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Unlabelled: We prospectively compared the diagnostic value of C-reactive protein (CRP) and white blood cell counts for detection of neonatal septicaemia. Sensitivity and specifity in receiver operating characteristics, and positive and negative predictive value of CRP and white blood cell count were compared in 195 critically ill preterm and term newborns clinically suspected of infection. Blood cultures were positive in 33 cases. During the first 3 days after birth CRP elevation (sensitivity 75%, specifity 86%), leukopenia (67%/90%), neutropenia (78%/80%) and immature to total neutrophil count (I/T) ratio (78%/73%) were good diagnostic parameters, as opposed to band forms with absolute count (84%/66%) or percentage (79%/71%), thrombocytopenia (65%/57%) and toxic granulations (44%/94%). Beyond 3 days of age elevated CRP (88%/87%) was the best parameter. Increased total (84%/66%) or percentage band count (79%/71%) were also useful. Leukocytosis (74%/56%), increased neutrophils (67%/65%), I/T ratio (79%/47%), thrombocytopenia (65%/57%) and toxic granulations had a low specifity. The positive predictive value of CRP was 32% before and 37% after 3 days of age, that of leukopenia was 37% in the first 3 days.Conclusion: During the first 3 days of life CRP, leukopenia and neutropenia were comparably good tests while after 3 days of life CRP was the best single test in early detection of neonatal septicaemia. Serial CRP estimations confirm the diagnosis, monitor the course of infection and the efficacy of antibiotic treatment. [ABSTRACT FROM AUTHOR]

Background: D-RBCs are produced by a rare gene that fails to encode for CcEe. Such persons may produce an antibody (Ab) of complex specificity such as anti-Rh17 (Hro). The anti-Rh 17 Ab may cross the placenta and cause severe hydrops fetalis. Case Report: A 34-year old pregnant woman G2P1001 was found to have a high-titer IgG Ab against high-frequency antigen with negative DAT. Further investigation showed her RBCs are D-. Her mother's and father's RBC phenotypes are O, D+ c+ e+ and A, D+, C+ e+ respectively. Her parents are unrelated. Her husband's RBC phenotype is O, D+C+c+E+e+. Sensitization presumably resulted from transfusion of two units of blood after her first delivery. Prenatal ultrasonography showed polyhydramnios and double bubble consistent with duodenal atresia. Amniocentesis at 31 weeks disclosed zone III OD at 450 on Liley graph. Hydrops fetalis developed two days prior to cesarean section. Two courses of betamethasone were given prior to delivery. The baby, delivered at 33 weeks with birth weight of 2121 g, had severe hydrops fetalis and was intubated immediately. Apgar scores were 4 and 7 at 1 and 5 min, respectively. He received surfactant and mechanical ventilation until day 19, and oxygen until day 25. Initial Hb was 6.9g/dl, platelets 100,000/ul, bilirubin 7.1/1.0 mg/ dl, and RBC type is O, C+D+e+. Two exchange transfusions (EXT) were done: a partial EXT and double volume EXT with D—blood reconstituted with FFP. Ab titer decreased from 1:256 after EXT to 1:16 at 5 weeks of life, with an estimated t1/2 of 6.7 days. Mixed jaundice was treated first with phototherapy, IVIG, and phenobarbital. Because of limited availability of D— blood, erythropoietin was initiated immediately. Cardiovascular complications included systemic hypotension, pulmonary hypertension, and patent ductus arteriosus which required surgical ligation. Laparotomy disclosed a preampullary duodenal atresia with malrotation; a duodenoduodenostomy and appendectomy were done. Persistent cholestatic jaundice was treated with phenobarbital, ursodiol, elementary diet (with MCT oil), and liposoluble vitamins. Conclusions: This is a case of severe hydrops fetalis due to hemolytic disease associated with D— possible de novo mutation, accompanied with duodenal atresia, and treated successfully with a combination of D— RBC and erythropoietin. [ABSTRACT FROM AUTHOR]

