Jochewed Werch

Hepatitis B Virus Antibody in Blood Donors and the Occurrence of Non-A, Non-B Hepatitis in Transfusion Recipients: An Analysis of the Transfusion-Transmitted Viruses Study

Patients who received transfusions and nontransfused control patients were followed to assess the incidence and cause of post-transfusion hepatitis and to identify donor factors that might relate to risk of hepatitis. We evaluated as risk factors in donors the presence of antibody to hepatitis B virus compared with elevated alanine aminotransferase (ALT) level. Units of blood that were positive for antibody to hepatitis B core antigen (anti-HBc) were associated with a twofold to threefold greater risk of non-A, non-B hepatitis in the recipients than were units without anti-HBc. In the absence of specific serologic tests for non-A, non-B agents, screening of donors for anti-HBc might be considered. Our data suggest that the incidence of non-A, non-B hepatitis might have been reduced by about one third by such screening. However, elevated ALT levels in donors had a similar association with non-A, non-B hepatitis in recipients but would have resulted in fewer units of blood being discarded than would screening for anti-HBc.

Non-A, non-B hepatitis transmission in chimpanzees: a project of the Transfusion-transmitted Viruses Study Group.

Experimental transmission of non-A, non-B hepatitis was apparently accomplished in 5 chimpanzees following inoculation with presumably infectious human sera. Administration of sera from implicated donors with normal alanine aminotransferase (ALT) values, as well as from those with abnormal ALT levels, resulted in the development of ALT abnormalities in the inoculated chimpanzees. Transmission from donors with normal ALT values implies that healthy carriers of non-A, non-B virus exist. Evidence is presented which indicates that a period of viremia precedes the clinical illness by at least 12 days.

Detecting bacteria in platelet concentrates by use of reagent strips

BACKGROUND : Iatrogenic infection of immunosuppressed or immunocompromised hosts secondary to receipt of blood components containing bacteria may result in serious adverse outcomes. Measurement of pH and glucose by use of inexpensive reagent strips has been proposed as a practical means of screening for bacteria in platelet concentrate (PC) units.

Prospective Study Indicating That Double-Antibody Radioimmunoassay Reduces the Incidence of Post-Transfusion Hepatitis B

Abstract This prospective study comprising 227 recipients illustrates that post-transfusion hepatis B infection probably would have been reduced considerably if a double-antibody radioimmunoassay (RIA-DA) method had been used to screen donor bloods for hepatitis B antigen (HBs Ag). In seven susceptible recipients (negative for HBs Ag and antibody to HBsAg) who received RIA-DA-positive blood alone clinical hepatitis B subsequently developed, or there was serologic evidence of exposure to hepatitis B virus. In contrast, a recently licensed solid-phase RIA technic (Ausria-125I) of comparable sensitivity failed to implicate a positive donor for five of these recipients, including two in whom clinical hepatitis B developed. Our RIA-DA procedure may be detecting additional antigenic determinants unrelated to HBs Ag. Anti-HBs detected in recipients before transfusion appears to offer protection from post-transfusion infection by hepatitis B virus. (N Engl J Med 290:1104–1109, 1974)

Bacterial Contamination of Platelet Units: A Case Report and Literature Survey with Review of Upcoming American Association of Blood Banks Requirements

The most common transfusion-associated infectious risk in the United States today is bacterial contamination of platelet components. Bacterial contamination is estimated to occur at an incidence of 1:1000 to 1:3000 in platelet units, with severe episodes estimated to occur in about one sixth of contaminated products. Increased awareness and prompt reaction of the medical team can greatly affect the outcome and save a patients life. The following case history illustrates this issue. A young woman developed chills and rigors while receiving 1 unit of leuko-reduced apheresis platelets for severe thrombocytopenia. The transfusion was stopped, blood cultures were drawn, and the patient developed clinical signs of sepsis. Cultures of both the platelet unit and the patients blood revealed coagulase-negative Staphylococcus. Microbial susceptibilities in both samples were identical. Pretransfusion blood cultures taken from the patient earlier that day were negative. The platelet unit had been stored for 5 days. We review this case and the literature describing the persistent problem of platelet unit contamination and at the same time highlight the efforts now directed by the American Association of Blood Banks and College of American Pathologists to address this issue. Although there is no uniform approach to dealing with bacterial contamination of platelets, the American Association of Blood Banks and the College of American Pathologists have promulgated new accreditation requirements in an effort to prevent bacterial sepsis associated with platelet transfusion. A new American Association of Blood Banks standard, which will be effective March 1, 2004, requires a combination of strategies both to limit the initial inoculation of bacteria into the blood component and to detect subsequent growth at room temperature (American Association of Blood Banks Association Bulletin #03-12). The new College of American Pathologists Checklist question, which became effective in December 2003, is a Phase 1 requirement that calls for inspected facilities to have a platelet bacteria detection method in place.

