela- NCGS Non-celiac gluten/wheat sensitivity tion of placebo and active substance). (C) Several confounders hamper the assessment of subjective symptoms during gluten-reduced or gluten-free diets. Introduction Depending on the selection of food items, e.g., an in- creased vegetable intake with soluble ﬁbers, diets may Non-celiac gluten sensitivity (NCGS) or non-celiac induce physiological digestive effects and can modify wheat sensitivity is an increasingly discussed disorder. gastrointestinal transit times independent from the The mechanism is unknown and reliable biomarkers avoidance of gluten. (D) A gluten-free diet is manda- for diagnosis are lacking. Whether it is a speciﬁc tory in celiac disease based on scientiﬁc evidence. disease entity and which wheat component is the re- However, a medically unjustiﬁed avoidance of gluten sponsible trigger is a long-running controversy [1–6]. may bear potential disadvantages and risks. (E) Due Reported symptoms may be caused by undiagnosed K Non-celiac gluten/wheat sensitivity (NCGS)—a currently undeﬁned disorder without validated diagnostic. . . 147 position article celiac disease, variants of irritable bowel syndrome the diagnosis of NCGS . The following issues will (IBS), or other undiagnosed functional disorders of be discussed: the gut [7, 8]. Thus, individuals reporting gastroin- 1. Absence of validated diagnostic criteria and/or suit- testinal (GI) symptoms after wheat consumption may able biomarkers, frequent self-diagnosis, undoc- be wrongly characterized with NCGS. Three interna- umented prevalence and unconﬁrmed etiology of tional expert meetings concerning NCGS have taken reported symptoms. place [9–11]. Those meetings were not organized 2. No reliable identiﬁcation of gluten as trigger of independent of “interested parties” and ﬁndings did NCGS during controlled food challenges due to not convincingly exclude possible conﬂict of interest an apriori bias of the subject toward experiencing of the participants and/or sponsors. From an aller- symptoms. gist’s point of view, the diagnostic algorithm proposed during the third expert meeting is inappropriate for I. Huttegger Dr. rer. medic. I. Reese () Pediatric Allergology and Pulmonology, Department of Dietary Counseling and Medical Nutrition Therapy Pediatrics and Adolescent Medicine, Salzburg State Clinics, Outpatient Center with Specialization in Allergy, Ansprenger Paracelsus Medical Private University, Salzburg, Austria Str. 19, 80803 Munich, Germany S. Lämmel · S. Schnadt email@example.com Patient Support Group: Deutscher Allergie- und C. Schäfer Asthmabund, DAAB, German Allergy and Asthma Outpatient Center of Allergy and Pulmonology Association, Mönchengladbach, Germany (Schwerpunktpraxis Collonaden), Dietary Counseling and L. Lange Medical Nutrition Therapy, Hamburg, Germany Department of Pediatrics, St. Marien Hospital, Bonn, J. Kleine-Tebbe Germany Outpatient & Clinical Research Center, Allergy and Asthma U. Lepp Center Westend, Berlin, Germany Respiratory Medicine and Allergology Outpatient Center Dr. B. Ahrens · V. Mahler Lepp, Buxtehude, Germany Division of Allergology, Paul Ehrlich Institute (Federal V. Mahler Institute for Vaccines and Biomedicines), Langen, Germany Department of Dermatology, Faculty of Medicine, Friedrich B. Ahrens · K. Beyer Alexander University Erlangen-Nürnberg, Erlangen, Department of Pediatrics, Division of Pulmonology, Germany Immunology and Intensive Care Medicine, Charité H. Mönnikes University Hospital, Berlin, Germany Department of Internal Medicine and Institute of O. Bachmann Neurogastroenterology, Martin-Luther Hospital, Berlin, Department of Gastroenterology, Hepatology and Germany Endocrinology, Hanover Medical School, Hanover, Germany J. Ockenga B. Ballmer-Weber Department of Gastroenterology, Endocrinology and Allergy Unit, Department of Dermatology, University Clinical Nutrition, Klinikum Bremen Mitte, Bremen, Hospital Zurich, Zurich, Switzerland Germany S. C. Bischoff B. Otto Institute of Clinical Nutrition, University of Hohenheim, Institute for Medical Education, University Hospital, Ludwig Stuttgart, Germany Maximilian University of Munich, Munich, Germany K. Blümchen Z. Szepfalusi Department of Pediatrics, Division of