Background: Adoptive immunotherapy using CD19-targeted Chimeric antigen receptor T cells (CAR-T) has revolutionized the treatment of relapsed/refractory diffuse large B-cell lymphoma (DLBCL). Data is limited on the propensity of infections and lymphohematopoietic reconstitution after Day 30 (D30) following CAR-T cell therapy. In this study, we evaluated the prevalence and nature of infectious complications in an expanded cohort of DLBCL patients treated with CD19 CAR-T therapy and its association with the dynamics of leukocyte subpopulation reconstitution post-CAR-T cell therapy., Methods: We conducted a retrospective study including 19 patients who received axicabtagene ciloleucel and investigated associations between cytopenia and infectious complications after D30., Results: Nineteen patients were included, consisting of 42% Hispanic, 32% Caucasian, 21% African-American, and 5% Asian subjects. Post-D30 of CAR-T infusion, 47% patients (n=9) developed an infection and 53% (n=10) remained infection-free. The most common infection type observed was viral (7 patients) followed by bacterial (5 patients) and fungal (3 patients). Of 25 total infectious events, 56% were grade 1 or 2 and 44% were grade 3 with 10 being viral in etiology. To determine the kinetics of lymphohematopoietic reconstitution and its association with infection risk, we evaluated the relationship between cytopenias and rates of infection after D30. Notably, compared to non-infection group, infection group had a higher median absolute lymphocyte count (ALC) (1,000/µL vs . 600/µL, P<0.05), a lower median absolute neutrophil count (ANC)/ALC ratio (1.6 vs . 3.1, P<0.05) and a lower median AMC/ALC at D30 (0.37 vs . 1.67, P<0.05). In addition, we observed that only 22% of patients had recovered ANC >1,500/µL in the infection group as opposed to 70% in the non-infection group at D90 (P<0.05). Fifty-eight percent of the patients (11/19) with relapsed refractory DLBCL achieved a complete response with a median follow-up of 233 days (7.7 months)., Conclusions: Although CAR-T cell therapy is highly effective, infectious complications remain an important cause of morbidity and mortality. Low ANC/ALC and AMC/ALC ratios at D30 are potential novel predictors of infection and can be considered in future prophylactic strategies., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://dx.doi.org/10.21037/sci-2021-008). Dr. Verma serves as an unpaid editorial board member of Stem Cell Investigation. Dr. Steidl has received research funding from GlaxoSmithKline, Bayer Healthcare, Aileron Therapeutics, Novartis, has received compensation for consultancy services and for serving on scientific advisory boards from GlaxoSmithKline, Bayer Healthcare, Novartis, Celgene, Aileron Therapeutics, Stelexis Therapeutics, Pieris Pharmaceuticals, Vor Biopharma, and Trillium Therapeutics, and has equity ownership in and is serving on the board of directors of Stelexis Therapeutics. Dr. Gritsman has received Research funding from iOnctura, SA. Dr. Shastri has received research funding from Kymera Therapeutics, consultancy fees from Guidepoint & GLG, honoraria from OncLive. Dr. Verma has received research funding from GlaxoSmithKline, BMS, Jannsen, Incyte, MedPacto, Celgene, Novartis, Curis, Prelude and Eli Lilly and Company, has received compensation as a scientific advisor to Novartis, Stelexis Therapeutics, Acceleron Pharma, and Celgene, and has equity ownership in Throws Exception and Stelexis Therapeutics. The other authors have no conflicts of interest to declare., (2021 Stem Cell Investigation. All rights reserved.)

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has a variable clinical course with significant mortality. Early reports suggested higher rates of SARS-CoV-2 infection in patients with type A blood and enrichment of type A individuals among COVID-19 mortalities., Study Design and Methods: The study includes all patients hospitalized or with an emergency department (ED) visit who were tested for SARS-CoV-2 between March 10, 2020 and June 8, 2020 and had a positive test result by nucleic acid test (NAT) performed on a nasopharyngeal swab specimen. A total of 4968 patients met the study inclusion criteria, with a subsequent 23.1% (n = 1146/4968) all-cause mortality rate in the study cohort. To estimate overall risk by ABO type and account for the competing risks of in-hospital mortality and discharge, we calculated the cumulative incidence function (CIF) for each event. Cause-specific hazard ratios (csHRs) for in-hospital mortality and discharge were analyzed using multivariable Cox proportional hazards models., Results: Type A blood was associated with the increased cause-specific hazard of death among COVID-19 patients compared to type O (HR = 1.17, 1.02-1.33, p = .02) and type B (HR = 1.32,1.10-1.58, p = .003)., Conclusions: Our study shows that ABO histo-blood group type is associated with the risk of in-hospital death in COVID-19 patients, warranting additional inquiry. Elucidating the mechanism behind this association may reveal insights into the susceptibility and/or immunity to SARS-CoV-2., (© 2021 AABB.)

