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Although individuals with sickle cell anaemia (SCA) have elevated baseline inflammation and endothelial activation, the acute phase response to maximal exercise has not been evaluated among children with SCA. We measured the acute phase response to maximal exercise testing for soluble vascular cell adhesion molecule (sVCAM) as well as interleukin 6 (IL6), total white blood cell (WBC) count, C-reactive protein (CRP) and D-dimer in a cohort of children with SCA and matched controls at baseline, immediately after, and 30, 60 and 120 min following exercise. Despite higher baseline levels of all biomarkers except CRP, the acute phase response from baseline to immediately after exercise was significantly greater in subjects versus controls for CRP (2.1 vs. 0.2 mg/l, P = 0.02) and D-dimer (160 vs. 10 µg/l, P < 0.01) only. Similar between-group trends were observed over time for all biomarkers, including sVCAM, IL6, total WBC, CRP and D-dimer. Lower fitness, defined by peak oxygen consumption (VO2), was independently associated with greater acute phase responses to exercise for sVCAM. Our results suggest maximal exercise may not be associated with any greater escalation of endothelial activation or inflammation in SCA and provide preliminary biomarker evidence for the safety of brief, high-intensity physical exertion in children with SCA. [ABSTRACT FROM AUTHOR]

Post-hematopoietic stem cell transplantation (hsCT) chimerism monitoring is important to assess relapse and therapeutic intervention. The purpose of our study is to compare two methods variable number tandem repeats (VNTR) vs. quantitative real- time polymerase chain reaction (qpCR) in terms of determining chimerism. 127 (peripheral blood n = 112, bone marrow n = 15) samples were simultaneously tested by VNTR using apO-B, D1s80, D1s111, D17s30, gene loci sRY and Zp3 and qpCR using 34 assays (Ca001-Ca034) that are designed to a bi-allelic insertion/deletion (indel) polymorphism in the human genome. samples were separated in three subsets: total WBC, T-cell and Myeloid cells. extraction of DNa was performed then quantified. We analyzed column statistics, paired t-test and regression analysis for both methods. There was complete correlation between the two methods. The simplicity and rapidity of the test results from the qpCR method is more efficient and accurate to assess chimerism. [ABSTRACT FROM AUTHOR]

Abstract: Hematopoietic stem‐cell transplantation (HSCT) is an effective mode of therapy in pediatrics for the treatment of both malignant and non‐malignant disorders. We compared the course of children transplanted with unrelated umbilical cord blood (UCB) to those transplanted with allogeneic sibling bone marrow (BM) for bone marrow failure syndromes. Thirteen patients with a median age of 6.3 years were transplanted for the following diseases between April 1992 and November 1997: myelodysplastic syndromes, aplastic anemia, Diamond–Blackfan anemia, myelofibrosis, paroxysmal nocturnal hemoglobinuria, osteopetrosis and dyskeratosis congenita. The stem cell source was BM in ten patients and UCB in three. We retrospectively examined the conditioning regimens, stem cell source and dose, days to engraftment, survival and complication rate to see whether there was a significant advantage in using one source over the other. The median time to an absolute neutrophil count > 500 per µL was 25 days for UCB patients and 16 days for BM patients. The median time to a platelet count > 20 000 per µL was 55 days for UCB patients and 22 days for BM patients. The 100‐day mortality was 66% in UCB patients and 20% in BM patients. The overall mortality rates were 66% and 40%, respectively. Three patients died prior to engraftment. Seven patients (54%) were still alive as of May 1999 with a median follow‐up of 1574 days post‐transplant. The patients transplanted with BM had faster engraftment and lower rates of graft‐versus‐host disease, 100‐day mortality and overall mortality. HLA‐matched sibling BM is preferred as a source but transplantation using unrelated UCB is still an option in treating pediatric bone marrow failure syndromes. [ABSTRACT FROM AUTHOR]

