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

Abstract

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. 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. Splenic volume was significantly larger in AIP (149±86ml) than in controls (97±38ml) and in CP (108±79ml) (P<0.0001 and 0.0002), and was smaller than in disease controls (222±134ml) (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±40ml) (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). 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.