Convalescent plasma with severe acute respiratory disease coronavirus 2 (SARS-CoV-2) antibodies (CCP) may hold promise as a treatment for coronavirus disease 2019 (COVID-19). We compared the mortality and clinical outcome of patients with COVID-19 who received 200 mL of CCP with a spike protein IgG titer ≥ 1:2430 (median 1:47,385) within 72 hours of admission with propensity score-matched controls cared for at a medical center in the Bronx, between April 13 and May 4, 2020. Matching criteria for controls were age, sex, body mass index, race, ethnicity, comorbidities, week of admission, oxygen requirement, D-dimer, lymphocyte counts, corticosteroid use, and anticoagulation use. There was no difference in mortality or oxygenation between CCP recipients and controls at day 28. When stratified by age, compared with matched controls, CCP recipients less than 65 years had 4-fold lower risk of mortality and 4-fold lower risk of deterioration in oxygenation or mortality at day 28. For CCP recipients, pretransfusion spike protein IgG, IgM, and IgA titers were associated with mortality at day 28 in univariate analyses. No adverse effects of CCP were observed. Our results suggest CCP may be beneficial for hospitalized patients less than 65 years, but data from controlled trials are needed to validate this finding and establish the effect of aging on CCP efficacy.

Background: Kidney allocation system allows blood type B candidates accept kidneys from A2/A2B donors. There is no mandate by UNOS on which the anti-A2 level is acceptable. We aimed to investigate the safety of kidney transplant in blood group B patients with anti-A2 titers ≤16., Methods: We performed 41 A2-incompatible kidney transplants in blood group B recipients between May 2015 and September 2019. Clinical outcomes were compared with a control group of 75 blood group B recipients who received blood group compatible kidney transplantation at the same period., Results: Of the 41 recipients, 85% were male, 48% African American, with a median age of 53 (20-73) y. Thirty-eight (93%) were deceased-donor and 3 (7%) were living-donor kidney transplant recipients. Pretransplant anti-A2 IgG titers were 2 in 16, 4 in 9, 8 in 6, and 16 in 5 and too weak to titer in 5 recipients. Eight patients had pretransplant donor-specific antibodies. During a median follow-up of 32.6 mo (6-57.3) patient and graft survival were 100% and 92% in the A2-incompatible kidney transplant group, and 91% and 92% in the blood group compatible group, respectively. Twelve A2-incompatible recipients underwent a 21 clinically indicated kidney biopsies at a median 28 d (6-390) after transplantation. None of the patients developed acute antibody-mediated rejection and 2 patients (5%) had acute T-cell-mediated rejection. Interestingly, peritubular capillary C4d positivity was seen in 7 biopsies which did not have any findings of acute rejection or microvascular inflammation but not in any of the rejection-free biopsies in the control group. C4d positivity was persistent in 5 of those patients who had follow-up biopsies., Conclusions: A2-incompatible transplantation is safe in patients with anti-A2 titers ≤16 with excellent short-term kidney allograft outcomes. C4d positivity is frequent in allograft biopsies without acute rejection., Competing Interests: The authors declare no funding or conflicts of interest., (Copyright © 2021 The Author(s). Transplantation Direct. Published by Wolters Kluwer Health, Inc.)

The concentration of circulating hematopoietic stem and progenitor cells has not been studied longitudinally. Here, we report that the proportions of Lin-CD34+38- hematopoietic multipotent cells (HMCs) and of Lin-CD34+CD38+ hematopoietic progenitors cells (HPCs) are highly variable between individuals but stable over long periods of time, in both healthy individuals and sickle cell disease (SCD) patients. This suggests that these proportions are regulated by genetic polymorphisms or by epigenetic mechanisms. We also report that in SCD patients treated with hydroxyurea, the proportions of circulating HMCs and HPCs show a strong positive and negative correlation with fetal hemoglobin (HbF) levels, respectively. Titration of 65 cytokines revealed that the plasma concentration of chemokines CCL2, CCL11, CCL17, CCL24, CCL27, and PDGF-BB were highly correlated with the proportion of HMCs and HPCs and that a subset of these cytokines were also correlated with HbF levels. A linear model based on four of these chemokines could explain 80% of the variability in the proportion of circulating HMCs between individuals. The proportion of circulating HMCs and HPCs and the concentration of these chemokines might therefore become useful biomarkers for HbF response to HU in SCD patients. Such markers might become increasingly clinically relevant, as alternative treatment modalities for SCD are becoming available.

