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Summary:We conducted a retrospective analysis of all allogeneic stem cell transplantation (ASCT) patients started on extracorporeal photopheresis (ECP) for the management of steroid-dependent (SD) or steroid-refractory (SR) cutaneous chronic graft-versus-host disease (cGVHD) following ASCT during a 36-month period (9/98-8/01). Only SD or SR patients who were treated by ECP after day 100 and who received at least 4 weeks of ECP were considered evaluable for this analysis. Out of 64 ASCT patients reviewed, 32 patients met the inclusion criteria. All 32 patients had been previously treated with systemic corticosteroids with 11 (34%) being SR and 21 (66%) SD. Cutaneous cGVHD was extensive in 28 patients (88%) and was accompanied by visceral (hepatic, gastrointestinal) cGVHD in 23 patients (72%). The 32 evaluated patients had received a median of three prior therapies before ECP, most commonly systemic corticosteroids, tacrolimus, and mycophenolate mofetil. Patients received a median of 36 ECP sessions (range 12-98) over a median of 5.3 months (range 1-28), with a median of six sessions per month. The complete response (CR) rate was 22% (n ¼ 7) and the partial response rate was 34% (n ¼ 11). In all, 28 patients were on systemic corticosteroid therapy at ECP initiation and 18 patients achieved 50% dose reduction while on ECP, yielding a 64% steroid-sparing response rate. Of seven CRs, five are ongoing. A total of 11 (34%) patients have died after ECP, with all cases due to visceral cGVHD or cGVHD-related infectious complications. All 21 surviving patients remain on at least some immunosuppressive cGVHD therapy (including ECP in eight). Overall, ECP displays a substantial response rate and, in particular, steroid-sparing activity in SR/SD extensive cutaneous cGVHD. However, most patients continue to require at least some chronic therapy and cGVHD-related morbidity and mortality remain high.

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Denileukin diftitox (Ontak), a recombinant fusion protein of diphtheria toxin and ligand, IL-2, binds to the IL-2 receptor, is internalized, and causes cell death. Denileukin diftitox was approved for the treatment of cutaneous T-cell lymphomas (CTCLs) with CD25+ expression. We prospectively stained lesional skin biopsy specimens from 113 mycosis fungoides and Sézary Syndrome patients for activation markers CD25 and CD30 to correlate expression with clinical tumor-node metastasis (TNM) stage, histologic grade, and response to denileukin diftitox. High expression was defined as positivity of > or =20% of lesional T-cells using immunohistochemistry (IHC). CD25 and CD30 expression was more common in lesions from advanced patients (P = 0.04 and 0.002, respectively). Advanced TNM (T3 or T4) was significantly associated with intermediate-grade (P = 0.002) and large-cell transformation histology (P = 0.04). Of interest, clinical responses were observed in 78.5% of patients with high CD25 expression versus 20% with low to undetectable CD25 expression (P = 0.01) among 24 patients receiving standard 5-day infusions of denileukin diftitox at 18 microg/kg/day. These data suggest that high CD25 expression by IHC is associated with advanced CTCL and with clinical response to denileukin diftitox therapy.

Psoriasis is a T cell-mediated inflammatory disease characterized by hyperproliferation and by aberrant differentiation. We found cathepsin D and zinc-alpha(2)-glycoprotein, two catalytic enzymes associated with apoptosis and desquamation, to be present in the stratum corneum of the normal epidermis but absent from the psoriatic plaque. Psoriasis is characterized by an altered response to interferon-gamma (IFN-gamma), including the induction of apoptosis in normal but not in psoriatic keratinocytes, often with opposite effects on gene expression of suprabasal proteins. We found that IFN-gamma binding and signaling were attenuated in psoriasis: The IFN-gamma receptor, the signal transducer and activator of transcription STAT-1, and the interferon regulatory factor IRF-1 were strongly up-regulated by IFN-gamma in normal keratinocytes, but not in psoriatic ones. IFN-gamma strongly up-regulated the expression of the catalytic enzymes cathepsin D and zinc-alpha(2)-glycoprotein in normal keratinocytes but down-regulated them in psoriatic ones; the reverse was true of the apoptotic suppressor bcl-2. We believe that the aberrant response to IFN-gamma plays a central role in the pathophysiology of psoriasis, particularly the disruption of apoptosis and desquamation.