MULTI-SUBSET DONOR LYMPHOID CHIMERISM PATTERNS DURING ACUTE GRAFT VERSUS HOST DISEASE AFTER LIVER TRANSPLANT.

Aim We monitored donor lymphoid chimerism (DLC) long term patterns by STR to investigate their clinical relevance to aGvHD. Methods 81 out of 879 liver transplant patients (2005-2013) who clinically suspected as aGvHD were tested for DLC. Short tandem repeat (STR) assay for DLC was run on the peripheral blood, T, NK, and CD8 + T cells. Cases with positive DLC in any preparation (>5%) were monitored until resolution of DLC or patient expiration. Results Three characteristic patterns of subset DLC were observed. The first pattern (5 patients) is characterized by low level D% that is detected only in CD8 + T cell on initial positive test (Fig. 1). In the second pattern, four patients on the initial positive DLC, had relatively higher CD8 + T cell D% combined with positive T cell D% (Fig. 1). These two patterns were associated with effective aGvHD control with complete resolution of DLC within a mean of 21 days. In the third pattern, four patients with positive DLC in all CD8 + T cells, NK cells and T cell were associated with longer duration for DLC resolution (114 days) (Fig. 2) and failure of treatment (Fig. 2). Conclusions Detection of DLC in both NK and CD8 + T cell preparations is associated with longer duration to DLC resolution and higher mortality rate. These results suggest that multi-subset DLC testing is a useful tool to support the diagnosis of aGvHD and predict the response to treatment.