The consequences of sickle cell disease (SCD) include ongoing hematopoietic stress, hemolysis, vascular damage, and effect of chronic therapies, such as blood transfusions and hydroxyurea, on hematopoietic stem and progenitor cell (HSPC) have been poorly characterized. We have quantified the frequencies of nine HSPC populations by flow cytometry in the peripheral blood of pediatric and adult patients, stratified by treatment and control cohorts. We observed broad differences between SCD patients and healthy controls. SCD is associated with 10 to 20-fold increase in CD34 dim cells, a two to five-fold increase in CD34 bright cells, a depletion in Megakaryocyte-Erythroid Progenitors, and an increase in hematopoietic stem cells, when compared to controls. SCD is also associated with abnormal expression of CD235a as well as high levels CD49f antigen expression. These findings were present to varying degrees in all patients with SCD, including those on chronic therapy and those who were therapy naive. HU treatment appeared to normalize many of these parameters. Chronic stress erythropoiesis and inflammation incited by SCD and HU therapy have long been suspected of causing premature aging of the hematopoietic system, and potentially increasing the risk of hematological malignancies. An important finding of this study was that the observed concentration of CD34 bright cells and of all the HSPCs decreased logarithmically with time of treatment with HU. This correlation was independent of age and specific to HU treatment. Although the number of circulating HSPCs is influenced by many parameters, our findings suggest that HU treatment may decrease premature aging and hematologic malignancy risk compared to the other therapeutic modalities in SCD.

The following fictional case is intended as a learning tool within the Pathology Competencies for Medical Education (PCME), a set of national standards for teaching pathology. These are divided into three basic competencies: Disease Mechanisms and Processes, Organ System Pathology, and Diagnostic Medicine and Therapeutic Pathology. For additional information, and a full list of learning objectives for all three competencies, see http://journals.sagepub.com/doi/10.1177/2374289517715040.

The severe pain, ischemia and organ damage that characterizes sickle cell disease (SCD) is caused by vaso-occlusion, which is the blockage of blood vessels by heterotypic aggregates of sickled erythrocytes and other cells. Vaso-occlusion is also a vasculopathy involving endothelial cell dysfunction, leukocyte activation, platelet activation and chronic inflammation resulting in the multiple adhesive interactions between cellular elements. Since platelets mediate inflammation as well as thrombosis via release of pro- and anti-inflammatory molecules, we hypothesized that platelets may play an active inflammatory role in SCD by secreting increased amounts of cytokines. Since platelets have been shown to contain mRNA and actively produce proteins, we also hypothesized that SCD platelets may contain increased cytokine mRNA. In this cross-sectional study, we sought to compare both the quantity of cytokines secreted and the cytokine mRNA content, between SCD and control platelets. We measured the secretion of Th1, Th2, and Th17-related cytokines from platelets in a cohort of SCD patients. We simultaneously measured platelet mRNA levels of those cytokines. Platelets from SCD patients secreted increased quantities of IL-1β, sCD40L, and IL-6 compared to controls. Secretion was increased in patients with alloantibodies. Additionally, mRNA of those cytokines was increased in SCD platelets. Platelets from sickle cell patients secrete increased amounts of inflammatory cytokines, and contain increased cytokine mRNA. These findings suggest a novel immunological role for platelets in SCD vasculopathy, in addition to their thrombotic role, and strengthen the rationale for the use of anti-platelet therapy in SCD.

Transfusion therapy is a life-sustaining treatment for patients with sickle cell disease (SCD), but can cause serious complications including alloimmunization. We previously reported diminished regulatory T cells (Tregs) and skewed Th2 responses in alloimmunized SCD patients. We hypothesized that the B cell regulatory (Breg) compartment, which controls Treg and Th differentiation, may also be compromised in allosensitized SCD patients. Phenotypically, we did not find differences in the frequency or numbers of CD24(hi) CD38(hi) and CD24(hi) CD27(+) B cell subsets, both previously identified as human Bregs, between alloimmunized and non-alloimmunized SCD patients on regular transfusions. However, at the functional level, CD19+ B cells from alloimmunized SCD patients expressed lower levels of IL-10 following stimulation as compared with non-alloimmunized patients (P < 0.05), and had reduced ability in inhibiting autologous CD14+ monocyte TNF-α expression (P < 0.05). These findings suggest that Bregs from alloimmunized and non-alloimmunized SCD patients differ in their ability to produce IL-10 and dampen monocyte activation, all consistent with an altered immunoregulatory state in alloimmunized SCD patients., (Copyright © 2013 Wiley Periodicals, Inc.)

