Psoriasis associated with idiopathic CD4+ T‐cell lymphopenia: a regulatory T‐cell defect?

• Published in: British journal of dermatology (1951) Vol. 171; no. 1; pp. 186 - 189
• Main Authors: Baroudjian, B., Viguier, M., Battistella, M., Beneton, N., Pagès, C., Gener, G., Bégon, E., Bachelez, H.
• Format: Journal Article
• Language: English
• Published: Oxford Wiley-Blackwell 01-07-2014
• Subjects: Adult; Biological and medical sciences; Chronic Disease; Dermatology; Hematologic and hematopoietic diseases; Humans; Male; Medical sciences; Other diseases. Hematologic involvement in other diseases; Psoriasis - etiology; Psoriasis - immunology; Psoriasis. Parapsoriasis. Lichen; T-Lymphocytes, Regulatory - immunology; T-Lymphocytopenia, Idiopathic CD4-Positive - complications; Skin disease; Regulation(control); Association; Leukopenia; Psoriasis; Immunological investigation; Dermatology; Idiopathic; T-Lymphocyte; Defect; Hemopathy; Lymphocytopenia
• ISSN: 0007-0963; 1365-2133
• DOI: 10.1111/bjd.12922

Summary
Idiopathic CD4+ lymphocytopenia (ICL) is a rare immunodeficiency syndrome of unknown origin for which the increased risks of opportunistic infections and of malignancies have been well established; however, skin dysimmune diseases, including psoriasis, have been scarcely reported up to now. We report herein the severe course of psoriasis in four patients with ICL, and show evidence for a defect in the skin recruitment of regulatory CD4+FoxP3+ T cells. These data raise the apparent paradigm of the occurrence of a severe immunomediated disease together with a profound T‐cell defect, a model that might also apply to other immune deficiencies associated with psoriasis.
What's already known about this topic?
While the risk of opportunistic infections and of malignancies has been previously stressed in idiopathic CD4+ T‐cell lymphocytopenia (ICL), the association with skin dysimmune disorders, mainly psoriasis, has been poorly addressed so far.
What does this study add?
We report four cases of severe psoriasis in patients with ICL and discuss the contribution of a regulatory T‐cell defect to the pathogenesis of psoriasis in this setting.