[860] Interstitial Cystitis, Another IgG4 Related Disease?

Yimin Ge, Haijun Zhou, Steven S Shen, Jae Y Ro. The Methodist Hospital, Weill Medical College of Cornell University, Houston, TX

Background: Interstitial cystitis (IC) is a chronic inflammation and/or injury to the bladder wall. Primary symptoms are urinary frequency, urgency and severe lower abdominal or perineal pain, which often resulting in serious impairment of quality of life. The cause of IC is largely unknown, though several theories including autoimmune, infection, toxic substance and genetic factor have been proposed. The histologic hallmark of IC is the presence of abundant mast cells infiltrating the muscle bundles. In addition, we recently noticed that plasma cells are notably increased in some of the cases, raising the possibility of an IgG4-related disease. We therefore evaluated the number of IgG4 positive plasma cells and the ratio of IgG4/IgG plasma cells in cases with IC.
Design: A total of 45 cases of clinically and histologically confirmed IC from 1/2006 to 9/2011 were retrieved from The Methodist Hospital. The female to male ratio was 41 to 4. The average age was 48.6 years (range 18-92 years). The specimens included 43 bladder biopsies and 2 cystectomies. Immunostains for IgG4 and IgG were performed on sections of paraffin blocks. The plasma cells positive (+) for IgG4 and IgG were counted and the IgG4/IgG ratio was calculated. Cases with more than 30 IgG4 + plasma cells per one high power field (HPF) with IgG4/IgG ratio greater than 50% were considered significant.
Results: There were 9 out of 45 patients had IgG + plasma cells greater than 30/HPF in bladder specimens. In four of the 9 cases, IgG4 + plasma cells were predominant with increased IgG4/IgG ratio. The number of IgG4 + plasma cells ranged from 31 to 82 per HPF (average 56/HPF). The IgG4/IgG ratios were from 51 to 56 with an average of 52.5. The four patients with increased IgG4 + plasma cells include one male (48 years) and three females (21, 77 and 84 years) with an average age of 57.5 years. Histologically, the four cases had similar features as other cases of IC in addition to increased plasma cells.
Conclusions: Due to lack of knowledge on etiology and pathogenesis, there is currently no effective treatment available for IC. Because IC varies so much in symptoms and severity, most researchers believe it is not one, but several diseases. Our findings suggest that a fraction of the patients with IC may be part of IgG4-related systemic disease. Further investigation of the mechanism is crucial to understand the pathogenesis and provide effective treatment for patients with IC.
Category: Genitourinary (including renal tumors)

Wednesday, March 21, 2012 1:00 PM

Poster Session VI # 144, Wednesday Afternoon


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