Rise of cytomegalovirus antibodies in an infectious-mononucleosis-like syndrome after transfusion

Prevalence of transfusion-transmitted infections in hospitalized patients before transfusion and volunteer blood donors in Zhejiang Province, China

OBJECTIVES

To assess the need for screening of transfusion-transmitted infections (TTIs) in blood products, we assessed TTI seroprevalence in blood donors and hospitalized patients.

METHODS

We collected 2760 serum samples from three regions of Hangzhou, Ningbo and Huzhou from April 2021 to March 2022, and they tested by enzyme-linked immunosorbent assay (ELISA) for Hepatitis B surface antigen (HBsAg), Hepatitis C (HCV), Treponema pallidum (TP), Cytomegalovirus (CMV), Epstein-Barr virus (EBV), Hepatitis E virus (HEV) and Human T-cell lymphotropic virus type 1/2 (HTLV-1/2) antibody levels.

RESULTS

Screening test results showed that the positive rates for HBsAg, anti-HCV and anti-TP were 3.01 %, 0.39 % and 0.18 %, respectively. The positive rates for CMV IgM and CMV IgG were 0.76 % and 96.96 %, while the positive rates for EB VCA-IgM and EB EA-IgG were 1.88 % and 10.47 %; those for HEV IgM and HEV IgG were 1.16 % and 26.05 %, while the HTLV-1/2 antibody positive rate was 0.04 %. The positive rates for CMV IgG, EB EA-IgG and HEV IgG in hospitalized patients before transfusion were higher than in volunteer blood donors, and the difference was statistically significant (P < 0.05). The overall co-infection rate was 0.29 %. The positive rates for EB VCA-IgM in the males were significantly higher than in females, and EB VCA-IgM and HEV IgG prevalence varied significantly by age.

CONCLUSION

Our data demonstrate the risk of TTI exposure and TTI transmission in the Zhejiang population, which poses a threat to blood safety. It is hoped that expansion of pathogen categories (CMV, EBV, HEV and HTLV-1/2) and blood screening programs will contribute to the future adoption of scientific blood transfusion methods.

Cytomegalovirus seroprevalence among blood donors: a systematic review and meta-analysis

Background

Screening for cytomegalovirus (CMV)-specific antibodies is not routine in some settings. Thus, transfusion of blood products poses risks for susceptible individuals.

Objectives

To investigate the global pooled CMV seroprevalence among volunteer blood donors.

Methods

This systematic review and meta-analysis was performed according to PRISMA guidelines. The databases searched included Embase, Google Scholar, Medline, PubMed, Web of Science, and Cochrane Library. Data were extracted independently and analyzed using STATA version 11.

Results

The global seroprevalence of CMV IgG, CMV IgM, and both CMV IgM and IgG was 83.16% (95% confidence interval [CI]: 78.55–87.77%, I² = 99.5%), 13.77% (95% CI: 11.59–15.95%, I² = 98.8%), and 23.78% (95% CI: 10.50–37.06%, I² = 98.7), respectively.

Conclusion

The global seroprevalence of CMV was high among blood donors. Therefore, regular CMV screening should be conducted to identify CMV-seronegative blood donors.

Transfusion-transmitted cytomegalovirus: behaviour of cell-free virus during blood component processing. A study on the safety of labile blood components in Switzerland

BACKGROUND

Nowadays, most blood products are leukocyte-reduced. After this procedure, the residual risk for transfusion transmitted cytomegalovirus (TT-CMV) is mostly attributed to cell-free viruses in the plasma of blood donors following primary infection or viral reactivation. Here, objectives are: 1) to study the behaviour of cell-free CMV through the blood component processing; 2) to determine the anti-CMV seroprevalence, the level of viremia, the window-period in blood donor population; and 3) to identify cases of TT-CMV in bone marrow transplant (BMT) recipients.

MATERIALS AND METHODS

Cell-free CMV was injected into blood bags originating from regular donors. Blood components were processed according to either the CompoSelect^® or the CompoFlow^® (Fresenius Kabi AG) techniques. Samples were analysed at each step for presence of virus DNA using quantitative polymerase chain reaction (PCR). The anti-CMV seroprevalence in our donor population was taken from our donor data system. The viremia was assessed in pooled plasmas samples from routine donations by quantitative PCR. Medical charts of 165 BMT anti-CMV seronegative recipients/anti-CMV seronegative donors who received CMV-unscreened blood products were reviewed.

RESULTS

Cell-free CMV passes without any decrease in viral load through all stages of blood processing. The anti-CMV seroprevalence was 46.13%. Four DNA positive samples out of 42,240 individual blood donations were identified (0.009%); all had low levels of viremia (range 11-255 IU/mL). No window-period donation was identified. No TT-CMV was found.

DISCUSSION

Cell-free CMV remains a concern with current blood component processing as it passes through all the processes. However, since low levels of CMV DNA were identified in the donations tested, and no BMT recipients had TT-CMV, the residual threat of TT-CMV after leukocyte reduction appears to be very low.

