PB2348 IMMUNE RECONSTITUION OF ΓΔT CELLS AFTER AUTOLOGOUS STEM CELL TRANSPLANTATION IN MULTIPLE MYELOMA – IMPACT OF REFRACTORINESS/RELAPSE AND PREVIOUS THERAPEUTICS ON RECOVERY

• Published in: HemaSphere 2019-06, Vol.3 (S1), p.1046-n/a
• Main Authors: Roque, A., Silva, I., Afonso, M. C., Cortesão, E., Espadana, A. I., Sarmento‐Ribeiro, A. B., Geraldes, C., Paiva, A., Ribeiro, M. L.
• Format: Article
• Language: English
• ISSN: 2572-9241; 2572-9241
• DOI: 10.1097/01.HS9.0000567856.90705.89

Background: γδT cells are a minor circulant effector/cytotoxic population involved in immune surveillance, with evidence supporting their anti‐multiple myeloma (MM) role. Although lymphocyte recover after autologous hematopoietic stem cell transplantation (aHSCT) has been extensively studied, there are limited data about γδT cells, with no information on the impact of previous therapeutic in its recovery. Aims: To evaluate γδT cells recovery in MM patients(pts), its impact in posttransplant recovery and the effect of previous treatment/response in γδT subsets reconstitution. Methods: We prospectively analysed 44 MM pts submitted to aHSCT (2016‐2018), previously to conditioning with melphalan 200 mg/m2 (Dc) and at 30 (D30), 60 (D60), and 100 (D100) days after aHSCT. The proportion (%) of γδT cells, performed by flow cytometry based on the expression of CD3/CD45/Vδ1/Vδ2/Vγ9/CD27, indicated the proportion of these cells among all T cells. Pts were divided into 3 groups: those who receive just 1‐line therapy previous aHSCT (NEW) and those who receive more than 1 line due to primary refractory disease (REFAC) or relapse after response (RECID), according to IMWG criteria. Toxicities were graded according to CTCAEv4.03. Results: Median age was 63 years (40‐69), with 64.0% of males, 27.3% ISS III. Median of previous therapeutic lines was 1(1‐4) – all pts had received bortezomib, 27.3% lenalidomide, 18.8% thalidomide, 9.1% daratumumab, and 4.6% pomalidomide; 36.4% received ≥1 novel anti‐MM agent. Median time diagnosis‐aHSCT was 11.1 months(5.3‐112.1) – 68.2%(n = 30) NEW, 16.6%(n = 6) REFAC and 18.2% (n = 8) RECID. The median number of previous lines was higher in REFAC vs RECID (2vs2; p = 0.015). There were no other characteristics differences at diagnosis between the 3 groups. There was no significant difference between NEW vs REFAC vs RECID in achieving at least very good partial response (VGPR) or higher previous to aHSCT (p = 0.224) or at D100 pos‐aHSCT (p = 0.905). RECID group presented a higher % of Vδ1 + γ9 + T cells (vs REFAC)(p = 0.007) and a lower of Vδ2 + γ9 + T(vs REFAC and NEW)(p = 0.060 and p = 0.027, respectively) at D100. There were no other differences between the 3 groups. Time to neutrophils >0.5 × 109/L (TTN) was higher in RECID group (vs NEW and REFAC) (p = 0.003 and p = 0.015, respectively). A higher TTN was positively correlated with a higher %Vγ9 + T (Coef. 21,4;p = 0.012), Vδ1 + γ9 + T(Coef 17.7;p = 0.007) and Vδ1 + γ9 + CD27 + T(Coef 35.9;