High prevalence of periodontitis in blood donors and the possibility of questionnaire-based screening - results of a cross-sectional study.

BACKGROUND: Periodontitis is an inflammatory disease of high prevalence and, thus, of potential relevance to the management of blood donation. OBJECTIVES: The aim of this cross-sectional study was to assess periodontal health and its associations to common blood parameters, as well as questionnaire-based periodontitis screening in blood donors. METHODS: Generally healthy blood donors were recruited and underwent oral examination. Thereby, the decayed-, missing- and filled-teeth index (DMF-T) and periodontal status, including periodontal probing depth and clinical attachment loss, were assessed. Based on periodontal status, periodontitis severity was classified into no/mild, moderate or severe. Six yes/no questions regarding periodontal complaints and history were asked. Furthermore, common blood parameters were analysed. RESULTS: A total of 148 participants (mean age 53·33 years) were included. The DMF-T was 15·28 ± 6·44. Nearly three quarters of participants suffered from a periodontitis (moderate 59·5% and severe 14·8%, total periodontitis 74·3%). Periodontitis severity was associated with the history of dental visits caused by periodontal complaints (P < 0·01) and previous periodontal therapy (P < 0·01). Only procalcitonin was initially found to be associated with blood periodontitis severity (P = 0·02). This observation was not confirmed by post-hoc testing between subgroups (Pi > 0·2). No further association between periodontitis severity and blood parameters was found (Pi > 0·05). CONCLUSION: The prevalence of periodontitis in German blood donors is high. However, further studies with sensitive testing of bacteria in peripheral blood are required in order to determine the relevance of this result for the safety of blood components.

Monitoring and treatment of anti-D in pregnancy.

Prophylactic anti-D is a very safe and effective therapy for the suppression of anti-D immunization and thus prevention of haemolytic disease of the foetus and newborn. However, migration from countries with low health standards and substantial cuts in public health expenses have increased the incidence of anti-D immunization in many "developed" countries. Therefore, this forum focuses on prenatal monitoring standards and treatment strategies in pregnancies with anti-D alloimmunization. The following questions were addressed, and a response was obtained from 12 centres, mainly from Europe.

Diagnostic accuracy of noninvasive polymerase chain reaction testing for the determination of fetal rhesus C, c and E status in early pregnancy.

OBJECTIVE: The aim of the study was to determine the sensitivity, specificity and accuracy of noninvasive tests for the fetal rhesus CcEc (RHCE) alleles C, c and E in early pregnancy. DESIGN: A prospective clinical trial was carried out to evaluate diagnostic accuracy. SETTING: Women were recruited at four centres specialising in prenatal diagnosis. Peripheral blood and amniotic fluid samples were obtained and sent to a single laboratory for analysis. SAMPLE: A total of 233 tests (46 for C, 87 for c and 100 for E) were performed on 181 specimens obtained from pregnant women at weeks 12 to 28 (median week 16) of gestation. METHODS: Following automated extraction of fetal DNA from maternal plasma, two different real-time polymerase chain reaction (PCR) protocols were used for the detection of the C, c and E alleles of RHCE. The results of the PCR were compared with genotyping results for the amniotic fluid. MAIN OUTCOME MEASURES: Failure rate, sensitivity, specificity and accuracy were the main outcome measures. RESULTS: Unequivocal results were obtained for all specimens. With the first PCR protocol, the sensitivity was 100% for C, 38% for c and 59% for E. In contrast, with the second protocol, the sensitivity for C, c and E was 100%. The specificity for all assays was found to be between 99% and 100%. CONCLUSIONS: A highly accurate protocol has been identified for the detection of fetal RHCE alleles in maternal plasma in early pregnancy. This noninvasive approach can be considered as a useful test in the management of pregnancies with anti-c, anti-E or anti-C alloimmunisation.

Molecular background of Rh D-positive, D-negative, D(el) and weak D phenotypes in Chinese.