Transfusion-transmitted CMV infection - current knowledge and future perspectives

Transmission of human cytomegalovirus (CMV) via transfusion (TT-CMV) may still occur and remains a challenge in the treatment of immunocompromised CMV-seronegative patients, e.g. after stem cell transplantation, and for low birthweight infants. Measures to reduce the risk of TT-CMV have been evaluated in clinical studies, including leucocyte depletion of cellular blood products and/or the selection of CMV-IgG-negative donations. Studies in large blood donor cohorts indicate that donations from newly CMV-IgG-positive donors should bear the highest risk for transmitting CMV infections because they contain the highest levels of CMV-DNA, and early CMV antibodies cannot neutralise CMV. Based on this knowledge, rational strategies to reduce the residual risk of TT-CMV using leucoreduced blood products could be designed. However, there is a lack of evidence that CMV is still transmitted by transfusion of leucoreduced units. In low birthweight infants, most (if not all) CMV infections are caused by breast milk feeding or congenital transmission rather than by transfusion of leucoreduced blood products. For other patients at risk, no definitive data exist about the relative importance of alternative transmission routes of CMV compared to blood transfusion. As a result, only the conduction of well-designed studies addressing strategies to prevent TT-CMV and the thorough examination of presumed cases of TT-CMV will achieve guidance for the best transfusion regimen in patients at risk.

Leading articles in medical journals in 1966

The British Journal of Hospital Medicine is 50 years old. This article takes a look back at articles published during the year of its inception from the British Medical Journal, the Lancet and the Journal of the American Medical Association.

Resistant pathogens, fungi, and viruses

Although originally described in Staphylococcus aureus, resistance among bacteria has now become a race to determine which classes of bacteria will become more resistant. Availability of antibacterial agents has allowed the development of entirely new diseases caused by nonbacterial pathogens, related largely to fungi that are inherently resistant to antibacterials. This article presents the growing body of knowledge of the herpes family of viruses, and their occurrence and consequences in patients with concomitant surgical disease or critical illness. The focus is on previously immunocompetent patients, as the impact of herpes viruses in immunosuppressed patients has received thorough coverage elsewhere.

Treatment of cytomegalovirus infections beyond acute disease to improve human health

Human cytomegalovirus is a common virus that establishes latency and persistence after a primary infection in 50-90% of populations worldwide. In otherwise healthy persons, the infection is generally mild or asymptomatic, although it may cause mononucleosis, prolonged episodes of fever, and hepatitis. However, in AIDS patients and transplant recipients who are immunosuppressed, severe, life-threatening infections may develop. CMV is also the most common congenital infection and may cause birth defects and deafness. Emerging evidence shows a high prevalence of this virus in patients with chronic inflammatory diseases or tumours of different origin, such as breast, colon, and prostate cancer, neuroblastoma, medulloblastoma, and glioblastoma. Several drugs are available to treat CMV infections. This review will highlight the possibility of using anti-CMV therapy to improve outcome not only in patients with acute CMV infections but also in patients with inflammatory diseases and cancer.

Prevention of Transfusion-Transmitted Cytomegalovirus Infections: Which is the Optimal Strategy?

Traditionally, leukoreduction and selection of blood products from seronegative donors have been used as alternative strategies to reduce the risk of transfusion-transmitted cytomegalovirus infections (TT-CMV) in atrisk patients. After the introduction of universal leukoreduction for red blood cell and platelet concentrates in Germany, a controversy evolved as to whether the additional selection of blood products from seronegative donors would reduce or even increase the risk of TT-CMV. This review summarizes the current knowledge about CMV infections in blood donors and the implications of this information on the effect of potential transfusion strategies. Even though there are conflicting data about the incidence of TT-CMV remaining after the introduction of leukodepletion, it has been clearly shown that both prevalence and concentration of CMV DNA in peripheral blood are highest in newly seropositive donors. Therefore, avoidance of blood products from these donors is the most important goal of any transfusion strategy. This goal can be reached by: i) selection of blood products from seronegative donors, ii) provision of CMV DNA-negative blood products, or iii) provision of blood from long-term seropositive donors. In cases of suspected TT-CMV, all implicated donors should be investigated carefully to gather further knowledge on which donors confer the lowest risk for TT-CMV.

Post-transfusion cytomegaloviremia and persistence of cytomegalovirus in blood

Cytomegaloviremia was documented in seven patients. Three patients were renal transplant recipients and two were liver transplant recipients. One was a postcardiac surgery patient, and one had acute myelogenous leukemia. The transplant patients had received only banked blood or fresh frozen plasma and developed evidence of infection about 1 month after surgery. Illness varied from no apparent signs to fever alone, fever and a morbilliform rash, hepatitis and an infectious mononucleosis syndrome. The virus was isolated from the blood erythrocyte layer, the leukocyte layer, and the plasma and serum, in that order of frequency. In vitro studies demonstrated persistence of inoculated cytomegalovirus in the presence of erythrocytes (and tissue culture media) for up to 21 days. In whole blood under banking conditions, inoculated virus was recovered after 28 days and, in fresh frozen plasma, after 97 days.