Aim: Chimerism analysis post HPCT has become an essential tool for the surveillance of engraftment, graft rejection or relapse. MDC is a dynamic process reflecting the competition of multiple coexisting cell populations. In the setting of a second HPCT it may be difficult to assess the percentage of donor chimerism or the risk of relapse. A retrospective study on chimerism within the framework of MDC was demonstrated in the recipient’s graft. Methods: We studied 13 patients (9 males, 4 females), median age of 9 (1-16) years, who received a 2nd HPCT for acute leukemias (ALL n=9, AML n=3, Infant Leukemia n=1) who relapsed after the 1st HPCT. All patients achieved complete remission with full donor chimerism (FDC) of the 1st donor prior to the 2nd HPCT. AlleleSEQR™ qPCR (RUO) was used in this analysis. The technology follows the comparative ΔΔ CT method for relative PCR quantification with the known DNA quantity in a reference sample. Our stepwise approach to MDC analysis began with identifying the correct reference sample for pre transplant evaluation. Assessment of individual possible informative markers for: recipient, 1st donor and 2nd donor were performed. There were two combinations to be measured: recipient vs. 2nd donor and 1st donor vs. 2nd donor. Results: All cases engrafted and recovered their counts of ANC>500 /μl in a median of 18.5 (10-25) days and un-sustained platelets >20.0 /μl in 19 (0-54) days. Chimerism was evaluated weekly for the first 100 days. Three patterns were observed: a) FDC + 2nd donor (n=8) (62%), b) MDC without recipient (n=3) (23%) and c) MDC + recipient (n=2) (15%). Of 13 patients, three relapsed 2 with pattern C and 1 in pattern A. Conclusions: It is imperative to identify the informative assays for all 3 genotypes in order to assess MDC and its outcome properly. This study provided a novel approach in the interpretation of MDC. Presence of recipient cells post second HPCT illustrated a higher chance of relapse. [Copyright &y& Elsevier]

WT1 gene expression has been proposed as a useful marker of minimal residual disease in leukaemia. Its utility in paediatric haematopoietic stem cell transplantation (HSCT) has not been studied. We studied the prognostic value of WT1 expression in peripheral blood prior to HSCT in 36 children with acute myeloid leukaemia (AML). Samples were obtained 2 weeks pre-transplant to determine the level of WT1 expression. WT1 expression was normalized using K562 cells as a control and a relative value of 0·5 was chosen as the cut-off point between high and low WT1 expression. The median level of pre-transplant WT1 expression in the 36 patients was 0·09 (range 0·0001–11·0), with 11patients having WT1 ≥ 0·5 and 25, WT1 < 0·5. After HSCT, 76% of patients with high pre-transplant WT1 expression relapsed, in contrast to 0% of the patients with low WT1 expression. Those with high WT1 expression had significantly lower 5-year event-free survival (EFS) (18%, 95% CI 0–40%) as compared to those with low WT1 expression (68%, 95% CI 50–86%, P = 0·007). Multivariate analysis showed that pre-transplant WT1 level is the only significant prognostic factor for the difference in EFS. Our finding suggests that elevated WT1 gene expression before HSCT in paediatric AML predicts relapse and poor long-term EFS. A larger prospective study is warranted to compare the value of high WT1 expression and other markers of minimal residue disease in predicting clinical outcomes after HSCT. [ABSTRACT FROM AUTHOR]

Abstract: Umbilical cord blood (UCB) has become a frequent source of allogeneic hematopoietic stem cells for transplantation. Of theoretical concern is a potential decrease in the graft vs. leukemia (GvL) effect, given the lesser degree of graft vs. host disease (GvHD) with this donor source. We report a case of recurrent acute non-lymphoblastic leukemia (ANLL) following stem cell transplantation with unrelated mismatched UCB, which responded to the induction of GvHD. The response was documented both morphologically and by evaluation of chimeric engraftment by molecular DNA techniques. In addition, WT-1, a purported marker of minimal residual disease in acute leukemia, correlated with remission status in this patient. In summary, the GvL effect is seen with allogeneic UCB transplantation and has the potential to be induced along with GvHD. [ABSTRACT FROM AUTHOR]