Prenatal diagnosis of the RhD fetal blood type on amniotic fluid by polymerase chain reaction.

Objective To assess the accuracy of a molecular assay for the determination of the fetal RhD status on amniotic fluid (AF) samples. Methods Amplification of DNA by polymerase chain reaction of a common sequence of the RhD and CE genes and of a unique sequence of the RhD gene was performed on AF directly or after DNA extraction. Samples of AF obtained from patients undergoing amniocentesis for standard obstetric indications were used for the study. Results Amplification of DNA was successful on 112 of 114 samples. One hundred four fetuses were found to be RhD positive and eight were found to be RhD negative. Serologic confirmation of the RhD blood type was available on 108 samples and DNA diagnosis was correct in all cases. Conclusion Polymerase chain reaction can be used to determine accurately the fetal RhD blood type from AF samples.

Delayed hemolytic transfusion reaction in sickle cell disease

ABSTRACT: This article reports the details of delayed hemolytic transfusion reactions in four patients with sickle cell disease. These cases demonstrate the characteristics of the reactions, the significant risks involved, and the principles useful in diagnosis and treatment. Patients with sickle cell disease are at particular risk for delayed hemolytic transfusion reactions because they may be transfused at intervals over many years; they frequently form alloantibodies because of antigenic differences from the donor population; and they may receive emergency care in different hospitals where transfusion records are not available. In addition, exchange transfusions, which are often used for patients with sickle cell disease and which were given in three of these cases, raise the risks through increased exposure to foreign erythrocyte antigens and through an increased volume of erythrocytes susceptible to hemolysis. It was concluded that the hazards of these transfusion reactions justify preventive measures, such as extended erythrocyte phenotyping of patients with sickle cell disease and extended phenotypic matching of transfused cells.

Resolution by erythrocytapheresis of the exposure of an Rh‐negative person to Rh‐positive cells: an alternative treatment

Acute trauma with severe bleeding caused the unavoidable transfusion of Rh‐positive red cells (RBCs) to a young, childless, Rh‐negative woman during surgery. Of the 10 units of RBCs given, 6 were Rh positive. An alternative treatment for large‐volume exposure involves the removal of some of the Rh‐positive cells transfused at a time when the patients condition could not be jeopardized by the shortage of Rh‐negative RBCs. It is believed that the combination of erythrocytapheresis followed by Rh immune globulin treatment was successful, when immunoprophylaxis alone might not have been. It is strongly recommended that partial RBC exchange for the removal of the unwanted RBCs be considered in addition to Rh immune globulin treatment in cases of large‐volume exposure such as the one presented.

Alterations in plasma volume and protein during cycle exercise throughout pregnancy

The purpose of this investigation was to determine the effects of cycle exercise on maternal plasma volume (PV) and protein dynamics during pregnancy. Sixteen healthy gravidas (age = 23 +/- 4.6 yr) cycled for 5 min (75 W) at 4 wk intervals throughout term. Venous blood samples were drawn immediately prior to and during the last minute of exercise. Relative (percent) PV changes during exercise were calculated from hematocrit ratios and hemoglobin concentrations. Plasma was analyzed for total protein ([TP]) and albumin ([ALB]) concentrations and colloid osmotic pressure (COP). Resting blood volumes were also estimated (carbon monoxide rebreathing) so that absolute PV (ml) and TP and ALB contents (g) could be determined. COP increases (P less than 0.001) during exercise were similar at all gestational ages. Plasma volume, TP, and ALB decreased during exercise with significantly (P less than 0.001) greater losses occurring from 29-32 wk gestation. This may indicate an increase in capillary permeability to large molecules when vascular volume was highest.

Prevention of Rh sensitization in the context of trauma: Two case reports

Transfusion of D+ red blood cells (RBCs) to D− recipients can be accidental or necessary due to D− RBC shortage. Alloimmunization can complicate future transfusions; implications for women of childbearing age are compounded by possible hemolytic disease of the fetus and newborn. Rh immunoprophylaxis is effective, and indicated, for preventing alloimmunization. Reports of massive D+ mismatch (e.g., in the case of fetal‐maternal bleed) are limited, and standard recommendations for managing these rare events are lacking. The cases discussed herein of women of childbearing age who suffered severe trauma requiring emergency surgery illustrate the dilemma of determining the ideal strategy for Rh immunoprophylaxis.