Prevention of transfusion-associated graft-versus-host disease by inactivation of T cells in platelet components

Patients with hematological malignancies and infants with congenital immunodeficiencies who received blood are two of many populations at risk for transfusion-associated graft-versus-host disease (TA-GVHD). Of the methodologies (eg, photoinactivation, peglyation, ultraviolet light, and irradiation) that can be used to prevent TA-GVHD, only irradiation of whole blood and cellular components is currently accepted practice of the US Food and Drug Administration (FDA). Among the newer methods that have been developed to reduce the risks of bacterial and viral contaminants of platelet transfusions, photochemical treatment (PCT) using psoralens and long-wavelength ultraviolet (UVA) irradiation modifies bacterial and viral genomes sufficiently to inhibit replication. Among a broad group of compounds, the synthetic psoralen compound amotosalen hydrochloride (HCl) (S-59) has been shown to be particularly effective in inactivating bacteria and viruses, without adversely affecting in vitro and in vivo platelet function.

Paediatric transfusion

Paediatric transfusion encompasses a wide range of clinical circumstances including the consideration of maternal antibodies, the changing nature of the transfusion recipient with respect to growth and development, and the management of inherited conditions which if optimally treated in early life may have problems which are delayed or less severe in adult life. Whilst the transfusion of adults and children has much in common, a child cannot be considered as a scaled down adult; there are many important differences. Developmental changes are most marked in the neonate and, together with the fact that their antibodies are maternally derived, this population provide some of the most striking challenges. The increased use of intra uterine transfusion adds an extra dimension here. A particular paediatric concern is the long-term consequences of transfusion. It is to be hoped that paediatric transfusion recipients will live long enough that any potential problems will manifest themselves, thus the aim must be to minimize transfusion risks.

Bone marrow aspiration, biopsy, and culture in the evaluation of HIV-infected patients for invasive mycobacteria and histoplasma infections

Bone marrow (BM) aspiration and biopsy are used commonly in clinical practice to diagnose invasive tissue infections caused by Mycobacterium avium intracellulare (MAC), Mycobacterium tuberculosis (TB), and Histoplasma capsulatum (HC) in patients with human immunodeficiency virus-1 (HIV) infection. However, the value of these invasive procedures relative to other diagnostic approaches has not been clearly defined. To determine the value of BM culture and BM histology in the diagnosis of opportunistic MAC/TB and HC infections in immunosuppressed patients with HIV, we retrospectively reviewed the records of 56 adult patients with HIV who underwent a single BM aspiration, biopsy, and culture because of unexplained fever and/or other clinical features suggestive of MAC/TB or HC infection. Thirty-two patients (57%) were ultimately diagnosed with MAC/TB or HC infection by positive cultures of BM, blood, sputum, or bronchoalveolar lavage fluid or by the histologic detection of organisms in biopsies of BM or other tissues. The diagnostic sensitivity of BM cultures was equal to that of blood cultures (20/32, or 63%). Granuloma and/or histologically apparent organisms were seen in BM biopsy specimens in 11 of 32 individuals (34%) ultimately diagnosed with MAC/TB or HC infections. Among these 11 cases, both granuloma and acid-fast staining organisms were found in the BM biopsy specimens of 2 individuals for whom both BM and blood cultures were negative. Certain clinical symptoms and signs at the time of BM examination were found by logistic regression analysis to be significantly associated with a subsequent diagnosis of MAC/TB or HC infections; these included high fever, long duration of febrile days prior to BM examination, and elevated direct bilirubin. In conclusion, while the diagnostic sensitivity of BM cultures was found to be no greater than that of blood cultures in detecting MAC/TB or HC infections in immunosuppressed HIV+ patients, histopathologic examination of BM specimens resulted in the relatively rapid identification of nearly one third of infected patients who underwent BM examination, and also identified infections in some patients who were culture negative. These findings support the continued use of BM aspiration, biopsy, and culture for the diagnosis of opportunistic MAC/TB or HC infections in immunosuppressed HIV+ patients, particularly when selected clinical features are present.

