Creutzfeldt-Jakob disease mortality in Canada, 1998 to 2013

BACKGROUND

Human prion diseases, known collectively as Creutzfeldt-Jakob disease (CJD), are fatal, infectious neurodegenerative disorders that occur in all human populations.

OBJECTIVE

To summarize national surveillance data for CJD in Canada between January 1, 1998, and December 31, 2013.

METHODS

Detailed investigations were conducted of individual suspected CJD cases, with collaboration between Canadian health professionals and investigators affiliated with a central CJD surveillance registry operated by the Public Health Agency of Canada. Data were collected on the clinical profile, family history, and results of paraclinical and laboratory investigations, including post-mortem neuropathological examination.

RESULTS

A total of 662 deaths from definite and probable CJD were identified in Canadian residents during the study period, comprising 613 cases of sporadic CJD (92.6%), 43 cases of genetic prion disease (6.5%), 4 cases of iatrogenic CJD (0.6%), and 2 cases of variant CJD disease (0.3%). The overall crude mortality rate for sporadic CJD was 1.18 per million per year [95% confidence interval (CI): 1.08,1.27]. Age-specific rates ranged from 0.05 [95% CI: 0.03,0.08] in persons under 50 years of age to 7.11 [95% CI: 6.20,8.11] in those aged 70 to 79. A significant net upward trend in age-adjusted rates was observed over the study period. Standardized mortality ratios, calculated for 10 individual Canadian provinces with reference to national average mortality rates, did not differ significantly from 1.0.

CONCLUSION

Creutzfeldt-Jakob disease remains rare in Canada, although mortality rates vary by two orders of magnitude between older and younger age groups. The upward trend in age-standardized sporadic CJD mortality rate over the study period can be better accounted for by gradually improving case ascertainment than by a real increase in incidence.

Monoclonal B cells detected in autologous PBSC grafts from patients with classical Hodgkin lymphoma: impact on relapse and survival following transplantation

Autologous peripheral blood stem cell transplantation (PBSCT) for Hodgkin lymphoma (HL) is curative for many patients with relapsed or refractory disease. Relapsing disease, however, remains a major problem. Neoplastic transformation of B-lymphocytes probably underlies the development of classical HL. Whether clonal B cells are critical for disease evolution and response to therapy in HL remains uncertain. We investigated the impact of clonal B cells detected in peripheral blood stem cell (PBSC) collections on the outcome of patients with HL undergoing transplant. Qualitative semi-nested PCR was carried out on genomic DNA from mononuclear cells from PBSCs to determine the presence of clonal immunoglobulin heavy chain (IgH) complementary-determining region 3 (CDR3) gene rearrangements. Clinical factors were assessed for their association with relapse, overall survival (OS) and progression-free survival (PFS). Among 39 patients undergoing PBSCT, 12 grafts (31%) were PCR positive for clonal IgH rearrangements. OS was better in the PCR-negative group (logrank test, P=0.041). The OS at 5 years was 81% in PCR-negative versus 39% in PCR-positive patients; hazard ratio was 3.23 (95% confidence interval: 0.98-10.63). There was a trend towards better PFS (logrank test, P=0.12), estimated as 71% at 5 years in PCR-negative versus 41% in PCR-positive patients. Clonal B-lymphocytes in PBSC collections of patients with HL identify patients at risk of poor outcome. Larger series are needed to confirm our observations. Insight regarding the role of monoclonal B cells may lead to improved therapies.

Serological evidence of hepatitis E virus infection in an indigenous North American population

BACKGROUND

Hepatitis E virus (HEV) infections are thought to be uncommon in North America. Recently, HEV transmission has been reported following the consumption of deer meat. Because deer are closely related to caribou and caribou meat is a staple of the Canadian Inuit and the American Eskimo diet, the present study explored the seroprevalence of HEV infection in an isolated Canadian Inuit community.

METHODS

Stored sera were thawed and tested for immunoglobulin (Ig) G and IgM anti-HEV by ELISA, and tested for HEV-RNA by reverse transcriptase polymerase chain reaction.

RESULTS

The study consisted of 393 sera (representing approximately 50% of the community's inhabitants). Eleven samples (3%) were IgG anti-HEV-positive. Their mean age was 29+/-8 years and three were male. Two of 11 (18%) were also IgM anti-HEV-positive. All IgG anti-HEV-positive individuals were HEV-RNA-negative. Liver biochemistry was normal in all. Seven of 11 (64%) were also positive for anti-hepatitis A virus, five (46%) were hepatitis B virus seropositive and none (0%) were positive for anti-hepatitis C virus. There were no associations between infections with HEV and other hepatropic viruses. Serological testing was negative for HEV infection in 25 caribou from an adjacent region.

CONCLUSION

The results of the present study showed that serological evidence of HEV infection was present in 3% of the observed Canadian Inuit population; the presence of IgM anti-HEV suggested recent infection and HEV did not appear to coinfect with other common hepatotropic viruses. The source of HEV infection in the population remains unclear. These findings are interesting but preliminary. Additional data are required to determine whether HEV infections are responsible for otherwise unexplained acute hepatitis in the Canadian Inuit population and visitors returning from northern North American communities.