Allergy, Pulmonology Pediatric Pulmonology, Allergy and Endocrinology, and Cystic Fibrosis, University Hospital Frankfurt, Frankfurt Department of Pediatrics and Adolescent Medicine, Medical am Main, Germany University of Vienna, Vienna, Austria S. Dölle ·T.Zuberbier ·M. Worm R. Treudler Department of Dermatology, Venereology and Allergology, Department of Dermatology, Venereology and Allergology, Allergy Center Charité (ACC), Charité University Hospital, Interdisciplinary Center of Allergology, University Medical Berlin, Germany Center Leipzig, Leipzig, Germany P. Enck A. Wassmann-Otto Department of Internal Medicine VI, Psychosomatic Dermatology Outpatient Center Hamburg-Alstertal, Medicine and Psychotherapy, University Hospital Tübingen, Hamburg, Germany Tübingen, Germany T. Werfel A. Enninger Department of Dermatology, Allergology and Venereology, Derpartment of General and Special Pediatrics, Olga Department of Immunodermatology and Experimental Hospital (Klinikum Stuttgart), Stuttgart, Germany Allergology, Hanover Medical School (MHH), Hanover, Germany 148 Non-celiac gluten/wheat sensitivity (NCGS)—a currently undeﬁned disorder without validated diagnostic. . . K position article 3. Several variables confounding the evaluation of Issue 2 subjective symptoms during gluten-reduced and/or -free diet. No reliable identiﬁcation of gluten as trigger of NCGS 4. Potential disadvantages and risks will prevail in case during controlled food challenges due and an apriori of medically unjustiﬁed gluten avoidance. bias of the subject toward experiencing symptoms. Re- 5. Proposed diagnostic procedure in suspected NCGS. sults from various studies with food challenges of clas- sical double-blind, placebo-controlled (DBPCFC) de- sign reveal that only a minority of individuals sus- Issue 1 pected of suffering from NCGS are able to correctly Absence of validated diagnostic criteria and/or suitable identify gluten as trigger [20–23]. It cannot be ex- biomarkers, frequent self-diagnosis, undocumented cluded that positive test results are triggered by the prevalence and unconﬁrmed etiology of reported symp- expectation of symptoms rather than gluten as a true toms. As validated diagnostic criteria are lacking elicitor [5, 20–22]. This postulate is supported by the to date, the prevalence of NCGS cannot be assessed. observation that most patients react comparably to Recent survey results are based primarily on self-diag- actual gluten and placebo [20–22]. In order to mit- nosis and reveal how many people think that they are igate the expectations of a patient, the number of affected rather than proving actual prevalence [12–14]. placebo challenges can be increased [24, 25]. Such Moreover, the exclusion of other diseases such as IBS, an approach may identify true gluten responders bet- celiac disease or functional GI disorders has not been ter than the proposed recommendation to increase systematically evaluated in published surveys and the number of gluten challenges . We recommend studies [4, 7, 8, 15–17]. Without an appropriate differ- a ratio of placebo to active of at least 2:1 in controlled ential diagnosis these data should be interpreted with challenges. This approach has been successfully uti- caution . A recent study in individuals reporting lized in a current study, determining that the major- wheat sensitivity suggests a compromised intestinal ity of patients with suspected NCGS cannot identify epithelial barrier as cause for a systemic immune gluten as trigger of their symptoms . activation . The identiﬁcation of possible triggers was not the aim of the study. The authors consider Issue 3 their ﬁndings only as a basis for further research. Several variables confounding the evaluation of subjec- tive symptoms during gluten-reduced and/or -free diet. A gluten-reduced diet can, according to food selec- Fig. 1 Important differ- ential diagnoses in case Diﬀerenal Diagnosis by gastroenterologist, of suspected non-celiac gluten/wheat sensitivity diean/ nutrionist, and allergist (NCGS) cover various dis- orders, including functional or inflammatory bowel dis- eases, allergies, enzyme deficiencies/malabsorption Inappropriate eang and autoimmune diseases Lactose intolerance/ habits? Irritable Bowel Disease? Fructose malabsorpon? suspected IBD Molity inﬂammatory diagnosis bowel disease? Disorders? NCGS Celiac Wheat disease? allergy? Interdisciplinary history covering Food and Symptom Diary - Gastroenterology -Dietary paern - Medical Nutrion Therapy - Food selecon - Allergy - Meal frequency K Non-celiac gluten/wheat sensitivity (NCGS)—a currently undeﬁned disorder without validated diagnostic. . . 