Weakly beta-haemolytic human intestinal spirochaetes antagonize the haemolytic activity of Clostridium perfringens alpha-toxin producer

The production of haemolytic antagonism between weakly beta-haemolytic human intestinal spirochaetes (wbetaHIS) related to human intestinal spirochaetosis and Clostridium perfringens alpha-toxin producer was investigated. A reduction of the clostridial haemolytic activity and a distortion of the haemolytic halo of clostridial alpha-toxin surrounded by a small zone of poorly cooperative haemolysis was clearly observed on the level of the spirochaetal growth area when 40 out of 41 wbetaHIS were cultivated in sheep blood agar plates together with Clostridium perfringens alpha-toxin producer. This phenomenon of haemolytic antagonism was observed only when wbetaHIS grew 72-96 hours sooner than C. perfringens and after the inoculum of the latter at a distance of 0 to 10 mm from wbetaHIS the plates were anaerobically incubated for an additional 48 hours and the bacteria were used at concentrations ranging from 10(7) to 10(4) CFU/ml. These results were also observed between C. perfringens and weakly beta-haemolytic intestinal spirochaetes related to animal intestinal spirochaetosis including avian strains and Brachyspira (Serpulina) pilosicoli of porcine origin.

Alternatives to standard blood transfusion: availability and promise

Largely due to concerns over safety, a wide variety of alternatives to the conventional blood bank products of red cells, platelet concentrates, plasma and fractionated plasma products are under development. This review attempts to survey the alternative therapies that are being developed, whether they provide viable solutions and what impact they might have on transfusion practice.

Mycoplasmal infections prevent apoptosis and induce malignant transformation of interleukin-3-dependent 32D hematopoietic cells

32D cells, a murine myeloid cell line, rapidly undergo apoptosis upon withdrawal of interleukin-3 (IL-3) supplement in culture. We found that 32D cells, if infected by several species of human mycoplasmas that rapidly activated NF-kappaB, would live and continue to grow in IL-3-depleted culture. Mycoplasma-infected cells showed no evidence of autocrine production of IL-3. Pyrrolidine dithiocarbamate (PDTC) blocked activation of NF-kappaB and led to prominent cell death. Heat-killed mycoplasmas or mycoplasmal membrane preparations alone could support continued growth of 32D cells in culture without IL-3 supplement for a substantial period of time. However, upon removal of heat-inactivated mycoplasmas, 32D cells quickly became apoptotic. In comparison, live Mycoplasma fermentans or M. penetrans infection for 4 to 5 weeks induced malignant transformation of 32D cells. Transformed 32D cells grew autonomously and no longer required support of growth-stimulating factors including IL-3 and mycoplasmas. The transformed 32D cells quickly formed tumors when injected into nude mice. Karyotyping showed that development of chromosomal changes and trisomy 19 was often associated with malignant transformation and tumorigenicity of 32D cells. Mycoplasmal infections apparently affected the fidelity of genomic transmission in cell division as well as checkpoints coordinating the progression of cell cycle events.

Interaction of Borrelia burgdorferi with peripheral blood fibrocytes, antigen-presenting cells with the potential for connective tissue targeting

BACKGROUND

Borrelia Burgdorferi has a predilection for collagenous tissue and can interact with fibronectin and cellular collagens. While the molecular mechanisms of how B. burgdorferi targets connective tissues and causes arthritis are not understood, the spirochetes can bind to a number of different cell types, including fibroblasts. A novel circulating fibroblast-like cell called the peripheral blood fibrocyte has recently been described. Fibrocytes express collagen types I and III as well as fibronectin. Besides playing a role in wound healing, fibrocytes have the potential to target to connective tissue and the functional capacity to recruit, activate, and present antigen to CD4(+) T cells.

MATERIALS AND METHODS

Rhesus monkey fibrocytes were isolated and characterized by flow cytometry. B. burgdorferi were incubated with human or monkey fibrocyte cultures in vitro and the cellular interactions analyzed by light and electron microscopy. The two strains of B. burgdorferi studied included JD1, which is highly pathogenic for monkeys, and M297, which lacks the cell surface OspA and OspB proteins.