A review of nearly two decades in an autologous blood programme: the rise and fall of activity

Autologous blood donation (ABD) has been widely recommended. Data from one of the oldest hospital-based programmes in Canada describe both activities and drawbacks. Data were compared over the nearly two decades of activity that peaked in 1996. A 5-year review of recent activity showed that of the 2410 patients referred for consideration, 1823 (75.64%) were accepted into the programme. Surgical services requested 5825 units of autologous blood. Of these, 3147 units were donated by 1536 patients, 803 units were transfused in the operating room and 558 units were given postoperatively. In total, only 1361 units (43.25%) were transfused. The mean age of the patients was 58 years (median 61 years and mode 69 years). The haemoglobin concentrations before donation were significantly higher, averaging 145.2 g L(-1) before donation and 114.9 g L(-1) immediately before surgery, whereas at the time of discharge, the haemoglobin concentration averaged 126.2 g L(-1) (P = 0.0001) in transfused patients. Data from this well-established ABD programme indicate less than 50% overall utilization. The activity in the programme increased until 1996 following which it dropped progressively. The low haemoglobin concentration after surgery is of concern and should foster a transfusion algorithm for these patients.

Comparison of antibody- and cell-mediated immune responses after intramuscular hepatitis C immunizations of BALB/c mice

Current treatments for hepatitis C infection have limited efficacy, and there is no vaccine available. The goal of this study was to compare the immune response to several immunization combinations against hepatitis C virus (HCV). Six groups of mice were immunized at weeks 0, 4, and 8 with different combinations of a candidate HCV vaccine consisting of 100 microg recombinant HCV core/E1/E2 (rHCV) DNA plasmid and/or 25 microg rHCV polyprotein and 50 microL Montanide ISA- 51. Four weeks after the last injection, all groups of mice were sacrificed and blood samples and spleens were collected for measuring the levels of specific HCV antibodies (total IgG, IgG1, and IgG2a). Cell proliferation and intracellular interferon-gamma were also measured. Among the groups of immunized mice, only the mice immunized with rHCV DNA plasmid, rHCV polyprotein, and montanide (group D) and mice immunized with rHCV polyprotein and montanide (group F) demonstrated a significant increase in the total IgG titer after immunization. IgG1 was the predominant antibody detected in both groups D and F. No IgG2a was detected in any of the groups. Proliferation assays demonstrated that splenocytes from group D and group C (rHCV DNA primed/rHCV polyprotein boost) developed significant anti-HCV proliferative responses. The combination of an rHCV DNA plasmid, rHCV polyprotein, and montanide induced a high antibody titer with a predominance of IgG1 antibodies and recognized the major neutralization epitopes in HVR1. In contrast, group C did not show an increase in anti-HCV antibodies, but did show a proliferative response.

Mortality from Creutzfeldt-Jakob disease and related disorders in Europe, Australia, and Canada

BACKGROUND

An international study of the epidemiologic characteristics of Creutzfeldt-Jakob disease (CJD) was established in 1993 and included national registries in France, Germany, Italy, the Netherlands, Slovakia, and the United Kingdom. In 1997, the study was extended to Australia, Austria, Canada, Spain, and Switzerland.

METHODS

Data were pooled from all participating countries for the years 1993 to 2002 and included deaths from definite or probable CJD of all etiologic subtypes.

RESULTS

Four thousand four hundred forty-one cases were available for analysis and included 3,720 cases of sporadic CJD, 455 genetic cases, 138 iatrogenic cases, and 128 variant cases. The overall annual mortality rate between 1999 and 2002 was 1.67 per million for all cases and 1.39 per million for sporadic CJD. Mortality rates were similar in all countries. There was heterogeneity in the distribution of cases by etiologic subtype with an excess of genetic cases in Italy and Slovakia, of iatrogenic cases in France and the UK, and of variant CJD in the UK.

CONCLUSIONS

This study has established overall epidemiologic characteristics for Creutzfeldt-Jakob disease (CJD) of all types in a multinational population-based study. Intercountry comparisons did not suggest any relative change in the characteristics of sporadic CJD in the United Kingdom, and the evidence in this study does not suggest the occurrence of a novel form of human bovine spongiform encephalopathy infection other than variant CJD. However, this remains a possibility, and countries currently unaffected by variant CJD may yet have cases.

Epidemiological study of hepatitis B virus infection in Manitoba, Canada, 1992–2003

In comparison with other Canadian provinces and most Western countries, the province of Manitoba maintains a different vaccination policy for hepatitis B. This policy provides selective antenatal screening for hepatitis B in women and an inoculation program for hepatitis B vaccination for fourth-grade pupils. There has been increasing concern for this policy with regard to its influence on secular trends of acute hepatitis B incidence in Manitoba. This created a need to summarise the epidemiological characteristics of hepatitis B virus (HBV) infection in Manitoba and to allocate finances and human resources for future prevention programs. The Cadham Provincial Laboratory in Winnipeg, a Canadian Public Health Laboratory, is responsible for testing all specimens for diagnosis of various common infectious diseases in Manitoba. During the period from 1 January 1992 to 31 December 2003, a total of 285,946 clinical specimens were submitted to this laboratory, which confirmed 310 cases of acute HBV and 7,556 cases of chronic HBV infection. A total of 18,168 individuals were identified as having vaccine-induced immune status. The incidence rate of acute HBV infection has significantly decreased from 6.52/100,000 person-years in 1996 to 0.86/100,000 person-years in 2003. Annual prevalence rates of chronic HBV infection in Manitoba increased slightly from 42.96 cases/100,000 population in 1992 to 71.47 cases/100,000 population in 2003. Incidence rates were generally higher in men than in women at all age groups, with values of 2.65 and 1.65 per 100,000 population, respectively (chi-square=15.768, p value <0.001). The highest incidence rate for both males and females was observed in the age group 30-34 years. The North Eastman and Winnipeg Regional Health Authorities showed significantly higher incidence rates of acute hepatitis B compared with the other nine Regional Health Authorities. Selective hepatitis B vaccination programs for children in Manitoba had achieved the greatest success in the prevention of vertical and horizontal transmission. There is an urgent need to develop cost-effective harm-reduction strategies for hepatitis B prevention among adults (aged 30-34) and groups at risk in Manitoba.

