International review of blood donation screening for anti-HBc and occult hepatitis B virus infection.

BACKGROUND: Hepatitis B core antibody (anti-HBc) screening has been implemented in many blood establishments to help prevent transmission of hepatitis B virus (HBV), including from donors with occult HBV infection (OBI). We review HBV screening algorithms across blood establishments globally and their potential effectiveness in reducing transmission risk. MATERIALS AND METHODS: A questionnaire on HBV screening and follow-up strategies was distributed to members of the International Society of Blood Transfusion working party on transfusion-transmitted infectious diseases. Screening data from 2022 were assimilated and analyzed. RESULTS: A total of 30 unique responses were received from 25 countries. Sixteen respondents screened all donations for anti-HBc, with 14 also screening all donations for HBV DNA. Anti-HBc prevalence was 0.42% in all blood donors and 1.19% in new donors in low-endemic countries; however, only 44% of respondents performed additional anti-HBc testing to exclude false reactivity. 0.68% of anti-HBc positive, HBsAg-negative donors had detectable HBV DNA. Ten respondents did universal HBV DNA screening without anti-HBc, whereas four respondents did not screen for either. Deferral strategies for anti-HBc positive donors were highly variable. One transfusion-transmission from an anti-HBc negative donor was reported. DISCUSSION: Anti-HBc screening identifies donors with OBI but also results in the unnecessary deferral of a significant number of donors with resolved HBV infection and donors with false-reactive anti-HBc results. Whilst confirmation of anti-HBc results could be improved to reduce donor deferral, transmission risks associated with anti-HBc negative OBI donors must be considered. In high-endemic areas, highly sensitive HBV DNA testing is required to identify infectious donors.

[The Role of Anti-HBc Testing on Donor Selection and Its Contribution to Current Alghorithms; Can the Gülhane Experience Be a Model for Turkey?] / Anti-HBc Testinin Bagisçi Seçimindeki Rolü, Güncel Algoritmaya Katkisi; Gülhane Deneyimi Türkiye için Örnek Model Olur Mu?

Additional or different test procedures can be applied to maximize transfusion safety by reducing the risk of transfusion-transmitted infections. Antibodies to hepatitis B core antigen (anti-HBc) is one of the most commonly used serologic marker in this context. The aim of the study was to analyse anti-Hbc test results performed within the scope of routine screening tests in our center and to examine the effect of the donor re-entry protocol established. A total of 57191 people who applied to Gülhane Regional Blood Center to donate blood between 2014-2019 were included in the study. All blood donations were screened for anti-HBc by chemiluminescense immunoassay (Architect i2000 SR, AXSYM, Abbott, IL, USA). Hepatitis B surface antibody (anti-HBs) and hepatitis B virus (HBV) deoxyribonucleic acid (DNA) (ABI Prism 7500 Real time PCR system, Applied Biosystems, USA) tests were performed in accordance with the donor recovery protocol for those who could be reached among those with positive for anti-HBc test results. Samples with > 100 IU/ml of anti-HBs levels and negative for HBV DNA test were included in the donor pool. Of the 57 191 blood donors involved in the study, 5125 (8.5%) were found as positive for anti-HBc. Of the donors, 54 035 (94.4%) were male and 3156 (5.5%) were female. The difference was found to be statistically significant in terms of gender distribution between the years of the study (p<0.001). The highest anti-HBc positivity rate (35.7%) was in the age group of 60 years and over while the lowest positivity rate (3.8%) was in the age group of 18-30 years (r= 0.549, p= 0.0001). The year with the highest anti-HBc seroprevalance (10.1%) was 2017, while the year with the lowest (7.9%) was 2014. The distribution of seropositivity over the years was statistically significant (p<0.001). In the study, anti-HBs and HBV-DNA test results of 439 donors were accessible and of which 301 (68.5%) were considered eligible to donate again according to the re-entry protocol. The isolated anti-HBc positivity and HBV-DNA positivity rates were 7.5% (33/430) and 0.2% (1/439) respectively,in blood donors to whom re-entry protocol was performed. The seroprevalance of anti-HBc below 10% during the six-year period in which the study was conducted is a critical data for the evaluation of this test within the scope of routine microbiological screening tests. Moreover, we have observed that donor losses due to the antiHBc testing can be significantly reduced with the implementation of donor re-entry protocols. Anti-HBc screening strategy should be decided by considering of HBV epidemiology, cost-effectivity and possible blood donor losses.

