Table 1

Coeliac disease: results of clinical trials with gluten challenge, changes in mucosal histopathology, serology and symptoms

	Patient, n	Amount of gluten	Challenge duration	Mean reduction in VhCRD*	Mean increase in CD3+ IELs	Marsh-Oberhuber classification	Serology	Symptoms	Other
Lähdeaho et al 201499	16	1.5 g	6 wk	0.6†	NA	NA	NA	NA	–
	21	2.0 g	6 wk	0.8†	Statistically significant increase†	NA	1/21 seroconverted to positive EMA	Trend towards more symptomatic in GSRS, CDQ and SF-36 questionnaires	αβ and γδ T cells per mm of epithelium elevated. No change in TG2 IgA deposits.
	13	3.0 g	6 wk	1.1†	NA	NA	NA	NA	–
	13	6.0 g	6 wk	1.7‡	NA	NA	NA	NA	–
Leffler et al 201378	10+10§	3 and 7.5 g§	Day 3	0.52¶	3.1 per 100 ECs¶	NA	Mean increase in IgA-TG2 titre was 1.03¶	Significant change in both CSI† and GSRS†	No significant change in lactulose to mannitol ratio.
Leffler et al 201378	10+10§	3 and 7.5 g§	Day 14	1.09‡	19.22 per 100 ECs¶	10/20 showed histological response	Mean increase in IgA-TG2 titre was 2.86†	Significant change in both CSI† and GSRS†	No significant change in lactulose to mannitol ratio.
Tack et al 013144	7	7 g	2 wk	NA	NA	3/7 deteriorated¶	1/7 seroconverted to positive IgA-TG2	No significant change in CDQ	5/5 had increased deposits of TG2 IgA at end.
Brottveit et al 2013 82	11	Four slices of bread	Day 4	NA	Data not presented¶	6/11 deteriorated	NA	4/11 had increased abdominal symptoms	IFN-γ, IL-8 and TNF-α genes increased.†
Lähdeaho et al 201154	10	3–5 g	12 wk	1.3†	39 per mm of epithelium‡	NA	5/10 had increase in IgA TG2 titres†	8 developed mild to moderate symptoms*	5/10 had increased deposits of TG2 IgA.
Lähdeaho et al 201154	11	1–2 g	12 wk	1.0†	20¶	NA	4/11 had increase in IgA TG2 titres†	7 developed mild to moderate symptoms*	4/11 had increased deposits of TG2 IgA.
Catassi et al 2007 145	13	10 mg	3 months	−1%¶	0%	None	No change	NA	–
Catassi et al 2007 145	13	50 mg	3 months	−20%††	+12%¶	2/13 deteriorated	IgA-TG2¶ IgG-AGA decreased†	NA	–
Holm et al 2006 146	10	14 g (range 7–19 g)	3–24 months	Statistically significant increase†	Statistically significant increase†	NA	EMA and IgA-TG2 positive in 5/10 at 1 month	4/10 developed symptoms at histological relapse	–
Catassi et al 1993 147	10	100 mg	4 wk	0.2†	8 per 100 ECs†	NA	4/10 seroconverted to positive in IgA AGA	None	–
Catassi et al 1993 147	10	500 mg	4 wk	0.5†	15 per 100 ECs†	NA	6/8 seroconverted to positive IgA AGA	3/10 showed clinical symptoms	–

*Over 0.4 is considered a statistically significant change.26
†Significant change compared with baseline (P≤0.05).
‡Significant change compared with baseline (P<0.001).
§The study consisted of a low and high gluten group with no significant differences between the groups in histology or serology. In the study, the data were presented after combining the two groups.
¶Non-significant change (P>0.05).
**Data not presented.
††Significant change compared with placebo (P<0.05).
CDQ, Celiac Disease Questionnaire; CSI, Celiac Symptom Index; EC, epithelial cells; EMA, endomysial antibody; GSRS, Gastrointestinal Symptom Rating Scale; IFN, interferon; IL, interleukin; NA, not available; SF-36, 36-Item Short-Form ; TG2, tissue transglutaminase; TNF, tumour necrosis factor; VgCRD, villous height crypt depth ratio; wk, week.