Incidence of cytomegaloviremia in blood-bank donors and in infants with congenital cytomegalic inclusion disease

During a 15-month period, cytomegalovirus (CMV) isolations were attempted from leukocytes derived from 290 healthy blood-bank donors. The major proportion of the specimens were tested 2 to 5 hr after donation. However, CMV was not recovered from any of the specimens examined. At the time of donation, 75% of donors had CMV complement-fixing antibodies demonstrable in titers of 10 to >/=320. The age of the study group ranged from 17 to 57 years. During the same time period and with the use of identical isolation techniques, postnatal cytomegaloviremia was demonstrated in four infants with cytomegalic inclusion disease. Failure to detect cytomegaloviremia in 290 normal blood donors questions its occurrence outside pathological conditions. These results do not support the concept that CMV infection, concurrent with post-transfusion mononucleosis syndrome, is transmitted through the blood donor's leukocytes.

Primary cytomegalovirus infection following open heart surgery

Among 674 patients undergoing open heart surgery in 1981-82, 86 (13%) were cytomegalovirus (CMV) antibody-negative when tested by an enzyme-linked immunosorbent assay prior to operation. At follow-up, 54 (67%) of 80 patients restudied had seroconverted after the operation, and 35 of the 54 seroconvertants had been ill with fever and elevated liver enzymes. Among the latter 35 patients, 26 demonstrated a significant rise in CMV antibody titre, most often detected in the third week following the onset of illness. The older patients were more susceptible to illness and seroconversion, and there was a positive correlation between age and the number of blood units given. Thus, at least one third of the seronegative patients developed symptomatic CMV illness after open heart surgery. This is a much higher incidence than earlier reported.

Treatment of congenital cytomegalovirus infection: implications for future therapeutic strategies

Cytomegalovirus (CMV) infection is the most common cause of congenital infection in the developed world, occurring in approximately 1% of all liveborns. Symptomatic disease occurs in 10% of all congenitally infected infants, resulting in a spectrum of clinical manifestations that include microcephaly, chorioretinitis, hepatosplenomegaly and sensorineural hearing loss, among others. Even those children who are asymptomatic at birth have a risk of hearing loss, with approximately 8% experiencing this sequela. Overall, congenital CMV infection accounts for one-third of all cases of sensorineural hearing loss. The economic burden of disease exceeds $2 billion annually in the USA. Therefore, this infection has been the target for antiviral therapy. Studies performed by the National Institute of Allergy and Infectious Diseases Collaborative Antiviral Study Group (CASG) have evaluated ganciclovir for the treatment of symptomatic congenital CMV infection with central nervous system involvement. In a randomized, controlled clinical trial of ganciclovir treatment (6 mg/kg iv every 12 h for 6 weeks) brainstem-evoked responses were utilized as the primary endpoint and demonstrated stabilization of hearing both at 6 months and >1 year. Treatment was associated with neutropenia in over 60% of treated patients. Since ganciclovir must be given intravenously, studies with its prodrug, valganciclovir, have been performed to assess pharmacokinetics and pharmacodynamics. Currently, a clinical trial of 6 weeks versus 6 months of valganciclovir is being performed by the CASG. Notably, only intravenous ganciclovir and orally administered valganciclovir have been used to treat congenital CMV infection. Hopefully, other drugs such as maribavir will be available for evaluation in this population.

HCMV microinfections in inflammatory diseases and cancer

Human cytomegalovirus (HCMV) is a wide-spread human virus that was mainly known to cause disease in immunocompromised patients. A new entity of infection can be diagnosed with high sensitive techniques; HCMV microinfections that often exhibit an altered pattern of IE protein expression. We have recently discovered that HCMV microinfections are very common in patients with inflammatory diseases and certain cancers. The discovery of active HCMV infections in tissue specimens from patients with inflammatory diseases raises the question of whether the infection is an epiphenomenon or whether the virus plays a causative role in disease development. After a primary infection, which is generally asymptomatic in immunocompetent individuals, HCMV establishes latency and persists in its host. In infected cells, the virus can produce over 250 proteins, but only about 50-60 are believed to be essential for viral replication. Thus, the vast majority of these viral proteins enable the virus to co-exist with its host. Such proteins act through highly sophisticated mechanisms to control different cellular and immunological functions in order to facilitate viral production and to avoid detection and elimination of the virus by the immune system. These proteins may also contribute to the development of common inflammation-related diseases.

Vacuum-assisted venous return reduces blood usage

OBJECTIVE

To determine whether vacuum-assisted venous return has clinical advantages over conventional gravity drainage apart from allowing the use of smaller cannulas and shorter tubing.

METHODS

A total of 150 valve operations were performed at our institution between February and July 1999 using vacuum-assisted venous return with small venous cannulas connected to short tubing. These were compared with (1) 83 valve operations performed between April 1997 and January 1998 using the initial version of vacuum-assisted venous return, and (2) 124 valve operations performed between January and April of 1997 using conventional gravity drainage. Priming volume, hematocrit value, red blood cell usage, and total blood product usage were compared multivariably. These comparisons were covariate and propensity adjusted for dissimilarities between the groups and confirmed by propensity-matched pairs analysis.