RESULTS

In this study, we demonstrate that B. burgdorferi binds to both human and monkey (rhesus) fibrocytes in vitro. This process does not require OspA or OspB. In addition, the spirochetes are not phagocytosed but are taken into deep recesses of the cell membrane, a process that may protect them from the immune system.

CONCLUSIONS

This interaction between B. burgdorferi and peripheral blood fibrocytes provides a potential explanation for the targeting of spirochetes to joint connective tissue and may contribute to the inflammatory process in Lyme arthritis.

[Advantages and limitations of intraoperative mechanical autotransfusion in al prostatectomies]

Intraoperative autotransfusion (MAT), preoperative autologous blood donation, and preoperative normovolaemic haemodilution are three different methods to avoid homologous blood transfusion during surgical procedures. The controversial use of MAT via cell saver in tumour surgery as well as contamination of the operative field with urine illustrate the particular difficulties of autologous blood transfusion in connection with radical prostatectomy. We investigated changes in the osmotic resistance of the retransfused red blood cells (RBC), bacterial contamination, changes in coagulation parameters, and the presence of tumour cells.

PATIENTS AND METHODS

After written informed consent, 24 patients who presented for radical prostatectomy were randomly allocated to either a group that used MAT or a group that used homologous transfusion. The patients received "balanced anaesthesia" with midazolam, fentanyl, atracurium, and nitrous oxide/oxygen. The analysed parameters from the preoperative period to the 3rd postoperative day are shown in Table 1. The Haemonetics 3 Plus Cell Saver was used for autotransfusion.

RESULTS

Our results showed that the haematologic parameters, coagulation factors, and serum chemistry did not differ between the two groups (Tables 2-4). However, there were significant differences during the investigated period. The osmotic resistance of the salvaged RBCs was higher than that preoperatively. Furthermore, there were no tumour cells in the autologous salvaged RBCs.

CONCLUSION

Our results showed no decrease in the quality of the autotransfused RBCs, urine was not retransfused; and there were no significant differences between the groups postoperatively. Although there were no tumour cells in the salvaged blood, the possibility of blood irradiation is discussed. We concluded that because of the risk of infection of homologous blood products, MAT is a safe possibility to reduce the amount of homologous blood transfusion required in connection with radical prostatectomy.

Nested polymerase chain reaction for detection of Ehrlichia equi genomic DNA in horses and ticks (Ixodes pacificus)

A nested polymerase chain reaction for detecting Ehrlichia equi in horses and ticks (Ixodes pacificus) was developed. A major second-round PCR product of 928 bp could be readily visualized in ethidium bromide-stained agarose minigels. An internal probe was used to verify the identity of the amplified product by non-radioactive (digoxigenin-based) Southern blotting; additional confirmation was provided by DNA sequence analysis. A dilution study testing the sensitivity of the PCR indicated that DNA derived from < = 7.6 but > 3 infected neutrophils was sufficient to generate a PCR signal. The specificity of the PCR was examined using a panel of rickettsiae, of which only E. equi and the closely-related human granulocytotropic ehrlichia produced PCR bands. In an in vivo infection study, E. equi DNA was detected in blood buffy-coat cells of an experimentally-infected horse on days three through 14 post-inoculation. In a separate study, three of six adult I. pacificus that as nymphs had been fed on an experimentally infected horse were found to be PCR-positive for E. equi.

