Population Of Healthy Blood Donors Research Articles

A Study of A1 and A2 Subtypes Among Whole-Blood Donors With Blood Groups A and AB at the Blood Center of a Tertiary Care Institute in Chhattisgarh.

The ABO blood group shows various subtypes due to the heterogeneity of A and B alleles. The frequency of these subtypes varies in different populations. Studies related to the frequency of subtypes of blood groups A and AB are lacking in this region. So, we planned this study to estimate the prevalence of A1and A2 subtypes among the healthy blood donor population. This was a prospective study performed in the blood center of a teaching hospital in the Chhattisgarh state. Healthy whole-blood donors were included in the study after written informed consent. The conventional test tube method was used for performing forward and reverse blood grouping. Testing with anti-A1 and anti-H lectin was performed in blood groups A and AB. Additional tests such as saliva testing for secretor status and adsorption-elution were performed if needed. Four thousand one hundred twelve donor samples were studied, out of which 1170 showed A antigen. Among 1170 samples, 74.6% were blood group A, and 25.4% were AB. Among blood group A, 92.3% were A1and 3.3% A2,and the rest were other subtypes, while in AB, it was 85.2% A1B and 14.8% A2B. Two cases of anti-A1 antibodies were also noted, which were clinically insignificant. We observed a significantly higher proportion of A2B than A2 in our study population. We also found a large proportion of Aint in the study participants. Testing with anti-A1 andanti-H lectin is recommended in blood groups A and AB to determine various subtypes and prevent any incompatibility.

Monocyte distribution width (MDW): study of reference values in blood donors.

Monocyte distribution width (MDW) is a new biomarker used as an early indicator of sepsis (ESId). It is often aids in the identification of patients who may develop sepsis. This study aims to establish the MDW reference interval (RI) within the healthy population of blood donors using EDTA-K2 as anticoagulant. Many hospitals use this biomarker as a means of identifying patients who present to the hospital with sepsis. A total of 274 samples obtained from healthy donors were analyzed. MDW measurements were taken within 2 h post-extraction. The RI was estimated using various statistical methodologies, including the recommended CLSI EP28-A3c guideline, non-parametric and robust methods, along with the Harrell-Davis bootstrap method applied to the entire sample. The RI estimated through non-parametric method was 14.77 CI90 % (14.36-14.97)-21.13 CI90 % (20.89-21.68); RI using the robust method was 15.64-19.05 and RI using the Harrell-Davis bootstrap method was 14.73 CI90 % (14.53-14.92)-21.14 CI90 % (20.88-21.40). Based on clinical applicability, we recommend utilizing the RI derived from the non-parametric method, aligning with the CLSI recommendations. Furthermore, we consider that our results can be taken as a reference in other laboratories that serve a population similar to our study cohort.

Prevalence of “weak B” phenotypes and their evaluation and differentiation in healthy blood donor population in Eastern India

Abstract BACKGROUND: Examples of group B red cells that react weakly or not at all with anti-B have been described. Subgroups of B such as B3, Bx, Bm, and Bel are rare and are less frequently reported. We studied the frequency of subgroups of B in our healthy blood donor population and serologically characterized and differentiated these subgroups. MATERIALS AND METHODS: The 9-year prospective study included 84,534 healthy blood donors. Initial blood grouping and antibody screening of all donor samples were performed using automated solid-phase assay. Any sample showing blood group discrepancy or weaker agglutination was subjected to further immunohematological investigations. RESULTS: Among 84,534 healthy donors, “B” blood group was found in 29,190 (34.53%). Weak B phenotypes were demonstrated in 9 (0.031%) B donors. Among the 9 weak B phenotypes, B3 was the most common followed by Bm. The frequency of B3, Bm, Bx, and Bel in our blood donor population was found to be 1 in 21,133, 1 in 28,178, 1 in 84,534, and 1 in 84,534, respectively. Red cell agglutination with anti-B and anti-AB varied from Wk+ to 2+ with or without mixed-field agglutination in the B3 and Bx phenotypes. Naturally occurring anti-B of immunoglobulin M type was detected in the Bx donor. Two (22.2%) of the 9 donors were found to be nonsecretor. Adsorption-elution demonstrated “B” antigen specificity in different strengths in Bm, Bx, and Bel phenotypes. CONCLUSION: We conclude that differentiating weak subgroups of “B” by serological assays is possible to a great extent with technical expertise. Mistyping weak subgroups of B as “O” group may lead to reporting errors and wrong blood transfusion. Therefore, blood centers in developing countries including India should establish simple techniques to detect and differentiate weak subgroups and develop procedures to ensure safe blood transfusion and transplantation.

