Screening for transfusion transmissible infections using rapid diagnostic tests in Africa: a potential hazard to blood safety?

Rapid diagnostic tests (RDTs) are routinely used in African blood centres. We analysed data from two cross-sectional studies representing 95 blood centres in 29 African countries. Standardized panels of sera containing varying concentrations of anti-human immunodeficiency virus (HIV) antibodies (Ab), hepatitis B virus antigen (HBsAg) and antihepatitis C virus (HCV) Ab were screened using routine operational testing procedures at the centres. Sensitivity of detection using RDTs was high for HIV Ab-positive samples, but low for intermediately HBsAg (51·5%) and HCV Ab (40·6%)-positive samples. These findings suggest that current RDT use in Africa could pose a hazard to blood safety.

A pilot external quality assurance study of transfusion screening for HIV, HCV and HBsAG in 12 African countries.

BACKGROUND AND OBJECTIVES: Serologic screening for the major transfusion transmissible viruses (TTV) is critical to blood safety and has been widely implemented. However, actual performance as measured by proficiency testing has not been well studied in sub-Saharan Africa. Therefore, we conducted an external quality assessment of laboratories engaged in transfusion screening in the region. MATERIALS AND METHODS: Blinded test panels, each comprising 25 serum samples that were pedigreed for HIV, HBsAg, HCV and negative status, were sent to participating laboratories. The panels were tested using the laboratories' routine donor screening methods and conditions. Sensitivity and specificity were calculated, and multivariable analysis was used to compare performance against mode of testing, country and infrastructure. RESULTS: A total of 12 African countries and 44 laboratories participated in the study. The mean (range) sensitivities for HIV, HBsAg and HCV were 91·9% (14·3-100), 86·7% (42·9-100) and 90·1% (50-100), respectively. Mean specificities for HIV, HBsAg and HCV were 97·7%, 97% and 99·5%, respectively. After adjusting for country and infrastructure, rapid tests had significantly lower sensitivity than enzyme immunoassays for both HBsAg (P < 0·0001) and HCV (P < 0·05). Sensitivity also varied by country and selected infrastructure variables. CONCLUSION: While specificity was high, sensitivity was more variable and deficient in a substantial number of testing laboratories. These findings underscore the importance of proficiency testing and quality control, particularly in Africa where TTV prevalence is high.

CD66c expression in B-cell acute lymphoblastic leukemia: strength and weakness.

INTRODUCTION: In B-cell acute lymphoblastic leukemia (B-ALL), testing at diagnosis for BCR/ABL1 gene rearrangements is mandatory for prognostic stratification and treatment decisions. Several diagnostic methods have been proposed using flow cytometry to identify BCR/ABL1(+) B-ALL. METHODS: We evaluated expression of the myeloid antigen CD66c by flow cytometry in B-ALL. We studied 94 patients with B-ALL. The t(9;22)(q34;q11) or BCR/ABL1 rearrangement was detected by cytogenetic analysis or RT/PCR. Myeloid antigens CD66c, CD13, CD33, CD117, Myeloperoxidase, CD15 and CD65 were determined by flow cytometry. RESULTS: Of these 94 cases, 17 (18%) cases displayed BCR/ABL1 gene rearrangements and 38 (40%) cases were CD66c positive. CD66c was the most common myeloid antigen expressed on malignant lymphoblasts. Its expression was correlated with BCR/ABL1 rearrangements (P = 0.0001): sensitivity 82%, specificity 69%, positive predictive value 37% and negative predictive value 95%. Co-expression of CD66c(+) CD13(+) was more frequent in BCR/ABL1(+) B-ALL (29%) than BCR/ABL1(-) cases (4%) (P = 0.0044). Some BCR/ABL1(-) B-ALL cases (including hyperdiploid or cases with normal karyotype) were CD66c positive (31%). CONCLUSION: CD66c expression is correlated, but not specifically, with BCR/ABL1 rearrangement. It would seem better to interpret the absence of CD66c expression with a lack of BCR/ABL1 rearrangement. This myeloid antigen could be interesting in the detection of minimal residual disease.

Characterization and comparison of bone marrow and peripheral blood mononuclear cells used for cellular therapy in critical leg ischaemia: towards a new cellular product.