Intracellular bacteria in blood smears in patients with central venous catheters

The presence of intracellular bacteria in blood smears is usually associated with overwhelming sepsis and an ominous prognosis. Recently, the hematology laboratory at our institution documented this finding in a group of mostly asymptomatic patients. We studied seven adult patients from a tertiary care university hospital in whom intracellular bacteria were found incidentally on routine manual differential cell counts of 100 white blood cells during a 12-month period. A retrospective review of the clinical and laboratory data was performed. All seven patients were immunosuppressed and had central venous catheters in place. The blood samples positive for intracellular bacteria were all catheter derived. Six patients were asymptomatic at the time of bacteria detection, but they had blood cultures that were positive for coagulase-negative Staphylococcus; five of these patients became symptomatic 1 to 14 days after bacteria detection. Bacteremia persisted in five of these six patients until the eventual removal of the catheters. The one symptomatic patient had Pseudomonas aeruginosa bacteremia and died shortly after admission. The finding of intracellular bacteria in routine differential blood cell counts from a central venous catheter blood specimen most likely indicates active infection. We recommend that central venous catheters be removed in such patients, even if the patient is asymptomatic.

Bacteria in blood for transfusion. A review

OBJECTIVE

To summarize reports of bacterial contamination of blood components for transfusion during this century, considering implicated microorganisms and patient outcomes, with identification and discussion of recommended methods to reduce or eliminate this problem.

DATA SOURCES

Articles published in the English-language literature from which summary tables of all reported bacterial infections were prepared by collating published case reports, including fatalities, emphasizing recent concerns about Yersinia contamination.

STUDY SELECTION

All case reports and related review articles relevant to issues about bacteria implicated in transfusion-associated sepsis were included.

DATA EXTRACTION

The author personally extracted all data.

DATA SYNTHESIS

With the exception of Yersinia species and Campylobacter jejuni in red blood cells and Salmonella heidelburg in platelets, the majority of bacteria implicated continue to be those found in the environment and as normal skin flora. Existing measures to identify contaminated components before transfusing them are inadequate. Manufacturing efforts to sterilize these components by various methods may result in greater benefit than those directed toward preventing contamination during collections.

CONCLUSIONS

Bacterial contamination remains a problem for transfusion medicine. Active research should continue to focus on elimination of contaminants by filtration, chemical additives, or irradiation, as well as innovative measures to detect and exclude infected units from transfusion.

Detection of herpes simplex virus DNA sequences in human blood and bone marrow cells

Herpes simplex virus type 1 (HSV1) establishes latent infections in neural tissues of humans and experimental animals. Utilizing a sensitive polymerase chain reaction (PCR) assay we detected HSV DNA sequences in blood cells of healthy prospective bone marrow transplant (BMT) donors and patients. In three healthy individuals studied, HSV DNA sequences were found in all blood cell types and also in bone marrow cells as well as in stem cell progenitor colonies isolated from in vitro cultures. Studies of BMT donor-recipient pairs suggested that HSV reactivation may occur in hematopoietic cells after transplantation, as the PCR signal intensity increased over time simultaneous with an increased antibody titer to HSV. In a mouse model for HSV infection, HSV DNA sequences were found in blood and bone marrow cells at the latent stage of infection, after intravenous (IV) inoculation, but not after ocular inoculation. These studies suggest that bone marrow cells may be an additional site of HSV latency capable of reactivation after BMT. These studies have broad implications for understanding pathogenesis of HSV disease and are of particular significance in situations where allogeneic bone marrow cells are given therapeutically.

Cytomegalovirus and latency: an overview

Cytomegalovirus (CMV) is a member of the herpes virus group. Infection results in a variety of disorders which depend largely on the immune status of the host. A well known property of CMV is that after primary infection the virus persists in the body of the host resulting in latency. Severe immunodepression or immunodeficiency can cause reactivation of the virus from its latent state, leading to endogenous reinfection. In contrast to other herpes viruses, such as herpes simplex virus which persists in neurons, and Epstein Barr virus which persists in B lymphocytes, little is known about the localization of latent CMV. In order to obtain more insight in the organ or cell type serving as a reservoir for latent CMV, it is important to know more about the course of natural infection and the cells and organs involved. When more information is available about the localization of latent virus, studies concerning the physical state of viral DNA or the extent of viral transcription and/or translation will follow in the near future. In this review some properties of the epidemiology and transmission of human CMV, as well as data about acute infection will be given. In addition, some characteristics of the localization of latent CMV and the physical state of the virus will be discussed. Where necessary, particularly regarding insight into CMV-host interactions, knowledge of animal, particularly murine, rat and guinea pig CMV infections, will be discussed.

