Clinical and pathological differences between serum immunoglobulin G4-positive and -negative type 1 autoimmune pancreatitis

Table 1 Comparison of clinical characteristics of serum immunoglobulin G4-positive and negative type 1 autoimmune pancreatitis patients n (%)

Variables	SIP	SIN	P value
Patients	17	8
Mean age, yr	62 (33-84)	60 (42-72)	0.359
Sex (M/F)	13:4	5:3	0.172
Diffuse type	8 (47)	3 (31)	0.390
Median serum IgG4 (mg/dL)	312 (145-4000)	33 (6-75)	0.030
Other organ involvement	10 (59)	1 (26)	0.016
Histologic examination
Resection	5 (26)	6 (75)	0.018
Biopsy	6 (32)	2 (25)
Not done	6 (32)
Mean follow up, mo	30	16	0.075
Relapse	6 (35)	2 (25)	0.850

SIP: Serum immunoglobulin G4 (IgG4)-positive; SIN: Serum IgG4-negative; F: Female; M: Male.