Antibody screening and identification in voluntary blood donors – Need of the hour

Background and Objectives: Although unexpected antibody screening is mandatory according to the Food and Drug Administration and National Blood Policy, the prevalence of irregular red cell antibody and its specificities are not much reported in the donor population of western India. The objective of this study is to find the prevalence of unexpected antibodies in healthy blood donor population of western India. Methods: This is a retrospective study conducted in one of the largest stand-alone blood centers in western India. Data were retrieved from the Integrated Blood Bank Management System (powered by the blood center located in Ahmedabad) software. The data were analyzed for a period of 24 months, from March 1, 2019, to March 31, 2021. Unexpected antibody screening of all voluntary healthy blood donors was performed with fully automated blood grouping equipment Immucor NEO and Diagast EVO using commercial Capture-R Ready Indicator Red Cells (Immucor, USA) and Hemascreen Pool (Diagast, France). Further antibody identification was performed with 11 cell panels. Results: A total of 53,724 volunteer blood donors donated at our blood center during the study period comprised 51,185 (95.27%) male donors and 2539 (4.72%) female donors. A total of 25 (0.046%) donors showed the presence of unexpected antibodies. Most frequent alloantibodies were anti-M (n = 4, 16%) and multiple antibody (n = 4, 16%). Conclusion: Implementation of unexpected antibody screening in all the healthy blood donors routinely and identification of antibodies in antibody screen-positive donors helped us to understand the prevalence of antibodies in our region and its importance in providing compatible blood components which are devoid of irregular antibodies and to avoid delayed transfusion reactions.

Serum iPTH range in a reference population: From an integrated approach to vitamin D prevalence impact evaluation

BackgroundThe iPTH upper reference limit (URL) reported by our laboratory provider (Abbott Laboratories) at Tor Vergata University Hospital was evaluated by internal verification procedures as not representative of our population and resulting as underestimated. In this study, a new reference interval has been investigated and established by comparing a direct and an indirect method based on a statistical reduction from results stored in the laboratory database. MethodsFor reference interval calculation from the healthy population, we analyzed a cohort of 100 blood donors (84% males and 16% females) screened with no bone-related and malabsorption diseases. We analyzed a cohort of 495 patients retrieved from more than 800 iPTH results by excluding subjects with pathological measurement for calcium, phosphorus, and creatinine for the reference interval evaluation. Patients with vitamin D results were included in the analysis. Vitamin D sufficiency status during the period from January to September 2020 was also evaluated by investigating 3,050 patients. ResultsThe iPTH reference interval of a healthy blood donor population was measured as 25.2–109.1 pg/mL (2.7–11.6 pmol/L) at 2.5 and 97.5 distribution percentile. The iPTH reference interval from data stored in the laboratory database was 19.3–112.5 pg/mL (2.0–11.9 pmol/L). Furthermore, 60% of the whole population had prevalently insufficient vitamin D concentration (<30 ng/dL; <75 nmol/L).The impact of vitamin D concentration on the iPTH reference interval was measured for insufficient vitamin D (<30 ng/dL; <75 nmol/L) as 15.2–127.7 pg/mL (1.6–13.5 pmol/L), desirable vitamin D (30–40 ng/ml; 75–100 nmol/L) as 25.6–105 pg/mL (2.7–10.7 pmol/L) and optimal vitamin D (>40 ng/ml; >100 nmol/L) as 26.2–89.2 pg/mL (2.8–9.4 pmol/L), respectively. ConclusionsThe URL reported in manufacturer datasheets likely refers to a normal population with non-pathological vitamin D levels. On the contrary, the considered population was mostly vitamin D insufficient, resulting in a URL shift. On this basis, we suggest describing in medical reports the iPTH range for vitamin D deficiency for diagnosis of primary hyperparathyroidism even when a specific vitamin D request is lacking. On the other hand, reporting optimal vitamin D-based iPTH reference interval could be clinically relevant in supplemented patients as a marker of treatment efficacy.

