To investigate whether the effect of ABO blood group on plasma von Willebrand factor (vWF) levels is mediated by the ABH antigenic determinants carried on N-linked glycans of vWF, we studied 158 group A and group O healthy volunteers. vWF antigen (vWF:Ag) and factor VIII antigen (FVIII:Ag) levels were highest in A(1)A(1) individuals and higher in A(1)O(1) than in A(2)O(1) or O(1)O(1) individuals. Plasma A transferase activity and the amount of A antigen expressed per unit vWF (AvWF) were significantly higher in A(1)A(1) than in A(1)O(1) individuals and higher in A(1)O(1) than in A(2)O(1) individuals. AvWF was correlated strongly with plasma levels of A transferase activity. Thus, we have clearly demonstrated a direct relationship between ABO genotype, A transferase expression, and the amount of A antigen expressed on circulating vWF. H antigen expression per unit vWF (HvWF) was highest in group O individuals. Among group A individuals, the pattern of HvWF expression was A(2)O(1)>A(1)O(1)>A(1)A(1). In group O and group A(2)O(1) individuals, HvWF was inversely correlated with plasma vWF levels. In contrast, among group A(1)A(1) and A(1)O(1) individuals, there was no relationship between AvWF and plasma vWF levels. These findings suggest that it is H antigen expression that mediates the ABO effect on plasma vWF concentration.

Jean-Pierre Allain and colleagues argue that, while unintended, the foreign aid provided for blood transfusion services in sub-Saharan Africa has resulted in serious negative outcomes, which requires reflection and rethinking.

Blood Services, which, in the UK, spend over 0.5% of the NHS budget, are generally subject to quality, regulatory, economic and political authority. As only persons in good health should give blood, Services have refined donor selection criteria and aim to base them on evidence; but they also have to balance the number of donations collected with product demand. Applying selection criteria inevitably leads to deferrals, which donors experience very negatively. Compared with successful donors, even temporary deferrals reduce return rates significantly, especially of first attenders. In order to encourage donor return and sustain supplies, selection criteria should be optimal. However, a major tool for managing patients--evidence from randomized controlled trials (RCTs)--cannot apply to donor selection, so criteria have to be defined by alternatives, such as clinical studies, epidemiology and even what experts deem to be pathophysiologically feasible. The recommended volume of blood taken from each donor at each attendance (450 mL, which was based on old studies) was increased because of greater processing losses (buffy-coat derived platelets, leucofiltration etc.). Although faint rates and donation-induced iron depletion are reduced by lowering bleeding volume and bleeding less frequently, other optimizing strategies including iron supplementation have been trialled and could be enhanced by more RCTs. Better but more complex indicators of donor iron status than one-off Hb thresholds are possible. Regulators and decision-makers must encourage more studies. This review does not consider aphaeresis donors of blood components other than red cells in detail, or the prevention of transfusion-transmitted infections.

Summary. Previous reports on the effect of Secretor and Lewis blood groups on plasma factor VIII±von Willebrand factor (FVIII±VWF) levels have produced con¯icting ®nd-ings. To determine whether either or both loci can in¯uence plasma FVIII±VWF complex levels, we studied the relationship between Secretor and Lewis genotypes, determined de®nitively using polymerase chain reaction±restriction fragment length polymorphism analysis, and plasma FVIII coagulant activity (FVIII:C) and VWF antigen (VWF:Ag) levels in 136 healthy volunteers. Overall, signi®cantly higher VWF:Ag levels were found in those individuals homozygous for the Se allele (genotype SeSe) than in those heterozygous for the Se allele (P < 0á001). To minimize any confounding in¯uence of ABO genotype/phenotype, we investigated the relationship between Secretor genotype and plasma FVIII±VWF levels within individuals of the same ABO blood group genotype. In the subgroup analysis of group O 1 O 1 individuals alone, VWF:Ag levels were again signi®cantly higher in those individuals with Secretor genotype SeSe than in those either heterozygous or homozygous for the se null allele. Among A 1 O 1 subjects, homozygous Secretors also had signi®cantly higher VWF:Ag levels. In contrast, we found no relationship between Lewis genotype and either VWF:Ag or FVIII:C levels. This study is the ®rst based on genotypic rather than serological analysis, and resolves the previously confounding effects of the Lewis and Secretor loci on plasma FVIII±VWF complex levels.

Women (568) and men (531) attending blood donation sessions in Wessex in September, 1992, were assessed for anaemia by the standard CuSO4 method on finger-prick (FP) blood samples. The haemoglobin (Hb) concentration on FP samples and on venous blood was also checked using the HemoCue. Different FP samples from the same donors revealed a wide variation on HemoCue. We recommend retaining the CuSO4 method on FP samples as the initial screen, and follow-up of apparent failures by determining the Hb concentration on venous sampling with the HemoCue. As 54% of females were found on venous samples to be below the current recommended threshold (125 g/L) for Hb concentration, we also recommend lowering the threshold to 115 g/L for women, and to 130 g/L for men. We further recommend a close re-examination of normal haematology values for adults.