Table 1.
Comparison between Type 1 and Type 2 AIP
| Variable | Type 1 AIP | Type 2 AIP |
|---|---|---|
| Mean age, yr | 60 (typically >40) |
30 (including children) |
| Male sex, % | 80 | 50 |
| Serum IgG4 elevation, % | 80–90 | 10 |
| Other organ involvement, %* | 50 | 0 |
| Inflammatory bowel disease, % | <5 | 40 |
| Presentation, % | ||
| Pain/acute pancreatitis | 10 | 60 |
| Painless jaundice | 80 | 30 |
| Others | 10 | 10 |
| Histology | ||
| Pattern of inflammation | Lobule centric | Duct centric |
| Lymphoplasmacytic infiltration | ++ | ++ |
| Storiform fibrosis | ++ | + |
| Obliterative phlebitis | ++ | + |
| Granulocytic epithelial lesion | - | ++ |
| Granulocytic acinar injury | - | ++ |
| IgG4+ cells | ++ | – or + |
| Steroid responsiveness, % | ~100 | ~100 |
| Relapse, % | 30–50 | <10 |
AIP, autoimmune pancreatitis; IgG4, immunoglobulin G4.
*Including upstream sclerosing cholangitis, sialadenitis, dacryoadenitis, tubulointerstitial nephritis, retroperitoneal fibrosis, and periaortitis.