Blood NAD levels are reduced in very old patients hospitalized for heart failure

Age-associated decline in nicotinamide adenine dinucleotide (NAD) tissue levels has emerged as potential driving mechanism in the establishment of energy metabolism perturbations in the context of chronic diseases, notably heart failure. The aim of this study was to measure the blood NAD levels in a healthy blood donor population and in a population of elderly patients hospitalized for decompensated heart failure. Whole blood sample was collected from 151 healthy voluntary blood donors, aged 19 to 68years, and from 19 patients aged 75 to 101years and hospitalized for decompensated heart failure in a geriatric ward. Metabolites were extracted by the hot buffered ethanol procedure and NAD was quantified in triplicate for each sample. The mean concentration of NAD in blood of healthy donors was 23.4 (SD 4.05) μmol/L. There was no significant correlation between NAD levels and donors' age nor sex in the healthy population when studied as a whole. However, the linear regression curves of NAD concentration plotted against age differed between males and females (p=0.0283) with a trend in males to decline with age that was not observed in females. The mean concentration of NAD in whole blood samples of the geriatric population was 20.7 (SD 3.6) μmol/L (p=0.007 versus the healthy blood donor population). There were no differences between males and females (p=0.7) nor between patients with ejection fraction inferior or superior to 50% (p=0.86) in the geriatric population. This study highlighted a diminution of NAD blood levels for elderly patients hospitalized for decompensated heart failure in comparison to a healthy population, suggesting that new therapeutics to restore NAD stock and energy metabolism would be a major progress in the management of this type of geriatric patients.

Establishing the 99th percentile of a novel assay for high-sensitivity troponin I in a healthy blood donor population.

The recommended cut-off of cardiac troponin (cTn) for the diagnosis of acute myocardial infarction (AMI) is the 99th percentile in a healthy reference population. We aimed to determine the 99th percentile of the novel ADVIA Centaur® High Sensitivity Troponin I assay (Siemens Healthcare Diagnostics) in fresh lithium heparin plasma samples from healthy blood donors. A total of 1000 apparently healthy blood donors were included. High-sensitivity (hs) cTnI, hs-cTnT, creatinine and N-terminal pro b-type natriuretic peptide (NT-proBNP) were measured in fresh lithium heparin plasma samples, and glycated hemoglobin (HbA1c) was measured in ethylenediaminetetraacetic acid (EDTA)-blood. The 99th percentile was estimated for the whole population, as well as for males and females separately. For the total population the 99th percentile of ADVIA Centaur® High Sensitivity Troponin I was 96 (65-149) ng/L. The estimated value differed significantly from results published by others and was highly dependent on which values were considered statistical outliers. The estimated 99th percentile for hs-cTnI in the population studied differed significantly from previously published results. There is a need for further specifications regarding how subjects used for estimating the 99th percentile of cTns in healthy populations should be recruited and how outlier values should be identified, as this can highly influence the diagnostic cut-off applied for AMI.

Serological evaluation and differentiation of subgroups of “A” and “AB” in healthy blood donor population in Eastern India

