Use of DPB1 T-cell epitope algorithm among italian transplant centers: A survey on behalf of Associazione Italiana di Immunogenetica e Biologia dei Trapianti.

The HLA-DPB1 locus has been demonstrated to have a significant role on patients' outcome after allogeneic HSCT, and the so-called T-cell epitope (TCE) algorithm has been incorporated in international guidelines for the selection of unrelated donors. The purpose of the present study is to measure, through a national survey conducted on behalf of the Associazione Italiana di Immunogenetica e Biologia dei Trapianti (AIBT), the extent of awareness and use of HLA-DPB1 TCE-based algorithms during the donor search. 89% of the HLA laboratories answered to a short questionnaire and the results showed a progressive increase of the laboratories typing DPB1 in patients and their potential donors during the search (from 44% to 79% during the 2010-2019 period) as well as the application of a TCE-based algorithm for the donor choice whenever possible (from 24% to 65% during the same period). The DP-permissiveness status is detailed in the official HLA typing report by 12%, 32% and 50% of laboratories in 2010, 2015 and 2019, respectively. The present data indicate an encouraging raise in the awareness of the HLA-DPB1 role in unrelated donor selection; noteworthy, mentioning the TCE-based permissiveness status in the HLA typing report of each potential unrelated donor represents a notable mean to raise awareness among transplant physicians and to support them in their task of choosing the best donor. Nonetheless, despite the compelling evidence of the predictive ability of TCE-based algorithms, further efforts are still needed to extend its application to all transplant centers in Italy.

Acute GVHD after allogeneic hematopoietic transplantation affects early marrow reconstitution and speed of engraftment.

Our aim was to study the influence of acute graft-versus-host disease (a-GVHD) on primary engraftment times after allogeneic transplantation. Primary engraftment and frequency of marrow granulocyte-macrophage colony-forming units and erythroid burst-forming units, at day +18, were studied in 126 allogeneic transplants. Patients were grouped according to the time when a-GVHD treatment with corticosteroids was started. The no-a-GVHD group are those who, during the first 3 months, had no need for a-GVHD treatment; the early-a-GVHD group are those who needed a-GVHD treatment within 19 days; and the postengraftment-a-GVHD group are those who were not on corticosteroid treatment at the time of engraftment but needed it after day +19. The no-a-GVHD group reached a neutrophil count (N) > 0.5 × 10(9)/L in a median of 17.8 days. The postengraftment-a-GVHD group reached N > 0.5 × 10(9)/L in a median of 21.4 days (p = 0.0003). The early-a-GVHD group had N > 0.5 × 10(9)/L in a median of +17.0 days (p = 0.23). When factors important for engraftment were studied in a multivariate analysis, postengraftment a-GVHD was a significant factor in delayed neutrophil and platelet engraftment. Both the early-a-GVHD and postengraftment-a-GVHD groups showed a significant reduction in frequency of granulocyte-macrophage colony-forming units and erythroid burst-forming units found in marrow at day +18. In conclusion, a-GVHD may influence early marrow reconstitution and is a relevant factor for primary myeloid and platelet engraftment.