Enhanced surveillance for childhood hepatitis B virus infection in Canada, 1999-2003

Since hepatitis B virus (HBV) infection can have serious sequelae, especially if infection occurs during childhood, there is a continuing need to examine its epidemiology so as to inform control measures. We analyzed trends in disease incidence and patterns of hepatitis B virus (HBV) transmission in both Canadian-born and non-Canadian-born children from 1999 to 2003, through the Enhanced Hepatitis Strain Surveillance System. Amongst Canadian-born children, the incidence of newly identified HBV infection per 100,000 declined significantly during the study period from 1.4 in 1999, to 0.5 in 2003 (RR, 0.75 per year; 95% CI, 0.60-0.95). Amongst non-Canadian-born children, the incidence of HBV infection per 100,000 ranged from 9.4 to 16.3, during the study period (linear trend test, p=0.69). Poisson regression analysis revealed that non-Canadian-born children were more likely to have HBV infection (RR, 12.3; 95% CI, 7.6 to 19.8), than Canadian-born children. HBV infection was found to be more common among children emigrating from high endemic area, than among Canadian-born children. Current Canadian immunization policy should take into consideration the protection of all children against HBV infection, including those coming from countries where mass hepatitis B vaccination programs have still not been launched.

Transcriptional analysis of human peripheral blood mononuclear cells after influenza immunization

Influenza A virus is a major cause of morbidity and mortality worldwide. There is a large knowledge base on the immune response to influenza. However, few studies have focused on global gene expression in immune cells after antigenic challenge. A better understanding of the host immune response is required for the development of more efficient means of prevention and treatment of influenza. In this study, global gene expression in peripheral blood mononuclear cells (PBMCs) after influenza immunization was analyzed. The differential gene expression in antigen-stimulated and non-stimulated PBMCs was determined by cDNA microarrays. To determine whether a specific gene profile was present during a proliferative memory cell response to influenza antigens, gene expression in response to PHA was compared with antigen-stimulated PBMCs. PHA induced the upregulation of 201 genes while influenza virus antigen upregulated more than triple that is 630 genes out of 1700 genes analyzed. Both influenza antigen and PHA commonly upregulated 138 genes. Interferon (IFN)-related genes were induced by influenza but not by PHA. The interferon-gamma induced protein precursor 10 (IP-10) was upregulated 27-fold while the interferon-induced 54 kDa protein exhibited a 13-fold increase. The following gene families were also selectively upregulated by influenza antigens: complement ligands and receptors, T cell activation genes, growth factors, genes related to antigen processing and inflammatory responses. With PHA, the genes TNF-R, CTSG, CD3 delta, C8B, CRF1 and CCR2 had higher expression compared with the viral antigen stimulation. Neutrophil defensins alpha-1 and two C-C chemokines, proteins MIP-1-beta and MIP-4, were among the genes upregulated by both PHA and influenza antigens. The results suggest that interferon-induced genes are one of the main transcriptional targets during the immune response to influenza virus.

Serological studies of West Nile virus in a liver transplant population

BACKGROUND

Solid organ transplant populations are at increased risk for serious clinical manifestations of West Nile virus (WNV) infection.

OBJECTIVE

To monitor liver transplant recipients during the 2003 WNV season in Manitoba and to identify incidence, clinical presentation and serology.

METHODS

Serial blood specimens were obtained from adult patients followed at the liver transplant outpatient clinic between May 2003 and October 2003. Studies for WNV infection included immunoglobulin (Ig) G and IgM enzyme immunoassay (EIA), hemagglutination inhibition (HI), plaque reduction neutralization test and reverse transcriptase-polymerase chain reaction.

RESULTS

None of the 79 patients had clinical presentations suggestive of WNV infection. On testing of the final serum specimen obtained, 14 patients (18%) had positive IgG anti-WNV by EIA and six patients (7%) had indeterminate IgG anti-WNV by EIA, although all were negative by IgM EIA. Four (20%) of the EIA-positive samples were reactive by HI, but all of these were negative by WNV plaque reduction neutralization test; this is consistent with the presence of non-West Nile flavivirus antibody in these sera. Blood specimens obtained throughout the season from EIA- and HI-positive individuals were uniformly negative for WNV-RNA by reverse transcriptasepolymerase chain reaction. Age, sex, hematology and biochemistry findings, hepatitis B or C virus status, immunosuppressive regimen (cyclosporin or tacrolimus) and pretransplant diagnosis of liver disease were similar for EIA-positive and EIA-negative patients. For the 10 patients with a positive IgG EIA maintained on cyclosporin, the cyclosporin level was 129.1+/-28.6 microg/L compared with 85.6+/-36.7 microg/L in 26 patients who were EIA-negative (P=0.002).

CONCLUSIONS

False-positive IgG EIA serology for WNV was common in this cohort of liver transplant recipients, and was associated with elevated serum cyclosporin levels.

The use of a bacteria detection system to evaluate bacterial contamination in PLT concentrates

BACKGROUND

Random-donor PLTs (RDPs) are functional at 7 days. Nevertheless, since the mid-1980s, concern for bacterial contamination has caused the storage period to be reduced to 5 days. The ability of a bacteria detection system (BDS, Pall) to determine bacterial contamination and permit extension of the PLT shelf life to 7 days was assessed.