RESULTS

Priming volume was 1.4 +/- 0.4 L for small-cannula vacuum-assisted venous return, 1.7 +/- 0.4 L for initial vacuum-assisted venous return, and 2.0 +/- 0.4 L for gravity drainage (P <.0001). Smaller priming resulted in higher hematocrit values both at the beginning of cardiopulmonary bypass (27% +/- 5% compared with 26% +/- 4% and 25% +/- 4%, respectively, P <.0001) and at the end (30% +/- 4% compared with 28% +/- 4% and 27% +/- 4%, respectively, P <.0001). Red cell transfusions were used in 17% of the patients having small-cannula vacuum-assisted venous return, 27% of the initial patients having vacuum-assisted venous return, and 37% of the patients having gravity drainage (P =.001); total blood product usage was 19%, 27%, and 39%, respectively (P =.002). Although ministernotomy also was associated with reduced blood product usage (P <.004), propensity matching on type of sternotomy confirmed the association of vacuum-assisted venous return with lowered blood product usage.

CONCLUSIONS

Vacuum-assisted venous return results in (1) higher hematocrit values during cardiopulmonary bypass and (2) decreased red cell and total blood product usage.

CMV and blood transfusions

Among the human herpesviruses, cytomegalovirus (CMV) is the only one that has assumed significant importance in blood transfusion. Transfusion transmission of CMV (TT-CMV) to seronegative immunocompromised patients can lead to lethal CMV disease. Studies over the past 30 years have demonstrated that monocytes latently infected with CMV represent the primary vector for TT-CMV, and that TT-CMV can be largely abrogated by transfusing at-risk patients with either seronegative units or blood filtered to remove white blood cells. However, the small number of cases of breakthrough TT-CMV that follow transfusion of either seronegative or filtered blood still produce morbidity and mortality. These circumstances have motivated ongoing efforts to provide improved protection from TT-CMV, including the use of CMV DNA amplification for blood screening, and pathogen inactivation to sterilise all blood components prior to transfusion.

Robotic selective sampling and total automation for anti-CMV screening

The provision of anti-cytomegalovirus (CMV)-negative blood products causes the blood banking community considerable logistical problems. This is due firstly to the fact that only a select group of patients require anti-CMV-negative units, namely the immunocompromised. Secondly, the prevalence of CMV antibody in the blood donor population is high and, thirdly, the demand for anti-CMV-negative blood components continues to increase. To address this problem, a system of robotic selective sampling and total assay automation for anti-CMV screening has been developed. An in-house computer program generates a worklist from the donation database of samples requiring screening to meet clinical demand. Algorithms incorporated in the program ensure that the minimum number of samples possible are selected for provision of anti-CMV-negative products. This 'intelligent' selection of samples substantially reduces reagent cost. Robotic pipetting from the electronically derived worklist, masterplate to test plate robotic transfer and use of an automated assay processor maintains specific sample identification throughout. Results are read mechanically and transmitted directly to the main computer system. Robotic selective sampling and total assay automation produces an efficient, secure, auditable and completely traceable system for the provision of anti-CMV-negative units. The system produced a substantial reduction in labour costs with a 40% reduction in reagent usage. This system can be readily adapted for screening other markers on a selective basis.

Lack of difference in cytomegalovirus transmission via the transfusion of filtered-irradiated and nonfiltered-irradiated blood to newborn infants in an endemic area

BACKGROUND

It is accepted that white cells contained in blood components are the most significant source of cytomegalovirus (CMV) infection in immunocompromised and immunodeficient recipients.

STUDY DESIGN AND METHODS

To determine whether white cell filtration of blood would be effective in preventing infection among newborn transfusion recipients in a hyperendemic area, a randomized study was performed. All donor blood units were irradiated before issue to prevent posttransfusion graft-versus-host disease. Recipients were monitored for CMV infection by seroconversion (development of IgM anti-CMV) and CMV-DNA isolation.

RESULTS

Three (9%) of 33 infants who received filtered blood and 1 (5%) of 19 infants given nonfiltered blood were infected with CMV, as determined by the presence of IgM anti-CMV and/or CMV DNA isolation.There was no significant difference in the rate of CMV infection in the two groups.

CONCLUSION

The CMV infection observed in the study may come from other routes such as breastfeeding, rather than from transfusion. Our findings suggest that the routine use of white cell-reduction filtration to reduce the risk of transmitting CMV is unwarranted for neonates in endemic regions.

