Study Of Immune Hemolytic Disease After Hematopoietic Stem Cell Transplantation

BackgroundImmune hemolytic disease(IHD)is a main and severe complication after hematopoietic stem cell transplantation(HSCT).Post-HSCT IHD may be resulted from allo-or auto-genetic immune reaction.Allogeneic immune-hemolysis is that immune cells and antibodies from the recipient attack red blood cells from donor,which is defined as host versus graft(HVG).In contrast,autogenetic immune hemolysis is that immune cells and antibodies from the donor attack red blood cells from donor,which is defined as graft versus graft(GVG).Although some centers have reported a few cases of post-HSCT IHD and discussed some possible pathogeny,including HLA mismatch,ABO blood-type mismatch and underlying disease,etc.Antigen-antibody reaction was thought as pathological mechanism,but few persons paid close attention to idea of GVG and HVG.Based on different understanding on GVG and HVG,a different therapy will be used.Before,steroids were usually given to patients with post-HSCT IHD,short remission may be gained,but relapse often occurred.Long-term use of steroids will result in more severe infection and even dead.This therapy responds showed the causes of post-HSCT IHD may be HVG not GVG.So,we began to use a opposite strategy,namely,tapering immunosuppressive drugs or/and giving donor lymphocyte infusion(DLI)or/and Rituximab since 2010.Rituximab may stop production of antibody leading post-HSCT IHD but not hinder function of T lymphocytes which will kill host immune-cells.Here,we analyzed retrospectively our data and given a summary as below.AimTo try to illustrate and proven the causes of Post-HSCT IHD,which is GVG or HVG,by analysis based on serum titer of ABO antibody,chimerism rate of donor cell,and responds of therapy.Patients and method707 HSCTs from our center since January 2010 to March 2017,were retrospectively analyzed.The item of analysis included age,gender,ABO blood-type,diseases and transplant type,etc.Standard of diagnosis of Post-HSCT IHD included:1:after HSCT,2:hemoglobin ≤80×109/L for three time in two consecutive week s,3:needed regular transfusion,and 4 positive Coomb’s test.Standard of complete remission(CR):1:without need of transfusion,2:hemoglobin≥80×109/L for three time in two consecutive weeks,3:negative Coomb’s test,3:100%donor cell chimerism,and negative ABO blood-type antibody from recipient.Standard of partial remission:without gaining CR standard but≥50%decline of transfusion.Statistic methods included statal3 chi-square test。35 cases were divided into three groups by host blood-type antibody titer and donor cell chimerism.Group 1(n=16),all cases were donor-recipient ABO blood-type mismatched and 100%donor cells chimerism but recipient ABO blood-type antibodies occurrence:antibody titer high(more than pre-HSCT value)or delayed decline(more than 3 months after HSCT).Group 2(n=13),mixed donor cell chimerism(75-98.8%).Group 3(n=6)full donor cell engraftment,100%donor cell chimerism without ABO blood-type antibody from recipient.In group 3,four with donor-recipient ABO mismatch,3 cases with acute GVHD and 5 cases with positive CMV test.In G1,ABO blood-type antibodies from recipient can indirectly prove host immune cell existence.In G2,chimerism<100%may directly prove host immune cell existence.In G3,although we had no direct evidence to prove recipient cells existence and some cases were along with GVHD,by responds of therapy host cells were still thought to be existence according to hypothesis of immune cells escapes and immune cells harbor in lymph nodesResultsPost-HSCT IHD incidence was 4.95%,336 patients with ABO blood-type mismatch,27 suffered from post-HSCT IHD,In contrast,oppositely only 8 patients had post-HSCT IHD among 339 patients with ABO blood-type match(7.14%versus 2.36%,p=0.001).Post-HSCT IHD occurred in 10 cases in 40 HSCT pairs of A blood-type donor and O blood-type recipient(A-O pair),2 in 54 B-O pairs and 2 in 10 AB-O pairs.statistic significant difference was found when comparing three groups(p=0.029).In comparison of O-A,O-B,O-AB,A-B,B-A,AB-A,AB-B,A-AB and B-AB HSCT pairs,incidence of post-HSCT IHD had not significant difference.According to Chi-square test,Mixed chimerism compared with 100%implantation,in adverse implantation the probability of immuno-hemolysis was greater,it was statistically significant(P=0.000,P<0.05).The percentage of hemolysis after transplantation for patients with matched sibling donors was 3.44%,for patients with unrelated donors was 7.38%(P=0.019<0.05),which appeared that the probability of post-transplantation hemolysis by unrelated donors was greater.Direct Coomb’s test was positive in all 35 patients with post-HSCT IHD.All 35 patients were cured after treatment with tapering immunosuppressive drugs or/and giving donor lymphocyte infusion(DLI)or/and Rituximab.Among them,immunosuppressive drugs were only gradually reduced in 7 cases.Rituximab was given in 11 cases,and 13 cases were treated with DLI.Two cases were not relieved after DLI and the mini-HSCT were performed after the conditioning of cyclophosphamide and Fludarabine,and then,the two patients were cured.SummaryThe cells and antibody leading post-HSCT IHD from host cells were proved by all 35 patients with post-HSCT IHD,who was cured with tapering immunosuppress drugs,plus or not Rituximab,and giving or not DLI.Pathology of post-HSCT IHD should be HVG.Although different chimerism occurred in group 1 and group 2,both groups patients were cured with same therapy.This showed rate of donor cells chimerism cannot identify GVG.Donor with A blood-type resulted in more post-HSCT IHD and occurred earler.High titer recipient blood-type antibody was a direct evidence of existence of host immune cells.GVHD occurrence cannot also deny existence of host immune cells,because lymphocyte have more capability to immune escapes and harbor.Tapering immunosuppress drugs,plus or not Rituximab and giving or not DLI were a correct therapy for post-HSCT IHD.