Program: Oral and Poster Abstracts
Session: 722. Clinical Allogeneic Transplantation: Acute and Chronic GVHD, Immune Reconstitution: Poster II
METHODS: 44 patients that received HLA-matched allogeneic SCT were included in this study. Controls consist of 15 patients that received autologous SCT and 30 healthy donors. Flow cytometric analysis was used to measure plasmacytoid DCs (pDCs), myeloid DC type 1 (mDC1), mDC2 and mDC3. Blood samples were obtained at day 0, 1 month post-SCT and then every other month until 1 year. The percentage and absolute counts of naïve CD4+ or CD8+ lymphocytes (TNA); (CD3+CD45RA+CCR7+), central memory (TCM); (CD3+CD45RA+CCR7neg), effector memory (TEM); (CD3+CD45RAnegCCR7neg) and terminal differentiation (TTD); (CD45RA+CCR7neg) was determined by flow cytometry. B lymphocytes and regulatory CD4+ T cells were also evaluated.
RESULTS: One month after allo-SCT, we found a significant increase in blood DCs followed by a gradual decrease and stabilization by 3 months post-allo-SCT. During the first year, all DC subsets including pDCs, mDC1, mDC2, mDC3 as well as CD4+ and CD8+ T cells were significantly diminished compared to autologous and healthy controls. Plasmacytoid DCs regeneration was in general the most affected and we found a positive correlation between pDC cells count and the number of naïve and central memory CD4+ lymphocytes. Similarly, pDCs counts also correlated with the number of naïve and memory CD8+ T cells. In contrast, effector CD4+ and CD8+ T cell showed a stronger correlation with mDC1. Patients with grade II-IV acute GVHD had lower DC counts compared with mild grade 0-1 aGVHD and a similar trend was also observed during the development of cGVHD, Importantly, loss of pDCs and mDC1 that preceded the development of cGVHD by 1 month was associated with the development of grade 3 cGVHD whereas loss of DCs during cGVHD was associated with milder 0-2 cGVHD. Thus far, our data support a model wherein loss of pDCs and mDC1 could represent potential biomarkers to predict the severity of cGVHD.
Disclosures: No relevant conflicts of interest to declare.
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