MATRA-A: A study on massive transfusion.

BACKGROUND: We use massive transfusion in various clinical conditions and it is associated with high mortality. Although some massive transfusion protocols improve patient outcomes, the clinical circumstances requiring it are not well defined. METHODS: MATRA-A is a multicenter retrospective study. Six University and Training Research Hospitals in Ankara participated in the study. We collected clinical data on patients (>18 years) who received massive transfusions (≥10 units/24 h) from 2017 through 2019. RESULTS: Overall, 167 (0·27% of transfused patients) received a massive transfusion of 2586 units of red blood cells (1·5% of total RBCs transfused). The median interquartile range values for RBCs, fresh frozen plasma (FFP) and platelets were 13 (11-176), 16 (9-33) and 4 (0-11), respectively. Surgical patients received 90% of massive transfusions. The most common clinical indications for massive transfusion were cardiovascular diseases (42·6%), trauma (20·3%) and malignancies (11%). FFP: RBC: Platelets ratio was 1·9:1:0·5. The overall and trauma-related mortality rates were 57·4% and 61·8%, respectively. The hospital mortality rates of trauma patients that received high vs. low ratio (FFP: RBCs > 1:1·5 vs. ≤1:1·5) transfusions were 47·6% and 86·6% and the difference was statistically significant (P = 0·03). CONCLUSION: Cardiovascular diseases and trauma occasion are the most common causes of massive transfusion. It is infrequent in clinical settings and is associated with high mortality rates. Additionally, in massively transfused trauma patients, a high FFP:RBCs ratio seems to be associated with increased survival. Focused prospective studies are required to define the areas that need improvement on a national scale.

Prevalence and Quantity of Parvovirus B19 DNA Among Blood Donors from a Regional Blood Center in Turkey.

OBJECTIVE: Parvovirus B19 causes a range of diseases and morbidity in humans and is transmissible by transfusion of blood, blood components and plasma derivatives. The objective of the study was to investigate the prevalence and quantity of B19 DNA among blood donors. METHOD: Totally 1053 samples were collected from March to July 2016 at a blood bank for detection of Parvovirus B19 DNA and serological status of blood donors. Testing of the presence of viral DNA was performed by a quantitative real-time PCR with a 101 copies/ml detection limit. All DNA positive and randomly selected 267 samples were tested for the presence of anti-B19 IgM and IgG by ELISA. RESULTS: Age distribution of donors was between 18-64; mean age was 27 and median was 23. Among the 1053 samples, 5 (0.47%) had PB19 DNA. All PB19 DNA positive donations had both B19 IgM and IgG antibodies. The DNA level for positive donations were between 0.9 × 102 to 3.1 × 104 copies/ml. IgG and IgM were present in 59.9% (160/267) and 0,74% (2/267) respectively among the healthy donors without PB19 DNA. CONCLUSION: Detected DNA concentration was less than 105 copies/ml. The presence of IgM in low level PB19 DNA positive donors may indicate that there might be a risk in transmission of PB19 to particularly immunosuppressed recipients. The clinical follow-up of blood donation with low level of PB19DNA should be considered to answer the questions about blood safety.

Regulatory consideration on preparation and clinical use of COVID-19 convalescent plasma.

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the cause of coronavirus disease (COVID-19), spreading from Wuhan to worldwide has been emerged since December 2019. Although scientists and researchers have been racing to develop specific therapeutic agents or vaccines against SARS-CoV-2 since the identification of the agent, either a drug or a vaccine has not been approved to treat or to prevent COVID-19 up to date. On the base of historical experiences, Convalescent Plasma (CP), a passive antibody therapy, has been evaluated as a hopeful and potential therapeutic option since the beginning of the COVID-19 outbreak. Immune plasma had been used previously for the treatment of H1N1 influenza virus, SARS-CoV-1 and MERS-CoV epidemics successfully. In this scope competent authorities are responsible to set up certain principles and criteria for the collection and clinical use of COVID-19 Convalescent Plasma (CCP). This document has been prepared to aid both for the convalescent plasma suppliers and the clinicians. The first part encompasses the supply of CCP and the second part lead the clinical use of CCP for the treatment of patients with severe COVID-19 infection. Turkish Ministry of Health developed a guide on collection and clinical use of CCP and created a web-based monitoring system to follow-up the patients treated with convalescent plasma in universal. This follow-up process is thought to be crucial for the creation and development of current and future treatment modalities. This guide would be a pathfinder for clinicians and/or institutions those eager to conduct CCP treatment more effectively.

