Comparison of the CELLEX™ and UVAR-XTS™ closed-system extracorporeal photopheresis devices in the treatment of chronic graft-versus-host disease.

Extracorporeal Photopheresis (ECP) is a cellular immunotherapy frequently used for steroid-refractory graft-versus-host disease (GVHD). Chronic GVHD (cGVHD), response to ECP is associated with survival benefit. The UVAR-XTSTM system and the more recently developed CELLEXTM device (both TherakosTM ) are the mainstay for ECP-delivery in the UK and US. No comparison of treatment outcomes has been reported. We retrospectively compared cGVHD response and steroid reduction and withdrawal in patients treated exclusively over 12 months with either the XTS (n = 51) or CELLEX (n = 50). Our hypothesis was that there would be no difference in clinical outcome or steroid changes in the 2 matched cohorts. We also compared infection incidence, infection-related death (IRD), and treatment time. Significant clinical improvement and regular capacity to reduce or cease steroids was encountered in both cohorts; at 6 months of ECP 70% of cutaneous cGvHD patients had partial or complete responses and 85% of patients receiving steroids pre-ECP had reduced dosage. In the XTS group we unexpectedly encountered both superior steroid reduction (86% dose at least halved vs. 61% for CELLEX, P = 0.01) and withdrawal (15 vs. 5 CELLEX, P = 0.01) and a trend for superior skin disease response in the CELLEX-treated cohort at 3 months. No inter-relationship was evident. Halving or greater reduction of steroid dose by 3 or 6 months was associated with reduced risk of IRD in the XTS cohort as was withdrawal at 6 months for the combined cohorts. By 6 months, XTS-treated patients had experienced fewer antibiotic-requiring infections (mean 1.9 vs. 2.8, P = 0.025). Origins for the disparities are unclear and warrant investigation.

Regulatory T Cells in Chronic Graft-Versus-Host Disease After Extracorporeal Photopheresis: Correlation With Skin and Global Organ Responses, and Ability to Taper Steroids.

BACKGROUND: Induction of immune tolerance by an increase in regulatory T (Treg) cells after extracorporeal photopheresis (ECP) is thought to contribute to how ECP exerts its therapeutic effect in patients with chronic graft-versus-host disease (cGvHD). We investigated whether percentages and absolute counts of Treg cells changed post-ECP, and examined correlation with response. METHODS: Absolute counts and % of CD4+ T cells and Treg cells (CD4 + CD25 + FOXP3 + CD127dim/-) were evaluated using flow cytometry in 32 patients with cGvHD treated by ECP for a minimum of 3 months, and up to 12 months. CD4+ or Treg cells at baseline to 12 months post-ECP were compared with changes in skin disease scores or global organ involvement, or the ability to taper steroids, at 14, 28, and 56 weeks. RESULTS: Regulatory T cells % increased significantly above any overall changes in CD4+ % at 6, 9, and 12 months post-ECP. There was no statistically significant association between Treg cells and skin or steroid response, whereas a larger increase in CD4+ count from baseline to 1 to 3 months corresponded to increased odds of being able to reduce steroid dose by 50% or greater at 14 weeks. Skin and global organ responders at 28 weeks had higher median Treg cell counts 3 months post-ECP than nonresponders, as did steroid responders at 56 weeks who were 12 months post-ECP. CONCLUSIONS: Regulatory T cell counts and % varied greatly among cGvHD patients, and the increase post-ECP was not significant until 6 months. No clear correlation was found between Treg cells and clinical improvement, suggesting that increases in Treg cell numbers and/or proportions are not driving the mechanism leading to a response after ECP.

Cleavage of chemokines CCL2 and CXCL10 by matrix metalloproteinases-2 and -9: implications for chemotaxis.

Proteolytic processing of chemokines is a complex process that can result in dramatic effects on their chemotactic activity. Results from gel electrophoresis and mass spectrometry using recombinant CCL2 and CXCL10, incubated with either MMP-2 or -9, indicate that both chemokines are cleaved by the enzymes. N-terminal truncation of four amino acids from CCL2, and four or five residues from CXCL10 occurred, but removal of four residues from the C-terminus of CXCL10 was also observed with both MMPs. The speed of the reaction was chemokine-dependent, with N-terminal processing of CCL2 being complete within 3h, whereas activity of the MMPs on CXCL10 remained incomplete at 48h. The effect on the chemotactic potential of N-terminal truncation of CCL2 by MMPs-2 and -9 was investigated using in vitro migration assays. Monocytic cells exhibited a 2-fold reduction in migration to MMP-cleaved CCL2 variants, compared to intact CCL2.