Expression of FOXP3 in HTLV-1-Associated Infective Dermatitissyndrome.
Carlos A Torres-Cabala, Elsa M Li-Ning-Tapia, Cesar Ramos, Jonathan L Curry, Victor G Prieto, Roberto N Miranda, Francisco Bravo. UT-MD Anderson Cancer Center, Houston, TX; Universidad Peruana Cayetano Heredia, Lima, Peru
Background: Human T-lymphotropic virus (HTLV)-1-associated infective dermatitis (ID) is a rare and severe chronic disease occurring mainly in children of certain areas of the world. These patients may subsequently present with cutaneous adult T-cell leukemia/lymphoma (ATLL) and HTLV-1-associated myelopathy (HAM)/tropical spastic paraparesis (TSP). The pathogenesis of ID remains undefined. Whereas it seems that regulatory T cells (CD4+CD25+FOXP3+ Tregs) represent the reservoir cells for HTLV-1 in ATLL and HAM/TSP, the status of Tregs in ID has not been reported to date.
Design: The immunohistochemical expression of FOXP3 was evaluated on sixteen skin biopsies from fifteen children and adults seen at the Dermatology Clinic, UPCH, Lima, Peru. All the patients fulfilled clinical and serological criteria for HTLV-1-associated ID. The histopathological findings of the biopsies were documented. FOXP3 status was analyzed in conjunction with patterns of expression of CD3, CD4, CD8, and CD25 by dermal and intraepidermal lymphocytes. Co-expression of CD4, CD25, and FOXP3 was assessed.
Results: The patients' age ranged from 5 to 82 years. Three histopathological patterns were identified. Some cases resembled seborrheic dermatitis, displaying spongiosis, parakeratosis, intracorneal neutrophils, and a superficial and deep perivascular lymphocytic infiltrate (7/16 cases). Other cases showed features of lichenoid dermatitis (8/16 cases). One case displayed a combination of the two previous patterns. All the cases showed intraepidermal lymphocytes, and in two cases, folliculotropism was identified. The presence of intraepithelial lymphocytes along with fibrosis of the papillary dermis (present in 6/16 cases) raised mycosis fungoides as a histopathological differential diagnosis. The lymphocytic infiltrate was mainly composed of CD3-positive T cells. All the cases showed a predominance of CD8-positive intraepidermal lymphocytes, whereas very rare CD4-positive cells were identified in 10/16 cases. CD25 was expressed in more than 10% of the cells in 4/16 (25%) cases; comparable FOXP3 expression was detected in 6/16 (37.5%) cases. Co-expression of CD25 and FOXP3 by more than 50% of the cells was seen in 14/16 cases.
Conclusions: Regulatory T cells (Tregs), defined as CD25+FOXP3+ T cells, are frequent in HTLV-1-associated ID and may correlate with the detected high numbers of CD8+ cells. Our results are in agreement with the postulate that early HTLV-1 infection stimulates the expression of FOXP3. Decreased expression of FOXP3, as reported in both HAM/TSP and ATLL, is not seen in ID.
Wednesday, March 2, 2011 1:00 PM
Poster Session VI # 125, Wednesday Afternoon