STUDY DESIGN AND METHODS

Blood was collected into CP2D and leukoreduced RDPs were prepared. Upon arrival at the hospital, a 2- to 3-mL aliquot was removed from each RDP and introduced into the Pall BDS pouch with a sterile docking device. The pouch was incubated at 37 degrees C for 24 hours and then the oxygen content was measured to determine bacterial contamination. Additionally, the RDPs were pooled and an aliquot was removed for culture with standard manual techniques. CCIs were calculated 1 hour after infusion.

RESULTS

A total of 12,062 individual RDPs were tested. The Pall BDS detected bacteria in 5 units. All of these were positive on repeat sampling. Propionibacterium acnes, coagulase-negative Staphylococcus, and Bacillus species were confirmed by manual technique in 3 units, one could not be identified, and one was negative. Aliquots from PLT pools were positive in 80 of 2201 pools when tested by manual methods. Of these, 79 were false-positives and 1 unit contained coagulase-negative Staphylococcus. The Pall BDS was easy to use and required less than 5 minutes for all manipulations. After 7 days of storage, the PLTs gave an average CCI of 16 x 10(11)+/- 3.39 x 10(11) 1 hour after transfusion (n = 9).

CONCLUSIONS

The Pall BDS permits evaluation of RDPs for bacterial contamination. Culture-negative PLTs were successfully transfused in our institution up to and including 7 days after storage with good CCIs.

Automated collection of blood components: their storage and transfusion

The performance of an automated device, the Gambro TRIMA, was evaluated for component production, and an in vivo assessment of the platelets was carried out. Red cell concentrates (RCCs), platelets and plasma were collected and stored according to standard blood bank procedures and evaluated for quality by in vitro measurements. Additionally, single-donor platelets (n=10) were transfused to thrombocytopenic patients after 5 days of storage. Platelet counts were measured after 1 h and the corrected count increment (CCI) was calculated. No significant changes were seen before or after procedure in donor haemoglobin, haematocrit, coagulation factors or platelet count. Return-line samples showed no increase in the level of plasma haemoglobin. Plasma haemoglobin and potassium increased following RBC storage, but there was no change in the red cell number. Platelet aggregation decreased from 52 to 11% (adenosine diphosphate) and the Kunicki morphology score dropped from 379 to 174. Little change was seen in the hypotonic shock response (69-63%) or in the percentage of CD62 expression (4.8-19.8) over time. The CCI averaged 28+/-26 x 10(3) microL(-1) in 10 patients 1 h after transfusion. The TRIMA machine collects RCCs, platelets and plasma in a variety of combinations in one session. For autologous collection, two units of RCC plus platelets can be collected at one time, reducing administrative and testing costs. The platelets have good in vivo recovery, as shown by the CCI values. An added advantage is that the TRIMA machine can be used in hospitals to generate components in times of shortage without the need for a component's laboratory.

Dysregulated expression of IFN-gamma and IL-10 and impaired IFN-gamma-mediated responses at different disease stages in patients with genital herpes simplex virus-2 infection

Cell-mediated T-helper type-1 (Th1) responses play a vital role in the immunopathogenesis of genital infections caused by herpes simplex virus 2 (HSV-2). We investigated the role of Th responses in HSV-2 infection at different disease stages by analysing the production of Th cytokines in HSV-stimulated peripheral blood mononuclear cells (PBMCs). IFN-gamma production decreased over time following a recurrence, whereas levels of IL-10, and to a lesser extent IL-2, remained elevated during this period. In addition, PBMCs from asymptomatic seropositive individuals produced high levels of IFN-gamma and low levels of IL-10, in contrast to individuals with a history of genital ulcers. Following a recurrence, virus copy number in the genital lesions decreased progressively over time, in a manner similar to IFN-gamma production by HSV-2-stimulated PBMCs. Enhanced production of IFN-gamma may modulate HSV replication and B7 expression on monocytic cells of HSV-infected individuals. In contrast to seronegative controls, IFN-gamma failed to enhance B7 expression on monocytic cells of HSV-infected individuals. In addition, monocytic cells from HSV-2-infected individuals with recurrent disease supported greater HSV replication than did those of HSV-infected asymptomatic individuals or seronegative controls. Furthermore, addition of IFN-gamma resulted in enhanced HSV replication in monocytic cells of HSV-infected individuals with recurrent disease, in contrast to the inhibition observed in HSV-seropositive asymptomatic individuals and seronegative controls. Taken together, our results suggest that dysregulated production of IFN-gamma at different disease stages and the impaired ability of monocytic cells to respond to IFN-gamma may play a role in the pathogenesis of recurrent genital herpes disease.

Prevalence of hepatitis E virus antibodies in Canadian swine herds and identification of a novel variant of swine hepatitis E virus

Swine hepatitis E virus is a newly identified potentially zoonotic virus from pigs of particular concern for possible direct transmission to a human xenotransplant recipient by organ transplantation. In the present study, prevalence of serum antibodies to hepatitis E virus was examined in Canadian swine herds. A total of 998 serum samples collected from 6-month-old healthy slaughter hogs were examined by enzyme immunoassay and Western blot analysis for antibodies to the recombinant open reading frame 3 (ORF3) protein of hepatitis E virus expressed in Escherichia coli. These samples represented more than 80 different swine production units from five major swine-producing provinces across Canada. From this study, 594 samples (59.4%) were found to be positive for hepatitis E virus antibody. The seroprevalence was higher in Quebec (88.8%) and Ontario (80.1%) than in Alberta and Saskatchewan (38.3%). By PCR using a pair of oligonucleotide primers deduced from the ORF2 sequence of human hepatitis E virus, a specific hepatitis E virus sequence was recovered from feces of pigs. The nucleotide sequence identity between the U.S. swine hepatitis E virus and the Canadian isolate (SK3) was only 85.8%, suggesting that genotypic variations may exist in swine hepatitis E virus in North America. Among 165 serum samples collected from humans in Saskatchewan, 2.4% were found to be positive for antibodies to the hepatitis E virus ORF3 protein. Our data indicate that hepatitis E virus is highly prevalent in commercial swine populations in Canada and support the suggestion that the swine hepatitis E virus may be an important zoonotic agent for humans.

