Abstract
Allogeneic stem cell transplantation (SCT) from HLA matched sibling donor is the standard treatment option in younger patients with severe aplastic anaemia (SAA). In the current study outcome of 70 patients with SAA undergoing allogeneic SCT at our institution from July 2001 to June 2007 is presented. Median follow up time was 727 days (range 100–2187). Three patients received 2nd SCT due to graft failure or rejection so actual number of SCT in the patients was 73. Median age of the patients was 16 years (range 5–38), 55 males, and 15 females. Seventeen had major ABO mismatch while sex mismatch in the form of female donor to male patient was present in 23 cases, 7 had both major ABO and sex mismatch. Sixty four patients were CMV positive while 6 had CMV negative status. Conditioning regimens included; cyclophosphamide (Cy) 200 mg/kg with either antilymphocyte globulin (ALG) 45 mg/kg (n=33) or antithymocyte globulin (rabbit ATG) 11.25 mg/kg (n=26); Cy plus Campath 100 mg (n=6), fludarabine 150 mg/m2 plus Cy 300 mg/m2 and ATG (n=8). All patient undergoing 2nd transplant received conditioning with Cy, fludarabine and ATG. GVHD prophylaxis was given with cyclosporin (CSA) plus prednisolone (41) with or without short course of methotrexate (29). Patients received PBSC (10) or bone marrow (12) alone or both (48). Mean mononuclear and CD34+ cell doses were 5.59 x 108/Kg and 4.8 x 106/Kg respectively. Median time to neutrophil recovery was 11 days (range 7–24). Neutropenic fever was seen in 60% cases, with mean duration of fever being 8 days. In majority (66%) no focus of infection could be found. Various isolates included gram negative rods (n=6), staphylococcus (n=2) and fungi (n=5). Other post-transplant infections were tuberculosis (n=2), herpes zoster (n=2) and transfusion associated falciparum malaria (n=2). Post-BMT non-infectious complications included acute GVHD (24%), chronic GVHD (08%), hemorrhagic cystitis (14%), seizures (5%), and VOD (3%). Graft rejection and primary graft failure was seen in 3 and 2 cases respectively. Three of them received 2nd transplant and had successful recovery while the other 2 died of septicemia. Six patients died during peri-transplant period, 3 at day 100, and 8 beyond day 100. One patient died of unrelated cause at 2 years post-transplant. Main causes of death were septicemia (n=4), conditioning regimen toxicity (n=3), VOD (n=2), GVHD (n=2) and disseminated aspergillosis (n=2). The overall and disease free survival was 76%. In univariate analysis using Logrank and Wilcoxon test factors correlated with better survival were patient’s age <15 years, disease duration <6 months, previous transfusions <20 events, conditioning with fludarabine/Cy/ATG, and absence of chronic GVHD. SCT from HLA matched sibling donor is effective treatment modality in majority of the young patients with SAA.
Serial chimerism analyses indicate that mixed haemopoietic chimerism influences the probability of graft rejection and disease recurrence following allogeneic stem cell transplantation (SCT) for severe aplastic anaemia (SAA): indication for routine assessment of chimerism post SCT for SAA