BACKGROUND AND OBJECTIVES: Autologous transplantation of either bone marrow (BM) or peripheral blood (PB) mononuclear cells (MNC) induces therapeutic angiogenesis in patients with peripheral arterial occlusive disease. Yet, the precise nature of the cellular product obtained from BM or PB and used in these therapeutic strategies remains unclear. MATERIALS AND METHODS: We have analysed the characteristics of BM-MNC and PB-MNC collected without mobilization and implanted in patients with critical limb ischaemia in a clinical trial of cellular therapy including 16 individuals treated by BM-MNC and eight by PB-MNC. These MNCs were characterized by cell counts, viability assessment and enumeration of leucocyte subsets, CD34 stem and endothelial progenitor cells (EPCs) (CD34+/CD133+/VEGF-R2+) by flow cytometry. Mean fluorescence intensity ratios were determined for CD34, CD133 and VEGF-R2 markers. All analyses were simultaneously performed in two laboratories. RESULTS: Accuracy and reliability between both laboratories were achieved. BM-MNCs and PB-MNCs were quantitatively and qualitatively heterogeneous and quite different from each other. Stem cells and EPCs were significantly more present in BM- compared to PB-cell products, but with similar mean fluorescence intensity ratios. A weakly positive correlation was observed between CD34+ cell counts and EPCs levels, confirming the specificity of cell identification. CONCLUSION: A great variability was observed in cell product characteristics according to their origin and also between individuals. These data stress the necessity of optimal characterization of cell products especially in multicentric clinical trials.

[Blood safety: malaria and blood donation in Africa]. / Sécurité transfusionnelle: paludisme et don de sang en Afrique.

Malaria is a principal cause of mortality in Africa and represents a major blood-borne disease. The studies made on the continent show that transfusion-associated malaria is highly prevalent in blood donors groups and that some risk factors and clinical manifestations are frequently observed. The disease is mostly asymptomatic and the signs are mild, which reduces significantly an efficient selection of the blood donors during the predonation interview and a secure supply of blood products. Furthermore, the lack of appropriate screening assays of the malaria in blood banks on the continent limit the diagnosis of the disease and hamper the blood safety. However, the prevention of transfusion-associated malaria is a frequently asked question. The destruction of the parasite in the blood bag and the recipient anti-malarial prophylaxis are the described possibilities, added to local programs against the vectors of the disease.

Seroprevalence of human herpes virus 8 antibody in populations at high or low risk of transfusion, graft, or sexual transmission of viruses.

BACKGROUND: The routes of transmission of human herpes virus 8 (HHV-8) remain unclear. In particular, HHV-8 transmission by blood components and organ transplantation is still debated and raises public health issues. The objective of this study was to determine the prevalence of anti-HHV-8 in selected populations of persons or patients with or without risk factors for the transmission of viral infections, in order to determine the routes of HHV-8 transmission. STUDY DESIGN AND METHODS: A total of 1431 persons or patients at low or high risk of sexually, blood-, or graft-transmitted viral infections were tested by means of a standardized immunofluorescence serologic assay detecting anti-HHV-8. RESULTS: The persons or patients could be classified into three distinct groups according to anti-HHV-8 prevalence: a low prevalence group (0.0% to 5.0%), including healthy blood donors, healthy pregnant women, multiply transfused patients with thalassemia major, and IV drug users; an intermediate prevalence group (5.0% to 20.0%), including organ donors, kidney transplant recipients, and multiply transfused patients with sickle cell disease; a high prevalence group (>20.0%), including HIV-negative persons at high risk of sexually-transmitted viral infections, and HIV-infected homosexual men and heterosexuals. CONCLUSION: The sexual route appears to be the main route of HHV-8 transmission; bloodborne transmission of HHV-8, if it exists, is rare. In contrast, organ transplantation recipients might be exposed to HHV-8 transmission by the transplanted organ, which raises the issue of systematic screening of organ donors.

[Human T-lymphotropic virus type I (HTLV-I): risk of transmission with transfusion]. / Virus lymphotrope-T humain de type I (HTLV-I): le risque de transmission transfusionnelle.

PATHOGENIC ROLE: The human T-lymphotropic virus type I (HTLV-I), the first human retrovirus discovered, is the etiologic agent of adult T-cell leukemia/lymphoma (ATL) and of HTLV-I associated myelopathy or tropical spastic paraparesis (HAM/TSP) and has a widespread but uneven worldwide distribution. HTLV-I has a high seroprevalence in Southern Japan, the Caribbean basin and Sub-Sahara Africa. Blood transfusion, intravenous drug use, breast feeding and sexual contacts are major routes of contamination. IMPLICATIONS FOR BLOOD TRANSFUSION: The screening of blood donors for antibody to HTLV-I became systematic in 1989 in French West Indies and in 1991 in Continental France. This review deals with the transfusional implications of the HTLV-I, which belongs to the group of the blood-borne viruses: the prevalence of transfusion-linked HTLV-I infection before the implementation of the specific preventive measures, the parameters influencing the risk of transfusional contamination (the type of blood products, the age of the blood product with regards to its collection date, the proviral load of the blood donor), the prognosis of HTLV-I infection in patients contaminated by transfusion, the prophylactic strategies of transfusion contamination and the residual risk of infection through HTLV-I-infected risk blood products.

