An investigation of secondary anti-D immunisation among phenotypically RhD-negative individuals in the Chinese population

Background

Despite the introduction of anti-D prophylaxis into clinical practice, RhD alloimmunisation remains a problem, particularly in the context of transfusions and pregnancy-induced alloimmunisation. The incidence of RhD alloimmunisation among phenotypically RhD-negative individuals is unknown in most countries. We investigated RhD alloimmmunisation in RhD-negative pregnant women and transfusion recipients in south-east China in order to optimise the prevention of this phenomenon.

Methods

We analysed the RhD alloimmunisation status of RhD-negative pregnant women and transfusion recipients in south-east China. The RhD blood types of the study population were identified by standard serological methods. The D antigen was further tested with the indirect antiglobulin test to exclude or confirm weak D or partial D types. RhC, c, E and e antigens were typed in all subjects. If anti-D antibody screening was positive, the specificity and titre of the antibody were determined. The Del phenotype was investigated by the polymerase chain reaction sequence-specific primer method.

Results

An anti-D antibody was found in 61 of 416 RhD-negative pregnant women (14.66%), and in 11 of 227 RhD-negative transfusion recipients (4.85%). None of the 72 RhD-negative pregnant women or transfusion recipients with anti-D had the Del phenotype. Anti-D antibodies were not detected among Del phenotype individuals and Del phenotypes were not found in anti-D antibody producing individuals.

Discussion

Our study suggests that the risk of alloimmunity-induced neonatal haemolysis increases in true RhD-negative multipara. Perinatal protection would be necessary in these patients, while antenatal anti-D testing and Rh immune globulin prophylaxis would be unnecessary for RhDel pregnant women. Pregnant women and transfusion recipients with the Del type seldom produce anti-D antibody. RhD-negative recipients are not at risk of alloimmunisation after transfusion with Del red blood cells.     

Prevalence,specificity and risk of red blood cell alloantibodies among hospitalised Hubei Han Chinese patients

Background

The prevalence, specificity and risk of red blood cell alloantibodies vary widely among different geographic areas, races, and diseases and according to different methods of study, but no data are available on the Chinese Han population, who were investigated in the present study.

Materials and methods

Antibody screening was conducted among 42,517 hospitalised Hubei Han Chinese individuals using column agglutination technology. Samples that were positive in antibody screening were subjected to antibody identification by the tube test. Clinical data, including gender, age, race, transfusion history and records of alloantibody detection, transfusion reactions or haemolytic disease of the newborn, were collected to analyse the prevalence and specificity of alloantibodies and complications associated with them.

Results

A total of 212 patients with alloantibodies were identified among 42,517 patients, yielding a prevalence of 0.50% in this study. Significantly different prevalence rates were observed according to age and sex. The most frequently identified alloantibodies were anti-E (87/212, 41.0%), anti-D (45/212, 21.2%), anti-M (41/212, 19.3%) and a combination of anti-E and anti-c (13/212, 6.1%). Haemolytic disease was observed in 13 infants with anti-D, three infants with anti-E and one infant with anti-Fy^a alloantibodies. Delayed haemolytic transfusion reactions occurred in four patients with alloantibodies.

Discussion

In hospitalised Hubei Han Chinese individuals, the overall prevalence of alloantibodies was 0.50%, with anti-E, anti-D and anti-M being the most frequently identified alloantibodies. These results indicate that anti-D and anti-E alloantibodies were major risk factors for haemolytic disease of the newborn or delayed haemolytic transfusion reactions in this study population.     

Antibody elutions in Thai patients with a positive direct antiglobulin test

Background

The direct antiglobulin test is performed to determine whether an anaemic patient with evidence of haemolysis has autoimmune or alloimmune haemolytic anaemia.

