Maria Lourdes Barjas-Castro

Probable transfusion-transmitted Zika virus in Brazil

Zika virus (ZIKV) is an emerging arthropod‐borne flavivirus transmitted by Aedes mosquitoes. Recent commentaries regarding ZIKV routes of transmission describe a potential transmission by transfusion. Herein, we report a probable case of transfusion‐transmitted ZIKV infection through a platelet transfusion that was detected from postdonation information.

Electrical properties of the red blood cell membrane and immunohematological investigation

Hemagglutination is widely used in transfusion medicine and depends on several factors including antigens, antibodies, electrical properties of red blood cells and the environment of the reaction. Intermolecular forces are involved in agglutination with cell clumping occurring when the aggregation force is greater than the force of repulsion. Repulsive force is generated by negative charges on the red blood cell surface that occur due to the presence of the carboxyl group of sialic acids in the cell membrane; these charges create a repulsive electric zeta potential between cells. In transfusion services, specific solutions are used to improve hemagglutination, including enzymes that reduce the negative charge of red blood cells, LISS which improves the binding of antibodies to antigens and macromolecules that decrease the distance between erythrocytes. The specificity and sensitivity of immunohematological reactions depend directly on the appropriate use of these solutions. Knowledge of the electrical properties of red blood cells and of the action of enhancement solutions can contribute to the immunohematology practice in transfusion services.

Bartonella spp. Bacteremia in Blood Donors from Campinas, Brazil

Bartonella species are blood-borne, re-emerging organisms, capable of causing prolonged infection with diverse disease manifestations, from asymptomatic bacteremia to chronic debilitating disease and death. This pathogen can survive for over a month in stored blood. However, its prevalence among blood donors is unknown, and screening of blood supplies for this pathogen is not routinely performed. We investigated Bartonella spp. prevalence in 500 blood donors from Campinas, Brazil, based on a cross-sectional design. Blood samples were inoculated into an enrichment liquid growth medium and sub-inoculated onto blood agar. Liquid culture samples and Gram-negative isolates were tested using a genus specific ITS PCR with amplicons sequenced for species identification. Bartonella henselae and Bartonella quintana antibodies were assayed by indirect immunofluorescence. B. henselae was isolated from six donors (1.2%). Sixteen donors (3.2%) were Bartonella-PCR positive after culture in liquid or on solid media, with 15 donors infected with B. henselae and one donor infected with Bartonella clarridgeiae. Antibodies against B. henselae or B. quintana were found in 16% and 32% of 500 blood donors, respectively. Serology was not associated with infection, with only three of 16 Bartonella-infected subjects seropositive for B. henselae or B. quintana. Bartonella DNA was present in the bloodstream of approximately one out of 30 donors from a major blood bank in South America. Negative serology does not rule out Bartonella spp. infection in healthy subjects. Using a combination of liquid and solid cultures, PCR, and DNA sequencing, this study documents for the first time that Bartonella spp. bacteremia occurs in asymptomatic blood donors. Our findings support further evaluation of Bartonella spp. transmission which can occur through blood transfusions.

Bartonella henselae Infects Human Erythrocytes

Bartonella henselae, a facultative intracellular bacterium, has been known as the agent of cat scratch disease, bacillary angiomatosis, peliosis hepatis, endocarditis, and bacteremic syndrome in humans. Bartonella species can cause intraerythrocytic infections and have been isolated from the bloodstream of patients by several methods. It was demonstrated that B. bacilliformis and B. quintana infect human endothelial cells and human erythrocytes and B. henselae infects erythrocytes of cats. The aim of this study was to investigate through transmission electron microscopy whether B. henselae infects mature human erythrocytes. One red blood cell (RBC) unit received an experimentally standard strain of B. henselae. Blood aliquots were collected from the infected unit immediately after inoculation, at 30 min and 1, 5, 10, and 72 h for ultrastructural evaluation. B. henselae was seen adhering to human erythrocytes 10 h after inoculation and inside the erythrocyte after 72 h. This study demonstrates that B. henselae adheres to and invades mature human erythrocytes. The results favor the possibility that erythrocytes can serve as a primary target in Bartonella spp. infections. From this observation, further studies are warranted to prevent Bartonella spp. transfusional transmission.

