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N van der Werf

Publications and source records attributed to N van der Werf.

4 recordsLinked to original sources
PubMed2001

Platelet glycoprotein complex Ia/IIa antibodies cause neonatal alloimmune thrombocytopenia but do not inhibit megakaryopoiesis and platelet recovery after allogeneic cord blood stem cell transplantation.

A sibling cord blood (CB) transplantation was performed in a boy with Wiskott-Aldrich syndrome. The CB (31 x 10(6) CD34(+) cells) derived from a newborn sister with neonatal alloimmune thrombocytopenia (NAIT) with 40,000 platelets/microl, caused by a maternal anti-HPA-5b and HLA-A2 antibody. Maternal serum did not inhibit clonogenicity after in vitro testing of megakaryopoiesis. Accordingly, this CB was accepted for sibling transplantation. The transplantation showed a good course with fast and sustained hematopoietic reconstitution (granulocytes >500/microl on day +16, platelets >50,000/microl on day +30). This case demonstrates a successful CB transplantation from a donor suffering from NAIT.

Antigens, CD↗
PubMed1999

Volume-dependent collection of peripheral blood progenitor cells during large-volume leukapheresis for patients with solid tumours and haematological malignancies.

We investigated the efficacy of peripheral blood progenitor cell (PBPC) collection during large-volume leukapheresis (LVL) in patients with solid tumours and haematological malignancies (n = 18). The time- and volume-dependent harvest of leucocytes (WBC), mononuclear cells (MNC), CD34+ cells and colony-forming cells (CFU-GM) during LVL was analysed in six sequentially filled collection bags processing four times the patient's blood volumes. The amounts of leucocytes (WBC) and the purity of mononuclear cells (MNC%) did not show any significant changes during LVL. The percentage of CD34+ cells remained constant for the first three bags but consecutively decreased from initially 1.71% CD34+ cells in the beginning of LVL to finally 1.34% CD34+ cells (P = 0.02). The mean numbers of colony-forming cells (CFU-GM) decreased from 74 microL-1 to 59 microL-1 during LVL (P = 0.16). Furthermore, the comparison of volume-dependent PBPC collection for patients with high, medium and low total yields of CD34+ cells showed similar kinetics on different levels for the three groups. We concluded that - relative to the initial total amount of PBPC harvested - comparable numbers of progenitor cells can be collected during all stages of LVL with a slight decreasing trend processing four times the patient's blood volumes.

Adolescent↗
PubMed1998

Cerebral venous sinus thrombosis in infancy and childhood: role of genetic and acquired risk factors of thrombophilia.

UNLABELLED: Over a 3 year period the R506Q mutation in the factor V (FV) FV:Q506 gene, FV, factor XII (FXII), prothrombin, protein C, protein S, antithrombin, heparin cofactor II, anticardiolipin antibodies and lipoprotein (a) (Lp(a)) were measured in 32 infants and children with sinus thrombosis. Heterozygous FV:Q506 (n=5), homozygous FV:Q506 (n=2), homozygous FXII deficiency (n=1), protein C deficiency type I (n=5), protein C deficiency type II (n=1), antithrombin deficiency type I (n=1) increased Lp (a) (n=5), activated protein C-resistance without mutation in the FV gene (n=2), and increased anticardiolipin IgG antibodies (n=2) were diagnosed in the children investigated. In a further two patients we found combinations of increased Lp(a) with moderate hyperhomocystinaemia and heterozygous plasminogen deficiency with heterozygous FXII deficiency. In addition, increased anticardiolipin IgG antibodies were found in combination with heterozygous FV:Q506 (n=1) and protein C type I deficiency (n=2) respectively. Out of 32 patients with venous sinus thrombosis, 3 showed additional peripheral venous vascular occlusion. Contributing factors were present in 31 out of 32 patients investigated. Family members of 10 affected children had suffered from venous thrombo-embolism prior to the study. CONCLUSION: Our data suggest that additional contributing factors may promote manifestation of cerebral venous sinus thrombosis in infants and children with an inherited prothrombotic state. Further prospective studies are required to evaluate their potential role as "triggering" agents.

Child↗