Background: JAL (RH48) is a low-prevalence antigen in the Rh blood group system and anti-JAL has caused hemolytic disease of the newborn. JAL is associated with either a haplotype carrying depressed C and e antigens or one carrying depressed c and e antigens. Blood samples from JAL+ people were tested, published serologic findings were confirmed, serologic studies were extended to include expression of other Rh antigens, and the antibody specificities produced by three sensitized JAL+ probands are reported., Study Design and Methods: Red blood cell (RBC) samples from 17 (12 probands) JAL+ persons were tested by hemagglutination using standard methods., Results: RBCs from both the Caucasian JAL+ probands had the (C)(e) haplotype and weakened C, e, hr(B), and hr(S) antigens. JAL+ samples from black persons had the (c)(e) haplotype and expressed weakened c, e, f, V, VS, hr(B), and hr(S) antigens. Plasma from three sensitized c+e+ JAL+ probands contained alloanti-c, alloanti-e, or alloantibody of apparent anti-Rh17 specificity. This study shows that this alloanti-Rh17-like antibody recognizes the high-prevalence antigen antithetical to JAL that has been named CEST., Conclusions: The presence of the JAL antigen has a quantitative (weakening) effect on the expression of C, e, hr(B), and hr(S) antigens in Caucasian persons and of c, e, f, V, VS, hr(B), and hr(S) antigens in people of black African ancestry. A qualitative effect also was demonstrated by the presence of alloanti-c or alloanti-e in the plasma of two transfused c+e+ patients and by an antibody (anti-CEST) that recognizes the high-prevalence antigen antithetical to JAL.

Background: Because antibody identification is labor-intensive, facilities with high volume and/or marginal technical support could benefit from partial automation., Study Design and Methods: After a validation study of automated solid-phase red cell (RBC) adherence assay (SPRCA; Galileo, Immucor) compared to tube polyethylene glycol antiglobulin antibody identification method (t-PEG), we evaluated Galileo followed by select RBC panels by t-PEG. Of 298 consecutive samples in which antibody identifications were performed in a 2-month period, 160 samples were examined by both Galileo and t-PEG., Results: There were concordant results between Galileo and t-PEG in 120 of 160 (75%) samples including cases with identical alloantibody identification (n = 99), panagglutinin (n = 9), and negative results (n = 12). Of the samples in which alloantibodies were identified, 99 of 108 (91.7%) were identical. In 9 samples with discrepant antibody identifications, 2 samples showed alloantibody specificity by Galileo (possible anti-K and anti-Jk(b)) but were negative by t-PEG. These antibodies were identifiable by t-PEG in subsequent samples. One sample showed anti-E by Galileo, while t-PEG revealed anti-Fy(a) and -E. Five samples showed alloantibody specificity by t-PEG and nonspecific reactivity or panagglutinin by Galileo. These included samples with anti-C (n = 2), anti-E (n = 2), and anti-Fy(a) (n = 1). One sample showed anti-E by t-PEG but was negative by Galileo. Galileo found a panagglutinin in 23 samples and nonspecific reactivity in 22 samples, whereas t-PEG found a panagglutinin in 12 samples but no nonspecific reactivity., Conclusions: Automated Galileo solid-phase red cell adherence assay can be a useful adjunct for antibody identification, although it detects more nonspecific reactivity than does t-PEG.

Plasmapheresis (PP) and intravenous immunoglobulin (IVIg) remove donor-specific antibodies, a cause of acute humoral rejection (AHR). We describe the use of PP and IVIg as rescue therapy for AHR. The records of 143 renal transplants performed between October 1, 2000 and April 1, 2002 were reviewed. Patients who underwent PP and IVIg therapy for AHR were identified. The data reviewed included age, sex, source of transplant, number of human leukocyte antigen mismatches, transplant number, number of PP and IVIg treatments, dose of IVIg, time of AHR, serum creatinine (SCr) level at AHR, SCr level after PP and IVIg at 3 months, days to achieve 30% decline in SCr, and graft survival. Immunosuppression included basiliximab induction, tacrolimus, and prednisone (+/- sirolimus or mycophenolate mofetil [CellCept, Roche Pharmaceutical, Nutley, NJ]). PP was followed by IVIg infusion. Nine patients were treated for AHR with PP and IVIg. All nine patients demonstrated biopsy-proven AHR. One graft was lost. Mean 3-month and 1-year SCr levels were 1.9 and 1.8, respectively, in the remaining eight patients. AHR in renal transplantation can be effectively treated with PP and IVIg.