A strategical re-thinking on National Blood Donor Pool: Anti-HBc positivity related re-entry mechanisms.

BACKGROUND AND OBJECTIVES: Screening of blood donations for antibodies against hepatitis B core antigen (anti-HBc) is used to prevent transfusion transmitted hepatitis B virus (HBV) infection. In this study, we studied the magnitude of blood donor gain by using a re-entry mechanism in our Blood Bank of Gulhane Military Academy of Medicine. MATERIALS AND METHODS: Between January and May 2013, 5148 voluntary blood donors were screened by ELISA method for HBsAg, anti-HBc total and other screening markers, prospectively. Samples with repeated reactivity for the presence of anti-HBc were further tested with four supplemental assays. RESULTS: We detected 515 (10%) anti-HBc positive and 4612 (90%) anti-HBc negative cases in 5127 HBsAg negative serum samples. A total of 461 (89.5%) blood units were reactive for at least one additional serologic parameter and 54 were (10.5%) negative. Isolated anti-HBc positivity rate was 1.3% (69/5127). In the isolated anti-HBc positive samples, 54 were also anti-HBe and HBeAg negative. HBV DNA was not detected in any of the samples. CONCLUSION: Applying the EDQM criteria would decrease our blood donor loss from 10% to 5.4%. As alternative re-entry mechanisms have already been presented in the literature, institution of a new policy is needed to enhance the limited blood donor pool in our system.

Is one-size-fits-all strategy adequate for platelet storage?

BACKGROUND: Platelet suspensions (PSs) are stored at room temperature. However, recent reports show that PSs stored at 4 °C possess superior hemostatic properties. We compared the viabilities and thrombin generation capacities of PSs stored either at 4 °C or 22 °C hours. MATERIALS AND METHODS: Twenty units of apheresis derived platelets (ADPs) from 20 male donors and 20 units of random platelet suspensions (RPSs) from another 20 male donors were obtained. Half of the ADPs and half of the RPSs (10 units/per group) were stored at 4 °C, the other halves of ADPs and RPSs (10 units/per group) were stored in agitators at 22 °C for 48 hours. The flow cytometric viability tests and thrombin generation tests of the PSs were assessed. RESULTS: The viabilities of both ADPs and RPSs group platelets, stored either at 4 °C or 22 °C for 48 hours, were not statistically significantly different. The ADPs and RPSs stored at 4 °C generated significantly higher peak thrombin levels than the platelets stored at 22 °C. Moreover, the ADPs group stored at 4 °C showed significantly shorter time to thrombin generation and reach peak levels. CONCLUSION: The PSs stored at 4 °C showed higher and faster thrombin generation capacities than the room temperature PSs. Given the superior hemostatic properties of refrigerated platelets, creating different storage temperature capabilities for specific transfusion purposes may be a prudent approach, especially for improving the outcome of bleeding trauma casualties.

[Rapid detection of extended-spectrum beta-lactamases by flow cytometry method]. / Genislemis spektrumlu beta-laktamazlarin akim sitometrisi yöntemiyle hizli tespiti.