Materials and methods

We determined the antibody specificity of eluted IgG antibodies from patients’ blood samples with a positive direct antiglobulin test. Overall, 134 Thai patients were included in this study. EDTA blood samples were obtained from recently transfused patients, patients with unexplained anaemia and patients who had serum antibodies detected during routine pre-transfusion tests from different hospital blood banks. These complicated samples were sent to the National Blood Centre of the Thai Red Cross Society for investigation and to find compatible blood components. Each blood sample underwent a direct antiglobulin test with the gel technique using polyspecific antihuman globulin and mononospecific anti-IgG and anti-C3d. Acid eluates were prepared from the samples for which the direct antiglobulin test was positive and the specificities of the eluted antibodies were determined by the gel technique.

Results

Of the samples tested, 101 showed a positive direct antiglobulin test result (75.4%) using polyspecific antihuman globulin sera whereas only 95 samples (70.9%) were positive with anti-IgG or anti-IgG and anti-C3d. Moreover, 54 of 95 eluates (56.8%) were positive for antibody screening and tested with the reagent panel cells. Twenty-one eluates had specific alloantibodies, which were concordant with the findings in the patients’ sera and all patients had a history of blood transfusion. Additionally, 33 eluates contained pan-agglutinins. Interestingly, alloantibodies could be determined using titration studies in 5 of 26 eluates with pan-agglutinins.

Conclusion

Although the direct antiglobulin test is not routinely performed in pre-transfusion screening, this test and elution studies would be useful in patients with a history of previous transfusions, and in those for whom compatible blood cannot be found.     

Detection of anti-IgA antibodies using the particle gel immunoassay: a rapid test for increased patient safety

Background

Patient safety is a major issue in transfusion medicine and commands continuous efforts to develop valid control methods aiming to avoid serious transfusion-related complications. Anti-IgA antibodies can cause anaphylactic transfusion reactions in IgA-deficient individuals. Since standard quantitative methods for anti-IgA measurement require considerable time to be performed, in an emergency situation it can be a challenge to prevent or to quickly interpret and manage acute transfusion reactions suspected to be a consequence of anti-IgA. The purpose of this study was to test and validate at our transfusion centre a rapid assay for the identification of patients with anti-IgA antibodies.

Materials and methods

Forty-six samples (6 from healthy controls and 40 from IgA-deficient patients) were collected. Sera were analysed blindly by three different clinical laboratory technologists using two DiaMed particle gel immunoassays (ID-PaGIA) for IgA deficiency and for antibodies to IgA. The results were subsequently checked with the results of a fluorescence enzyme immunoassay conducted in the reference immunology laboratory.

Results

The ID-PaGIA had a sensitivity of 91.7% and specificity of 97.1% for the IgA deficiency test. With regards to the detection of anti-IgA antibodies, the sensitivity was 89.3% and the specificity 100%. The reproducibility of the test was 100%.

Discussion

The ID-PaGIA screening assays are suitable for the investigation of transfusion-related anaphylactic reactions in a routine blood bank laboratory. Although the gel card technique does not quantify the level of anti-IgA antibodies, it is readily available, providing an effective and simple method for the diagnosis of anti-IgA related anaphylaxis and guidance for the appropriate transfusion practice in an emergency.     

The persistence of red cell alloantibodies

Background

Red cell alloantibodies may disappear over time and cause a delayed haemolytic reaction if their past existence is not known before a transfusion. Only few quantitative data have already been presented on this topic.

Study design and methods

We retrieved the records of alloantibodies detected between 1989 and 2008 in our institution. All warm-reacting alloantibodies were included, with the exception of ABO antibodies, anti-D in women of childbearing age (it was impossible to rule out Rh prophylaxis) and antibodies produced by transfusion-dependent beta-thalassaemia patients (their transfusion history was too unusual).

Results

We found 673 antibodies, produced by 525 patients, which had been tested again after the initial detection. The median follow-up was 319 days. The overall rate of non-persistence was 37%, corresponding to 251 antibodies, produced by 216 patients. Non-persistent antibodies were associated with a longer follow-up (409 vs. 236 days; p=0.012), more tests after detection (2 vs. 1; p<0.001), and a lower maximum score (2+ vs. 3+; p<0.001). Antibody specificity, too, influenced the duration of persistence. Among common antibodies, anti-D was the most long-lived (14% non-persistence); anti-Jk^a the most short-lived (43% non-persistence). Antibodies detected in the second decade of the study were less persistent (p<0.001). They were also weaker (maximum score: 2+ vs. 3+; p<0.001). This probably reflects the increased sensitivity of the screening tests over the course of time. Age, sex and whether the patient had produced multiple alloantibodies were not significant covariates. A minority of non-persistent antibodies (33/251, 13%) were detected again after a negative result (intermittently-detected antibodies). They had a longer follow-up (885 vs. 341 days; p=0.002), more tests after detection (5 vs. 2; p<0.001), and a higher maximum score (3+ vs. 2+; p=0.001).