Intrapericardial treatment of inflammatory and neoplastic pericarditis guided by pericardioscopy and epicardial biopsy--results from a pilot study

From a registry of 136 patients undergoing pericardiocentesis, 14 patients with autoimmune and 15 patients with neoplastic effusions were selected. All underwent pericardioscopy, epicardial and pericardial biopsy with histologic, immunohistologic, and polymerase chain reaction/or in situ hybridization analysis for microbial DNAs and RNA. Pericardioscopy identified neoplastic effusions by the high occurrence of protrusions. Fibrin threads and layers and neovascularization were found in both groups. For identification of the inflammatory and neoplastic process, the combined analysis of the cytology of the effusion and epicardial biopsy evaluation proved to be most important. Epicardial biopsy demonstrated a slightly higher sensitivity for identifying neoplastic disorders in the pericardium than cytology alone. Pericardial biopsy was inconclusive. Intrapericardial administration of 1 g of crystalloid triamcinolone in autoreactive pericarditis prevented recurrence in 13 of the 14 cases after 3 months and in 12 of the 14 cases after 1 year. In neoplastic effusion, intrapericardial administration of 50 mg cis-platin for 24 h prevented recurrence of a hemodynamically relevant effusion after 3 months in all, and after 6-12 months in 14 of 15 patients. Mortality in neoplastic effusion due to noncardiac tumor progression was 47 and 80%, respectively, after 3 and 6 months, as can be expected in endstage neoplastic disease. This pilot study demonstrates that local drug application is feasible, life-saving, and well tolerated by the patients. It opens perspectives for local drug application in other cardiac disorders as well.

Evaluation of CAPTURE CMV solid phase testing over the allowable shelf-life of red blood cells (adenine-saline added)

BACKGROUND

CAPTURE CMV (IMMUCOR Inc., Norcross, GA) is a solid-phase screening test used to detect IgM and IgG antibodies to cytomegalovirus (CMV). CAPTURE CMV is licensed for testing whole blood (WB) in citrate phosphate dextrose (CPD) preserved segments of units of red blood cells (RBC) only up to 7 days of storage. We determined if CAPTURE CMV could produce consistent results in CPD preserved WB segments from RBC adenine-saline added (ASA) for their 42 day shelf-life.

METHODS

Ten CMV-seropositive and 10 CMV-seronegative RBC (ASA) tested by CAPTURE CMV during the first week of storage were studied. Segments were tested weekly for 6 weeks.

RESULTS

All 10 units that initially tested as CMV-seropositive remained strongly seropositive. All 10 units initially CMV-seronegative, remained seronegative.

CONCLUSION

CAPTURE CMV testing provides consistent results over the entire shelf-life of RBC (ASA).

Productive cytomegalovirus (CMV) infection exclusively in CD13-positive peripheral blood mononuclear cells from CMV-infected individuals: implications for prevention of CMV transmission

BACKGROUND

Monocytes are suggested to harbor latent cytomegalovirus (CMV) in peripheral blood, which concurs with the finding that all CMV-susceptible cells carry the CD13 surface molecule. Here, we investigated whether all latently and productively CMV-infected peripheral blood mononuclear cells (PBMCs) could be eliminated by depletion of CD13-expressing cells.

METHODS

Depletion of CD13-positive cells was performed with monoclonal antibodies and magnetic cell separation (MACS) beads followed by MACS. CMV DNA and cDNA were amplified by polymerase chain reaction with specific primers for two CMV genes, major immediate early and phosphoprotein 150. The presence of infectious virus was tested by incubating homogenized in vitro- or in vivo-infected PBMCs with human fibroblasts. CMV infection of fibroblasts was detected by intracellular expression of CMV proteins.

RESULTS

Elimination of CD13-positive PBMCs removed productively in vitro- and in vivo-infected cells, as demonstrated by detection of infectious virus only in PBMC fractions containing CD13-positive cells. In support of this finding, CMV RNA was not detected in pure CD13-negative cell fractions. Furthermore, CMV DNA was found exclusively in CD13-positive PBMCs obtained from patients with acute CMV infection.

CONCLUSIONS

Our data suggest that CMV replicates exclusively in CD13-positive PBMCs. These findings have important clinical applications, because the elimination of CD13-positive cells may reduce the risk for transmission of latent CMV in blood products and bone marrow grafts and thereby also decrease the risk for CMV-induced complications, such as chronic graft-versus-host disease in bone marrow transplant patients.

Spread of Human Cytomegalovirus (HCMV) After Infection of Human Hematopoietic Progenitor Cells: Model of HCMV Latency

Clinical experience and laboratory data suggest that human cytomegalovirus (HCMV) is present in peripheral blood of seropositive individuals in a latent or persistent state and can be transmitted via blood products and be reactivated in seropositive imunocompromised patients. The pathophysiology of HCMV latency and the nature of HCMV interaction with hematopoietic cells remains unknown. In this study, we investigated the infection of bone marrow (BM) progenitor cells and their progeny as a model of HCMV latency. A clinical isolate and the recombinant laboratory strain Towne/lox containing the Escherichia coli β galactosidase (β-gal) gene regulated by immediately early (IE) HCMV promoter were used to infect highly purified CD34+ cells. Although the infection of these cells with a clinical isolate was associated with an inhibition of proliferation by 59%, an expansion of progeny derived from these cells was possible. Polymerase chain reaction analysis and staining for β-gal have shown that HCMV persisted in infected BM CD34+ cells and their progeny for up to 4 weeks. However, IE and late gene products (mRNA and protein) were detected only late in the course of infection and their expression correlated with terminal macrophage differentiation of the CD34+-derived progeny. Although early infection of CD34+ progenitor cells was not productive (as shown by the plaque assay), infectious virus could be recovered from the terminally differentiated cultures. BM progenitor cells may serve as a reservoir of the latent virus with limited transcription. Proliferation and monocytic maturation of infected progenitors may lead to the numerical expansion of HCMV-infected cells, which serve as a source of HCMV dissemination and reactivation.