Extended-spectrum beta-lactamases (ESBL), produced by Enterobacteriaceae members are enzymes that especially cause a resistance to cephalosporin group antibiotics commonly used in clinics. Early and rapid detection of ESBL production is crucial for antimicrobial treatment and infection control; however the methods used for this purpose are time consuming (24 to 48 hours). The aim of this study was to determine a flow cytometry based-test which provides to detect ESBL producing bacteria in a short time. A total of 38 ESBL-producing (29 Escherichia coli, 9 Klebsiella pneumoniae) and 10 non-producing (5 E.coli, 5 K.pneumoniae) Enterobacteriaceae strains isolated between 2012 and 2013 were included in this study. The identification and antibiotic susceptibility tests of the isolates were performed by using Phoenix(TM) 100 automated system (Becton Dickinson, USA). The presence of bla(TEM), bla(SHV), bla(CTX-M1), bla(CTX-M2) and bla(CTX-M9) genes were investigated in ESBL positive isolates via polymerase chain reaction method. At least one of the ESBL genes were detected in 36 out of 38 isolates and no genes were detected in two E.coli isolates. In flow cytometric method, the percentages of death cells exposed to cephalosporin [(ceftazidime (CAZ) or cefotaxime (CTX)] and clavulanic acid (CLA) combination, were compared with death cells exposed only to cephalosporin (CAZ or CTX). CLA index values (CAZ-CLA and CTX-CLA indices) were obtained for CTX and CAZ. Index values which was higher than 1.5 just for one cephalosporin were accepted as GSBL positive. The mean index values for CTX-CLA in ESBL positive strains according to their genotypic characteristics were between 1.14 and 7.22, while those values for CAZ-CLA were between 0.85 and 5.6. When the two groups of 38 ESBL positive and 10 ESBL negative strains were evaluated, statistically significant difference was detected for both CAZ-CLA and CTX-CLA indices (p< 0.005). CTX-CLA indices (p= 0.001) shown a better determination of ESBL when CAZ-CLA and CTX-CLA indices were compared statistically. In conclusion, flow cytometry is a rapid and reliable method for the detection of ESBL in clinical microbiology laboratories when compared with the other methods.

The usefulness of anti-HCV signal to cut-off ratio in predicting hepatitis C viremia and the effect of genotype differences on signal to cut-off ratio.

OBJECTIVE: In the hepatitis C virus (HCV) diagnostic algorithm, an anti-HCV screening test is recommended first. In countries with low HCV prevalence, anti-HCV testing can often give false-positive results. This may lead to unnecessary retesting, increased costs, and psychological stress for patients. METHODS: In this study, the most appropriate S/Co (signal-cutoff) value to predict HCV viremia in anti-HCV test(+) individuals was determined, and the effect of genotype differences was evaluated. Of the 96,515 anti-HCV tests performed between 2020 and 2023, 934 were reactive. A total of 332 retests and 65 patients without HCV-ribonucleic acid (RNA) analysis were excluded. Demographic data were calculated for 537 patients, and 130 patients were included in the study. RESULTS: The average age of 537 patients was 55±18 years, and 57.1% were women. The anti-HCV positivity rate was 0.62% (602/96,515), and the actual anti-HCV positivity rate was 0.13% (130/96,515). Anti-HCV levels were higher in HCV-RNA(+) patients than in HCV-RNA-negative individuals (p<0.0001) (Table 1). Receiver operating characteristic curve analysis identified the optimal S/Co value to be 10.86 to identify true positive cases. Sensitivity was 96.1%, specificity was 61.2%, positive predictive value (PPV) was 44.2%, and negative predictive value (NPV) was 98% (Figure 2). A total of 107 (82.3%) of the patients were identified as GT1, and the most common subtype was GT1b (n=100). CONCLUSION: If anti-HCV S/Co is ≥10.86, direct HCV RNA testing may be recommended; However, the possibility of false positivity should be considered in patients with a S/Co value below 10.86.

[Investigation of various virulence factors among the hospital and community-acquired Staphylococcus aureus isolates by real-time PCR method]. / Hastane ve Toplum Kaynakli Staphylococcus aureus Izolatlarinda Çesitli Virülans Faktörlerinin Gerçek Zamanli PCR Yöntemiyle Arastirilmasi