BACKGROUND AND OBJECTIVES: The aim of this study was to elucidate the genetic background of D-negative and D(el) in the Chinese population. MATERIALS AND METHODS: We investigated nine D-positive, 76 D-negative, 26 D(el) and three weak D Chinese individuals by amplification and sequencing of the complete coding region of the RHD gene from genomic DNA. A new RHD polymerase chain reaction with sequence-specific primers (PCR-SSP) method was developed with optimized specificity for typing Chinese individuals. RESULTS: In D-positive samples the RHD sequence was in complete concordance with RHD in other populations. In 12 of 76 (15.8%) D-negative individuals we detected regions of RHD. Three new alleles were found. All 26 D(el), as well as two weak D, individuals carried an RHD 1227A allele. In the remaining weak D sample we identified a weak D type 15. CONCLUSIONS: It should now be possible to correctly predict the RhD phenotype in Chinese subjects. D(el) can also be designated as a particular weak D type.

Prospective, randomized, sequential, crossover trial of large-volume vs. normal-volume leukapheresis procedures: effects on subpopulations of CD34(+) cells.

Some data exist on the influence of leukapheresis volume on the number of harvested peripheral blood hematopoietic progenitor cells (HPC), but less is known about the influence on the composition of HPC. We therefore performed a prospective, randomized crossover trial to evaluate the effect of large-volume (LVL) vs. normal-volume leukapheresis (NVL) on subpopulations of CD34(+) cells in the harvest product of 15 patients with breast cancer and 8 patients with non-Hodgkin's lymphoma. Patients were randomly assigned to start either with an LVL on day 1 followed by an NVL on day 2 or vice versa. The number of HPC, the extraction efficiency defined as difference between yield in the harvest and decrease in peripheral blood, and the relative proportion as well as the absolute numbers of CD34(+) cells coexpressing CD38, CD90, HLA-DR, CD117, CD7, CD19, CD41, or CD33 were evaluated. There was no significant difference with regard to the percentages of the subsets on comparison of LVL to NVL procedures. Only the absolute median number of CD34(+)HLA-DR(-) cells was significantly (P=0.02) higher in LVL harvests compared with the corresponding NVL components, which can be explained on the basis of the higher yield and the higher extraction efficiency in LVL compared with NVL. LVL results in a higher yield of CD34(+) cells and leads to an intra-apheresis recruitment of HPC but the relative composition of the harvested CD34(+) cells is not changed significantly. In addition, the amount of early, HLA-DR(-), hematopoietic HPC seems to be increased by an LVL.

RHD sequencing: a new tool for decision making on transfusion therapy and provision of Rh prophylaxis.

The serological differentiation of weak D from partial D, D-negative and D-positive is not always unequivocal. Therefore, sequencing of the RHD gene is required in some cases. Very recently, several new differences between RHD and RHCE have been identified which permitted us to design primers close to the exon/intron boundaries of the RHD-exons. We evaluated these primers in 83 D-positive and 18 D-negative blood donors and applied the new method for the characterization of the RHD gene in six individuals with weak D phenotype. The amplification reactions were concordant with serological findings in 100 of 101 donors (99.0%). In one D-positive donor the PCR for exons 2 and 5 gave a negative result, while the sequence of the remaining eight exons was unchanged. By sequencing samples with very weak D serological reactions, we identified weak D type 4.2.2 and weak D type 15, both previously reported to be associated with anti-D-alloimmunization. Consequently, we recommended the selection of D-negative blood in the weak D type 4.2.2 patient, and the provision of Rh prophylaxis for pregnant women with weak D type 15. In summary, a new RHD sequencing method was developed which can be applied if serological reactions are inconclusive.

Filtration of methylene blue-photooxidized plasma: influence on coagulation and cellular contamination.