Spread of Human Cytomegalovirus (HCMV) After Infection of Human Hematopoietic Progenitor Cells: Model of HCMV Latency

Clinical experience and laboratory data suggest that human cytomegalovirus (HCMV) is present in peripheral blood of seropositive individuals in a latent or persistent state and can be transmitted via blood products and be reactivated in seropositive imunocompromised patients. The pathophysiology of HCMV latency and the nature of HCMV interaction with hematopoietic cells remains unknown. In this study, we investigated the infection of bone marrow (BM) progenitor cells and their progeny as a model of HCMV latency. A clinical isolate and the recombinant laboratory strain Towne/lox containing the Escherichia coli β galactosidase (β-gal) gene regulated by immediately early (IE) HCMV promoter were used to infect highly purified CD34+ cells. Although the infection of these cells with a clinical isolate was associated with an inhibition of proliferation by 59%, an expansion of progeny derived from these cells was possible. Polymerase chain reaction analysis and staining for β-gal have shown that HCMV persisted in infected BM CD34+ cells and their progeny for up to 4 weeks. However, IE and late gene products (mRNA and protein) were detected only late in the course of infection and their expression correlated with terminal macrophage differentiation of the CD34+-derived progeny. Although early infection of CD34+ progenitor cells was not productive (as shown by the plaque assay), infectious virus could be recovered from the terminally differentiated cultures. BM progenitor cells may serve as a reservoir of the latent virus with limited transcription. Proliferation and monocytic maturation of infected progenitors may lead to the numerical expansion of HCMV-infected cells, which serve as a source of HCMV dissemination and reactivation.

A novel mechanism for virus-induced autoimmunity in humans

A novel mechanism for virus-induced autoimmunity in humans is described. Infection of immunocompromised bone marrow-transplanted patients with human CMV results in the formation of autoantibodies specific for the cell-surface protein CD13 (aminopeptidase N). CD13 is present on all CMV-susceptible cells and infection can be specifically blocked by antibodies against CD13. CMV particles carry CD13, which is incorporated in the viral envelope during budding of viral nucleo-capsids into Golgi-derived vacuoles. Antibodies against CD13 are virus-neutralizing, in efficiency comparable to antibodies against viral envelope glycoproteins. Autoantibodies against CD13 are present in patients who develop chronic GVHD following allogeneic bone marrow transplantation. This lesion shows striking similarities to certain autoimmune diseases in humans, of which scleroderma is one example. In vivo binding of antibodies to tissue structures known to be targets for chronic GVHD has been demonstrated in patients with chronic GVHD. Finally, patient serum containing CD13-specific antibodies binds to skin and mucosa tissue sections in vitro, a binding which is inhibited by CD13-specific monoclonal antibodies. Thus a virus infection can activate an immune response against a specific autoantigen, providing possibilities for destruction of non-infected host cells, as originally proposed by Fujinami & Oldstone (1985), and also for the molecular mimicry model for induction of autoimmunity. Our findings lend support to the idea that inhibiting the transfer of CMV infection in bone marrow transplants will reduce morbidity and mortality from CMV infection but will also reduce the incidence of chronic GVHD. Elimination of CD13+ cells in bone marrow is not believed to interfere with the chance of recipient repopulation, and may be a way to decrease morbidity and mortality substantially following BMT. For all patients, every effort should be taken to prevent a post-BMT CMV infection in order to reduce the risk of the later development of chronic GVHD.

CD13-specific autoimmunity in cytomegalovirus-infected immunocompromised patients

Cytomegalovirus (CMV) infection has been suggested to be associated with various autoimmune manifestations, such as hemolytic anemia, granulocytopenia, and the formation of autoantibodies. Earlier we found that CMV is associated with a human protein, CD13 (aminopeptidase N), emanating from CMV-infected cells and serving an important function during CMV infection of susceptible cells. We hypothesized that CD13 might become immunogenic if presented to the immune system as a part of the CMV virion. The presence of CD13-specific antibodies was tested using a microcytotoxicity assay against CD13-positive human monocytes, or by flow cytometric assays against mouse cells transfected with human CD13; specificity was assessed by specific blocking with monoclonal antibodies. CD13 reactivity was also demonstrated in immunoprecipitation experiments. CD13-specific antibodies were identified in 15 of 33 bone marrow transplant patients, but exclusively in patients who had experienced either CMV disease (9/10) or CMV viremia (6/9), and appeared at the time of CMV detection. None of the remaining 14 patients without signs of CMV infection were positive for CD13 antibodies (P<0.0001). No antibody of this specificity was found in any of the control individuals (0/24), including patients with various autoimmune diseases, CMV-seropositive or -seronegative healthy individuals, and patients with acute EBV or HSV-1 infections. Thus, the CMV-associated autoantigen CD13 is immunogenic during CMV infection in bone marrow transplant patients. A specific response against autoantigens associated with infectious virus particles is suggested as a new and general mechanism to explain virus-induced autoimmune manifestations in man.