Staphylococcus aureus is the most common cause of skin and soft tissue infections in the community and the most important cause of nosocomial infections. In this research, it was aimed to detect the presence of staphylococcal enterotoxin A to D (SEA, SEB, SEC and SED, respectively), toxic shock syndrome toxin-1 (TSST-1), Panton-Valentine leukocidin (PVL) and SCCmec phenotype in methicillin-resistant S.aureus (MRSA) isolates and to demonstrate the genotypic association between hospital acquired and community acquired isolates. In the study the virulence factors of 147 S.aureus strains isolated from various clinical samples at Gulhane Military Medical Academy Hospital Microbiology Laboratory between 2007 and 2010 were investigated by real-time polymerase chain reaction. MLVA (multiple locus variable number of tandem repeat analysis) method was used to demonstrate the genotypic association between hospital-and community-acquired isolates. Seventy-two (%48.9) of 147 S.aureus isolates were determined as community acquired and 75 (%51.1) as hospital acquired. Ninety-three (63.2%) isolates possesed at least one toxin (77 strains harboured one, and 16 strains harboured more than one). Of the isolates in which toxin was detected 59.1% (55/93) were hospital acquired, 40.9% (38/93) were community acquired. SEA was determined in 59 (40.1%), SEB in 8 (5.4%), SEC in 12 (8.1%), SED in 8 (5.4%), TSST- 1 in 17 (11.5%) and PVL in 6 (4.0%) of the isolates. Methicillin resistance was determined in 61.1% (44/72) of the hospital acquired isolates and 6.7% of the (5/75) community acquired isolates. In our study, SCCmec type III was detected in 90.9% (40/44) of hospital acquired MRSA isolates and SCCmec type IV in 40.0% (2/5) of community acquired MRSA isolates. Most of the strains (40/47; 85.1%) carrying SEA were hospital acquired, and they were determined as methicillin-resistant. According to MLVA, hospital and community acquired groups' clustering rates, number of clones, number of unique profile were determined as; 73.6% and 57.3%; 34% and 47%; 19% and 32%, respectively. It was concluded that high prevalence of SEA toxin in hospital acquired MRSA isolates indicated that there was a possible association between the presence of toxin and antimicrobial resistance.

Effectiveness of Vapocoolant Spray on Venipuncture Pain in Young Male Donors: A Randomized Controlled Trial.

The aim of this single-blinded, randomized controlled study was to determine the effectiveness of vapocoolant spray in reducing pain related to venipuncture in young, healthy male blood donors. The participants were separated into 2 groups by randomization. The donors in the control group (n = 44) were not given any intervention during the blood collection process. Vapocoolant spray was applied to the donors in the vapocoolant spray group (n = 44). The pain score was 1.90 ± 1.47 for the vapocoolant spray group and 3.23 ± 2.21 for the control group, and the difference between the groups was found to be statistically significant (P = .02). The study result showed that the use of vapocoolant spray for pain management is an effective method of reducing pain related to venipuncture during the process of blood donation in young male donors.

[Resistance rates to major anti-tuberculosis drugs in Mycobacterium tuberculosis strains isolated from seven different regions of Turkey in 2003-2006 period]. / Ulkemizin yedi farkli bölgesinden 2003-2006 yillari arasinda izole edilen mycobacterium tuberculosis suslarinin majör antitüberkoloz ilaçlara direnç oranlari.

Multi-drug resistance in Mycobacterium tuberculosis (MDR-TB) is a global problem and has increased especially in areas where tuberculosis control programmes are inefficient. The aim of this study was to detect the resistance rates against isoniazide (INH), rifampisin (RMP), ethambutol (EMB) and streptomycin (SM) in M. tuberculosis strains collected from 7 different regions including 62 cities and sent to Refik Saydam Hygiene Center National Tuberculosis Reference and Research Laboratory. Of the patients included, 7.61% were children, 92.39% were adults; 76.16% were male and 23.84% were female. These strains were isolated from sputum (n = 885, 81.11%), gastric lavage (n = 49, 4.49%), pleural fluid (n = 43, 3.94%), urine (n = 30, 2.74%), bronchoalveolar lavage (n = 22, 2.01%), and other clinical samples (n = 62, 8.46%) such as cerebrospinal fluid, lymph node, abscess material, lung tissue. The susceptibilities of the 1091 M. tuberculosis strains against the major anti-tuberculosis drugs were determined by the proportion method in Lowenstein-Jensen medium. Three hundred ninety two of the isolates were from Central Anatolia, 146 from Black Sea, 419 from Aegean, 28 from Mediterranean, 20 from Marmara, 64 from Eastern Anatolia and 21 from South Eastern Anatolia regions of Turkey. The distribution of the strains according to years were as follows: 88 in 2003, 114 in 2004, 341 in 2005 and 548 in 2006. Resistance to at least one of the drugs tested was found in 264 (14.20%) strains. Overall drug resistance rates to INH, RMP, EMB and SM were 12.3%, 10.1%, 6% and 15.8%, respectively. MDR-TB rate was 10% for this 4 years study period. MDR-TB rate was detected as 13.2%, 9.7%, 10.1% and 9.6% in children, adult, male and female patients, respectively. MDR-TB rate did not exhibit a statistically significant difference in terms of sex, age and study years (p > 0.05). However, this rate showed statistically significant difference in terms of geographical regions (p < 0.05). This study emphasized that regular surveillance of M. tuberculosis resistance to the major anti-tuberculosis drugs will provide valuable data for the effective national control and treatment of tuberculosis.