Epidemiology of hepatitis B in Canada

OBJECTIVE

To provide a current and comprehensive review of the epidemiology of hepatitis B virus (HBV) in Canada.

DATA SOURCES

Published and unpublished epidemiological studies and surveillance reports of the past decade, primarily from Canada were studied. Fifty reports addressing HBV surveillance, incidence and prevalence, transmission-associated risk factors, co-infections, and prevention strategies were reviewed.

DATA SYNTHESIS

HBV infection is an important vaccine-preventable infectious disease in Canada. The incidence rate of clinically recognized, acute HBV infection in 1998/1999 was estimated to be 2.3/100,000 people or approximately 700 cases a year. The prevalence of HBV carriers is estimated to be 0.5% to 1.0% of the population, but varies substantially according to population-specific risk factors. Most acute HBV infections are associated with injection drug use or high risk heterosexual activities, but 20% to 30% of acute cases did not report any identified risk factors. Surveillance activities such as the National Notifiable Disease Reporting system provide information regarding trends and risk factors. The primary preventive strategy for HBV consists of universal immunization for preadolescents and/or infants. Other strategies, such as the universal prenatal screening and postnatal immunization, and the prevention of nosocomial acquisition, are also important. The recently described hepatitis B surface antigen (HBsAg) escape mutants may not be detected by current HBsAg test assays, and the existing HBV vaccines may not protect vaccinees from infections by such mutants.

CONCLUSION

Ongoing surveillance and research are required to assess risk factors for HBV transmission, evaluate the effectiveness of immunization programs and monitor the impact of HBsAg escape mutants.

A cross-sectional study of SEN virus in liver transplant recipients

A new DNA virus, referred to as SEN virus (SEN V), has been isolated and is associated with blood-product transfusion and possibly Non A to Non E hepatitis. We performed a cross-sectional analysis of SEN V in liver transplant recipients at our center. Polymerase chain reaction was used to test for 2 genotypes of SEN V (SEN V:C/H and SEN V:D) in 58 unselected patients. Comparisons were made between SEN V--positive and SEN V--negative groups in terms of age, time posttransplantation, indications for transplantation, serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, and cytomegalovirus and Epstein-Barr virus status. Thirty of 58 transplant recipients (51.7%) were SEN V positive; 15.5% were positive for SEN V:C/H, 24.1% for SEN:D, and 12.1% for both strains. No significant differences were found based on primary indication for transplantation, including hepatitis C virus (HCV). Of the 14 of 21 patients with HCV seropositivity and HCV reinfection, 79% were positive for SEN V (P =.02). There was no difference in the proportion of patients with abnormal serum ALT and/or AST levels. A trend for the SEN V--positive group to have a greater mean ALT level (82 v 41 U/L; P =.067) was attributable to the subgroup with HCV recurrence because there was no difference in mean ALT levels (34.9 v 34.5 U/L; P =.968) in non--HCV-infected transplant recipients. Even in the subgroup (n = 14) with recurrent HCV, there was no statistically significant difference in mean ALT levels (140 v 105 U/L; P =.665). Age and cytomegalovirus or Epstein-Barr virus status were not significantly different between the 2 groups, but a significant difference in posttransplantation time was noted (16.8 v 32 months; P =.021). We conclude that SEN V is common among liver transplant recipients but does not appear to cause graft dysfunction as an isolated agent. There is a suggestion that SEN V may be associated with HCV recurrence, but we did not detect biochemical differences attributable to SEN V.

Preventing the spread of hepatitis B and C viruses: where are germicides relevant?

Hepatitis B virus (HBV) and hepatitis C virus (HCV) are the most prevalent bloodborne pathogens. Infections caused by these organisms can become chronic and may lead to liver cirrhosis and carcinoma. Limited chemotherapy is now available, but only HBV can be prevented through vaccination. Both viruses are enveloped and relatively sensitive to many physical and chemical agents; their ability to survive in the environment may not be as high as often believed. As a result, their spread occurs mainly through direct parenteral or percutaneous exposure to tainted body fluids and tissues. Careful screening of and avoiding contact with such materials remain the most effective means of protection. Nevertheless, the indirect spread of these viruses, although much less common, can occur when objects that are freshly contaminated with tainted blood enter the body or contact damaged skin. Germicidal chemicals are important in the prevention of HBV and HCV spread through shared injection devices, sharps used in personal services (such as tattooing and body piercing), and heat-sensitive medical/dental devices (such as flexible endoscopes) and in the cleanup of blood spills. Microbicides in vaginal gels may also interrupt their transmission. General-purpose environmental disinfection is unlikely to play a significant role in the prevention of the transmission of these viruses. Testing of low-level disinfectants and label claims for such products against HBV and HCV should be discouraged. Both viruses remain difficult to work with in the laboratory, but closely related animal viruses (such as the duck HBV) and the bovine viral diarrhea virus show considerable promise as surrogates for HBV and HCV, respectively. Although progress in the culturing of HBV and HCV is still underway, critical issues on virus survival and inactivation should be addressed with the use of these surrogates.

