Prenatal screening service for fetal RHD genotyping to guide prophylaxis: the two-year experience of the Friuli Venezia Giulia region in Italy

BACKGROUND

Fetal RHD genotyping of cell-free fetal DNA (cff-DNA) from RhD-negative pregnant women can be used to guide anti-D prophylaxis: the knowledge of fetal RhD type can direct and restrict the use of prenatal anti-D immunoglobulin exclusively to RhD-negative women carrying a RhD-positive fetus. Since November 2019 in the region of Friuli Venezia Giulia (Italy) a prenatal screening service has been offered to RhD-negative women at 22-24 weeks of gestation.

MATERIALS AND METHODS

The cff-DNA is extracted from a simple peripheral maternal blood sample to analyze the fetal RHD gene: the results are interpreted as RHD-positive fetus, RHD-negative fetus, or Inconclusive. The service is shared with all regional hospitals and tests are provided free of charge by the National Health System.

RESULTS

Overall, 142 RhD-negative pregnant women were recruited in nearly 2 years. Fetal RHD genotyping was negative in 53 pregnancies and positive in 89 pregnancies. Thus, unnecessary treatment of pregnant women and exposure to a scarce plasma-derived medicinal product was avoided, by the use of a single blood sample, in 37.8% of cases, representing 100% of the RhD-negative women carrying a RhD-negative fetus in our cohort.

DISCUSSION

The first Italian region-wide screening service for fetal RHD genotyping has been implemented for 2 years, despite the COVID-19 pandemic, in order to obtain the predicted fetal RhD phenotype before the 28^th week of gestation, during which prenatal prophylaxis is usually administered. Giving prenatal anti-D immunoglobulin exclusively to RhD-negative women carrying a RhD-positive fetus reduces the overall use of anti-D immunoglobulin, which is becoming an ever more limited resource. The high sensitivity of the procedure provides evidence that the implementation of a diagnostic test in a reference laboratory guarantees the quality of the results, the concordance of reports and the sustainability of costs, representing an excellent guide to targeted use of prophylaxis.

Horiba Micros ES 60 Blood Cell Analyzer in Blood Donor Eligibility: A Validation Study

Background: Eligibility criteria for blood donation require hemoglobin levels of ≥12.5 g/dL for women and ≥13.5 g/dL for men, and a platelet count of ≥180 × 109/L. Screening methods before donation should ensure high accuracy, precision, and ease in operation. We assessed the performance, precision, and repeatability of the Horiba Micros ES 60 (Horiba) compared to the Beckman Coulter DXH 800. Methods: Performance was compared by testing samples for each of the 11 devices across 6 sites in the Transfusion Service of Friuli Venezia Giulia Region, Italy. We measured precision by calculating the coefficient of variation (CV), concordance with ρ-Pearson’s correlation coefficient, and accuracy with F-tests. The intra-assay agreement was examined in the 11 devices, and repeatability was performed by using CV and the Kruskal−Wallis test. Results: The precision of Horiba was acceptable. Overall, ρ-Pearson’s coefficients indicated a strong correlation and positive relationship between all variables. The Bland−Altman plots showed that most of the differences lay within the limits of agreement. All CV were below the reference threshold for all the parameters. Finally, the Kruskal−Wallis test reported non-significant statistical differences for all parameters, except platelet count (p < 0.000). Conclusions: Horiba is adequate for routine pre-donation screening. The intra-assay agreement further demonstrates the accuracy of the device.

An antivenin resistant, IVIg-corticosteroids responsive Viper Induced Thrombocytopenia

In this case report the hospital management of an acute, severe thrombocytopenia in a 57-year-old man in the north-east of Italy is reported. Thrombocytopenia developed immediately after the viper bite, despite the absence of clinical signs of envenomation. No hemorrhage, ecchymoses or other signs of coagulopathy developed during the hospitalization; two doses of antivenin FAB–Fragments had no effect on thrombocytopenia, which instead responded promptly to intravenous immunoglobulins (IVIg) and glucocorticoids. Direct and indirect anti-platelet antibodies against anti-GP IIb/IIIa and Ia/IIa were detected during the treatment and turned negative after 20 weeks. The rationale of such off-label treatment is the interpretation of the thrombocytopenia as a venom-induced immune thrombocytopenia which led to splenic sequestration of platelets. To our knowledge, there is no literature about venom-induced immune thrombocytopenia against GP IIb/IIIa and Ia/IIa protein in European countries and subsequent response to IVIg and corticosteroids.

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Thrombocytopenia is a known effect of viper envenomation.

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Antivenin FAB–Fragments may be ineffective for thrombocytopenia.