BACKGROUND: Virus inactivation of plasma can be achieved by photodynamic methods in the presence of phenothiazine dyes such as methylene blue (MB). Subsequent filtration may increase the efficacy of virus inactivation and reduce adverse effects of WBC contamination and MB. STUDY DESIGN AND METHODS: This study examined the effect of filtration with three different filters (MBF1, MBF2, and MBF3) on MB concentration, residual cells, coagulation factors, and activation measures of coagulation, fibrinolysis, and complement in MB-treated (1 microM/L) plasma units. RESULTS: Filtration reduced the concentration of MB by > or = 89 percent. WBCs were depleted by 92 percent (MBF1) and >99.9 percent (MBF2 and MBF3). Treatment with MB significantly decreased the coagulation potency from levels in untreated plasma, as measured by thromboplastin time ratio (112 +/- 18% vs. 95 +/- 11%), activated partial thromboplastin time (40 +/- 3 sec vs. 44 +/- 3 sec), thrombin time (16.9 +/- 1.1 sec vs. 18.6 +/- 1.5 sec), factor VIII (1.09 +/- 0.21 U/mL vs. 0.85 +/- 0.13 U/mL), and vWF (0.94 +/- 0.65 U/mL vs. 0.65 +/- 0.24 U/mL). Filtration did not further decrease these values, while factor XI (0.75 +/- 0.22 U/mL vs. 0.37 +/- 0.20 U/mL) and prekallikrein values decreased in MB plasma units filtered with the MBF3. In addition, activated factor XII (0.7 +/- 0.5 microg/L vs. 4.5 +/- 1.0 microg/L) increased. CONCLUSION: WBCs and MB can be eliminated from MB-treated plasma units by filtration. Differences in biocompatibility of the different filters, especially the influence on the contact phase of coagulation, must be taken into consideration.

Hepatitis C virus transmission through quarantine fresh-frozen plasma.

In 1994, quarantine fresh-frozen plasma (Q-FFP) was introduced in Germany in order to reduce the risk of HIV and HCV transmission. In 1998, an acute HCV infection of a patient was reported to us. The look-back revealed that this patient had received two Q-FFP from a donor who had seroconverted for HCV in the meantime. Recipients of further plasma donations from this donor were identified. Back-up specimens of these donations were investigated in several laboratories. A total of 25 additional HCV-PCR positive plasma units had been transfused to 12 further patients. HCV infections were diagnosed in seven of these recipients, three patients had already been deceased. One of the remaining two recipients was already HCV positive prior to transfusion, in the other patient, no HCV infection was detectable. This patient had received three units of an "early" plasma donation , which was tested negative by PCR in one laboratory, but positive in the other. The subsequent, clinically infectious donation had the same discrepant PCR results. Thus, eight cases of HCV transmission were revealed and classified as "certain" with regard to causality, also due to an identical HCV genotype, i.e. 3e. Some of these infections would have been prevented by application of a different anti-HCV assay. The assay used in the respective plasmapheresis station was in-sensitive in this individual case for more than 400 days after the first PCR positive donation. This caused the release of the above mentioned infectious units. Upon re-testing the backups, three of four other anti-HCV assays revealed a positive result already 104 days after the first PCR-positive donation. The donor had increased ALAT levels (> 23 IU/L) at nine of 28 donations, two of these were higher than 2.5 times the upper normal limit, and two were higher than 68 IU/L, which is the cut-off value for male blood donors in Germany. The results of these (look-back) studies arouse several queries, i.e. differences in the diagnostic sensitivity between current anti-HCV and PCR tests, the accuracy of risk-estimates (especially when based on hemovigilance studies for Q-FFP), the value of ALAT testing, and currently practised release algorithms for Q-FFP.

Testing of individual blood donations for HCV RNA reduces the residual risk of transfusion-transmitted HCV infection.

BACKGROUND: To allow cost-effective RNA testing with NAT techniques, the national authorities of several countries have planned or already introduced tests of mixed specimens, that is, plasma pools. STUDY DESIGN AND METHODS: High-throughput extraction, amplification, and detection of HCV RNA from individual blood donations were optimized and validated. The feasibility of the method and the frequency of anti-HCV-negative, HCV RNA-positive donations were determined in a prospective study of 27,745 allogeneic and 792 autologous individual donations. RESULTS: The 50- and 95-percent detection limits of the method were determined at 44 IU per mL and 162 IU per mL, respectively (World Health Organization HCV reference material). When 201 HCV RNA-positive sera were taken as a reference, the sensitivity was 97.5 percent. The assay specificity was determined at 99.77 percent. During a 20-month period, two seronegative blood donors tested positive in HCV PCR. The viral load of these donations was 6 x 10(6) and 3 x 10(7) copies per mL, respectively. Thus, the yield of HCV RNA testing in this study was 7. 63 per 100,000 screened donations (95% CI, 1.25-22.07). In both PCR-positive donors, seroconversion was found in subsequent blood samples. CONCLUSION: This study compares the feasibility of single-donation HCV RNA screening, with the detection of a relatively high percentage of window-phase donations, to data reported from groups using HCV RNA testing of plasma pools. The relative yield of NAT of individual donations versus minipools should be directly investigated in the near future.