Background and Objectives: Weak subgroups of A antigen in A or AB blood group can be differentiated by various immunohematological investigations. These weak phenotypes mainly result from weaker expression of an alternate weak allele present at the ABO loci. Weak subgroups of A antigen either reacts weakly with anti-A antisera such as A3, Ax, and Aendor do not react at all such as Am, Ay, and Ael. In this study, we characterized and differentiated the broad and weak subgroups of A in ABO blood group system through various immunohematological investigations. Methods: The prospective study included 67,954 healthy blood donors. Initial blood grouping and antibody screening of all donor samples were performed using an automated solid-phase assay. Samples showing blood group discrepancy or weaker agglutination were subjected to battery of serological investigation including saliva hemagglutination inhibition test and adsorption-elution procedures. Results: Among 16,034 A group donors, A1were 13,276 (82.8%), A22750 (17.15%), and weak subgroups were 8 (0.05%). Among AB group, A1B donors were 5621 (84.93%), A2B 996 (15.05%), and weak subgroups of AB were 1 (0.015%). The unexpected naturally occurring anti-A1antibodies (1.9%) were of IgM type optimally reactive at 4°C with titer ranging from 1 to 8. Red cells' agglutination with anti-A and anti-AB varied from Wk + to 2+ with or without mixed field agglutination in A3, Ax, and Aendphenotypes. While saliva study revealed specific substances, adsorption-elution demonstrated “A” antigen specificity in different strengths in Am, Ay, and AmB phenotypes. Conclusion: The subgroups of A and AB are attributed to a reduced number of A antigen sites on the red cells. We conclude that differentiating weak subgroups of “A” by serological assays is possible to a great extend with technical expertise; however, molecular genotyping is essential because it confirms the result.

Comparative Analysis of Electrochemiluminescence Assay and Chemiluminescent Microparticle Immunoassay for the Screening of Hepatitis C.

The primary objective of the study was to identify a highly sensitive and specific screening technique for the detection of Hepatitis C infection in healthy blood donors in a low prevalence area for HCV. In this study, two of the most commonly used methods for Anti-HCV screening, i.e., Electrochemiluminescence Immunoassay (ECLIA) and Chemiluminescent Microparticle Immunoassay (CMIA) were performed among 517 selected healthy blood donors. The clinical performance of ECLIA and CMIA was compared on the basis of their operational variables, i.e., Sensitivity, Specificity, Accuracy, Youden's J index, Positive and Negative predictive values and False discovery, False positive and False negative rate, etc., Both ECLIA and CMIA are highly sensitive (100%) and specific (98%) in terms of anti HCV detection among the blood donors. According to the clinical performance of ECLIA and CMIA, both are efficient in detecting anti-HCV antibodies among the asymptomatic population of healthy blood donors. But as both of them are associated with false positive results, it is recommended to have Polymerase chain reaction on the reactive samples to detect the HCV RNA.

Reference values for serum folate and vitamin B12 in a Spanish population using an electrochemiluminiscent method

BackgroundDespite being the most widely used medical decision-making tool, reference intervals are not usually determined by clinical laboratories, due to the highly demanding activities and costly process it involves. However, scientific societies encourage individual clinical laboratories to establish their own reference values. This is especially important in the cases of folate and vitamin B12, due to strong differences in vitamin status among different populations. ObjectiveOur aim is to establish reference intervals for folate and vitamin B12 levels in a healthy blood donor population using an electrochemiluminiscent method (ROCHE DIAGNOSTICS). MethodFolate and vitamin B12 levels were measured in 141 healthy blood donors aged between 18 and 65 years. Biochemical analyses were performed using a Modular E170 analyzer (ROCHE DIAGNOSTICS) and an electrochemiluminiscent method. Reference intervals were calculated with a non-parametric percentile method following the CLSI guidelines. ResultsThere were not significant differences in folate or cobalamin levels between age or sex subgroups. The limits of the reference interval for folate were 2.2 and 18ng/mL (5–40.7nmol/L), and 213.8 and 763.3pg/mL (158.2–564.8pmol/L) for vitamin B12. These intervals differed from those claimed by the manufacturer. ConclusionsOur results emphasize the convenience of building reference values based on the population served by the laboratory, in order to unequivocally rule out deficiencies of folate or vitamin B12.

Iron deficiency among blood donors: experience from the Danish Blood Donor Study and from the Copenhagen ferritin monitoring scheme.