Screening for HBV, HCV and HIV genomes in blood donations: shortcomings of pooling revealed by a multicentre study simulating real-time testing.

This study was undertaken in order to determine whether screening of viremic blood donations by testing of pooled donor samples could constitute a technically feasible transfusional safety measure. A pilot study of real-time simulation, on a day-to-day basis, of screening of three viral genomes (hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV)) was conducted by five French Blood Centers on plasma samples collected from blood donors and studied within undiluted samples and within sample pools of various sizes. This study was carried out within time conditions compatible with the release of platelets. For the detection of HCV and HIV genomes, the five laboratories achieved a sensitivity that decreased with the size of the sample pool. Four were successful in detecting all undiluted samples. In the 1/10 diluted samples, four failed to detect one HIV or HCV sample. In the 1/100 diluted samples, all laboratories failed to detect one or more HIV or HCV samples. For HBV genome, no participating laboratories detected all of the samples of the panel, even undiluted samples, and the sample pooling considerably affected sensitivity. The improvement and standardization of assays needs to be attained, and training of laboratories appears to be a step crucial for routine screening of viral genomes in blood donations.

Natural history of GBV-C/hepatitis G virus infection through the follow-up of GBV-C/hepatitis G virus-infected blood donors and recipients studied by RNA polymerase chain reaction and anti-E2 serology.

The aims of this study were to determine the outcome and the natural history of GBV-C/hepatitis G virus (HGV) infection and to establish the frequency of acute or persistent infections in multiply-transfused individuals and blood donors. We used a GBV-C/HGV RNA polymerase chain reaction (PCR) and an assay evidencing antibodies to the envelop protein E2, which is considered a marker for virus clearance. Among 16 PCR-positive recipients, 11 were still positive for GBV-C/HGV RNA at the end of the study period; six of the 16 recipients were GBV-C/HGV infected during the study period and thus had a well-defined date of infection. The 16 patients were shown to carry GBV-C/HGV RNA over a mean period of 4.4 years, for a mean observational period (defined as the follow-up period since the first sample positive for GBV-C/HGV RNA) of 5.3 years. Within the limits of the study period, the patients with a well-defined date of infection were positive for GBV-C/HGV RNA during a mean period of 4.7 years. If defined by the presence of GBV-C/HGV RNA for at least 6 months, the persistent infection rate was 100% in this recipient cohort. Serum anti-E2 antibody was evidenced at least once in five (31.2%) recipients and, except in one case, became detectable after the loss of GBV-C/HGV RNA. Among the 11 blood donors, all were still positive for GBV-C/HGV RNA after a mean follow-up period of 7.7 months. The persistent infection rate was 100% in this donor cohort. Once acquired, the infection to GBV-C/HGV generally tends to persist in immunocompetent patients.

Virological and immunological data of AIDS patients treated by passive immunotherapy (transfusions of plasma rich in HIV-1 antibodies).

BACKGROUND AND OBJECTIVES: In human immunodeficiency virus (HIV) infections, passive immunotherapy can be carried out through infusions of virus-inactivated plasma from symptomless HIV-infected persons with abundant HIV antibodies. MATERIALS AND METHODS: We carried out a prospective, randomized, double-blind, controlled, passive immunotherapy study, which compared two groups. One received plasma rich in HIV antibodies, the other a standard seronegative plasma. RESULTS: Measurement of the plasma HIV RNA load showed in both groups a significant decrease in the mean viral copy number at the end of the first month, followed by an increase at the third month. Beyond the third months, a significant decrease in viral load was observed only in the treatment group. A significant difference in favor of the treatment group was observed for plasma viremia by HIV culture. For the cytokines involved in the viral replication and for the immune activation markers such as neopterin and beta 2-microglobulin, the biological analysis in plasma failed to show a significant difference in either group. Clinically, the treatment group benefited by delay in the appearance of the first AIDS-defining event and reduction in the cumulative incidence of such events. CONCLUSION: One possible interpretation is that passive immunotherapy affects plasma viral load, but there is no evidence that HIV-specific antibodies are exclusively responsible for the observed effects.

Detection of human herpesvirus 8 DNA sequences before the appearance of Kaposi's sarcoma in human immunodeficiency virus (HIV)-positive subjects with a known date of HIV seroconversion.

The presence of human herpesvirus 8 (HHV-8) DNA sequences was sought by polymerase chain reaction (PCR) in peripheral blood mononuclear cells of 4 groups: 6 human immunodeficiency virus (HIV)-infected persons with well-defined dates of seroconversion, during the period between the diagnosis of HIV infection and the appearance of Kaposi's sarcoma (KS); 45 HIV-positive persons with no symptoms of HIV infection; 11 AIDS patients with KS; and 14 AIDS patients without KS. HHV-8 DNA PCR was positive in 3 of the 6 patients during HIV infection preceding the appearance of KS and in all but 1 of 11 AIDS patients with KS. HHV-8 DNA PCR was negative in all but 1 of the 45 HIV-positive persons with no symptoms of infection and in all but 1 AIDS patient without KS. These results indicate that HHV-8 DNA may be detected several years before the occurrence of KS in HIV-infected subjects.