D(Va) category phenotype and genotype in Japanese families.

BACKGROUND AND OBJECTIVES: The genetic background of the D(Va) category phenotype has been described in two Caucasian individuals. We were interested in the RHD sequence of 7 Japanese D(Va) individuals and their families. MATERIALS AND METHODS: With SSP-PCR we tested exons 4, 5 and 7 of the RHD gene and used restriction enzymes for testing nucleotide associated with the D(Va) phenotype. RESULTS: A single RHD G667 C697 allele was present in 5 individuals with D(Va) category phenotype, and in 2 individuals we found a D-CE-D hybrid gene (exon 5 had been replaced). The D(Va)Ce gene complex was found in all families. CONCLUSION: The changes of the RHD gene described in European D(Va) individuals were also observed in Japanese families.

Severe HDN due to anti-Ce that required exchange tranfusion.

BACKGROUND: Rh system antibodies are commonly encountered in blood bank practice as well as during pregnancy. Nevertheless, no examples of anti-Ce (RH7) have been reported as a cause of HDN that requires exchange transfusion. CASE REPORT: A 38-year-old woman in her fourth pregnancy was typed as blood group O D+, C-, c+, E+, e-. Anti-C and anti-e were detected in her serum during a routine prenatal work-up. Further evaluation, including flow cytometric analysis, revealed the presence of a strong anti-Ce and a weak anti-e. Her partner was typed as group A D+, C+, c-, E-, e+. A seemingly healthy male infant was delivered at 40 weeks of gestation. The infant's RBCs were typed as group O D-, C+, c+, E+, e+ with a positive DAT (titer 128). Twenty-five hours after birth, the baby had to be transferred to the neonatal intensive care unit because of rapidly rising total serum bilirubin. Despite intensive treatment, including double phototherapy, albumin infusion, and the administration of furosemide and IVIG, the total serum bilirubin level increased during the following day and exchange transfusion with 2 units of type O D-, C-, c+, E+, e- had to be performed; this resulted in a prompt decrease in total serum bilirubin without relapse. CONCLUSION: Anti-Ce caused severe HDN requiring exchange transfusion. This highlights the need for a close follow-up throughout pregnancy if unexpected RBC antibodies are present, to permit the provision of compatible blood in case of a rare antibody.

Quantitative PCR for counting residual white blood cells in blood products.

Leukocyte depleted blood components are frequently used to reduce alloimmunization and the risk of transfusion transmitted infection. Counting residual white blood cells in filtered blood products requires sensitive and reliable techniques. After separation of white blood cells from 500 microliters of 20 non-filtered and 54 filtered blood products we used polymerase chain reaction (PCR) and fluorimetric detection for the quantification of genomic DNA. The results were compared with results from Nageotte chamber counting. The accurate limit of detection of PCR was determined at 1 WBC/microliter (intra-assay coefficient of variation: 16.3%). PCR correlated well with Nageotte chamber counts (r = 0.77, p < 0.001, n = 74). Concordant results were obtained in 51 filtered and 20 non-filtered blood products. Discrepant results were obtained in 3 filtered whole blood units: In these blood products > 12 WBC/microliters were counted in Nageotte chamber and PCR gave a negative result. After component preparation fresh-frozen plasma and red cell concentrates of these units contained < 1 WBC/microliter using both methods. In conclusion we describe a quantitative PCR method which had about the same sensitivity and specificity as Nageotte chamber testing. However, PCR is more laborious than the standard method. As well, as reliable PCR testing requires expensive instruments and staff experienced in molecular biology, the standard method is more cost effective.

Application of RHD and RHCE genotyping for correct blood group determination in chronically transfused patients.

BACKGROUND: In chronically transfused patients, conventional blood group typing may be impossible because of mixed-field agglutination. STUDY DESIGN AND METHODS: In 27 patients with congenital anemia and lifelong transfusion history, genotyping for D, RHD, and RHCE was performed with polymerase chain reactions. These results were compared with the blood group typing results documented in the medical record. RESULTS: Two of 27 cases had been typed D-negative by serologic tests and D-positive by genotyping. In 20 patients, the CDE formula had been determined serologically according to the medical record; 4 of these patients were Cc by serologic tests and C/C by genotyping. One patient typed ee by serologic tests, and genotyping revealed heterozygosity (E/e). CONCLUSION: In patients with a lifelong transfusion history, serologic blood group determination may be impossible, and pretransfusion test results are not always available or reliable. In whites, Rh-matched transfusions are possible with genotyping. The genetic background of the RH genes has to be elucidated in other ethnic groups, such as in black patients with sickle cell disease, before genotyping can be applied without restriction.