Blood components collected from blood donors are an invaluable part of modern-day medicine. A healthy blood donor population is therefore of paramount importance. The results from the Danish Blood Donor Study (DBDS) indicate that gender, number of previous donations, time since last donation and menopausal status are the strongest predictors of iron deficiency. Only little information on the health effects of iron deficiency in blood donors exits. Possibly, after a standard full blood donation, a temporarily reduced physical performance for women is observed. However, iron deficiency among blood donors is not reflected in a reduced self-perceived mental and physical health. In general, the high proportion of iron-deficient donors can be alleviated either by extending the inter-donation intervals or by guided iron supplementation. The experience from Copenhagen, the Capital Region of Denmark, is that routine ferritin measurements and iron supplementation are feasible and effective ways of reducing the proportion of donors with low haemoglobin levels.

Evaluation of OSMOCELLS, a new semi-automatic device for osmotic fragility assessment.

The osmotic fragility (OF) test was a central test for the diagnosis of hereditary red blood cell (RBC) disorders (mostly hereditary spherocytosis (HS), but thalassaemia as well). Nowadays although the traditional multitubes method has lost a prominent place, many laboratories still perform such a laboured test, despite the lack of standardization. In fact, the evaluation of OF may offer an inexpensive screening for RBC disorders. We present a new semi-automatic device, allowing the continuous recording of OF, by an updated dialysis method. Repeatability, stability over time, influence of the anticoagulant were evaluated among a population of healthy blood donors. The test was then performed among patients presenting inherited RBC disorders (HS or haemoglobinopathies) where OF is typically altered. Repeatability was excellent; the parameters were greatly influenced by the nature of the anticoagulant and interestingly appeared stable for 48h. Patients with RBC disorders displayed the expected profile in regard with their disease: patients with HS all presented an increased OF while patients with haemoglobinopathy displayed resistant profiles. The device offers a substantial improvement in terms of standardization and consistency of the results and may offer a considerable gain for general laboratories.

Variables That Affect Results of PFA-100 in a Group of Healthy Blood Donors in the Slovak Population

Abstract Background: The platelet function analyzer (PFA-100) is a system analyzing platelet function determined for detection of the functional inherited and acquired platelet disorders, screening of von Willebrand disease (vWD) and recently also considered as useful for monitoring of antiplatelet treatment. The PFA-100 test uses a high shear flow system to simulate in vitro the conditions to which platelets are subjected at the site of a damaged blood vessel wall. Aim of study: We decided to establish the reference intervals of PFA closure time (CT) in the Slovak population of healthy blood donors. Patients and methods: Fifty age and gender matched healthy blood donors were enrolled in the study. We investigated the relationships between PFA-100 CT, gender and ABO blood groups. Results: The reference intervals for CT measured on CEPI (collagen/epinephrine) and CADP (collagen/adenosine diphosphate) cartridge in 3.2% citrated blood were 86 - 199 sec. and 42 - 119 sec., respectively. Blood group O was associated with significantly longer CEPI CT (p&lt;0.05) compared to non - O groups. The prolongation of CADP CT in blood donors with blood group O was without significance. The influence of gender as another variable analyzed with CT has not been evaluated as statistically significant. Conclusion: PFA-100 CT should be interpreted carefully with consideration of both the patient’s clinical presentation and laboratory variables such as ABO blood group.

Hypercoagulation Screening as Marker of Occult Cancer in a Population of Healthy Blood Donors: The Hypercan Prospective Study