Platelet-rich plasma as an additional therapeutic option for infected wounds with multi-drug resistant bacteria: in vitro antibacterial activity study.

PURPOSE: Infected wounds, such as diabetic foot infections, are mostly polymicrobial and microorganisms have high resistance rates to antimicrobials. Infected wounds in diabetic patients have high cost, morbidity, and mortality rates. Based on these facts, there is a need for supportive localized treatment options such as platelet-rich plasma (PRP) implementations. Demonstrating the in vitro antimicrobial effect, our aim was to lead up to clinical trials of localized PRP implementations in infected wounds such as diabetic foot infections. In this study, we aimed to demonstrate the in vitro antibacterial activity of PRP against methicilin-resistant Staphylococcus aureus (MRSA) and three more multi-drug resistant bacteria species that are important and hard-to-treat in wound infections. MATERIALS AND METHODS: In vitro antimicrobial activity of autologous PRP, platelet-poor plasma (PPP), and phosphate-buffered saline (PBS) on methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus spp., extended spectrum beta lactamase producing Klebsiella pneumoniae, and carbapenem-resistant Pseudomonas aeruginosa was compared by assessment of bacterial growth on agar plates and antimicrobial susceptibility test results. RESULTS: When compared to control group, PRP and PPP significantly suppressed bacterial growth of MRSA, K. pneumoniae, and P. aeruginosa at 1st, 2nd, 5th, and 10th hours of incubation (p < 0.05). VRE was the only bacteria that PRP and PPP showed limited activity against. When compared to PPP, PRP showed higher activity against MRSA, K. pneumoniae, and P. aeruginosa. However, the differences between PRP and PPP were statistically significant only against MRSA and P. aeruginosa at the first hour of incubation. CONCLUSIONS: Emerging PRP and other platelet-derived products seem to be promising alternative tools besides antibiotic treatment, debridement, negative pressure wound therapy, hyperbaric oxygen therapy, and other treatment options for treating diabetic foot infections.

Evaluating the effect of donor anxiety levels and lifestyle characteristics on the activation of platelet concentrates.

BACKGROUND: Smoking, alcohol use, performing regular physical exercise, dietary habits, and anxiety level may cause platelet activation. We aimed to evaluate the anxiety levels, smoking status, alcohol intake, and sportive habits of donors, and determine their impact on the quality of apheresis-platelets. METHODS: State and Transient Anxiety Inventory (STAI) was used to determine the level of donors' anxiety. STAI has two subscales: S-anxiety scale (STAI-I) and T-anxiety scale (STAI-II), each comprising 20 questions rated on a 4-point Likert scale. Data on smoking, alcohol consumption, and performing regular physical exercise were obtained from a questionnaire filled out before donation. Flow cytometric analysis was used to quantify activated platelets. RESULTS: The STAI-I level of 86 participants was normal, while that of 12 was higher. No significant difference was found in the active platelet absolute count [1.8×1011 (2.7) and 1.4×1011 (1.3), respectively; P=0.665] between donors with normal STAI-I levels and those with higher STAI-I levels. Of 98 donors, 42 had normal STAI-II levels, while 56 had higher STAI-II levels. No significant difference was found in the active platelet absolute count [2.3×1011 (3.1) and 1.5×1011 (2.3), respectively; P=0.224] between donors with normal STAI-II levels and those with higher STAI-II levels. Platelet counts of individuals who perform regular physical exercise were significantly higher than those of individuals who did not perform regular physical exercise (6.3±1.4×1011 vs. 5.5±1.4×1011). CONCLUSION: The quality of apheresis platelets is not affected by anxiety levels and lifestyle characteristics of blood donors. There is no need to organize apheresis blood donor pool considering with these subjects.