149 position article tion (i. e., if rich in vegetables with soluble ﬁber), in- not possible. A thorough differential diagnostic work- duce physiological digestive effects and alter intestinal up is mandatory (Fig. 1), which includes the following: transit time independently of gluten content. There- a comprehensive and interdisciplinary patient history fore, certain food components such as soluble ﬁber in combination with the evaluation of a food intake/ are supposed to elicit a therapeutic effect. Hence, pa- symptom diary; if justiﬁed an allergy work-up; and tients may beneﬁt from a gluten-free diet by chang- a deﬁnitive exclusion of celiac disease—to be mean- ing food composition and thereby inducing physio- ingful, gluten must be part of the diet for at least three logical digestive effects and, thus, altering intestinal months in sufﬁciently high amounts (15–20 g gluten transit time physiologically rather than by eliminating per day, equaling 4–5 slices of bread). gluten . A temporary gluten reduction, but not to- tal gluten avoidance is recommended in the German Conclusion IBS guideline . As mentioned therein, IBS-afﬂicted individuals can beneﬁt from a change of ﬁber quality. Without a conﬁrmed diagnosis, a gluten-free diet is Optimal beneﬁt can be achieved if soluble ﬁber, such unjustiﬁed and not recommended. Patients who in- as those in psyllium husks and certain vegetables, are tend to continue to restrict their diet despite the rec- increased in parallel to a reduction of cereal ﬁber . ommendation should be encouraged to seek profes- Thus, IBS patients will beneﬁt from their food selec- sional nutritional counselling. tion in favor of soluble ﬁber but not from gluten avoid- Acknowledgements The authors gratefully thank Steve Love, ance. Thisviewissupported by theobservation made PhD, Laguna Niguel, CA, USA, for reading the manuscript, in several studies that many individuals beneﬁt from helpful suggestions, and editorial assistance with the English a diet free from gluten while only a minority identiﬁed translation. gluten in a DBPCFC [6, 20–23, 26]. Apart from gluten, Conﬂict of interest The authors declare that they have no many other potential triggers are discussed, such as competing interests. fructans, amylase-trypsin inhibitors (ATIs), etc. [3, 4, Open Access This article is distributed under the terms of 28]. the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which per- Issue 4 mits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the origi- Potential disadvantages and risks will prevail in case of nal author(s) and the source, provide a link to the Creative medically unjustiﬁed gluten avoidance. A strict gluten- Commons license, and indicate if changes were made. free diet is mandatory in conﬁrmed celiac disease. In contrast, potential disadvantages and risks exist in the case of self-diagnosis without professional dietetic References support [27, 29, 30]. Risks of gluten-free diet without 1. Makharia A, Catassi C, Makharia GK. The overlap between a medically proven indication are as follows: irritable bowel syndrome and non-celiac gluten sensitivity: masking of undiagnosed celiac disease [17, 18], a clinical dilemma. Nutrients. 2015;7:10417–26. triggering of an eating disorder, such as Orthorexia 2. Kabbani TA, Vanga RR, Lefﬂer DA, Villafuerte-Galvez J, nervosa , Pallav K, Hansen J, et al. Celiac disease or non-celiac gluten ● sensitivity? An approach to clinical differential diagnosis. eliciting or worsening of constipation, potentially AmJ Gastroenterol. 2014;109:741–6. quiz 747. causing rectal diseases [31, 32], and 3. Fasano A, Sapone A, Zevallos V, Schuppan D. Nonceliac increased risk of dyslipidemia . gluten sensitivity. Gastroenterology. 2015;148:1195–204. 4. Gibson PR, Skodje GI, Lundin KEA. Non-coeliac gluten Furthermore, there are known disadvantages of sensitivity. J Gastroenterol Hepatol. 