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Venom induced immune thrombocytopenia against GP IIb/IIIa and Ia/IIa.

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A treatment based on IVIg and corticosteroids led to a prompt recovery of a severe antivenin-resistant Venom induced thrombocytopenia.

A new HLA-B allele, HLA-B*35:481

The novel allele HLA-B*35:481 differs from HLA-B*35:05:01 by two nucleotide substitution in exon 3.

A multi-centre study on the performance of the molecular genotyping platform ID RHD XT for resolving serological weak RhD phenotype in routine clinical practice

BACKGROUND AND OBJECTIVES

There is concern regarding the lack of prevention of unnecessary transfusion of RhD negative red cells and unnecessary administration of Rh immunoglobulin (RhIG) to pregnant women. In this study, performance of ID RHD XT, a genotyping assay for identification of six RHD allelic variants and human platelet antigens HPA-1a/1b was assessed.

MATERIALS AND METHODS

Whole blood samples presenting weak, discrepant or inconclusive D phenotype results were genotyped with ID RHD XT and compared to reference molecular tests. Candidacy for RhIG prophylaxis was determined by analysing samples from pregnant women. Hands-on time to complete the procedures was measured.

RESULTS

Overall, 167 samples were tested (55 donors, 56 patients, 52 pregnant women and four newborns). Agreement between ID RHD XT and the reference method was 100% (51% weak D type 1, 2 or 3; 35·5% weak D Types 1, 2 or 3 not detected; 4% RHD deletion; 1% RHD*Pseudogene; 1% RHD*DIIIa-CE(3-7)-D; and 4% no amplification variant detected for RHD genotype; and 64% HPA-1a/a; 30% HPA-1a/b; and 3% HPA-1b/b for HPA-1 genotype). Call rate was 98·2%. ID RHD XT identified 40% of the pregnant women that would not have required RhIG prophylaxis. Overall hands-on time was 25-45 min to process a batch of 24 samples, and four hours for total assay time.

CONCLUSION

ID RHD XT yielded reproducible results for RHD typing in serologically weak D phenotype individuals. ID RHD XT was proven useful for the correct management of patients with RhD serological discrepancies and the rational use of RhIG in pregnancy.

Fetal RHD detection from circulating cell-free fetal DNA in maternal plasma: validation of a diagnostic kit using automatic extraction and frozen DNA

OBJECTIVE

This study aimed to validate non-invasive RHD genotyping of cell-free fetal DNA (cff-DNA) using different DNA extraction methods and of fresh and frozen extracted cff-DNA.

BACKGROUND

Non-invasive RHD genotyping of cff-DNA predicts fetal RhD phenotype, allowing for the rational implementation of antenatal immunoprophylaxis and representing a big step forward in the management of RhD-immunised women. Validation of a diagnostic method is mandatory before its clinical application.

METHODS

RhD-negative pregnant women were recruited at different gestational ages. The cff-DNA extraction was carried out using manual and automatic methods in order to improve cff-DNA yield and optimise the extraction. Fetal RHD genotyping was performed using a commercial real-time polymerase chain reaction (PCR) kit, and the results were compared with postnatal serological RhD determination on cord blood.

RESULTS

Overall, 133 plasma samples were examined for the validation process, and a total of 423 tests were performed. No differences have been observed between the two extraction methods or between fresh or frozen cff-DNA regarding cff-DNA stability and quality parameters. There was 100% concordance between fetal RHD genotyping of cff-DNA and RhD phenotype on cord blood for both extraction methods on both fresh and frozen cff-DNA.

CONCLUSION

Our study shows the reliability of automatic and manual cff-DNA extraction methods and the possibility of freezing extracted cff-DNA when performing RHD genotyping. This result might be relevant for improving laboratory work and organisation through the development of a standardised procedure for fetal RHD genotyping on cff-DNA, laying the foundations for evidence-based use of anti-D Ig prophylaxis in RhD pregnant women.

Identification of six new RHCE variant alleles in individuals of diverse racial origin

BACKGROUND

The introduction of molecular methods into routine blood typing is prompting the identification of new blood group alleles. Discrepancies between the results of genotyping and serology or chance events uncovered during genotyping prompted additional investigations, which revealed six new RHCE variant alleles.

STUDY DESIGN AND METHODS

Samples from eight blood donors, two patients (one prenatal), and a patient's relative, all of diverse racial origin, were analyzed by standard serology methods, targeted genotyping arrays, DNA sequencing, and allele-specific polymerase chain reaction.

