- Email: [email protected]
Symposium S04 Quality improvement and risk management
Communications volume. All patients received corticoids while vincristine was added in patients who had no response after 10 plasma exchange. RESULTS : We performed 213 plasma exchange in 11 episodes of TTP. Median of exchanges was 19 (range 8-42). Analytical parameter at the onset were Haemoglobin 85 (55-122) g/l, Platelets 46 (6-130) x109/l, lactate dehydrogenase 1678 (426-5056) U/l, creatinin 113 umol/l (67-267). As replacement fluid, MB virus-inactivated plasma was used in 9 episodes, fresh frozen plasma in 1 and cryosupernatant in the last one. Seven patients achieved a complete response, in 1 (TTP mitomicine-related), a partial response was observed and one case of no response was done (TTP postbone marrow transplant). Two patients presented a relapse that was treated with the same scheme achieving a complete response with 5 and 13 exchanges. One death was observed (TTP mitomicine related) due to a cardiac failure. Adverse effects could be observed in 27 % being hypocalcemia the most frequent. CONCLUSIONS : In our experience the use of methylene blue virusinactivated plasma in plasma exchanges for TTP has a pattern of response similar to fresh frozen plasma.
11s
S04-002 WBC-REDUCTION AND COUNTING LOW LEVEL OF WBC : UNRESOLVED PROBLEMS AND NEED FOR STANDARDISATION / HARMONISATION SEGHATCHIAN J., KRAILADSIRI P.
S04-001
NATIONAL BLOOD SERVICE, LONDON, UK [email protected] The key unresolved questions in universal WBC-reduction are how counting with different technologies influences WBC-reduction statistical monitoring, the performance of various filters or other WBC-reduction processes over time. Earlier investigation in our laboratories revealed that the cause of WBC-reduction failure is multifactoral and can be donor, operational, filter or WBC-reduction process design, frequency of donation and counting technology dependent. Regarding WBC counting, the unresolved issues are : (i) variability in gating strategy used by flow cytometry ; (ii) aggressive nature of some reagent leading to rapid shredding of WBC and presence of some aggregates/debris in some samples ; (iii) effects of the presence of apoptotic cells and some bacteria colonies. These can affect WBC results to variable degrees, depending on the types of blood products, filters and counting technologies. We have employed several methods to solve these issues. Both the analyses of apoptotic cells and WBC subsets by monoclonal antibodies are found to be useful in identifying the cause of discrepancy between counting methods. Adjusting the gate on flow cytometry often help in making the results interchangeable. Re-filtering the failed WBC-reduced products and recovering WBC from the used filter by back-flushing with AB plasma was also found to be a useful approach for apportioning the cause of WBC-reduction failure as well as the discrepancy in WBC results. When channelling or cracked filters are seen, large numbers of platelet as well as all sub-population of WBC are detected. Furthermore, Often debris are enriched by the refiltering process and sometimes identifiable by ICAM-3. Harmonisation and standardisation of WBC counting is pre-requisite in order to understand and identify the cause as well as to provide a cure.
QUALITY MANAGEMENT PROJECT FOR BLOOD TRANSFUSION
S04-003
Quality improvement and risk management Chair: Marcel Joussemet, FRA – Danièle Sondag-Thull, BEL S124678200100146X/MIS
DHINGRA N., EMMANUEL J.C., VERCAUTEREN G., NOEL L.
BLOOD TRANSFUSION SAFETY TEAM, BLOOD SAFETY AND CLINICAL TECHNOLOGY, WORLD HEALTH ORGANIZATION, GENEVA, SWITZERLAND [email protected] Objective : Quality management in all areas of blood transfusion is crucial for provision of safe blood. WHO has developed an innovative global project « Quality Management Project (QMP) for Blood Transfusion Services » in order to assist and support countries in the development of quality management systems for blood transfusion services. Methods : QMP has been developed as a long term project in collaboration with WHO Regions, Collaborating Centres and Experts in Transfusion Medicine. The 4 major components of QMP are : identification and strengthening of regional quality training centres, organization of Quality Management Training (QMT) courses with specially developed training materials, establishment of external quality assessment schemes (EQAS) and creation of effective quality networks. The 1st QMT course was held for the WHO African Region in 2000. Activities in this project will be carried out in most of the WHO regions in 2001. Results : Consultations for planning and evaluation of QMP were held in 2000. Global endorsement and support was obtained from WHO Regions as well as from the Experts. Implementation of QMP will include training of blood transfusion staff as quality managers working in networks and responsible for quality management systems at national level. Regional quality training centres each with dedicated QMT coordinators have been identified as focal points for this network. 2 Conclusion : Development and implementation of quality management system in blood transfusion services through this collaborative project will lead to improvement in safety, adequacy and quality of blood for all the patients requiring blood transfusion. This would help in achieving the ultimate goal of global blood safety.
