[1408] Clinical and Pathological Implications of Foxp3 Expression in Adult T-Cell Leukemia/Lymphoma in US/Caribbean Cases

J Ouyang, SRS Gottesman, K Killoran, K Leveaux, A Braverman, X Zhang, V Kaushik, CA Axiotis. SUNY Downstate Medical Center, Brooklyn, NY; Kings County Medical Center, Brooklyn, NY

Background: Foxp3, a novel forkhead transcription factor essential for the development and function of CD4+CD25+ T regulatory cells (Treg) has recently been identified in 36-68% of Japanese Adult T- cell leukemia/lymphoma (ATLL) patients. Foxp3+ ATLL cells may have Treg-like suppressive activity and patients with Foxp3+ ATLL may be more clinically immunosuppressed than those with Foxp3 ATLL. Differences between the two groups' clinical courses, prognoses, and survival have not been demonstrated. Pathology and Foxp3 expression have not been correlated with clinical course, and survival in non-Japanese ATLL.
Design: We identified 24 US/Caribbean patients of ATLL from 1997-2009, for whom clinical follow-up information and pathologic material were available. All cases were classified morphologically, and diagnosed as ATLL on the basis of the Shimoyama criteria for clinical and laboratory findings. Immunohistochemistry was performed on all cases utilizing the Foxp3 antibody (clone 221D/D3) which recognizes Foxp3 in the nucleus and does not cross react with other Foxp proteins. Age, gender, calcium level, and serum lactate dehydrogenase (LDH) concentration were compared to Foxp3 status by student t-test. The Kaplan-Meyer method and log rank test were used to evaluate survival data. Four cases of HTLV1 T-cell lymphoma were also immunostained for Foxp3.
Results: Foxp3 was expressed in the majority of lymphoma nuclei in 10/24 cases of ATLL (42%). One of seven cases (14%) of acute ATLL, and 9/17 (53%) cases of lymphomatous ATLL were Foxp3+. Morphology was pleomorphic medium or large cell in 23 cases, 10 Foxp3+; 1 pleomorphic small cell case was Foxp3−. Age distribution, gender, overall and median survival, opportunistic infections, and calcium and LDH levels, did not differ significantly in the Foxp3+ and Foxp3− groups (p>0.05). Three cases of HTLV1− T-cell lymphoma were Foxp3−, while 1 with pleomorphic small cell morphology was Foxp3+.
Conclusions: US/Caribbean ATLL Foxp3 expression is similar to that of Japanese cases. Foxp3 expression does not seem correlated with clinical course or survival in our cases. More data on Foxp3 expression in HTLV1- T cell lymphoma, and its clinical significance, is needed.
Category: Hematopathology

Tuesday, March 23, 2010 9:30 AM

Poster Session III # 197, Tuesday Morning


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