RESULTS

Six new RHCE alleles were identified, namely, RHCE*cE84A, RHCE*ce202G, RHCE*ce307T, RHCE*Ce377G, RHCE*ce697G,712G,733G,744C, and RHCE*Ce733G.

CONCLUSION

While implementation of new assays in commercial genotyping platforms to detect the polymorphisms reported here may not be justified given their apparent rarity, software interpretative algorithms may benefit from the identification of new alleles for a more accurate determination of genotypes and prediction of phenotypes.

Molecular RH blood group typing of serologically D-/CE+ donors: the use of a polymerase chain reaction-sequence-specific primer test kit with pooled samples

The known presence of RHD blood group alleles in apparently D– individuals who are positive for C or E antigens leads to an appropriate investigation for the RHD gene on the red blood cells (RBCs) of D– blood donors, thus preventing their RBCs from immunizing D– recipients. Ready-to-use polymerase chain reaction–sequence-specific primer (PCR-SSP) typing kits are available and allow single-sample results. The need to perform this testing on a large number of donors affiliated with the Transfusion Department of Udine (Northern Italy) led to the use of molecular genetic RH blood group typing with PCR-SSP test kits and DNA samples mixed in pools. From a population of 35,000 blood donors screened for D antigen by serologic typing, a total of 235 samples, distributed in pools of 5 DNA samples, were investigated. Positive results were reevaluated by opening the pools and retesting single samples. Validation of DNA-pool typing with commercial kits was done. Among 235 genotyped samples, 12 were found to be PCR positive (5.1%), exhibiting DEL genotype and RHD-CE-D hybrid alleles. Our data demonstrate that the use of a PCR-SSP commercial test kit with pooled samples is a helpful and valid method to correctly detect RHD alleles. As a consequence, we reclassified our donors as carriers of potentially immunogenic alleles.

Abnormal arachidonic acid content of red blood cell membranes and main lithogenic factors in stone formers

BACKGROUND

Increased arachidonic acid content in red blood cell membranes of stone formers (SF) has recently been reported and is hypothesized as representing the underlying causal factor for both hyperoxaluria and hypercalciuria. We performed the present study to see whether we could confirm this finding and to test whether any relationship exists between the fatty acid composition of red blood cell membranes and the main metabolic factors involved in stone formation.

METHODS

In 21 SF and 40 healthy controls subjects the fatty acid composition of red blood cell membranes was assessed. In addition, the following parameters were evaluated in SF: daily and fasting urinary calcium excretion, fractional intestinal calcium absorption, 1,25-dihydroxy-vitamin D, intact parathyroid hormone, hydroxyproline in fasting urine, daily urinary excretion of oxalate, citrate, urate, electrolytes, urea, sulphate, relative supersaturation for calcium oxalate monohydrate.

RESULTS

The red blood cell membrane of SF had a lower content of arachidonic acid, linoleic acid, and docosahexaenoic acid than that of control subjects. Arachidonic acid content was not correlated with any of the parameters studied. However, when patients were grouped according to the degree of oxalate excretion, hyperoxaluric SF had a higher arachidonic acid content and arachidonic/linoleic acid ratio than SF with normal oxalate excretion.

CONCLUSIONS

Our results do not confirm the finding of an increased arachidonic acid content of red blood cell membrane in SF. On the contrary, reduced arachidonic acid levels were found in our patients. However, hyperoxaluric SF had a relatively higher arachidonic acid content than SF with normal urinary oxalate excretion.

Severe energy impairment consequent to inactivation of mitochondrial ATP synthase as an early event in cell death: a mechanism for the selective sensitivity to H2O2 of differentiating erythroleukemia cells

Irreversible damage to Friend's erythroleukemia cells was caused by induction of endogenous heme biosynthesis with the differentiating agent N,N'-hexamethylene bisacetamide followed by a 30-min exposure to 0.25 mM H2O2. Early irreversible ATP depletion was observed concomitant with oxidative inactivation of the mitochondrial ATP synthase. Cell proliferative capacity was also impaired within 2 h of the treatment, and progressive delayed cell lethality, starting 2 h after the insults, was also found. Based on the prevention provided by specific antioxidants and on the absence of malodialdehyde production, all the effects were ascribed to the oxidant action of .OH radicals, or closely related species, generated through iron-catalyzed reactions of H2O2, which apparently caused site-directed oxidative modifications of iron-binding proteins, in particular mitochondrial ATP synthase, rather than peroxidation of membrane lipids. Similar effects were mimicked even in the parental cell line when oligomycin was used to inhibit selectively mitochondrial ATP synthase activity, thereby lowering the enzyme activity to a level similar to that found in H2O2-damaged differentiating cells. Hence, induction of erythroid differentiation makes the mitochondrial ATP synthase a major target of H2O2 by enhancing the availability of redox-active iron in the local environment of the enzyme. Subsequent oxidative inactivation of the mitochondrial ATP synthase, resulting in severe energy impairment, leads to loss of cell growth capacity. Erythroleukemia cells may serve as a model system for the combination of two selective properties: (1) the capacity for carrying out efficient heme synthesis and/or for undergoing iron overload-like state; and (2) subsequent enhanced sensitivity to reactive oxygen species generators. Early severe mitochondrial dysfunction and energy impairment may be a major part of the mechanism of the sensitivity.