Conclusions

Red cell antibodies commonly disappear. To avoid delayed haemolytic reactions, it is necessary to rely on previous records, which should be readily available.     

A simple diagnostic strategy for RhD typing in discrepant cases in the Indian population

Background

The D antigen is the most immunogenic antigen in the Rh system. D variants must be considered if there is a significant discrepancy in the strength of reaction obtained with different anti-D reagents, a discrepancy between current and historical test results and if anti-D is detected in an individual serologically typed as RhD positive. A panel of monoclonal anti-D reagents can be used to identify partial D and weak D variants. The aim of this study was to develop a strategy for RhD typing in discrepant cases.

Materials and methods

Sixty RhD discrepant samples referred to our Institute for confirmation of RhD status were tested with a panel of 12 monoclonal anti-D reagents (ALBAclone advanced partial RhD typing kit) and Rh phenotype was determined using C, c, D, E, and e antisera.

Results

Ninety-three percent of the RhD discrepant cases were classified into weak and partial D using this kit. Among the D variants characterised, 37% belonged to DFR, 23% to DOL, 12% to weak D, and the remaining 21% to DAR, DV, DMH, DCS and DVI categories. Ninety-seven percent of the D variants were “C” antigen positive. Out of the panel of 12 monoclonal anti-D used, cell line LHM-70/45 gave negative reactions with all RhD discrepant cases and cell lines LHM-76/59, LHM-76/55 and ESD-1 gave positive reactions with all 60 RhD discrepant cases studied.

Discussion

The Advanced partial D kit was very useful in characterising and identifying D variants in the Indian population. A preliminary strategy for the detection and identification of D variants in discrepant cases could be to test for the presence of “C” antigen with anti-C, and for “D” antigen with anti-D of cell line LHM 70/45. A more comprehensive, but simple way to identify D variants in routine RhD typing is to use two anti-D reagents i.e LHM 70/45 and one out of LHM-76/59, LHM-76/55 and ESD-1. D variants can be further characterised by using the partial D typing kit and molecular genotyping in specialised laboratories.     

Analysis of density and epitopes of D antigen on the surface of erythrocytes from DEL phenotypic individuals carrying the RHD1227A allele

Background

The characteristics of the D antigen are important as they influence the immunogenicity of D variant cells. Several studies on antigenic sites have been reported in normal D positive, weak D and partial D cases, including a comprehensive analysis of DEL types in Caucasians. The aim of this study was to assess D antigen density and epitopes on the erythrocyte surface of Asian type DEL phenotypic individuals carrying the RHD1227A allele in the Chinese population.

Materials and methods

A total of 154 DEL phenotypic individuals carrying the RHD1227A allele were identified through adsorption and elution tests and polymerase chain reaction analysis with sequence-specific primers in the Chinese population. D antigen density on the erythrocyte surface of these individuals was detected using a flow cytometric method. An erythrocyte sample with known D antigen density was used as a standard. Blood samples from D-negative and D-positive individuals were used as controls. In addition, D antigen epitopes on the erythrocyte surface of DEL individuals carrying the RHD1227A allele were investigated with 18 monoclonal anti-D antibodies specific for different D antigen epitopes.

Results

The means of the median fluorescence intensity of D antigen on the erythrocyte membrane surface of D-negative, D-positive and DEL individuals were 2.14±0.25, 193.61±11.43 and 2.45±0.82, respectively. The DEL samples were estimated to have approximately 22 D antigens per cell. The samples from all 154 DEL individuals reacted positively with 18 monoclonal anti-D antibodies specific for different D antigen epitopes.