Establishing practice guidelines for surgical blood management

Medical practice guidelines have been promoted as a way to improve the cost-effectiveness of medical care. Algorithms for the transfusion of red blood cells, plasma, and platelets may be especially useful in the surgical setting if they incorporate point-of-care information that is both physiologic and patient-specific for transfusion decision making. Therefore, the goals of guidelines for surgical blood management should be twofold. They should (1) acknowledge patient-specific variability while addressing physician- and institution-dependent variables; and (2) improve blood component management by developing more physiologic clinical indicators of the need for allogeneic red blood cell transfusion.

On the need for improved transfusion indicators in cardiac surgery

Guidelines for transfusion practice have had limited impact in altering physician transfusion behavior in patients undergoing cardiac operations. This may be due to a lack of consensus on the relative risks and benefits of blood in these patients who are anemic, limited access to timely data that are necessary on which to base transfusion decisions, the recognition that empiric hemoglobin/hematocrit thresholds are limited clinical indicators of the need for blood, or a combination of these. We present an overview of current transfusion and blood conservation practices in this setting, along with possible approaches to guide the decision-making process by coupling the use of transfusion algorithms with point of care testing to use more physiologic indicators of the need for blood transfusion.

Stability of cytomegalovirus antibodies in plasma during prolonged storage of blood components

Cytomegalovirus (CMV) antibody testing is currently limited by manufacturers' guidelines to specimens stored for 7 days or less. We examined the stability of CMV antibodies in plasma from platelets and whole-blood units during storage using a rapid, automated, recombinant protein-based immunoassay which qualitatively detects total antibody to human CMV. Testing of single-donor apheresis platelets was performed on baseline serum and platelet-free plasma and on platelet-free plasma 8 days later. Indeterminate, positive, and negative CMV antibody results were maintained over time for 97% (75 of 77) of the platelet specimens. For whole-blood units, initial testing of donor serum and plasma obtained from erythrocyte segments took place within 7 days of phlebotomy. Indeterminate, positive, and negative CMV antibody results were maintained on subsequent analyses performed on erythrocyte segments at 2, 4, 6, and 8 weeks for 100% of whole-blood specimens. An important potential benefit of CMV antibody testing of stored platelets and blood is the elimination of a costly, dedicated, CMV-negative inventory. The study suggests that CMV antibody testing can be conveniently and reliably performed on blood components over the entire storage period.

Human cytomegalovirus infection of the monocyte/macrophage lineage in bone marrow

Peripheral blood monocytes (PBM) are one site of persistence of human cytomegalovirus (HCMV) in healthy carriers. However, because PBM circulate only briefly before entering the tissues and are difficult to infect with HCMV, it has been suggested that they may acquire HCMV during development in the bone marrow. Consistent with this, we show evidence that bone marrow progenitors from healthy HCMV carriers contain endogenous HCMV DNA as detected by PCR. We also show that bone marrow precursors are readily infected by clinical isolates of HCMV in vitro but that no viral gene expression occurs until these cells become differentiated. In contrast, incubation of these cells at any developmental stage with the laboratory strain AD169 resulted in few cells expressing viral immediate-early genes, and this correlated with a lack of entry of AD169 virus. These observations are consistent with bone marrow progenitors acting as a reservoir for HCMV and transmitting the viral genome to PBM, in the absence of lytic-gene expression, until they leave the circulation and undergo tissue-specific differentiation to macrophages.

Definition of a subset of human peripheral blood mononuclear cells that are permissive to human cytomegalovirus infection

The identity of cells responsible for transmission of human cytomegalovirus (HCMV) in blood products or bone marrow transplants is unknown. We have tested the capacity of HCMV to in vitro infect human peripheral blood mononuclear cells (PBMC) from healthy donors and found that certain PBMC are permissive to HCMV infection. In vitro-infected viable cells were double stained for surface expression of different HMCV proteins and for cell-type-specific antigens to allow the identification of sensitive cells. All analysis were performed on viable cells, using HCMV-specific monoclonal antibodies and automated flow cytofluorimetry. PBMC were infected either with the laboratory-adapted HCMV strain AD169 or with a virus isolate obtained from a viremic patient. Up to 25% of all PBMC could express the major immediate-early antigen as well as the pp65 antigen, known at the lower matrix protein. Infected cells were mainly CD14+ monocytes, but also a small population of large CD8+ cells were susceptible to HCMV infection. CD19+ B lymphocytes were resistant to HCMV infection. Different populations of infected cells were enriched by using Dynabeads coated with cell-type-specific antibodies, and the presence of infectious virus was demonstrated by incubating the selected and sonicated cell material on human fibroblasts. Only material from infected monocytes and from CD3+ CD8+ cells gave rise to HCMV-specific plaques. The presence of HCMV mRNA as a sign of active viral transcription of the major immediate-early and late pp150 genes in infected cells was demonstrated by using nested reversed polymerase chain reaction. A common denominator was found for all cells that could be infected with HCMV. The CD13 antigen, a 130- to 150-kDa integral membrane protein identical to the enzyme aminopeptidase N, was expressed on all HCMV-permissive cells.