Incomplete Antibodies May Reduce ABO Cross-Match Incompatibility: A Pilot Study.

OBJECTIVE: Any erythrocyte transfusion among humans having type A or B blood groups is impossible due to antibodies causing fatal transfusion complications. A cross-match test is performed to prevent immune transfusion complications before transfusion. Our hypothesis is that the fragment antibody (Fab) part of the antibody (incomplete antibody) may be used to prevent an immune stimulus related to the complete antibody. Therefore, we designed a pilot study to evaluate the effectiveness of these incomplete antibodies using cross-match tests. MATERIALS AND METHODS: Pepsin enzyme and staphylococcal protein A columns were used to cut anti-A and anti-B monoclonal antibodies and purify their Fab (2) fragments, respectively. An Rh-positive erythrocyte suspension with purified anti-A Fab (2) solution and B Rh-positive erythrocyte suspension with purified anti-B Fab (2) solution were combined correspondingly. Cross-match tests were performed by tube and gel centrifugation methods. The agglutination levels due to the anti-A and anti-B Fab (2) antibodies and their effects on the agglutination normally observed with complete antibodies were then measured. RESULTS: No agglutination for the purified incomplete anti-A Fab (2) with A Rh+ erythrocyte and anti-B Fab (2) with B Rh+ erythrocyte combinations was observed in the tube cross-match tests. These agglutination levels were 1+ in two wells in the gel centrifugation cross-match tests. Fab (2)-treated erythrocytes were also resistant to the agglutination that normally occurs with complete antibodies. CONCLUSION: We determined that the Fab (2) fragments of antibodies may not only be used to obtain a mild or negative reaction when compared to complete antibodies, but they might also be used for decreasing ABO incompatibility. Incomplete antibodies might be a therapeutic option in autoimmune hemolytic anemia and they may also be used in solid organ or hematopoietic stem cell transplantation. Therefore, we have planned an in vivo study to prove these in vitro findings.

Bringing Packed Red Blood Cells to the Point of Combat Injury: Are We There Yet?

Objective: Hemorrhage is the leading cause of injury-related prehospital mortality. We investigated worst-case scenarios and possible requirements of the Turkish military. As we plan to use blood resources during casualty transport, the impact of transport-related mechanical stress on packed red blood cells (PRBCs) was analyzed. Materials and Methods: The in vitro experiment was performed in the environmental test laboratories of ASELSAN®. Operational vibrations of potential casualty transport mediums such as Sikorsky helicopters, Kirpi® armored vehicles, and the NATO vibration standard MIL-STD-810G software program were recorded. The most powerful mechanical stress, which was created by the NATO standard, was applied to 15 units of fresh (≤7 days) and 10 units of old (>7 days) PRBCs in a blood cooler box. The vibrations were simulated with a TDS v895 Medium-Force Shaker Device. On-site blood samples were analyzed at 0, 6, and 24 h for biochemical and biomechanical analyses. Results: The mean (±standard deviation) age of fresh and old PRBCs was 4.9±2.2 and 32.8±11.8 days, respectively. Six-hour mechanical damage of fresh PRBCs was demonstrated by increased erythrocyte fragmentation rates (p=0.015), hemolysis rates (p=0.003), and supernatant potassium levels (p=0.003) and decreased hematocrit levels (p=0.015). Old PRBC hemolysis rates (p=0.015), supernatant potassium levels (p=0.015), and supernatant hemoglobin (p=0.015) were increased and hematocrit levels were decreased (p=0.015) within 6 h. Two (13%) units of fresh PRBCs and none of the old PRBCs were eligible for transfusion after 6 h of mechanical stress. Conclusion: When an austere combat environment was simulated for 24 h, fresh and old PRBC hemolysis rates were above the quality criteria. Currently, the technology to overcome this mechanical damage does not seem to exist. In light of the above data, a new national project is being performed.