New micromethod for the determination of lamotrigine in human plasma by high-performance liquid chromatography

An extraction procedure and reversed-phase high-performance liquid chromatographic assay is described and validated for the determination of lamotrigine in human plasma. The method involves extraction with chloroform-isopropanol after alkalinization with a carbonate buffer, back-extraction into 0.05% phosphoric acid and separation by reversed-phase HPLC using a 5-micron Supelco diphenyl column (150 x 4.6 mm I.D.). Quantitation was performed by measurement of the UV absorbance at a wavelength of 265 nm. This method was carried out on 50-200 microliters samples of plasma, depending on whether they were pediatric or adult samples. The lower limit of quantitation was 0.2 microgram/ml using 200 microliters of plasma. A linear response was tested from 0.5 to 20 micrograms/ml. Within- and between-day accuracy and precision were always below 10.0% at all analysed concentrations. The method selectivity towards the most used antiepileptic drugs has been proven. Satisfactory performances were obtained in the evaluation of samples from epileptic patients.

Automated high-performance liquid chromatographic separation with spectrofluorometric detection of a malondialdehyde-thiobarbituric acid adduct in plasma

An automated HPLC separation method for the detection of malondialdehyde (MDA) in plasma samples of a healthy population is described. The procedure involves a first step of acidic hydrolysis and complex formation with thiobarbituric acid (TBA), then a protein precipitation step, and finally the separation of TBA-MDA adducts through a complete HPLC apparatus with spectrofluorometric quantification. This procedure is very useful for a routine laboratory because of its rapidity (tR = 1.7 min), simplicity and applicability, and the method gives very good results with respect to linearity (0.1-12 mumol/l), precision (within-assay C.V.%: 8, between-assay C.V.%: 10) and accuracy (recovery average: 91.66%).

Is Serum PSA Measurement a Good Test for Early Diagnosis of Prostate Cancer? Results of a Pilot Study and Cost Analysis

Over the last years - late 1970s to early 1990s - the incidence of prostate carcinoma has nearly doubled, even though many more patients die suffering from prostate cancer than because of it. This finding, together with the slow growth of this tumor and the absence of a controlled trial that would suggest a benefit from screening, makes early diagnosis of this disease quite questionable. On the other hand, it is well known that prostatic carcinoma is curable as long as it is intracapsular, and that there is an ever increasing encouragement to early detection in all diseases. The costs of screening and the difficulty in balancing the benefits of screening against its negative effects, such as psychological impact and overtreatment, must be taken into account as well. In our opinion, one of the advantages of early diagnosis should be that the patients’ quality of life improves, because the stage at diagnosis and, as a result, the number of patients suffering from bone metastasis decrease, and unknown benign pathologies can be cured. These observations are not at all negligible. Our study aims to demonstrate that by using PSA as an initial test, the screening costs are reasonable and the disease incidence is just as expected.

H2O2-induced damage to beef heart mitochondria F0F1 ATP synthase complex: differential sensitivity of the F1 and F0 moieties

Exposure of purified mitochondrial F0F1 ATP synthase to H2O2 resulted in a marked inhibition of the ATPase activity, irrespective of the purification procedure used and of the incorporation of the enzyme complex into phospholipid vesicles. The inactivation appeared consequent to oxidative modifications of the F1 moiety, whereas damage to the F0 sector, leading to low enzyme activity through impaired binding with F1, seemed not to occur. In fact, when H2O2-inactivated complex was deprived of F1, no loss of the capacity of the F0 sector thus obtained to properly reassemble with untreated purified F1 was apparent, because the resulting enzyme complex showed full activity and oligomycin sensitivity. On the contrary, the exposure of the isolated components F1 or F0 to H2O2, followed by reassembly with untreated F0 and F1 respectively, resulted in both cases in lower catalytic activity of the reconstituted complexes, whereas low oligomycin sensitivity was exhibited only in the case of F0 treatment, suggesting the inactivation in this case as due to oxidative modifications leading to impaired binding with F1.