Rituximab in IgG4-RD: A Phase 1-2 Trial

Inclusion Criteria: Patients will be included in the trial based on the following disease-specific criteria: * Age 18 or older * Diagnosis of IgG4-RD, based upon either pathological criteria\* (for those who have undergone biopsies) or clinical criteria.\*\* The criteria for pathological and clinical diagnoses are specified below. * The subject can be either steroid-naive, in relapse, steroid dependent, or refractory to steroids. Subjects who are steroid dependent or refractory are eligible for enrollment if steroid dose has not been increased in the past 2 weeks, and their treating physician plans to withdraw steroids completely (by dose taper) within 8 weeks of starting rituximab. * Pathological diagnosis: * Histopathologic features consisting of a lymphoplasmacytic infiltrate and storiform fibrosis within involved organs. Other histopathologic features consistent with IgG4-RD (e.g., obliterative phlebitis) may be present but are not required. * Either an IgG4/IgG plasma cell ratio of \> 50% within the affected organs or more than 10 IgG4-bearing plasma cells per high-power field. All patients with pathologic diagnoses will have their specimens reviewed by pathology investigators. \*\*Clinical diagnosis: • Organ involvement in a pattern consistent with IgG4-RD. This must include dysfunction of one of the following organs: pancreas (autoimmune pancreatitis); salivary glands (chronic sclerosing sialadenitis); lacrimal glands; orbital pseudotumor; kid…