Transfusion-acquired cytomegalovirus infection in children in a hyperendemic area

Thirty-nine children without previous cytomegalovirus (CMV) infection received blood transfusion in the National Taiwan University Hospital. The overall transfusion-acquired CMV infection rate was 36% (14/39). Donor CMV seropositive rate was 70%. None of the nine children who had received seronegative blood became infected, in contrast to 14 of the 21 children (67%) who had received seropositive blood (P = 0.002). Another significant risk factor associated with CMV infection was the use of fresh blood: 13 of 15 (87%) with fresh seropositive blood were infected, in contrast to one of six (17%) with "old" seropositive blood (P = 0.01). Most of the fresh blood was used within 24 hours. This blood processing method was shown to account for the extremely high rate of CMV infection in those who had received fresh seropositive blood. The results indicated that the incidence of CMV infection can be reduced by avoiding the use of fresh blood, especially blood less than 24 hours old. For such a population in Taiwan with high prevalence of positive CMV antibody, this approach was more applicable than screening donor blood for CMV antibody.

Guillain-Barré polyradiculoneuritis after blood transfusion

We report the case of a 72 year-old woman who developed acute polyradiculoneuritis 7 days after a series of 4 blood transfusion. While blood transfusion is not listed as an antedecent event of Guillain-Barré syndrome (GBS), GBS following surgical procedures is well known. In the present case the close temporal relationship and the absence of all factors which usually precede the onset of the disease including surgery, suggest a possible role of blood transfusion in the onset of the GBS.

Prevention of transfusion-acquired cytomegalovirus infection in infants by blood filtration to remove leucocytes. Neonatal Cytomegalovirus Infection Study Group

A multicentre, controlled trial was carried out to determine whether removal of leucocytes from blood by means of 'Imugard IG500' (Terumo) filters would prevent transfusion-acquired cytomegalovirus (CMV) infection in newborn infants. 72 infants whose mothers were seronegative and who received some seropositive blood were followed for 6 months for evidence of CMV infection. There were no significant differences between the groups who received filtered and unfiltered blood in median gestation, birthweight, or amount of seropositive blood received (median volume 32.5 ml and 34.5 ml, respectively). 9 (21%) of the 42 infants who received unfiltered blood and none of the 30 who received filtered blood were infected with CMV. All infected infants weighed less than 1500 g at birth; they represented 31% of very low birthweight (VLBW) infants at risk of CMV infection. None of 24 VLBW infants who received filtered seropositive blood was infected. 1 infected infant died and 5 had clinical features consistent with CMV infection. The results show that transfusion-acquired CMV infection is preventable by filtration of blood through a leucocyte filter. This method has advantages over other methods of removing leucocytes or the use of only seronegative blood for newborn infants.

Transfusion transmitted infectious agents, excluding hepatitis and human immunodeficiency viruses

A number of viruses, parasites and bacteria can be transmitted by blood. Blood seronegative for cytomegalovirus (CMV), effectively prevents CMV infection in seronegative bone marrow recipients. Such blood is available at larger blood transfusion services. Immune anti-CMV globulin can also be helpful in protection of transplant recipients. Human T-lymphotropic virus, type 1 (HTLV-1) causing leukemia and myelopathy can also be transmitted by blood. Blood banks are considering donor screening in areas where the prevalence of this virus is significant. Parvoviruses that may cause crises in haemolytic anaemias present a potential hazard of transfusion. Malaria and syphilis are currently not very important infectious complications of transfusion, whereas prolonged storage of platelets has reemphasised the risk of bacterial growth in blood products.

Transfusion-associated viral infections

Viral infections are a frequent occurrence following transfusion of blood products. While generally benign, these infections are capable of causing significant morbidity and mortality. Therefore, it is prudent to follow several general approaches diligently to reduce the risks of these infections in patients undergoing transfusions of blood products. These suggested measures include the following: 1. Prescribe and administer blood and blood products only when absolutely needed. 2. Use volunteer blood donors only. 3. Avoid use of pooled blood products when possible. 4. Use only blood and blood products that have been appropriately tested for HBsAg and HIV. 5. Use ALT determinations to screen blood products and eliminate those with high level. 6. Avoid the use of clotting-factor concentrates but, if necessary, use only those which have been heat-treated. 7. Limit use of leukocyte transfusion. 8. Use only CMV seronegative blood and blood products or frozen deglycerolized red cells in patients at high risk for posttransfusion CMV infection.