Prevalence of GBV-C/hepatitis G virus viremia and anti-E2 in Canadian blood donors

BACKGROUND AND OBJECTIVES

GB virus C (GBV-C)/hepatitis G virus (HGV) is a recently recognized parenterally and sexually transmitted agent. The prevalence of GBV-C/HGV markers in Canadian blood donors has not been previously studied and was therefore determined.

MATERIALS AND METHODS

Blood donors [identity unlinked (IU), short-term temporarily deferred (STTD) and autologous groups] and donor samples with antibodies to hepatitis C (anti-HCV) or hepatitis B core were tested for GBV-C/HGV RNA and for antibodies to E2 antigen (anti-E2).

RESULTS

GBV-C/HGV RNA was found in 1.1% and anti-E2 in 7.3% of the combined IU/STTD donor group. Viremia was much more common in anti-HCV-positive samples (12.5%); anti-E2 was present in >50% of this group. In the STTD group, female gender was significantly associated with viremia.

CONCLUSION

GBV-C/HGV infection is relatively common in Canadian donors, and a small proportion are viremic. The association of female gender and viremia was unexpected. Further study is needed to clarify the epidemiology and natural history of GBV-C/HGV infection.

Prevalence of GBV-C/hepatitis G virus viremia and anti-E2 in Canadian blood donors

BACKGROUND AND OBJECTIVES

GB virus C (GBV-C)/hepatitis G virus (HGV) is a recently recognized parenterally and sexually transmitted agent. The prevalence of GBV-C/HGV markers in Canadian blood donors has not been previously studied and was therefore determined.

MATERIALS AND METHODS

Blood donors [identity unlinked (IU), short-term temporarily deferred (STTD) and autologous groups] and donor samples with antibodies to hepatitis C (anti-HCV) or hepatitis B core were tested for GBV-C/HGV RNA and for antibodies to E2 antigen (anti-E2).

RESULTS

GBV-C/HGV RNA was found in 1.1% and anti-E2 in 7.3% of the combined IU/STTD donor group. Viremia was much more common in anti-HCV-positive samples (12.5%); anti-E2 was present in >50% of this group. In the STTD group, female gender was significantly associated with viremia.

CONCLUSION

GBV-C/HGV infection is relatively common in Canadian donors, and a small proportion are viremic. The association of female gender and viremia was unexpected. Further study is needed to clarify the epidemiology and natural history of GBV-C/HGV infection.

Transfusion-transmitted malaria in Canada

Three cases of transfusion-transmitted malaria in Canada are described. Although very rare, this diagnosis should be considered in transfusion recipients who have undiagnosed symptoms consistent with malaria. Thick and thin blood smears should be urgently examined to exclude this possibility.

A novel, automated method of temperature cycling to produce cryoprecipitate

BACKGROUND

Cryoprecipitate continues to find wide application in transfusion practice. Current AABB standards call for a minimum of 80 units (U) of factor VIII and 150 mg of fibrinogen per bag of cryoprecipitate. However, individual cryoprecipitates can vary greatly in content, with as many as 20 different factors known to affect the yield.

STUDY DESIGN AND METHODS

Plasma was processed in a new, rapid, automated device (CryoSeal, Thermogenesis) with computer-controlled temperature cycling to produce cryoprecipitate.

RESULTS

In repeat runs (n = 20), the automated procedure yielded a product containing 184 mg of fibrinogen and 158 U of factor VIII in 55 minutes. Additional studies using plasma pools to compare the quality of the machine-generated products to those of traditionally prepared cryoprecipitate showed comparative recoveries of 182 and 187 mg of fibrinogen and 172.1 and 129.7 U of factor VIII and no significant difference in the levels of plasminogen, protein C, or protein S.

CONCLUSION

The new system offers an automated method of cryoprecipitate production in which the steps involved in temperature cycling are initiated sequentially, producing within 1 hour a preparation that is equivalent to standard cryoprecipitate.

Xenotransplantation and the potential risk of xenogeneic transmission of porcine viruses

The clinical success of allotransplantation and the shortage of donor organs have led to a proposal for the use of animal organs as alternative therapeutic materials for humans. In that regard, swine are preferable to non-human primates as a source of donor organs. While applications for clinical trials for xenotransplantation have not yet been received in Canada, several trials have already been authorized in the United States. A major concern, however, is the potential for xenogeneic transmission of viruses from animals to humans via organ, tissue, or cellular transplantation or via ex vivo exposure of humans to porcine biologic materials. Xenotransplantation allows viruses to bypass the normal immunological defense mechanisms of the recipient. Furthermore, the use of immunosuppressive drugs following transplantation may facilitate the xenogeneic transmission of zoonotic agents. Of porcine viruses, swine hepatitis E virus does not cause any clinical symptoms in the natural host but is a likely zoonotic agent that can infect humans and cause hepatitis. Porcine circovirus type 1 is prevalent in swine populations with no known association with clinical disease, while circovirus type 2 causes post-weaning multi-systemic wasting syndrome. Porcine endogenous retrovirus is integrated into the host chromosomes while porcine cytomegalovirus undergoes latent infection. Two additional porcine herpesviruses have recently been identified in swine and have been named porcine lymphotrophic herpesviruses. These herpesviruses can potentially become reactivated in human recipients after xenotransplantation. All in all, there are a number of viruses in swine that are of primary concern to screen and eliminate from xenotransplantation protocols. Epidemiology and the current knowledge on xenogeneic risk of these viruses are discussed.

