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Scurfy mice are deficient in regulatory T cells (Tregs), develop a severe, generalized autoimmune disorder that can affect almost every organ and die at an early age. Some of these manifestations resemble those found in systemic lupus erythematosus (SLE). In addition, active SLE is associated with low Treg numbers and reduced Treg function, but direct evidence for a central role of Treg malfunction in the pathophysiology of lupus-like manifestations is still missing. In the present study, we characterize the multiorgan pathology, autoantibody profile and blood count abnormalities in scurfy mice and show their close resemblances to lupus-like disease. Scurfy mice have dysfunctional Tregs due to a genetic defect in the transcription factor Forkhead box protein 3 (Foxp3). We analyzed skin, joints, lung and kidneys of scurfy mice and wild-type (WT) controls by conventional histology and immunofluorescence (IF) performed hematological workups and tested for autoantibodies by IF, immunoblotting and enzyme-linked immunosorbent assay. We also analyzed the intestines, liver, spleen and heart, but did not analyze all organs known to be affected in scurfy mice (such as the testicle, the accessory reproductive structures, the pancreas or the eyes). We transferred CD4+T cells of scurfy or WT mice into T cell-deficient B6/nude mice. We confirm previous reports that scurfy mice spontaneously develop severe pneumonitis and hematological abnormalities similar to those in SLE. We show that scurfy mice (but not controls) exhibited additional features of SLE: severe interface dermatitis, arthritis, mesangioproliferative glomerulonephritis and high titers of anti-nuclear antibodies, anti-double-stranded DNA antibodies, anti-histone antibodies and anti-Smith antibodies. Transfer of scurfy CD4+T cells (but not of WT cells) induced autoantibodies and inflammation of lung, skin and kidneys in T cell-deficient B6/nude mice. Our observations support the hypothesis that lupus-like autoimmune features develop in the absence of functional Tregs.

IMPORTANCE In the recent World Health Organization–European Organisation for Research and Treatment of Cancer classification, primary cutaneous CD4+ small- to medium-sized pleomorphic T-cell lymphoma is listed as a provisional entity that is histopathologically characterized by pleomorphic CD3+/CD4+/CD8−/CD30− T lymphocytes. Clinically, it is characterized by solitary tumors mostly affecting the head and neck area and by an indolent clinical course with an estimated 5-year survival of about 60% to 80%. Currently, therapeutic options include topical or systemic treatment with glucocorticoids, local excision of solitary lesions, radiotherapy, and chemotherapy (eg, cyclophosphamide) in cases of aggressive clinical behavior or systemic disease. OBSERVATIONS We present the case of a 21-year-old female patient with a 5-year history of a solitary, slowly growing tumor of the right cheek. Histopathologic findings revealed a primary cutaneous CD4+ small- to medium-sized pleomorphic T-cell lymphoma with an admixture of numerous CD20+ B cells representing almost half of the infiltrate. In this patient we achieved a temporary (13 months) complete remission of the lymphoma by oral treatment with doxycycline monohydrate, 200 mg per day. CONCLUSIONS AND RELEVANCE Doxycycline is a relatively nontoxic and well-tolerated oral agent and should be considered as a therapeutic option in primary cutaneous CD4+ small- to medium-sized pleomorphic T-cell lymphoma, especially in cases with a high percentage of B lymphocytes and no signs of systemic disease.

ABSTRACTA 60-year-old patient with aplastic anemia presented with vesicular varicella-like skin lesions on her face, arms, legs, back, and abdomen. However, diagnosis for herpetic infection was negative. Findings of a skin biopsy led to a tentative histologic diagnosis of toxoplasmosis, and infection with Toxoplasma gondiiwas confirmed by immunohistochemistry and PCR. Cutaneous toxoplasmosis is a rare finding in immunocompromised patients and might mimic other infectious diseases, and vesicular lesions associated with toxoplasmosis have not been reported previously.