Comparison of cytokine and phosphoprotein profiles in idiopathic and Crohn’s disease-related perianal fistula

Table 1 Clinical features

	Idiopathic	Crohn’s Disease	P value
Mean PDAI (SD)	5.67 (2.76)	8.07 (3.99)	0.01a
Mean EQ VAS (SD)	71.2 (21.1)	63.4 (20.2)	0.22
Mean EQ index (SD)	0.734 (0.259)	0.715 (0.214)	0.80
Seton in situ, n (%)	21 (44)	3 (23)	0.22
Number of fistulae, n (%)			0.09
Single unbranched	31 (65)	3 (23)
Single branched	15 (31)	7 (54)
Multiple	2 (4)	3 (23)
Parks’ classification, n (%)			0.54
Inter-sphincteric	7 (15)	1 (8)
Trans-sphincteric	38 (79)	10 (77)
Supra-sphincteric	3 (6)	2 (15)
High primary tract	15 (31)	6 (46)	0.34
Secondary tract(s), n (%)			0.02a
None	31 (65)	4 (31)
Infralevator	14 (29)	5 (38)
Supralevator	3 (6)	4 (31)
Horseshoe, n (%) extension(s)	12 (25)	5 (38)	0.49
Collection(s) , n (%)	16 (33)	12 (92)	< 0.001a
Thickened rectum, n (%)	1 (2)	7 (54)	< 0.001a

Perineal Disease Activity Index, EuroQoL visual analogue score and index measured at pre-operative clinic assessment. Continuous data was compared using t-test. Discrete data compared using Fisher’s Exact test. P < 0.05 was considered significant.

^aP < 0.05. PDAI: Perineal Disease Activity Index; SD: Standard deviation; EQ: EuroQol; VAS: Visual analogue score.

Table 2 Summary of comparisons between idiopathic and Crohn's disease perianal fistulae

	Similarities	Differences
PDAI		Significantly higher PDAI in Crohn’s disease
EQ-5D-5L	Similar EQ VAS and EQ index
Morphology	Similar distribution of types by Parks’ classification	More multiple fistulae in Crohn’s disease
	Similar prevalence of high fistulae and horseshoe extensions	Significantly more supralevator extensions, collections and rectal thickening in Crohn’s disease
Cytokine concentrations	Similar concentrations of 27 cytokines at all four biopsy sites	Significantly higher IL-12p70 concentration at internal opening in Crohn’s disease
	(EGF, eotaxin, G-CSF, GM-CSF, IFN-α2, IFN-γ, IL-10, IL-12p40, IL-13, IL-15, IL-17, IL-1α, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, IP-10, MCP-1, MIP-1α, MIP-1β, TNF-α, TNF-β, RANTES and VEGF)	Significantly lower IL-1RA/IL-1β ratio concentration at internal opening in Crohn’s disease
Phosphoprotein concentrations	Similar levels of 39 phosphoproteins at the four specimen sites
	(EGFR/ErbB1, HER2/ErbB2, HER3/ErbB3, FGFR1, FGFR3, FGFR4, InsR, IGF-IR, TrkA/NTRK1, TrkB/NTRK2, Met/HGFR, Ron/MST1R, Ret, ALK, PDGFR, c-Kit/SCFR, FLT3/Flk2, M-CSFR/CSF-1R, EphA1, EphA2, EphA3, EphB1, EphB3, EphB4, Tyro3/Dtk, Axl, Tie2/TEK, VEGFR2/KDR, Akt/PKB/Rac (at Thr308), Akt/PKB/Rac (at Ser473), p44/42 MAPK, S6 Ribosomal Protein, c-Abl, IRS-1, Zap-70, Src, Lck, Stat1 and Stat3)

See supplementary material for cytokine and phosphoprotein names in full. PDAI: Perineal Disease Activity Index; EQ: EuroQol; VAS: Visual analogue score.