Prevention of cytokine accumulation in platelets obtained with the COBE spectra apheresis system

BACKGROUND AND OBJECTIVES

Febrile nonhemolytic transfusion reactions frequently accompany platelet transfusions and may be due to accumulation of cytokines mediating inflammation during storage of platelet concentrates (PCs). We wished to determine whether PCs collected using the COBE(R) SpectraTM Apheresis System (Version 4) were sufficiently leukocyte reduced (LR) to limit cytokine accumulation during storage.

MATERIALS AND METHODS

Cytokine accumulation - interleukin (IL)-1beta, IL-6, IL-8, tumor necrosis factor-alpha (TNF-alpha) - and release of platelet alpha-granule - P-selectin, transforming growth factor-beta1 (TGF-beta1), platelet-derived growth factor AB (PDGF-AB), von Willebrand factor (vWf) - or dense granule (serotonin) markers were investigated during a 7-day storage period comparing apheresis-collected, LR PCs (LR PCs) and random donor platelets prepared from whole blood (WB).

RESULTS

Leukocyte counts were reduced 99.95% comparing LR PCs (5.7 x 10(5)/l) and WB PCs (1.09 x 10(9)/l). Little or no accumulation of leukocyte-derived cytokines was observed in LR PCs during storage in contrast to WB PCs. A reduction in the release of platelet alpha-granule proteins, such as P-selectin, TGF-beta1 and PDGF-AB, was observed on day 0 for LR PCs compared to WB PCs with little or no difference observed from day 3 to 7. Plasma vWf levels were higher in LR PCs compared to WB PCs on days 0-7.

CONCLUSION

Leukocyte levels in PCs collected with the COBE Spectra Apheresis System are sufficiently low to limit cytokine production during 7 days of storage.

Quality assurance of progenitor cell content of apheresis products: a comparison of clonogenic assays and CD34+ enumeration. The Canadian Apheresis Group and Canadian Bone Marrow

The most common methods used for evaluation of the haematopoietic stem cell content of peripheral blood apheresis products are the colony forming cell assay and the enumeration of CD34+ cells by flow cytometry. The Canadian Apheresis Group and the Canadian Bone Marrow Transplant Group established a multicentre study to compare the reproducibility of colony forming cell assays and CD34+ enumeration by flow cytometry in six transplant centres routinely performing haematopoietic stem cell apheresis. Over a 5-month period in 1996, 31 fresh apheresis samples were shipped by overnight courier for testing at six centres to perform CD34+ enumeration by flow cytometry and clonogenic assays. The mean coefficient of variation and range for the following assays were: cell count 36% (2.6-148%), CFU-GM 82% (46-123%), CD34+ absolute/kg 60% (14-174%) and CD34+ per cent 42% (12-84%). The wide variation in cell count in this pilot study highlights the difficulties related to provision of samples for quality assessment programmes. Results showed poor interinstitutional reproducibility even among selected samples with similar cell counts for both CFC and CD34+ assays demonstrating the need for development and implementation of an interinstitutional quality assurance programme for haematopoietic stem cell assessment. Provision of a reliable source of testing material will be a necessary next step.

Primer specific and mispair extension analysis (PSMEA) as a simple approach to fast genotyping

A simple method, primer specific and mispair extension analysis (PSMEA) with pfu DNA polymerase was developed for genotyping. PSMEA is based on the unique properties of 3'-->5' exonuclease proofreading activity. In the presence of an incomplete set of dNTPs, pfu was found to be extremely discriminative in nucleotide incorporation and proofreading at the initiation step of DNA synthesis, completely preventing primer extension when mispair(s) are found adjacent to the 3'-end of the primer. This has allowed us to accurately detect nucleotide variations, deletions and insertions for fast genotyping.

Effect of filtration of platelet concentrates on the accumulation of cytokines and platelet release factors during storage

BACKGROUND

Platelet transfusions are frequently accompanied by febrile nonhemolytic transfusion reactions. These may be due, in part, to the release of cytokines interleukin 1 beta (IL-1 beta), interleukin 6 (IL-6), interleukin 8 (IL-8), and tumor necrosis factor alpha (TNF-alpha) by white cells (WBCs) into the plasma during storage of platelet concentrates (PCs). Acting as endogenous pyrogens, these agents may induce inflammatory responses.

STUDY DESIGN AND METHODS

This study proposed to determine if WBC reduction in PCs by filtration significantly reduced the levels of cytokines normally generated during storage of unfiltered PCs up to 5 days. Serotonin, platelet-derived growth factor (PDGF-AB), and von Willebrand factor levels were also assessed to establish whether or not filtration or storage elicited significant platelet activation and granule release.

RESULTS

Filtration significantly reduced total WBC counts by 99.1 percent before storage (p < 0.001) without affecting total platelet counts. Compared to unfiltered PCs, filtration prevented a rise in the levels of each cytokine by Day 3 for IL-1 beta (27.7 vs. 0.6 pg/mL; p < 0.05), IL-6 (114.2 vs. 0.4 pg/mL; p < 0.001), and IL-8 (4.2 vs. 0.02 ng/mL; p < 0.001). By Day 5, further increases in the levels of all cytokines were noted in unfiltered PCs, but Day 0 levels remained in filtered PCs (IL-1 beta: 105.4 vs. 0.4 pg/mL, p < 0.001; TNF-alpha: 42.2 vs. 7.5 pg/mL, p < 0.025; IL-6: 268.8 vs. 0.4 pg/mL, p < 0.001; and IL-8: 7.6 vs. 0.02 ng/mL, p < 0.001). From Day 0 to Day 5, there were significant increases in serotonin (21.3 vs. 6.3 ng/mL, p < 0.05), PDGF-AB (72.6 vs. 25.8 ng/mL, p < 0.001), and von Willebrand factor (4.7 vs. 2.7 IU/mL, p < 0.05) in unfiltered PCs, with similar increased levels being observed in filtered PCs during storage.