Quantitation of passively acquired human immunodeficiency virus (HIV) antibodies in AIDS patients transfused with a plasma that is rich in HIV antibodies.

BACKGROUND: Passive immunotherapy in human immunodeficiency virus (HIV) infection is based on transfusions of plasma that is rich in HIV antibodies. STUDY DESIGN AND METHODS: To verify whether the clearance of transfused antibodies will maintain an elevated titer of specific antibodies between biweekly transfusions of plasma, the titers of anti-HIV-1 in plasma and in transfusion recipients were measured. Samples from 12 recipients were analyzed by automated scanning of Western blot, before transfusion and at Days 2, 7, and 14 after transfusion. RESULTS: The p24 antibody became detectable or higher than the baseline after transfusion and remained detectable until the second transfusion. Anti-p24 titers were variable and dependent on the antibody titer of the transfused plasma and the baseline p24 antigen titer. CONCLUSION: Biweekly transfusion of plasma with a high anti-HIV titer maintains a high anti-p24 titer between transfusions in AIDS patients treated with passive immunotherapy.

Correlation between viral DNA load and serum anti p19 antibody concentration in symptomless human T-lymphotropic virus type-I (HTLV-I)-infected individuals.

In order to determine whether serum anti-human T-cell lymphotropic virus type I (HTLV-I) antibody concentration is correlated with cellular viral DNA load, these 2 biological parameters were established in 22 symptomless HTLV-I carriers. The proviral copy (PVC) number was determined through quantificative polymerase chain reaction. Specific antibody titers were determined by Western blot with the end-point dilution method; the quantification of each antibody was performed through ScanBlot by determination of the peak height of each Western-blot band. A positive correlation was observed between the PVC number and the titer of total antibodies. When the association between the peak height of each antibody and the PVC number was studied, a significant positive correlation was observed only with anti-p 19. Further evaluation through follow-up studies of symptomless HTLV-I individuals is needed to clarify the value of anti-HTLV-I antibody titer as a predictor of disease progression.

Epidemiologic comparison of human T-lymphotropic virus type I-infected blood donors from endemic and nonendemic regions over a 3-year period.

BACKGROUND: Screening for human T-lymphotropic virus type I (HTLV-I) infection became systematic in 1989 in the French West Indies for blood from all donors and in France for blood from natives of endemic areas; in 1990, it was extended to blood from donors with at-risk sex partners and in July 1991 to blood from all donors. STUDY DESIGN AND METHODS: The epidemiologic characteristics of individuals found through the screening of donated blood to be HTLV-I infected were compared for an endemic region (Guadeloupe, French West Indies) and a nonendemic region (Paris area) over a 3-year period (1989 through 1991). RESULTS: In Guadeloupe, 131 HTLV-I-infected individuals were detected in the screening of 28,801 units; in the Paris area, 38 HTLV-I-infected donors were detected in the screening of 109,824 units. All Guadeloupean HTLV-I-infected donors were natives of endemic areas. Among the 38 Parisian HTLV-I-infected donors, 21 were natives of endemic areas, 10 were natives of endemic areas and had received transfusions, 2 were whites who had received transfusions, and 5 were whites who had had heterosexual contact with natives of endemic areas. The percentage of HTLV-I-infected individuals whose blood would have been excluded because of positivity for one or more markers for other viruses did not significantly change over the study period and did not significantly differ between regions (41%). Among the eight Parisian HTLV-I-infected blood donors detected after July 1991, six would not have been detected without the biologic screening. CONCLUSION: The generalization of biologic screening of HTLV-I-infected donated blood in France was useful for the prevention of HTLV-I and HTLV type II infections through transfusion.

B19 parvovirus DNA in solvent/detergent-treated anti-haemophilia concentrates.

A transfusional B19 parvovirus infection may have severe consequences in immunocompromised hosts. The presence of B19 DNA was investigated with a polymerase chain reaction (PCR) assay in 30 batches of solvent/detergent-treated clotting factor concentrates (12 batches of factor VIII, 16 batches of factor IX, 1 batch of factor VII, and 1 batch of PPSB). B19 DNA was detected in 6 (20%) batches, including 3 factor VIII and 3 factor IX concentrates. Because of the frequency of B19 DNA in batches of clotting factors, measures to prevent transfusional risk of B19 infection via these blood products are justified, especially in recipients immunocompromised by HIV infection.