High-throughput extraction, amplification, and detection (HEAD) of HCV-RNA in individual blood donations.

BACKGROUND: High-throughput nucleic acid amplification techniques (NATs) are required for the detection of viral genomes in individual blood donations and might be helpful in any virological laboratory. OBJECTIVE: To develop and automate a method for the detection of hepatitis C virus RNA in individual blood donations, compatible with the time schedule of routine blood bank screening an product release. STUDY DESIGN: The viral RNA was isolated with the use of target specific capture oligonucleotides and magnetic beads. This extraction method was combined with reverse transcription/amplification (RT/PCR) and fluorescence detection. We adapted our method on a pipetting robot and pipetted all steps in a single room. When the pipetting was completed, microtiter plates were heat-sealed with foils and placed into a thermocycler. Positive reactions were detected with a fluorescent dye in a second room. Aerosols were avoided with programmed slow pipetting steps and with a special device constructed for the removal of the used disposable tips. During a 7 month period, we used this method in routine testing of individual donations prior to the release of all blood components. RESULTS: The total number of 11,700 individual donations including platelet concentrates were analysed. We tested up to 192 specimens in one run within 7 h. The frequency of cross-contamination using the automated procedure was 0.1%. Five specimens have been found repeatedly reactive for HCV-RNA, four of these were anti-HCV positive, one sample from a repeat donor was negative in anti-HCV assays. A seroconversion was detectable at his next presentation, 6 months later. CONCLUSION: In this pilot study, we demonstrate that automated HCV-RT-PCR testing is practicable for individual donations in high-throughput. Additionally, the described PCR approach could easily be adapted to the detection of other viral genomes by the use of specific primers.

RHD genotyping in weak D phenotypes by multiple polymerase chain reactions.

BACKGROUND: Weak D phenotypes involve a quantitative variation of D. The genomic basis in weak D has been disputed, however. STUDY DESIGN AND METHODS: Five sequence-specific polymerase chain reactions (SSP-PCRs) on exons 2, 5, and 7 of the RHD gene were evaluated in 248 white and 98 Japanese blood donors and compared with the results obtained by amplification of intron 4 and serology. All methods and SSP-PCR testing on the 3' non-coding region of the RHD gene were applied to the genotyping of 94 DNA samples derived from individuals expressing weak D phenotypes. RESULTS: Concordant results were obtained with all genotyping and phenotyping methods in testing 201 D-positive and 145 D-negative donors. Four of 94 weak D samples were typed as D-negative by amplification of intron 4 and SSP-PCR on exon 5. Phenotyping with monoclonal antibodies revealed a DVI category in one of these cases and DFR phenotype in three of these cases. One weak D sample, which reacted like normal D-positive cells with all applied monoclonal antibodies, was typed falsely negative by SSP-PCR on exon 5 because of a point mutation at nucleotide 667 (T-->G) that resulted in a Phe223Val amino acid substitution. In this individual, heterozygosity was found at two other amino acid positions (Glu233Gln and Val238Met) by restriction fragment length polymorphism analysis. CONCLUSION: Genetic diversity in weak D phenotypes is rare. Only 1 of 90 true weak D phenotypes (1.1%) had a genetic variation in testing on seven gene regions of the RHD gene.

Evaluation of the GTI-ASP-1 platelet antigen genotyping kit for the determination of the HPA-1 genotype.

The human platelet antigen system HPA-1 is involved in most cases of neonatal alloimmune thrombocytopenia and posttransfusion purpura, and occasionally causes refractoriness to platelet transfusions. Complete concordance was obtained in genotyping for HPA-1 in all samples tested with the HPA-1 genotyping kit and a ligation-based typing method. However, the genotyping kit is less sensitive than ligation- based typing, which could be of importance when testing cells from amnionic fluid or from chorionic villi.