Evidence of Regulatory T-Cell Immunophenotype in a Subset of HTLV-I-Associated Infective Dermatitis: An Early Sign of Progression?
CA Torres-Cabala, EML Li-Ning-Tapia, C Ramos, JL Curry, VG Prieto, F Bravo. UT - MD Anderson Cancer Center, Houston, TX; Universidad Peruana Cayetano Heredia, Lima, Peru
Background: Infective dermatitis associated with HTLV-I (IDH) is a childhood eczema that rarely presents in adults. It has been postulated that IDH may represent a cofactor for the subsequent development of cutaneous adult T-cell leukemia/lymphoma (ATLL.) The status of CD25-positive regulatory T cells in this entity is unknown, despite the well-established fact that ATLL cells usually display a CD4, CD25-positive immunophenotype. Here, we report the histopathological and immunohistochemical findings of IDH in a cohort of affected children and adults from Peru.
Design: Sixteen skin biopsies from fifteen patients were examined. Patients ranged in age from 5 to 82 years. All the patients were positive for HLTLV-I by serology. Histological assessment and evaluation of CD3, CD4, CD8, and CD25 by immunohistochemistry were performed. CD25 expression was scored as focal (fewer than 10%), moderate (10 to 50%), and diffuse (greater than 50% of the lymphocytes.).
Results: The lymphocytic infiltrate was categorized as lichenoid (8/16 cases), superficial and deep perivascular (7/16), and mixed (1/16.) Neutrophils in stratum corneum, parakeratosis, and spongiosis were seen in 11/16 biopsies. Fibrosis of the papillary dermis was identified in 6/16 cases. Exocytosis of lymphocytes in the epidermis, at least focal, was present in all the cases. Folliculotropism was present in two cases. The lymphocytic infiltrate was predominantly composed of CD3-positive T cells. The epidermotropic cells were mainly CD8-positive T cells. Only very rare CD4-positive cells were present in most of the cases (10/16.) In six cases, a population of CD4-positive T cells was seen in the dermis showing focal epidermotropism. From these six cases, four (4/16, 25%) displayed a moderate to diffuse expression of CD25 by the infiltrating lymphocytes.
Conclusions: Our study demonstrates that a subset of IDH shows a population of CD4-positive, CD25-positive T cells with possible regulatory immunophenotype. This population may contribute to an impaired cell-mediated immune response and potentially to progression to ATLL. Expression of CD25 by a subset of IDH may have therapeutic implications in the management of these patients.
Wednesday, March 24, 2010 1:00 PM
Poster Session VI # 97, Wednesday Afternoon