Serum beta 2-microglobulin as a biomarker in inflammatory bowel disease

Table 1 Demographic characteristics and comparison of serum Beta 2 microglobulin levels with other laboratory markers between patients and controls n (%)

	Controls	UC	CD	P value
	n = 30	n = 43	n = 35
Mean age	38.90 ± 11.05	42.72 ± 13.52	38.28 ± 13.15	0.254
Gender (F/M)	18 (60)/12 (40)	17 (40)/26 (60)	19 (54)/16 (46)	0.188
Duration (yr)		5.04 ± 5.81	4.50 ± 3.70	0.729
Inactive/active		14 (33)/29 (67)	12 (34)/23 (66)
		Left type 29 (67)	Ileal type 24 (69)
Disease location		Extensive 14 (33)	Ileocolonic 11 (31)
B2-M	1.71 ± 0.44	2.41 ± 0.87	2.24 ± 1.01	0.002	UC vs C 0.002
					CD vs C 0.033
					UC vs CD 0.642
CRP	0.57 ± 0.83	1.82 ± 2.94	1.59 ± 2.79	0.188
ESR	10.18 ± 11.31	21.21 ± 18.37	22.76 ± 22.81	0.021	UC vs C 0.047
					CD vs C 0.026
					UC vs CD 0.931
WBC (× 103)	7.09 ± 1.75	7.52 ± 2.84	7.48 ± 3.91	0.190
Albumin	4.43 ± 0.24	4.00 ± 0.62	4.05 ± 0.63	0.005	UC vs C 0.006
					CD vs C 0.023
					UC vs CD 0.916

Data are expressed as absolute numbers (percentage), mean ± SD or median (interquartile range). UC : Ulcerative colitis; CD : Crohn Disease; F: Female; M: Male; B2-M: Beta 2 microglobulin; CRP: C reactive protein; WBC: White blood count; C: Control; ESR: Erythrocyte sedimentation rate.

Table 2 Overall accuracy and receiver operating characteristic analyses of beta 2 microglobulin and other inflammation markers to differentiate active from inactive ulcerative colitis

	AUC	Sensitivity (%)	Specificity (%)	NPV (%)	PPV (%)
B2-M (cut off: 2.02)	0.757	79.3	78.6	88.5	64.7
CRP (cut off: 0.55)	0.731	67.9	75.0	86.4	50.0
WBC (× 103)	0.656	72.4	58.3	80.8	46.7
(cut off: 6.50)
ESR (cut off: 14.5)	0.677	69.0	58.3	80.0	43.8

AUC: Area under the curve; B2-M: Beta 2 microglobulin; CRP: C reactive protein; WBC: White blood count; ESR: Erythrocyte sedimentation rate; NPV: Negative predictive value; PPV: Positive predictive value.

Table 3 Comparison of serum beta 2 microglobulin levels with other laboratory markers between active and inactive ulcerative colitis patients

	Inactive CD	Active CD	P value
	n = 14	n = 29
B2-M	1.88 ± 0.41	2.66 ± 0.92	0.004
CRP	0.41 ± 0.27	2.43 ± 3.34	0.046
ESR	14.00 ± 7.85	24.20 ± 20.65	0.106
WBC (× 103)	6.41 ± 1.47	7.96 ± 3.16	0.119
Albumin	3.99 ± 0.50	4.01 ± 0.67	0.948

B2-M: Beta 2 microglobulin; CRP: C reactive protein; WBC: White blood count; ESR: Erythrocyte sedimentation rate.

Table 4 Comparison of serum beta 2 microglobulin levels with other laboratory markers between active and inactive Crohn’s disease patients

	Inactive CDn = 12	active CDn = 23	P value
B2-M	1.73 ± 0.31	2.50 ± 1.15	0.033
CRP	0.24 ± 0.12	2.23 ± 3.22	0.050
ESR	11.45 ± 11.21	28.17 ± 25.08	0.044
WBC (× 103)	7.81 ± 2.28	7.33 ± 4.53	0.742
Albumin	4.50 ± 0.42	3.83 ± 0.60	0.002

CD: Crohn’s disease; B2-M: Beta 2 microglobulin: CRP: C reactive protein; ESR: Erythrocyte sedimentation rate; WBC: White blood count.

Table 5 Overall accuracy and receiver operating characteristic analyses of beta 2 microglobulin and other inflammation markers between active and inactive ulcerative colitis patients

	AUC	Sensitivity (%)	Specificity (%)	NPV (%)	PPV (%)
B2-M (Cut off: 1.84)	0.828	78.3	75.0	85.7	64.3
CRP (Cut off: 0.35)	0.903	78.3	81.8	90.0	64.3
WBC (× 103)	0.379	47.8	56.5	68.8	33.3
(Cut off: 6.80)
ESR (Cut off: 13.5)	0.761	78.3	72.7	85.7	61.5

AUC: Area under the curve; B2-M: Beta 2 microglobulin; CRP: C reactive protein; WBC: White blood count; ESR: Erythrocyte sedimentation rate; NPV: Negative predictive value; PPV: Positive predictive value.