Inverse relationship of interleukin-6 and mast cells in children with inflammatory and non-inflammatory abdominal pain phenotypes

Table 1 Sample characteristics for non-inflammatory and inflammatory groups n (%)

Variable	Overall(n = 48)	Group		P value (χ2/t)
		Non inflammatory(n = 26)	Inflammatory (n = 22)
Sex
Male	22 (45.8)	11 (42.3)	11 (50)	0.59
Female	26 (54.2)	15 (57.7)	11 (50)
Race
Caucasian	43 (89.6)	23 (88.5)	20 (90.9)	0.58
Asian	2 (4.2)	1 (3.8)	1 (4.5)
African American	1 (2.1)	1 (3.8)	0 (0)
Mixed	1 (2.1)	0 (0)	1 (4.5)
Hispanic	1 (2.1)	1 (3.8)	0 (0)
Age (mean ± SD)	11.9 ± 2.9	11.9 ± 2.4	12 ± 3.5	0.21
range (yr)	(5-17)	(8-16)	(5-17)
BMI (mean ± SD)	18.9 ± 4.3	19.5 ± 5.2	18.2 ± 2.8	0.43
range	(13-38.8)	(13.8-38.8)	(13-24.5)
Diagnosis
RAP	17 (35.4)	17
IBS	8 (16.6)	8
Crohn’s disease	12 (25)		12
Ulcerative colitis	8 (16.6)		8
Gastritis	2 (4.1)		2
Location of biopsy
Upper	15 (31.3)	12 (46.2)	3 (13.6)
Lower	33 (68.8)	14 (53.8)	19 (86.4)
Lactose intolerance
Yes	24	16	8	0.38
No	24	10	14

BMI: Body mass index; IBS: Irritable bowel syndrome; RAP: Recurrent abdominal pain.

Table 2 Overall comparison of biomarkers by phenotypic group (mean ± SD)

	Group		P value
	Non inflammatory(n = 26)	Inflammatory(n = 22)
Interleukin-6	1.50 ± 0.65	2.35 ± 0.61	0.004
Mast cells (HPF)	3.54 ± 2.92	2.63 ± 1.83	0.049
Enterochromaffin cells	1.95 ± 0.81	1.84 ± 0.69	0.81
5-hydroxytryptamine	1.14 ± 0.64	1.05 ± 0.39	0.18
Substance P, % stained (ratio +/-)	69.23% (18/26)	45.45% (10/22)	0.49

HPF: High power field.