Background: More than 80 percent of D- patients who receive D+ blood become alloimmunized to the D antigen. Anemia occurs in most AIDS patients at some point in the disease. D- patients with AIDS may require blood transfusion and, during times of blood shortage, may receive D+ RBCs. They would be expected to become alloimmunized to the d antigen., Study Design and Methods: The records of the transfusion service between January 1996 and July 2000 were reviewed for D- patients who received D+ blood. IATs were performed before the initial transfusion and subsequently when the patient required further RBC transfusion., Results: Eight D- AIDS patients who received multiple transfusions (three women and five men; age range, 31-44 years; mean, 44 years) who received between 2 and 11 units (mean, 6.25) of D+ RBCs were identified. Antibody screens were performed at 8 to 65 weeks after transfusion. It was found that none of the eight D- AIDS patients developed anti-D. ABO antibodies were found as expected. During the same period, it was found that six D- patients admitted with other diagnoses who received 1 to 9 units of D+ RBCs, all developed anti-D within 7 to 19 weeks of transfusion., Conclusion: Patients with AIDS may not form alloantibodies to the D antigen. This may be attributable to their immunodepressed state, particularly to the decrease in CD4+ T lymphocytes. Therefore, during blood shortages, transfusion of D+ blood to D- AIDS patients may be without any subsequent consequence.

We describe the most frequent emergencies in pediatrics and discuss their differential diagnosis and therapy. Dyspnea, shock, coma, convulsions, infectious CNS affections, head injury and burns are reported in detail. The importance of correct diagnosis and correct clinical assessment is emphasized, as they influence therapy and further management of the patients.

In a prospective investigation of 17 children with severe croup, we analyzed the effect of epinephrine inhalations and mild sedation with chloral hydrate on transcutaneous carbon dioxide pressure (tcPCO2), pulse oximetry measurements, and croup scores. There was a highly significant reduction (p less than 0.001) in the tcPCO2 values and croup scores after inhalation of epinephrine. The changes in the tcPCO2 values correlated with the clinical findings. Mild sedation also significantly improved the croup scores but failed to influence the tcPCO2 values. There was not statistically significant difference in pulse oximetry saturation, fraction of administered oxygen, heart rate, or respiratory rate before and after inhalation of epinephrine or chloral hydrate administration. Monitoring tcPCO2 appears to be a reliable and objective tool for managing patients with upper airway obstruction, whereas croup scores may be misleading.

Hotfoot (ho) mutation is a recessive trait in mice, characterized by motor disorder and male sterility, that maps to chromosome 6. We have identified a transgenic mouse pedigree with a similar trait. Using genetic and molecular approaches, we have demonstrated that the foreign DNA element is located in or near the ho locus. This new allele, designated hoJwg and presumably created by insertional mutagenesis, should make it possible to clone the ho gene. Male infertility in hoJwg male homozygotes was determined to be due to inability of sperm to penetrate the zona pellucida. This was demonstrated by rescuing mutant males by a new technique of gamete micromanipulation, zona pellucida drilling. These findings show that zona drilling is useful both for analysis and preservation of animals with reduced male fertility.

Many patients undergo cardiac surgery with preexisting congenital and acquired coagulation defects. Almost all of these can be recognized and corrected preoperatively. CPB itself induces a variety of abnormalities of coagulation, affecting plasma proteins, platelets, and the fibrinolytic system. These abnormalities do not always cause clinically significant bleeding. When they do, logical laboratory assessment and blood-component usage can usually correct the defect. The use of blood products is associated with allergic, viral, and hemolytic risks. Exciting advances have been made in the use of synthetic alternatives to blood products. Both DDAVP and aprotinin seem promising in this respect, but more investigation is needed into the mechanisms of action and possible thrombotic complications of these drugs. In the future, anesthesiologists and surgeons may look forward to more safe and effective therapy of bleeding in cardiac surgical patients.