INTRODUCTION and AIM: The HYPERCAN study is an ongoing prospective Italian multicenter trial, designed to test whether the persistence of a laboratory hypercoagulation abnormalities may predict early cancer diagnosis in healthy subjects (Project A), or prognosis and response to therapy in patients with cancer (Project B). The aim of this abstract is to present a preliminary analysis of data collected for project A.MATERIAL AND METHODS: A large healthy population of Italian blood donors from Bergamo and Milan areas (North Italy) is prospectively enrolled after informed written consent and followed-up for 5 years for the occurrence of cancer. As established by a monitoring schedule, blood donors are periodically screened for a series of serological, biochemical and clinical parameters, and tested for viral infections. We plan to enroll 10,000 donors of both gender, age range 35-65, in 5 years. Blood samples from each study subject are collected at enrollment and after 8-10 months, and processed to obtain plasma, buffy coat, and serum subsamples, which are stored in a dedicated biobank until testing for hypercoagulation biomarkers. Demographic and clinical data are collected, including age, gender, body mass index (BMI), current medications, relevant comorbidities, routine hematological and biochemical workup. In addition, subjects are asked to fill in a questionnaire on lifestyle, smoke and dietary habits. An identification of all malignant tumors, according to the categories 140-208 (International Classification of Diseases) is carried out every 6 months.RESULTS: Between April 2012 and June 2016, 6,607 blood donors (70% males; median age 48 years) have been recruited. Routine biochemical and hematological workups are into the normal range values in more than 90% of subjects. The analysis of questionnaires reveals that 57% of the donors were not smokers, 15% regular smokers, 28% ex-smokers; 49% of them were moderate/low alcohol consumer (≥ 2 drink/die). The crude incidence of all malignant cancers in the Bergamo/Milan area is 552 cases/100,000 persons/year in males and 382 cases/100,000 person/year in females. According to the Cancer Registry, 57 cancer cases (38 males and 19 females) are to be expected in the general population in the age range 35-65 years, after a median follow-up of 2.5 years. In our population, at June 2016, after a median follow-up of 2.5 years, we recorded a total of 46 cancer cases (35 M / 11 F). Five cases were excluded because diagnosis occurred within 6 months from enrollment (incident cancer cases); the remaining 41 cases included in the analysis were diagnosed with cancer 6-28 months from enrollment (median time to diagnosis = 24.8 months). Median age at diagnosis of cancer was 53 years. The most frequent tumor type in male donors was prostate cancer (25.8%), followed by colo-rectal (19.3%) and thyroid (12.9%) cancers. In female donors, breast cancer was the most frequent (40%). Currently, the enrollment of healthy donors and follow-up is ongoing, as well as the identification of new cancer cases. Next, according to the original plan, samples from 3 matched cancer-free donors for each cancer-case donor (cancer: non-cancer = 1:3 ratio) will be analyzed in parallel for hypercoagulation markers.CONCLUSIONS: This preliminary analysis reveals that the distribution of tumor types in our population reflects the same as reported for the general population of the same geographic area. Second, in our population of healthy blood donors, the incidence of cancer diagnosis is lower than that predicted from epidemiological data. This message supports the concept that a healthy lifestyle can be effective to prevent cancer.Project funded by AIRC "5xMILLE" n. 12237 grant from the "Italian Association for Cancer Research (AIRC)". DisclosuresFalanga:Pfizer: Speakers Bureau; Aspen: Speakers Bureau; Janssen: Speakers Bureau.

The hide and seek of Plasmodium vivax in West Africa: report from a large-scale study in Beninese asymptomatic subjects.

Background Plasmodium vivax is considered to be absent from western Africa, where the prevalence of Duffy-negative red blood cell phenotype proves to be high. Several studies have, however, detected P. vivax infection cases in this part of Africa, raising the question of what is the actual prevalence of P. vivax in local populations. MethodsThe presence of P. vivax was investigated in a large population of healthy blood donors in Benin using microscopy, serology and molecular detection. The seroprevalence was measured with species-specific ELISA using two recombinant P. vivax proteins, namely rPvMSP1 and rPvCSP1. Specific molecular diagnosis of P. vivax infection was carried out using nested-PCR. The performances and cut-off values of both rPvCSP1 and rPvMSP1 ELISA were first assessed using sera from P. vivax-infected patients and from non-exposed subjects.ResultsAmong 1234 Beninese blood donors, no parasites were detected when using microscopy, whereas 28.7% (354/1234) of patients exhibited had antibodies against rPvMSP1, 21.6% (266/1234) against rPvCSP1, and 15.2% (187/1234) against both. Eighty-four samples were selected for nested-PCR analyses, of which 13 were positive for P. vivax nested-PCR and all Duffy negative. ConclusionThe results of the present study highlight an unexpectedly high exposure of Beninese subjects to P. vivax, resulting in sub-microscopic infections. This suggests a probably underestimated and insidious parasite presence in western Africa. While the vaccination campaigns and therapeutic efforts are all focused on Plasmodium falciparum, it is also essential to consider the epidemiological impact of P. vivax.Electronic supplementary materialThe online version of this article (doi:10.1186/s12936-016-1620-z) contains supplementary material, which is available to authorized users.