Generation of Platelet Microparticles after Cryopreservation of Apheresis Platelet Concentrates Contributes to Hemostatic Activity.

OBJECTIVE: In the last decade, substantial evidence has accumulated about the use of cryopreserved platelet concentrates, especially in trauma. However, little reference has been made in these studies to the morphological and functional changes of platelets. Recently platelets have been shown to be activated by cryopreservation processes and to undergo procoagulant membrane changes resulting in the generation of platelet-derived microparticles (PMPs), platelet degranulation, and release of platelet-derived growth factors (PDGFs). We assessed the viabilities and the PMP and PDGF levels of cryopreserved platelets, and their relation with thrombin generation. MATERIALS AND METHODS: Apheresis platelet concentrates (APCs) from 20 donors were stored for 1 day and cryopreserved with 6% dimethyl sulfoxide. Cryopreserved APCs were kept at -80 °C for 1 day. Thawed APCs (100 mL) were diluted with 20 mL of autologous plasma and specimens were analyzed for viabilities and PMPs by flow cytometry, for thrombin generation by calibrated automated thrombogram, and for PDGFs by enzyme-linked immunosorbent assay testing. RESULTS: The mean PMP and PDGF levels in freeze-thawed APCs were significantly higher (2763±399.4/µL vs. 319.9±80.5/µL, p<0.001 and 550.9±73.6 pg/mL vs. 96.5±49 pg/mL, p<0.001, respectively), but the viability rates were significantly lower (68.2±13.7% vs. 94±7.5%, p<.001) than those of fresh APCs. The mean endogenous thrombin potential (ETP) of freeze-thawed APCs was significantly higher than that of the fresh APCs (3406.1±430.4 nM.min vs. 2757.6±485.7 nM.min, p<0.001). Moreover, there was a significant positive poor correlation between ETP levels and PMP levels (r=0.192, p=0.014). CONCLUSION: Our results showed that, after cryopreservation, while levels of PMPs were increasing, significantly higher and earlier thrombin formation was occurring in the samples analyzed despite the significant decrease in viability. Considering the damage caused by the freezing process and the scarcity of evidence for their in vivo superiority, frozen platelets should be considered for use in austere environments, reserving fresh platelets for prophylactic use in blood banks.

Freezing of Apheresis Platelet Concentrates in 6% Dimethyl Sulfoxide: The First Preliminary Study in Turkey.

OBJECTIVE: Transfusion of platelet suspensions is an essential part of patient care for certain clinical indications. In this pioneering study in Turkey, we aimed to assess the in vitro hemostatic functions of platelets after cryopreservation. MATERIALS AND METHODS: Seven units of platelet concentrates were obtained by apheresis. Each apheresis platelet concentrate (APC) was divided into 2 equal volumes and frozen with 6% dimethyl sulfoxide (DMSO). The 14 frozen units of APCs were kept at -80 °C for 1 day. APCs were thawed at 37 °C and diluted either with autologous plasma or 0.9% NaCl. The volume and residual numbers of leukocytes and platelets were tested in both before-freezing and post-thawing periods. Aggregation and thrombin generation tests were used to analyze the in vitro hemostatic functions of platelets. Flow-cytometric analysis was used to assess the presence of frozen treated platelets and their viability. RESULTS: The residual number of leukocytes in both dilution groups was <1x106. The mean platelet recovery rate in the plasma-diluted group (88.1±9.5%) was higher than that in the 0.9% NaCl-diluted group (63±10%). These results were compatible with the European Directorate for the Quality of Medicines quality criteria. Expectedly, there was no aggregation response to platelet aggregation test. The mean thrombin generation potential of post-thaw APCs was higher in the plasma-diluted group (2411 nmol/L per minute) when compared to both the 0.9% NaCl-diluted group (1913 nmol/L per minute) and the before-freezing period (1681 nmol/L per minute). The flow-cytometric analysis results for the viability of APCs after cryopreservation were 94.9% and 96.6% in the plasma and 0.9% NaCl groups, respectively. CONCLUSION: Cryopreservation of platelets with 6% DMSO and storage at -80 °C increases their shelf life from 7 days to 2 years. Besides the increase in hemostatic functions of platelets, the cryopreservation process also does not affect their viability rates.