Case Study: Pemphigus Foliaceus in a Shih Tzu

Pemphigus foliaceus, an autoimmune skin disease in dogs, is usually treated with high-dose corticosteroids and other immunosuppressant drugs with common adverse effects. Stem cell therapy may be a promising alternative. Mesenchymal stem cells mediate the adaptive and innate immune responses through inhibition of a variety of cell types. 

In this case study, adipose tissue-derived mesenchymal stem cells (ATMSCs) were employed in the successful treatment of steroid-refractory pemphigus foliaceus in a dog. A 10-year-old shih tzu with pemphigus foliaceus was referred to a veterinary teaching hospital with severe pruritus, anorexia, weight loss, and classic generalized lesions. Full workup, including impression smear cytology, skin scrapings, CBC, serum chemistry panel, and skin biopsies were consistent with pemphigus foliaceus. The patient was treated with oral prednisolone (4 mg/kg/day) and cephalexin (60 mg/kg/day). Signs improved but reoccurred after 1 month. Cyclosporine (5 mg/kg/day) and azathioprine (2 mg/kg/day) were added, but clinical signs did not improve. Stem cell therapy was initiated with canine ATMSCs experimentally transfected with canine cytotoxic T-lymphocyte antigen 4 (CTLA4). CTLA4-expressing ATMSCs were injected intravenously (1 × 10⁶ cells/kg) at 2-8 week intervals for 21 treatments over 20 months. Pruritus and skin lesions improved after 1 treatment. Over several treatments, oral prednisolone was gradually reduced to 0.25 mg/kg/day and azathioprine was discontinued. The dog remained in remission for 1 year with minimal pruritus and crusting even after the gradual cessation of stem cell therapy. The authors conclude that CTLA4-ATMSCs could be beneficial in treating pemphigus foliaceus in dogs.