CONCLUSION

These data indicate that the accumulation of high levels of cytokines in stored PCs could be prevented by WBC-reduction filtration of PCs without the induction of significant platelet activation or granule release. As cytokines have the potential to induce febrile nonhemolytic transfusion reactions in patients, the transfusion of WBC-reduced PCs would be expected to reduce the frequency and severity of such reactions.

Anti-hepatitis C virus (HCV) screening at a Canadian Red Cross center: significance of a positive c100 HCV enzyme-linked immunosorbent assay

The c100 hepatitis C virus (HCV) enzyme-linked immunosorbent assay (ELISA) has been used to screen blood donors to prevent transfusion-associated non-A,non-B hepatitis. This test is not specific, and only about 25 percent of c100 HCV ELISA-positive blood samples appear to transmit hepatitis C. However, the intensity of the ELISA (sample/cutoff ratio [S/C], greater than 2) could identify a subpopulation of donors that are at high risk for transmitting hepatitis. Blood samples from 20,186 volunteer blood donors at a Canadian Red Cross blood transfusion center were screened for antibodies to HCV using the c100 HCV ELISA. Fifty-nine (0.3%) of these donors were repeatably reactive on ELISA. When their samples were tested with the c100 recombinant immunoblot assay (RIBA) and second-generation RIBA (RIBA-2), 26 (44%) and 31 (52%) samples, respectively, were found to be positive. Thirty-three of the 59 ELISA-reactive donors had an S/C greater than 2. Of these 33 donors, 30 (91%) had elevated alanine aminotransferase (ALT), 27 (82%) were RIBA-2 positive, and 22 (67%) had risk factors for hepatitis. In contrast, of the 26 ELISA-reactive donors with S/C less than 2, only 7 (27%) had elevated ALT, and 4 (15%) were RIBA-2 positive and also had high risk factors for hepatitis. Thus, while the HCV ELISA may lack specificity, its intensity can serve to identify a subgroup of donors that are at high risk for transmitting hepatitis.

Late pseudo-exacerbation of myasthenia gravis due to ectopic thymoma invading lower cranial nerves

Dysarthria, dysphagia and repeated aspiration in a 54-year-old woman diagnosed and treated for myasthenia gravis 7 years earlier were initially thought to represent a late exacerbation of myasthenia. A cervical mass invading the jugular foramen and causing multiple lower cranial nerve palsies was biopsied and found to represent invasive ectopic thymoma.

Effects of cimetidine on in vitro transformation of peripheral monocytes to macrophages in healthy volunteers and cancer patients

Monocyte-to-macrophage transformation is a phenomenon which correlates with the absolute number of mononuclear cells, principally lymphocytes, contained in the culture. The addition of cimetidine to cultures of mononuclear cells from the peripheral blood of healthy volunteers enhances monocyte transformation (probably by way of blocking the H2 receptors of suppressors T lymphocytes) regardless of the absolute number of monocytes in the culture or of basal transformation rates. Removal of the lymphocytes from the cultures lowers the basal transformation rate and prevents the effect of cimetidine. The addition of histamine to the cultures causes significant depression of the monocyte transformation rate; this effect is partly offset by the concurrent addition of cimetidine. In the case of cancer patients, mononuclear cell cultures from peripheral blood fail to respond to cimetidine even though basal transformation rates are not significantly different from those of healthy controls; this suggests some intrinsic impairment of monocyte function, possibly mediated by blocking factors produced by the tumor.

Effect of lithium carbonate on monocyte to macrophage maturation in cancer patients

A decrease in the maturation process of monocytes into macrophage is observed in cancer patients. In this study the Authors examined: the maturation pattern of monocytes into macrophages in 14 patients of both sexes, between 45 and 70 years of age, with solid tumours of the lung, breast and gastrointestinal tract, without any infection; the variations induced on the maturation pattern as results of the administration of lithium carbonate. The results (evaluated statistically) show that in all patients there was a significant increase of monocytes-macrophages maturation from basal values, after 14 days of lithium carbonate treatment. Moreover, we also observed that 14 days after withdrawing of lithium carbonate, the values of monocytes-macrophages maturation return to their basal ones. The increase, as percentage of mean basal values, is higher in patients having low basal values of maturation.

[Observations about the use of different types of enzymes in immunohistological diagnosis of autoimmune diseases. Comparative study with indirect immunofluorescence technique (author's transl)]

The Authors have evaluated the use of anti-human immunoglobulins conjugated with peroxidase, alkaline-phosphatase, glucose-oxidase as a diagnostic tool for assaying autoantibodies. A comparison study was done using the classical indirect immunofluorescence technique. Immunoenzymatic techniques, of minor cost compared to immunofluorescence, have revealed a better appreciation of global and particular structure of the tissue in examination. From the three enzymes examined peroxidase revealed itself as first choice, because, other than having on overlapping sensitivity to immunofluorescence, it can allow a further ultrastructural study.