Investigation of red blood cell antigens with highly fluorescent and stable semiconductor quantum dots

We report a new methodology for red blood cell antigen expression determination by a simple labeling procedure employing luminescent semiconductor quantum dots. Highly luminescent and stable core shell cadmium sulfide/cadmium hydroxide colloidal particles are obtained, with a predominant size of 9 nm. The core-shell quantum dots are functionalized with glutaraldehyde and conjugated to a monoclonal anti-A antibody to target antigen-A in red blood cell membranes. Erythrocyte samples of blood groups A+, A2+, and O+ are used for this purpose. Confocal microscopy images show that after 30 min of conjugation time, type A+ and A2+ erythrocytes present bright emission, whereas the O+ group cells show no emission. Fluorescence intensity maps show different antigen expressions for the distinct erythrocyte types. The results obtained strongly suggest that this simple labeling procedure may be employed as an efficient tool to investigate quantitatively the distribution and expression of antigens in red blood cell membranes.

Elastic properties of irradiated RBCs measured by optical tweezers

BACKGROUND : Gamma irradiation of RBCs results in the production of reactive oxygen capable of initiating the process of membrane lipid peroxidation and accelerates the leakage of potassium ions from RBCs, resulting in an increase of internal viscosity.

Elastic properties of stored red blood cells from sickle trait donor units

Background and Objectives  Red blood cells (RBCs) from patients with sickle cell disease present reduced deformability. The aim of this study was to analyse the elasticity of stored RBCs from patients with the sickle cell trait (AS).

The new noninvasive occlusion spectroscopy hemoglobin measurement method: a reliable and easy anemia screening test for blood donors

BACKGROUND: The tests used for anemia screening in blood donors are based on fingerstick samples, leading to discomfort and complaints. The aim of this study was to analyze the feasibility of occlusion spectroscopy method in blood banks and to compare the method with fingerstick hemoglobinometer and hemoglobin (Hb) determination on an automatic blood analyzer.

Optical Tweezers as a New Biomedical Tool to Measure Zeta Potential of Stored Red Blood Cells

During storage, red blood cells (RBCs) for transfusion purposes suffer progressive deterioration. Sialylated glycoproteins of the RBC membrane are responsible for a negatively charged surface which creates a repulsive electrical zeta potential. These charges help prevent the interaction between RBCs and other cells, and especially among each RBCs. Reports in the literature have stated that RBCs sialylated glycoproteins can be sensitive to enzymes released by leukocyte degranulation. Thus, the aim of this study was, by using an optical tweezers as a biomedical tool, to measure the zeta potential in standard RBCs units and in leukocyte reduced RBC units (collected in CPD-SAGM) during storage. Optical tweezers is a sensitive tool that uses light for measuring cell biophysical properties which are important for clinical and research purposes. This is the first study to analyze RBCs membrane charges during storage. In addition, we herein also measured the elasticity of RBCs also collected in CPD-SAGM. In conclusion, the zeta potential decreased 42% and cells were 134% less deformable at the end of storage. The zeta potential from leukodepleted units had a similar profile when compared to units stored without leukoreduction, indicating that leukocyte lyses were not responsible for the zeta potential decay. Flow cytometry measurements of reactive oxygen species suggested that this decay is due to membrane oxidative damages. These results show that measurements of zeta potentials provide new insights about RBCs storage lesion for transfusion purposes.

Risk Factors for Bartonella species Infection in Blood Donors from Southeast Brazil

Bacteria from the genus Bartonella are emerging blood-borne bacteria, capable of causing long-lasting infection in marine and terrestrial mammals, including humans. Bartonella are generally well adapted to their main host, causing persistent infection without clinical manifestation. However, these organisms may cause severe disease in natural or accidental hosts. In humans, Bartonella species have been detected from sick patients presented with diverse disease manifestations, including cat scratch disease, trench fever, bacillary angiomatosis, endocarditis, polyarthritis, or granulomatous inflammatory disease. However, with the advances in diagnostic methods, subclinical bloodstream infection in humans has been reported, with the potential for transmission through blood transfusion been recently investigated by our group. The objective of this study was to determine the risk factors associated with Bartonella species infection in asymptomatic blood donors presented at a major blood bank in Southeastern Brazil. Five hundred blood donors were randomly enrolled and tested for Bartonella species infection by specialized blood cultured coupled with high-sensitive PCR assays. Epidemiological questionnaires were designed to cover major potential risk factors, such as age, gender, ethnicity, contact with companion animals, livestock, or wild animals, bites from insects or animal, economical status, among other factors. Based on multivariate logistic regression, bloodstream infection with B. henselae or B. clarridgeiae was associated with cat contact (adjusted OR: 3.4, 95% CI: 1.1–9.6) or history of tick bite (adjusted OR: 3.7, 95% CI: 1.3–13.4). These risk factors should be considered during donor screening, as bacteremia by these Bartonella species may not be detected by traditional laboratory screening methods, and it may be transmitted by blood transfusion.