ABSTRACT
BACKGROUND: With the implementation of universal leucoreduction of blood components in several industrialised countries, the problems associated with leucocyte filtration of sickle cell trait blood have been reconsidered. In this study, we assessed the use of high performance filters for leucoreduction of packed red blood cells donated from subjects with sickle cell trait and evaluated the incidence and recurrence of altered red blood cell filterability. MATERIALS AND METHODS: Twenty-one volunteer donors with HbAS were compared to 21 donors with HbAA selected at random. The main parameters analysed were residual white blood cell count and post-filtration haemolysis. Filtration times, flow, volume and haemoglobin loss of the packed red blood cells were also determined. RESULTS: In all, 33% of HbAS red blood cell units with slow flow and prolonged filtration time had high residual white blood cell counts. In 7.7% of cases, despite flow through the filter, the units were not leucoreduced properly. Haemoglobin and volume loss were significantly greater in the slow filtration group. Significant post-filtration haemolysis was present in half of the units with high residual white blood cell counts. DISCUSSION: Despite the development of new technology for filtration, the problem of filterability of blood from donors with sickle cell trait is not yet resolved. Altered filterability of blood from sickle cell trait donors cannot be predicted from the donors' characteristics and recurrence of the problem is not observed between donations. Screening blood donors for sickle cell trait to ensure the safety and quality of blood products for transfusion does, therefore, remain a relevant issue.
Subject(s)
Leukocyte Reduction Procedures , Sickle Cell Trait/blood , Air , Anticoagulants/pharmacology , Blood Donors , Blood Preservation , Blood Volume , Citrates/pharmacology , Erythrocyte Deformability , Female , Hemoglobins/analysis , Hemolysis , Humans , Leukocyte Count , Leukocyte Reduction Procedures/methods , Male , Oxygen/pharmacology , Sampling StudiesABSTRACT
BACKGROUND: WBC depletion by filtration may prevent the transmission of HTLV-I, which requires cell-to-cell contact. The removal of HTLV-I-infected cells in routinely filtered blood cell components was measured. STUDY DESIGN AND METHODS: The study was conducted in Martinique where systematic screening for HTLV-I and -II and universal leukoreduction are mandatory. HTLV-I was quantified by use of real-time PCR in 8 RBC units and 4 PLT concentrates before and after filtration. HTLV-I proviral load in PBMNCs was determined in five of the eight HTLV-I-infected blood donors. RESULTS: The amount of MNC-associated HTLV-I DNA in RBC units before filtration was 21 x 10(6)+/- 29 x 10(6) copies (mean +/- SD). HTLV-I was detected in 4 of 8 RBC units after filtration, with a number of copies in the MNC fraction ranging from 20 to 140, following a 4.9 to 5.8 log reduction. Flow cytometry analysis performed in 2 of the filtered RBC units containing detectable HTLV-I showed suboptimal and out-of-range leukoreduction (0.56 x 10(6) and 1.22 x 10(6) residual WBCs). HTLV was not detected in filtered RBCs from the blood donor with the highest percentage of HTLV-I-infected PBMCs (9%). CONCLUSION: This study confirms that HTLV-I-infected cells can be detected in filtered blood cell components and shows that optimal leukoreduction is critical for HTLV-I removal.
Subject(s)
Blood Cells/virology , Blood Donors , Deltaretrovirus Infections/virology , Human T-lymphotropic virus 1/isolation & purification , Leukapheresis , Viral Load , Blood Platelets/virology , Computer Systems , DNA, Viral/analysis , Deltaretrovirus Infections/blood , Erythrocytes/virology , Filtration , Flow Cytometry , Human T-lymphotropic virus 1/genetics , Humans , Monocytes/virology , Polymerase Chain Reaction , Quality Control , Sensitivity and SpecificityABSTRACT
A quantitative real-time PCR assay was developed to measure the proviral load of human T-lymphotropic virus type I (HTLV-I) in peripheral blood mononuclear cells (PBMCs). The HTLV-I copy number was referred to the actual amount of cellular DNA by means of the quantitation of the albumin gene. Ten copies of HTLV-I DNA could be detected with 100% sensitivity, and the assay had a wide range of at least 5 log(10). Intra- and inter-assay reproducibility was evaluated using independent extractions of PBMCs from an HTLV-I-infected patient (coefficients of variation, 24 and 7% respectively). The performance of this TaqMan PCR assay, coupled with its high throughput, thus allows reliable routine follow-up of HTLV-I proviral load in infected patients. Preliminary results using clinical samples indicate a higher proviral load in patients with HTLV-I-associated myelopathy/tropical spastic paraparesis than in asymptomatic carriers, and also suggest the usefulness of this quantitative measurement to assess the etiological link between HTLV-I and adult T-cell leukaemia/lymphoma-like syndromes.