ABO Blood Group and Risk of Thromboembolic and Arterial Disease: A Study of 1.5 Million Blood Donors.

ABO blood groups have been shown to be associated with increased risks of venous thromboembolic and arterial disease. However, the reported magnitude of this association is inconsistent and is based on evidence from small-scale studies. We used the SCANDAT2 (Scandinavian Donations and Transfusions) database of blood donors linked with other nationwide health data registers to investigate the association between ABO blood groups and the incidence of first and recurrent venous thromboembolic and arterial events. Blood donors in Denmark and Sweden between 1987 and 2012 were followed up for diagnosis of thromboembolism and arterial events. Poisson regression models were used to estimate incidence rate ratios as measures of relative risk. A total of 9170 venous and 24 653 arterial events occurred in 1 112 072 individuals during 13.6 million person-years of follow-up. Compared with blood group O, non-O blood groups were associated with higher incidence of both venous and arterial thromboembolic events. The highest rate ratios were observed for pregnancy-related venous thromboembolism (incidence rate ratio, 2.22; 95% confidence interval, 1.77-2.79), deep vein thrombosis (incidence rate ratio, 1.92; 95% confidence interval, 1.80-2.05), and pulmonary embolism (incidence rate ratio, 1.80; 95% confidence interval, 1.71-1.88). In this healthy population of blood donors, non-O blood groups explain >30% of venous thromboembolic events. Although ABO blood groups may potentially be used with available prediction systems for identifying at-risk individuals, its clinical utility requires further comparison with other risk markers.

Seroprevalence of Borrelia burgdorferi in occupationally exposed persons in the Belgrade area, Serbia.

Lyme disease (LD) is a natural focal zoonotic disease caused by Borrelia burgdorferi, which is mainly transmitted through infected Ixodes ricinus tick bites. The presence and abundance of ticks in various habitats, the infectivity rate, as well as prolonged human exposure to ticks are factors that may affect the infection risk as well as the incidence of LD. In recent years, 20% to 25% of ticks infected with different borrelial species, as well as about 5,300 citizens with LD, have been registered in the Belgrade area. Many of the patients reported tick bites in city’s grassy areas. The aim of this study was to assess the seroprevalence of B. burgdorferi in high-risk groups (forestry workers and soldiers) in the Belgrade area, and to compare the results with healthy blood donors. A two-step algorithm consisting of ELISA and Western blot tests was used in the study. Immunoreactivity profiles were also compared between the groups. The results obtained showed the seroprevalence to be 11.76% in the group of forestry workers, 17.14% in the group of soldiers infected by tick bites and 8.57% in the population of healthy blood donors. The highest IgM reactivity was detected against the OspC protein, while IgG antibodies showed high reactivity against VlsE, p19, p41, OspC, OspA and p17. Further investigations in this field are necessary in humans and animals in order to improve protective and preventive measures against LD.

Polymorphisms in theCLDN1andCLDN7genes are related to differentiation and tumor stage in colon carcinoma