2017;32:86–9. a gluten-free diet regarding 5. Molina-Infante J, Carroccio A. Suspected nonceliac gluten inadequate nutrition [29, 30], sensitivity conﬁrmed in few patients after gluten challenge ● in double-blind, placebo-controlled trials. Clin Gastroen- impaired quality of life , terol Hepatol. 2017;15:339–48. higher food costs , and 6. Lebwohl B, Lefﬂer DA. Exploring the strange new world of potential heavy metal contamination [36, 37]. non-celiac gluten sensitivity. Clin Gastroenterol Hepatol. 2015;13:1613–5. Therefore, a recommendation for a temporarily lim- 7. Enck P, Aziz Q, Barbara G, Farmer AD, Fukudo S, Mayer ited gluten reduction (as mentioned in the German EA, et al. Irritable bowel syndrome. Nat Rev Dis Primers. IBS guideline) is reasonable. In contrast, a recommen- 2016;2:16014. dation for a gluten-free diet without medically proven 8. Drossman DA, Hasler WL. Rome IV-functional GI disor- diagnosis (celiac disease) is not currently warranted. ders: disorders of gut-brain interaction. Gastroenterology. 2016;150:1257–61. 9. Sapone A, Bai JC, Ciacci C, Dolinsek J, Green PH, Hadji- Issue 5 vassiliou M, et al. Spectrum of gluten-related disorders: consensus on new nomenclature and classiﬁcation. BMC Proposed diagnostic procedure in suspected NCGS. Med. 2012;10:13. Lacking viable criteria, a proven diagnosis of NCGS is 150 Non-celiac gluten/wheat sensitivity (NCGS)—a currently undeﬁned disorder without validated diagnostic. . . K position article 10. Catassi C, Bai JC, Bonaz B, Bouma G, Calabro A, Carroccio 24. Dölle S, Grünhagen J,Worm M.Dem Täter auf derSpur: A, et al. Non-Celiac Gluten sensitivity: the new frontier of Indikation und praktische Umsetzung von Nahrungsmit- gluten relateddisorders. Nutrients. 2013;5:3839–53. telprovokationen im Erwachsenenalter. Allergologie. 11. Catassi C, Elli L, Bonaz B, Bouma G, Carroccio A, Castillejo 2016;39:523–32. G, et al. Diagnosis of non-celiac gluten sensitivity (NCGS): 25. Niggemann B, Beyer K, Erdmann S, Fuchs T, Kleine-Tebbe theSalerno experts’ criteria. Nutrients. 2015;7:4966–77. J, Lepp U, et al. Standardisierung von oralen Provokation- 12. vanGilsT,NijeboerP,IJssennagger CE,Sanders DS,Mulder stests bei Verdacht auf Nahrungsmittelallergie. Allergo J. CJ, Bouma G. Prevalence and characterization of self- 2011;20:149–60. reported gluten sensitivity in the Netherlands. Nutrients. 26. Dale HF,Hatlebakk JG,Hovdenak N,Ystad SO,Lied GA. 2016;8:E714. The effect of a controlled gluten challenge in a group of 13. Aziz I, Lewis NR, Hadjivassiliou M, Winﬁeld SN, Rugg N, patients with suspected non-coeliac gluten sensitivity: A Kelsall A, et al. A UK study assessing the population randomized, double-blind placebo-controlled challenge. prevalence of self-reported gluten sensitivity and referral Neurogastroenterol Motil. 2018; https://doi.org/10.1111/ characteristics to secondary care. Eur J Gastroenterol nmo.13332. Hepatol. 2014;26:33–9. 27. Layer P, Andresen V, Pehl C, Allescher H, Bischoff SC, 14. LisDM,StellingwerffT,ShingCM,AhujaKD,FellJW.Explor- Claßen M, et al. S3-Leitlinie Reizdarmsyndrom: Deﬁnition, ing the popularity, experiences, and beliefs surrounding Pathophysiologie, Diagnostik und Therapie. Gemein- gluten-freediets in nonceliac athletes. IntJ SportNutr Exerc same Leitlinie der Deutschen Gesellschaft für Verdauungs- Metab. 2015;25:37–45. und Stoffwechselkrankheiten (DGVS) und der Deutschen 15. Marild K, StordalK,Bulik CM,RewersM, Ekbom A, LiuE, Gesellschaft für Neurogastroenterologie und Motilität et al. Celiac disease and anorexia nervosa: a nationwide (DGNM). Z Gastroenterol. 2011;49:237–93. study. Pediatrics. 2017;139:e20164367. 28. SkodjeGI,SarnaVK,MinelleIH,RolfsenKL,MuirJG,Gibson 16. Biesiekierski JR, Newnham ED, Shepherd SJ, Muir JG, Gib- PR, et al. Fructan, rather than gluten, induces symptoms son PR. Characterization of adults with a self-diagnosis of in patients with self-reported non-celiac gluten sensitivity. nonceliac gluten sensitivity. Nutr Clin Pract. 2014;29:504–9. Gastroenterology. 2018;154:529–539.e2. 