Spirochetosis in California game chickens

An outbreak of spirochetosis occurred in a flock of 75 game chickens in California during fall 1991. Affected birds were weak and anemic. Many had greenish diarrhea. Spirochetes were seen on Giemsa-stained blood smears and in silver-stained tissue sections of kidney, liver, and spleen. Splenomegaly, which is reported to be characteristic of fowl spirochetosis, was not observed in two acutely infected chickens.

Theoretical aspects of detection of bacteraemia as a function of the volume of blood cultured

Clinically significant bacteraemia in adults is characterized by low numbers of circulating bacteria. Assuming a Poisson or a binomial distribution we have calculated the probability of detecting bacteria as a function of the concentration in blood, estimated the concentration of bacteria in blood from a given test result, and calculated the blood volume required to detect bacterial growth with a probability of 95% at a given mean number of colony-forming units (cfu) per sample unit. These theoretical assumptions have been used on an empirical population of patients with proven bacteraemia.

RESULTS

18% of Staphylococcus aureus bacteraemias and 29% of Escherichia coli bacteraemias have circulating bacteria with an estimated spread of less than 0.04 cfu/ml. With a 95% probability of detection of a bacteraemia, a concentration in blood corresponding to 3 cfu/sampling unit is necessary. In our empirical material, where 30 ml was cultured, the probability of detection of E. coli bacteraemias would have decreased by 11% if 20 ml had been cultured, and 27% if only 10 ml had been cultured. The corresponding figures for S. aureus were 6% and 15%, respectively. For low grade E. coli bacteraemias (< 0.04 cfu/ml) the decrease would have been 33% and 67%, respectively.

Safe biotechnology (5). Recommendations for safe work with animal and human cell cultures concerning potential human pathogens

The benefits of using animal or human cell cultures have been clearly demonstrated in diagnostic and therapeutic research and in their application for manufacturing. Cell cultures serve as a tools for the production of vaccines, receptors, enzymes, monoclonal antibodies and recombinant DNA-derived proteins. They represent an integral part of drug development for which corresponding facilities, equipment and manufacturing processes are required. Although the cells themselves offer no particular risk to workers in laboratories and production areas or to the environment, the cell cultures may be contaminated with viruses, mycoplasma, bacteria, yeast and fungi or might contain endogenous viruses. The containment level for animal and human cells is therefore determined by the risk class of these agents. The history of animal and human cell cultures has proved that they can be handled safely. The recommendations in this publication concern the safe handling of cell cultures (tissue explants, primary cell cultures) and permanent cell lines of animal and human origin. A classification system of safety precautions has been elaborated according to the potential for contamination with the pathogenic agents involved.

Hairy cell transformation of human peripheral blood lymphocytes by Coxiella burnetii

Hairy cell (HC) transformation of human peripheral blood lymphocytes (PBL) by Coxiella burnetii was studied to clarify the significance of persistency of C. burnetii in a hairy cell line (designated "TOL"). TOL cells which exhibited HC characteristics in hairy cell leukemia (HCL) were persistently infected with C. burnetii. Two strains of C. burnetii, our isolate from TOL cells and the original isolate in 1935, the Nine Mile strain from American Type Culture Collection (ATCC, U.S.A), were inoculated to PBL cultures. HC transformation not only by our isolates (87%) but also by Nine Mile strain (100%) was demonstrated in an average of 20 days. The original observation that Coxiella induced HC transformation in vitro was also confirmed in experiments with PBL exposed to C. burnetii in vivo. Spontaneous development of HC were observed in cultures of PBL only from coxiellemic cases (12/24) but not from C. burnetii negative cases (0/57). All HC cell lines (34) as determined by their morphology and cytochemical markers of HC in HCL remained infected with C. burnetii invariably.