Tight junction is composed of transmembrane proteins important for maintaining cell polarity and regulating ion flow. Among these proteins are the tissue-specific claudins, proteins that have recently been suggested as tumor markers for several different types of cancer. An altered claudin expression has been observed in colon, prostatic, ovarian, and breast carcinoma. The aim of this study was to analyze the allele frequencies of three common single nucleotide polymorphisms (SNPs) in the genes for claudin 1 and claudin 7 in colon cancer (CC) patients and in a control population of healthy blood donors. Pyrosequencing was used to genotype the CLDN1 SNP rs9869263 (c.369C>T), and the CLDN7 SNPs rs4562 (c.590C>T) and rs374400 (c.606T>G) in DNA from 102 formalin fixed paraffin embedded (FFPE) colon cancer tissue, and 111 blood leukocyte DNA from blood/plasma donors. These results were correlated with clinical parameters such as TNM stage, tumor localization, tumor differentiation, complexity index, sex, and age. We found that there was a significant association between the CLDN1 genotype CC in tumor samples and a higher risk of colon cancer development (OR 3.0, p < 0.001). We also found that the CLDN7 rs4562 (c.590C>T) genotype CT had a higher risk of lymph node involvement (p = 0.031) and a lower degree of tumor differentiation (p = 0.028). In the control population, the allele frequencies were very similar to those in the HapMap cohort for CLDN7. The CLDN1 rs9869263 genotype (c.369C>T) was related to increased risk of colon cancer, and the CLDN7 rs4562 genotype (c.590C>T) was related to tumor differentiation and lymph node involvement in colon carcinoma. Further studies are warranted to ascertain their potential uses as biomarkers predicting tumor development, proliferation, and outcome in this disease.

Comparison of several functional methods to evaluate the immune response on stable kidney transplant patients

The introduction of new immunosuppressive drugs in the last two decades has been associated with a significant decline in the prevalence of acute rejection and a huge improvement of graft survival. Monitoring blood levels of immunosuppressive drugs is the most common way to control drug doses in renal transplant patients. This approach is useful and widely used but doesn't give accurate information about the immune status of the patient. For this goal, there are many “in house” protocols which give more information, but cannot be standardized, limiting their applicability to compare results between different laboratories. In this study we compare three classical functional methods to evaluate the immune response: Mixed lymphocyte reaction (MLR), phytohemagglutinin stimulated peripheral blood lymphocytes (PBLs), and anti-CD3 monoclonal antibodies (mAbs) against PBL with the only FDA-labeled assay to measure the patient immune status: Cylex ImmuKnow® that measures the intracelullar ATP in CD4+ lymphocytes. We used n=111 stable renal transplant patients, all the patients with more than one year functioning grafts. We referred the results to a control population of healthy blood donors (n=125).Results: Measurement of intracellular ATP in CD4+ lymphocytes is able to differentiate immunosuppressed populations in renal transplant patients from health controls (242.30±21.62 vs. 386.43±25.12, p 0.0001). By contrary, there were no differences between controls and renal recipients when functional response was measured by MLR, PHA and anti-CD3 mAbs (2.48±0.45 vs. 2.37±0.41; 2.84±0.76 vs. 2.37±0.32; 2.32±0.34 vs. 1.89±0.38 respectively). In summary, our results show that the measurement of ATP in CD4+ lymphocytes gives more accurate information in comparison to the classical methods.

UK approach to assessing assays and filters designed to reduce the risk of transfusion-transmitted vCJD

Three cases of vCJD transmission by blood transfusion have been reported in the UK, and a fourth case discovered at post-mortem. Modelling has been conducted to predict the number of cases that may occur in the future through transfusion, based on estimates of prevalence, infectivity and susceptibility, and a number of steps have been taken to reduce the risk of transmission. These include deferral of previously transfused donors, leucocyte depletion of all components, importation of plasma for certain patient groups and for fractionation, and the collection of the majority of platelets from single donors (by apheresis). However, even with these interventions, some future cases are still predicted. The UK-wide Advisory Committee on the Safety of Blood, Tissues and Organs (SaBTO) considers the evidence for clinical and cost-effectiveness of any proposed intervention, such as prion assays and filters, and makes recommendations to the governments of the UK. The development of prion assays is challenging as prions do not generate an immune response, do not have nucleic acid and are present in blood in very low concentrations against a high background of normal prion protein. It is critically important that prion assays show high levels of sensitivity and — especially —specificity for a healthy blood donor population. Assessment is impacted by the very short supply of positive human samples, necessitating the use of animal models. Filters that are capable of removing prions from blood components have been developed and CE marked, but it is again necessary to use animal models to study their efficacy. Guidelines have been produced for the assessment of the quality of red cells filtered through these devices, and a clinical safety study has recently been completed. In conclusion, the evaluation of screening assays and prion filters is challenging, time-consuming and costly, but these evaluations are critical to policy making.