Discussion

In this study, D antigen density on the erythrocyte surface of DEL individuals carrying the RHD1227A allele was extremely low, there being only very few antigenic molecules per cell, but the D antigen epitopes were grossly complete.     

The importance of antenatal prevention of RhD immunisation in the first pregnancy

Background

The aim of this study was to examine which pregnancies are associated with RhD immunisation and haemolytic disease of foetus and newborn (HDFN) when postnatal RhD prophylaxis is applied.

Material and methods

This retrospective cohort study included pregnancies with RhD immunisation; each of the pregnant women received anti-D immunoglobulin after delivery, miscarriage or invasive antenatal diagnostic procedures. For each pregnancy we analysed the order of pregnancy that caused immunisation as well as the order of the monitored pregnancy and whether the anti-D antibodies caused HDFN.

Results

Anti-D antibody was detected in 1.2% of RhD-negative pregnancies. Out of 89 monitored pregnancies, 56 (63%) were immunised by the first pregnancy, 21 (24%) by the second one, and 12 (13%) by subsequent pregnancies. HDFN occurred in 28 cases; 25 of them were the consequence of the immunisation in the first pregnancy. The most severe cases of HDFN, perinatal death (n=2) and intrauterine transfusion (n=7) were consequence of immunisation during the first pregnancy. Significantly more cases of HDFN were caused by immunisation in the first pregnancy than by immunisation in subsequent pregnancies (χ²=12, p<0.01).

Conclusion

RhD immunisation could be reduced in more than half cases by administering anti-D immunoglobulin at the beginning of the third trimester of pregnancy, especially the first pregnancy.     

Interlaboratory study to evaluate the performance of laboratories involved in West Nile virus RNA screening of blood and blood components by nucleic acid amplification testing in Italy

Background

An Italian interlaboratory study was run in 2010 to assess the performance of Blood Transfusion Services in detecting the genome of West Nile virus (WNV) in plasma.

Materials and methods

Each laboratory received a panel of samples containing four samples negative for WNV and six positive samples with a nominal viral concentration close to or below the 95% detection limit of two commercially available nucleic acid amplification tests (NAT) for WNV, the PROCLEIX® WNV kit and the Cobas® TaqScreen West Nile Virus kit.

Results

Ten laboratories took part in the study. All correctly identified the positive samples with a viral concentration above the 95% detection limit. No pre- or post-analytical errors were observed.

Conclusions

The interlaboratory study run in 2010 allowed participants to assess the performance of the NAT methods applied in their seasonal routine screening of blood donations.     

A survey of the current use of anti-D immunoprophylaxis and the incidence of haemolytic disease of the newborn in Italy

Introduction

The Italian Society of Transfusion Medicine and Immunohaematology (SIMTI) carried out a survey on the current use of anti-D immunoprophylaxis (IP) in Italy, on its ways of use and on the impact that it has had on decreasing haemolytic disease of the newborn (HDN), due to maternal-foetal incompatibility for the D antigen.

Materials and methods

The survey was carried out using a questionnaire prepared by the Working Group established for this purpose by the SIMTI. The questions were divided into five groups: the ways of carrying out IP, evaluation of foetal-maternal haemorrhage, serological tests after IP, the current incidence of HDN, and data on exchange transfusions.

Results

Data were obtained from 69 Transfusion Services (TS). Four of these give IP antenatally, whereas in the remaining cases IP is given after birth. Almost all the TS evaluate the amount of foetal-maternal haemorrhage in order to give additional doses of anti-D IgG, with the most widely used method being the Kleihauer-Betke test. Data were collected from 176,010 pregnancies: 18,639 were D-negative women, of whom 18,440 were not immunised. There were 136 cases of HDN with anti-D antibodies, and 39 of these required exchange transfusions (ET). Furthermore, there were 1,535 pregnant women with anti-A and/or anti-B IgG, which were clinically significant in 83 and required ET in 37. Finally, 40 women had antibodies, directly related to the pregnancy, against antigens other than D (in eight of these cases ET was necessary).