17. Biesiekierski JR, Muir JG, Gibson PR. Is gluten a causeof gas- 29. Lebwohl B,Cao Y, Zong G, Hu FB,Green PHR, Neugut AI, trointestinal symptoms in people without celiac disease? etal. Longtermglutenconsumptioninadultswithoutceliac Curr Allergy Asthma Rep. 2013;13:631–8. disease and risk of coronary heart disease: prospective 18. Ludvigsson JF, Lefﬂer DA, Bai JC, Biagi F, Fasano A, Green cohortstudy. BMJ. 2017;357:j1892. PH,etal. TheOslodeﬁnitionsforcoeliacdiseaseandrelated 30. Fry L, Madden AM, Fallaize R. An investigation into the nu- terms. Gut. 2013;62:43–52. tritional composition and cost of gluten-free versus regular 19. Uhde M, Ajamian M, Caio G, De Giorgio R, Indart A, Green foodproducts in theUK. J HumNutr Diet. 2018;31:108–20. PH, et al. Intestinal cell damage and systemic immune 31. Andresen V, Enck P, Frieling T, Herold A, Ilgenstein P, Jesse activation in individuals reporting sensitivity to wheat in N, et al. S2k guideline for chronic constipation: deﬁnition, theabsenceof coeliac disease. Gut. 2016;65:1930–7. pathophysiology, diagnosis and therapy. Z Gastroenterol. 20. ZaniniB,BascheR,FerraresiA,RicciC,LanzarottoF,Marullo 2013;51:651–72. M, et al. Randomised clinical study: gluten challenge 32. Muller-Lissner S, Tack J, Feng Y, Schenck F, Specht Gryp induces symptom recurrence in only a minority of patients R. Levels of satisfaction with current chronic constipation who meet clinical criteria for non-coeliac gluten sensitivity. treatment options in Europe—an internet survey. Aliment AlimentPharmacol Ther. 2015;42:968–76. Pharmacol Ther. 2013;37:137–45. 21. Di Sabatino A, Volta U, Salvatore C, Biancheri P, Caio G, 33. Welstead L. The gluten-free diet in the 3rd millennium: De Giorgio R, et al. Small amounts of gluten in subjects rules, risks andopportunities. Diseases. 2015;3:136–49. with suspected nonceliac gluten sensitivity: a randomized, 34. Shah S, Akbari M, VangaR,Kelly CP,Hansen J,Theethira T, double-blind, placebo-controlled, cross-over trial. Clin etal. Patientperceptionoftreatmentburdenishighinceliac Gastroenterol Hepatol. 2015;13:1604–1612.e3. disease compared with other common conditions. Am J 22. BiesiekierskiJR,PetersSL,NewnhamED,RosellaO,MuirJG, Gastroenterol. 2014;109:1304–11. GibsonPR.Noeffectsofgluteninpatientswithself-reported 35. Pfeiffer K, Kohlenberg-Müller K. Was kostet eine gluten- non-celiac gluten sensitivity after dietary reduction of fer- freie Ernährung bei Zöliakie? Verzehrserhebungen und mentable, poorly absorbed, short-chain carbohydrates. Selbsteinschätzungen zum diätetisch bedingten Aufwand. Gastroenterology. 2013;145:320–328.e1–3. Aktuel Ernahrungsmed. 2015;40:P1_6. 23. Elli L, Tomba C, Branchi F, Roncoroni L, Lombardo V, 36. BulkaCM, DavisMA, KaragasMR, AhsanH,Argos M. The Bardella MT, et al. Evidence for the presence of non-celiac unintended consequences of a gluten-free diet. Epidemiol- gluten sensitivity in patients with functional gastrointesti- ogy. 2017;28:e24–e5. nal symptoms: results from a multicenter randomized 37. Raehsler SL, Choung RS, Marietta EV, Murray JA. Accumula- double-blind placebo-controlled gluten challenge. Nutri- tion of Heavy Metals in People on a Gluten-Free Diet. Clin ents. 2016;8:84. Gastroenterol Hepatol. 2018;16:244–51. K Non-celiac gluten/wheat sensitivity (NCGS)—a currently undeﬁned disorder without validated diagnostic. . . 151
Allergo Journal International – Springer Journals
Published: May 28, 2018
It’s your single place to instantly
discover and read the research
that matters to you.
Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.
All for just $49/month
Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly
Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.
Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.
Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.
All the latest content is available, no embargo periods.
“Hi guys, I cannot tell you how much I love this resource. Incredible. I really believe you've hit the nail on the head with this site in regards to solving the research-purchase issue.”Daniel C.
“Whoa! It’s like Spotify but for academic articles.”@Phil_Robichaud
“I must say, @deepdyve is a fabulous solution to the independent researcher's problem of #access to #information.”@deepthiw
“My last article couldn't be possible without the platform @deepdyve that makes journal papers cheaper.”@JoseServera