Evaluating Sirolimus to Treat Autoimmune Blistering Dermatosis Pemphigus

Inclusion Criteria: 1. Subject must be 18 years of age or older. 2. Subject must have an established diagnosis of pemphigus disorder via biopsy and/or serologic titer, as determined appropriate by the lead researcher. 3. Subject must have active disease at the time of enrollment, as defined by a positive Nikolsky sign. 4. Subject must not be taking any immunosuppressive medication or therapy other than corticosteroids. 5. Subject must be able to understand and follow directions. 6. If female, subject is not currently breast feeding and/or pregnant as confirmed via negative pregnancy test, no potential for pregnancy, or if of child-bearing age, agrees to using birth control for entire duration of study and 12 weeks after end of study. Exclusion Criteria: 1. Subject may not be under 18 years old. 2. Subject cannot understand or follow directions. 3. Subject may not have any condition that could, in the opinion of the investigator, compromise the subject's ability to give written consent and/or comply with the study procedures, such as a history of substance abuse or a psychiatric condition. 4. If female and of child bearing age, is pregnant or unwilling to use birth control during the study period. 5. Subject may not have any of the following laboratory abnormalities at baseline: * total white blood cell count \< 2,000/mm3 or platelet count \< 100,000/mm3 * creatinine \>1.5mg/dL * urine analysis protein of 2+ or greater * fasting triglycerides \> 400 mg/dL, fasting total cholesterol \> 300 mg/dL, or fasting LDLcholesterol \> 160 mg/dL * transaminases \> 2 times the upper limit of normal 6. Subjects may not be using any of the following medications: systemic antifungals, antiepileptics, HIV protease inhibitors, cimetidine, cisapride, clarithromycin, danazol, diltiazem, erythromycin, metoclopramide, rifabutin, rifampin, rifapentine, troleandomycin, or verapamil 7. Subject may not consume grapefruit juice and/or St. John's Wort (hypericum perforatum) throughout the duration of the study. 8. Subject may not have other significant concurrent medical conditions, including * Active malignancy, including evidence of cutaneous basal or squamous cell carcinoma or melanoma, or history of cancer (other than fully resected and surgically cured cutaneous basal cell and squamous cell carcinoma) within 5 years before the first 13 of 25 sirolimus dose. If malignancy occurred more than 5 years ago, documentation of disease-free state since treatment is required. * Known immunodeficiency syndromes, including HIV * Renal failure or insufficiency, as defined by laboratory parameters above * Significant proteinuria, as defined by laboratory parameters above * History of high cholesterol, lipids, or liver disease, as defined by laboratory parameters above * Uncontrolled hypertension, as defined by a blood pressure \> 140/90 despite optimal medical therapy, as prescribed by primary care doctor * Any condition that, in the opinion of the investigator, might cause this study to be detrimental to the subject * Any active Common Terminology Criteria (CTC) grade 2 (localized infection; requiring local intervention) or higher infection (including chronic or localized infections) within 30 days prior to screening, at screening, or during screening period prior to first dose of sirolimus