Conclusions

The survey carried out by SIMTI was able to give a sufficiently full and accurate picture of current Italian practices concerning the use and ways of use of anti-D IP in pregnancy and the puerperum, as well as the incidence and characteristics of HDN. Furthermore, this survey was the basis for guidelines on the management of HDN, produced by SIMTI in collaboration with the Italian Society of Obstetricians and Gynaecologists.     

The evaluation of three diagnostic tests for the detection of equine influenza nucleoprotein in nasal swabs

Background

Equine influenza (EI) is a highly contagious respiratory disease of horses.

Objectives

The aim of this study was to evaluate two rapid antigen detection kits (Directigen or DFA, and Espline) and a commercial ELISA for the detection of EI nucleoprotein in nasal swabs.

Method

Nasal swab samples from naturally and experimentally infected horses were used to compare the sensitivity and specificity of these assays to virus isolation (VI) and real-time RT-PCR.

Results

If real-time RT-PCR was considered as the gold standard, the sensitivity of the other tests in field samples was 68% (DFA), 35% (ELISA), 29% (Espline), and 9% (VI). These tests had 100% specificity when compared to real-time RT-PCR. A receiver operating characteristic (ROC) curve indicated that decreasing the cutoff of the ELISA would increase sensitivity with some loss of specificity. In samples from experimentally infected horses, the sensitivity of the tests compared with real-time RT-PCR was 69% (VI), 27% (DFA), 6% (Espline), and 2% (ELISA). The specificity was 100% for Espline and ELISA and 95% for VI and DFA.

Conclusions

This study illustrated that DFA is the most sensitive antigen detection test evaluated for the diagnosis of EI and that it can detect virus in some subclinical infected and vaccinated horses. The results suggest that DFA is a useful adjunct to laboratory tests and may be effective as a screening test in a quarantine station or similar facility where horses are monitored daily.     

Validation and development of an immunonephelometric assay for the determination of alpha-1 antitrypsin levels in dried blood spots from patients with COPD

OBJECTIVE:

To validate and develop an immunonephelometric assay for the determination of alpha-1 antitrypsin (AAT) levels in dried blood spots from COPD patients in Brazil.

METHODS:

We determined AAT levels in serum samples and dried blood spots from 192 COPD patients. For the preparation of dried blood spots, a disk (diameter, 6 mm) was placed into a tube, eluted with 200 µL of PBS, and stored overnight at 4ºC. All of the samples were analyzed by immunonephelometry in duplicate. We used the bootstrap resampling method in order to determine a cut-off point for AAT levels in dried blood spots.

RESULTS:

The correlation coefficient between the AAT levels in serum samples and those in dried blood spots was r = 0.45. For dried blood spots, the cut-off value was 2.02 mg/dL (97% CI: 1.45-2.64 mg/dL), with a sensitivity, specificity, positive predictive value, and negative predictive value of 100%, 95.7%, 27.2%, and 100%, respectively.

CONCLUSIONS:

This method for the determination of AAT levels in dried blood spots appears to be a reliable screening tool for patients with AAT deficiency.     

Residues Arg568 and Phe592 contribute to an antigenic surface for anti-ADAMTS13 antibodies in the spacer domain

Background

The majority of patients diagnosed with thrombotic thrombocytopenic purpura have autoantibodies directed towards the spacer domain of ADAMTS13.

Design and Methods

In this study we explored the epitope specificity and immunoglobulin class and immunoglobulin G subclass distribution of anti-ADAMTS13 antibodies. The epitope specificity of anti-spacer domain antibodies was examined using plasma from 48 patients with acute acquired thrombotic thrombocytopenic purpura by means of immunoprecipitation of ADAMTS13 variants containing single or multiple alanine substitutions. Using similar methods, we also determined the presence of anti-TSP2-8 and CUB1-2 domain antibodies in this cohort of patients.

