The haematology analyser Coulter GEN.S gives a set of data -'positional parameters'- defining white blood cell (WBC) populations by mean of index values (mean and standard deviation of volume, conductivity and scatter, used to identify the WBC populations). The volume and conductivity parameters related to the lymphocytes were analysed at diagnosis in patients suffering from chronic B-lymphocytic leukaemia (B-CLL), other non-CLL lymphoproliferative disorders (OLPD) and viral diseases. The standard deviation of volume index (SDVI) is significantly higher in the three groups, whereas the mean volume index (MVI) is significantly lower in B-CLL, and increased in OLPD and viral diseases. These two groups could be distinguished by their mean conductivity index (MCI), which is significantly lower in viral disease group. Cut-offs were calculated for each parameter by the mean of Receiver Operating Characteristic (ROC) analysis. The study of the detection performances showed that the combination of lymphocyte count with SDVI, MVI and MCI could be used with a good sensitivity and specificity to discriminate between the most frequent lymphocyte pathologies, even in patients with normal lymphocyte count.

Quantitative measures of allele-specific gene expression allow the indirect detection of mutations or sequence variants in regulatory elements or in other non-coding regions that may result in significant physiological or pathological changes of gene expression and may contribute to Mendelian or multifactorial disorders. We have devised a simple method, based on RT-PCR and single nucleotide primer extension (SNuPE) with unlabelled dideoxynucleotides, followed by DHPLC (denaturing high performance liquid chromatography). We established optimal conditions for separation of the extended products corresponding to the alleles of the c.655A>G (p.Ile219Val) SNP, which is the most frequent exonic polymorphism of MLH1. We then genotyped 99 unrelated control subjects and measured the allele-specific MLH1 expression in the 40 heterozygous controls found in this group. This method allowed us to define a narrow range of normal biallelic expression of MLH1, each allele contributing between 44.7% and 55.3% of the total expression. We then measured the allele-specific expression in hereditary nonpolyposis colorectal cancer (HNPCC) patients with MLH1 mRNAs bearing different stop-codon or frame-shift mutations, or in-frame deletions, in order to detect the effects of nonsense-mediated mRNA decay (NMD). Defects that induce mRNA instability were identified unambiguously and the data were consistent with current models of NMD. This study provides a sensitive tool to identify indirectly MLH1 defects that may escape detection in genomic DNA screenings but result in a quantitative change at the mRNA level.

The analysis of CPD in combination with CytoDiff analysis shows promise for the rapid and accurate identification of lymphocyte pathologies in routine practice.

Background and Objectives Implementing a ferritin testing policy for whole blood (WB) donors may prevent iron deficiency (ID, ferritin <26 ng/mL) and anaemia, but may induce donation losses. As part of a national prevention plan in France, we aimed to estimate its impact on ID, anaemias and WB donations among donors at high risk of ID. Materials and Methods A micro‐simulation model was developed to evaluate different scenarios compared to the current situation without ferritin testing as a reference scenario. The following scenarios were simulated: a minimum scenario with a 6‐month deferral for donors with absent iron store (AIS, ferritinemia <15 ng/ml), a main scenario with additional delayed invitations for donors with ferritinemia 15–25 ng/ml and a supplementation scenario with additional iron supplementation for 50% of the donors with AIS. Results In the main scenario, 52,699 WB donations per year were estimated to be lost after 1 year (−8%), falling to 27,687 (−4.7%) after 5 years. IDs and anaemias were reduced by 13.6% and 29.3%, respectively, after 1 year. The supplementation scenario increased the number of prevented IDs and anaemias to 24.1% and 35.4%, respectively, after 1 year, and halved the number of anaemias at 5 years. The latter scenario also had the least impact on the number of donations (−3.2% after 5 years). Conclusion A ferritin testing policy resulting in delayed donations for ID donors is effective in reducing IDs and anaemias, but significantly impacts the number of donations, thereby posing a self‐sufficiency challenge.

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