Reduction of splenic volume by steroid therapy in cases with autoimmune pancreatitis

Abstract

Objectives: Splenomegaly is sometimes recognized in autoimmune diseases and chronic pancreatitis; however, it has not yet been studied in autoimmune pancreatitis (AIP). The current study analyzed splenic volume and its associated factors in cases with AIP.

Methods: Splenic volume was measured using computed tomography (CT) volumetric analysis in 46 cases with AIP and compared with 92 age- and gender-matched controls, and 46 disease controls (liver cirrhosis). Forty-six cases of chronic pancreatitis were also analyzed. Cases with AIP were investigated for factors associated with splenic volume and splenic volume change in response to steroid therapy.

Results: Splenic volume was significantly larger in AIP (149 ± 86 ml) than in controls (97 ± 38 ml) and in CP (108 ± 79 ml) (P < 0.0001 and 0.0002), and was smaller than in disease controls (222 ± 134 ml) (P = 0.003). In AIP cases, splenic volume was associated with age and gender (P = 0.04 and 0.02), and splenomegaly was recognized in 20 % (9/46) of cases. Abnormal uptake of (18)F-fluorodeoxyglucose was not detected in the spleen by positron emission tomography. Splenic vein (SpV) was frequently involved in AIP (67 %), but was all recanalized after steroid therapy. Splenic volume in cases with AIP was minimized to 77 % of the original (122 ± 40 ml) (P < 0.0001) and this trend was remarkable in cases with splenomegaly (66 %). In AIP, high serum IL-2 receptor level, diffuse pancreatic enlargement, and SpV stenosis were significantly associated with splenic shrinkage due to steroid treatment (P = 0.002, 0.02, and 0.03).

Conclusions: Splenomegaly was sometimes recognized in cases with AIP; however, these cases can be treated with steroids, especially in cases with diffuse pancreatic swelling and SpV stenosis.