Results

Antibody profiling revealed that anti-ADAMTS13 immunoglobulin G1 and immunoglobulin G4 predominate in plasma of patients with acquired thrombotic thrombocytopenic purpura. Analysis of anti-spacer domain antibodies revealed that Arg568 and Phe592, in addition to residues Arg660, Tyr661, and Tyr665, also contribute to an antigenic surface in the spacer domain. The majority of patients (90%) lost reactivity towards the spacer domain following introduction of multiple alanine substitutions at Arg568, Phe592, Arg660, Tyr661 and Tyr665. Anti-TSP2-8 and anti-CUB1-2 domain-directed antibodies were present in, respectively, 17% and 35% of the patients’ samples analyzed.

Conclusions

Immunoglobulin G directed towards a single antigenic surface comprising residues Arg568, Phe592, Arg660, Tyr661 and Tyr665 predominates in the plasma of patients with acquired thrombotic thrombocytopenic purpura.     

Screening for Diabetic Retinopathy Using Computer Vision and Physiological Markers

Background

Hyperglycemia and diabetes result in vascular complications, most notably diabetic retinopathy (DR). The prevalence of DR is growing and is a leading cause of blindness and/or visual impairment in developed countries. Current methods of detecting, screening, and monitoring DR are based on subjective human evaluation, which is also slow and time-consuming. As a result, initiation and progress monitoring of DR is clinically hard.

Methods

Computer vision methods are developed to isolate and detect two of the most common DR dysfunctions—dot hemorrhages (DH) and exudates. The algorithms use specific color channels and segmentation methods to separate these DR manifestations from physiological features in digital fundus images. The algorithms are tested on the first 100 images from a published database. The diagnostic outcome and the resulting positive and negative prediction values (PPV and NPV) are reported. The first 50 images are marked with specialist determined ground truth for each individual exudate and/or DH, which are also compared to algorithm identification.

Results

Exudate identification had 96.7% sensitivity and 94.9% specificity for diagnosis (PPV = 97%, NPV = 95%). Dot hemorrhage identification had 98.7% sensitivity and 100% specificity (PPV = 100%, NPV = 96%). Greater than 95% of ground truth identified exudates, and DHs were found by the algorithm in the marked first 50 images, with less than 0.5% false positives.

Conclusions

A direct computer vision approach enabled high-quality identification of exudates and DHs in an independent data set of fundus images. The methods are readily generalizable to other clinical manifestations of DR. The results justify a blinded clinical trial of the system to prove its capability to detect, diagnose, and, over the long term, monitor the state of DR in individuals with diabetes.     

Patients undergoing colorectal cancer screening underestimate their cancer risk and delay presentation for screening

BACKGROUND:

Colorectal cancer (CRC) is the third most common cancer in Canada. Screening guidelines recommend that first-time screening should occur at 50 years of age for average-risk individuals and at 40 years of age for those with a family history of CRC.

OBJECTIVE:

To examine whether persons with a positive CRC family history were achieving screening at 40 years of age and whether average-risk persons were achieving screening at 50 years of age.

METHODS:

The present study was a cross-sectional analysis of subjects who entered a colon cancer screening program and were undergoing CRC screening for the first time.

RESULTS:

A total of 778 individuals were enrolled in the present study: 340 (174 males) with no family history of CRC, and 438 (189 males) with a positive family history of CRC. For the group with a positive family history, the mean (± SD) age for primary screening was 54.4±8.5 years, compared with 58.2±6.4 years for the group with no family history. On average, those with a positive family history initiated screening 3.8 years (95% CI 2.8 to 4.8; P<0.05) earlier than those without. Adenoma polyp detection rate for the positive family history group was 20.8% (n=91) compared with 23.5 % (n=80) for the group with no family history.

CONCLUSIONS:

Individuals with a positive CRC family history are initiating screening approximately four years earlier than those without a family history; nevertheless, both groups are undergoing screening well past current guideline recommendations.     

Survey on the prevention and incidence of haemolytic disease of the newborn in Italy

Background

In 2010, the Italian Society of Immunohaematology and Transfusion Medicine (SIMTI) carried out a survey of the incidence of haemolytic disease of the newborn (HDN) and the prevention of HDN caused by anti-Rh(D) in Italian Transfusion Structures (TS).

Materials and methods

A questionnaire divided into the following five sections was administered: (i) types of services provided and maintenance of legally required registers, (ii) immunoprophylaxis (IP), (iii) red cell typing and searches for irregular antibodies, (iv) evaluation of foetal-maternal haemorrhage (FMH), and (v) incidence of HDN in 2010. Of the 280 TS sent the questionnaire, 176 (63%) replied.

Results

A HDN register was available in 55.5% of the TS (n =91). Immunoprophylaxis with a dose of anti-D IgG was given to all Rh(D) negative and Rh(D) variant puerpera with Rh(D) positive newborns: in more than 93% of cases the dose was between 1,500 IU (300 μg) and 1,250 IU (250 μg). Antenatal IP between the 25^th and 28^th week was proposed by 42 TS (26%). Seventy percent of the TS (n =115) did not make any evaluation of FMH. The number of births surveyed in 2010 was 203,384, the number of Rh(D) negative pregnancies was 13,569, while anti-D antibodies were present in 245 pregnancies. There were 111 cases of HDN due to anti Rh(D) incompatibility and in 40 of these, intrauterine transfusion (n =8) or exchange transfusion (n =32) was necessary. In 94 cases HDN was due to other irregular antibodies: in 4 of these cases intrauterine transfusion was needed and in 11 other recourse was made of exchange transfusion. Finally, there were 1,456 newborns with ABO HDN of whom 13 underwent exchange transfusion.

Discussion

The data collected give a picture of the incidence of HDN in Italy and of the methods of managing IP and could form the basis for an update of the SIMTI recommendations on the management and prevention of this disease.     

Discovery and verification of gelsolin as a potential biomarker of colorectal adenocarcinoma in the Chinese population: Examining differential protein expression using an iTRAQ labelling-based proteomics approach

OBJECTIVE:

To identify and validate potential biomarkers of colorectal adenocarcinoma using a proteomic approach.

METHODS:

Multidimensional liquid chromatography/mass spectrometry was used to analyze biological samples labelled with isobaric mass tags for relative and absolute quantitation to identify differentially expressed proteins in human colorectal adenocarcinoma and paired normal mucosa for the discovery of cancerous biomarkers. Cancerous and noncancerous samples were compared using online and offline separation. Protein identification was performed using mass spectrometry. The downregulation of gelsolin protein in colorectal adenocarcinoma samples was confirmed by Western blot analysis and validated using immunohistochemistry.

RESULTS:

A total of 802 nonredundant proteins were identified in colorectal adenocarcinoma samples, 82 of which fell outside the expression range of 0.8 to 1.2, and were considered to be potential cancer-specific proteins. Immunohistochemistry revealed a complete absence of gelsolin expression in 86.89% of samples and a reduction of expression in 13.11% of samples, yielding a sensitivity of 86.89% and a specificity of 100% for distinguishing colorectal adenocarcinoma from normal tissue.

CONCLUSIONS:

These findings suggest that decreased expression of gelsolin is a potential biomarker of colorectal adenocarcinoma.     

Detection of West Nile virus RNA (lineages 1 and 2) in an external quality assessment programme for laboratories screening blood and blood components for West Nile virus by nucleic acid amplification testing

Background

A second Italian External Quality Assessment Programme was run in 2011 to assess the performance of Blood Transfusion Centres in detecting West Nile virus RNA in plasma.

Materials and methods.

Each participant received two panels containing negative samples and samples positive for West Nile virus lineages 1 and 2, some of which with a viral concentration close to or below the 95% limit of detection of the respective commercial nucleic acid amplification test assay: the PROCLEIX WNV Assay or the Cobas TaqScreen West Nile Virus Test.

Results

Eleven laboratories took part in the External Quality Assessment Programme. All of them correctly identified the positive samples with a viral concentration above the 95% limit of detection. No false positive results or pre-/post-analytical errors were observed.

Discussion.

The External Quality Assessment Programme run in 2011 allowed participants to assess the performance of the nucleic acid amplification test methods applied in their seasonal routine screening of blood donations. The results confirm the 95% limit of detection reported by the test kits’ manufacturers for both West Nile virus lineages.