STATISTICAL QUALITY CONTROL METHODS FOR THE MONITORING AND THE IMPROVEMENT OF THE VIRAL NAT (NUCLEIC ACID TESTING) PROCESS PERFORMANCES
REIFENBERG J.M.*, COSTE J*, CORNILLOT C.**, ASSAL A.***, MOREL P.****, BARLET V.***** * MONTPELLIER (FRANCE) ** EFS DIRECTION MÉDICALE ET SCIENTIFIQUE, PARIS (FRANCE) *** EFS CENTRE ATLANTIQUE, TOURS (FRANCE) **** EFS BOURGOGNE FRANCHE-COMTÉ, DIJON (FRANCE) ***** EFS RHÔNEALPES, GRENOBLE (FRANCE) [email protected] In the frame of the introduction of viral NAT in the screening of blood donations, quality control procedures are a part of the program. Indeed, in all processes it is necessary to monitor the extent to which the product or laboratory analysis results meet specifications. In general, two troublemakers may interfere in quality processes : (1) deviation from target specifications, and (2) extended variability around target specifications. Control Charting is one of the tools of Statistical Process Control (SPC) which allows to monitor an on-going production process. Among the different types of Control Charts, the more commonly used is the Shewhart Control Chart, which is designed to be applied on measurable variables. Such chart performs graphic representation of the process variability, allowing to distinguish the normal random causes of variability from the abnormal ones. This statistical method is an efficient preventive tool, which rapidly displays drifts in a process. When a trend emerges or when sample results fall outside the pre-specified limits, the process is notified to be out of control, and troubleshooting must be performed in order to identify the cause of the deviation. During the French Multicentric Feasibility Study of the introduction of viral NAT for HCV and HIV-1 in screening of blood donations, an experimental assay of x-bar and R Control Chart was conducted using the
12s
Communications
Relative Light Units (RLU) results, obtained with the Chiron-GenProbe Multiplex HIV-1/HCV TMA Assay, for the negative and HCV and HIV1 positive calibrator control specimens, and their related Internal Controls. In a first step, the assay was worked out with the results obtained by a single screening laboratory (EFS Pyrénées-Méditerranée, Montpellier) which performed TMA-screening on pool format Then, in a second phase, the study was extended to other sites such as EFS Rhône-Alpes, Grenoble, also working with pools and EFS Bourgogne Franche-Comté, Dijon which performed single testing. The results of this study demonstrated that SPC, combined with statistical methods for sampling inspection of reagents batches, can efficiently contribute to the monitoring of viral NAT technologies, which will become more and more automated in the coming years.
S04-004 QUALITY CONTROL OF BLOOD PRODUCTS REGULATORY ASPECTS IN FRANCE
PETERMANN R.*, DELESALLE N.*, GOUJON N.*, HUYGHE G.**, MOUILLOT L.*, TISSIER M.H
AFSSAPS - DLC, UNITÉ PRODUITS SANGUINS ET THÉRAPIE CELLULAIRE*, UNITÉ MICROBIOLOGIE**, SAINT-DENIS, FRANCE [email protected] In France, according to the law 98-535 of July 1st 1998 the « Agence Française de Sécurité Sanitaire des Produits de Santé » (AFSSaPS) organizes the control of blood products. The « Direction des Laboratoires et des Contrôles » has the responsability of the external quality control in order to supervise the quality of the blood components producted in blood banks in France [Red Blood Cells (RBC), platelet concentrates (PC) and fresh frozen plasma (FFP)]. This control includes not only a verification of transport conditions but also the check of labelling and biological assays (sterility, physical chemistry, virology and immuno-hematology). In 2000, seven operations of control have been conducted. The main problems corresponded principally to the PC and FFP transport conditions and the computerized mentions of labels. However, concerning the biological assays, different abnormalities were noted : the number of white cells (RBC), the pH, the level of VIII Factor (FFP), and a bacterial contamination by Propionebacterium acnes in a RBC. For 2001, the intensification of the control concern principally RBC and FFP, focusing on the count of white cells (RBC and FFP) and the level of VIII Factor (FFP) this being due to the introduction of procedures of removal potential presence of ATNC.
New and emerging viral infections relevant to blood transfusion Chair: Jean-Jacques Lefrere, FRA – Alfred Prince, USA S1246782001001471/MIS S05-001 SEROPREVALENCE OF ANTI-HUMAN HERPES VIRUS 8 IN POPULATIONS AT HIGH OR LOW RISK OF BLOOD, GRAFT OR SEXUAL TRANSMITTED VIRUSES : IS SYSTEMATIC VIRUS SCREENING NECESSARY ?
CHALLINE D., ROUDOT F., MERCIER B., BROSSARD Y., GIROT R., GIRARD D., MARIOTTI M., PAWLOTSKY JM., LEFRERE JJ. CHALLINE D, ROUDOT F, MERCIER B, BROSSARD Y, GIROT R, GIRARD D, MARIOTTI M, PAWLOTSKY JM, LEFRERE JJ. HOPITAL HENRI-MONDOR, CRETEIL ; EFS ; CHP, PARIS ; HOP. TENON, PARIS ; INTS, PARIS, FRANCE. [email protected]
Background : Sexual transmission of HHV-8 has been suggested, whereas its transmission by blood products and organ transplantation remains controversial. Molecular biology techniques and in-house serological tests were not suitable for large-scale screening and the results obtained with these non-standardized assays were difficult to compare because of various performances in terms of sensitivity, specificity and reproducibility. The objective of this study was to determine the prevalence of anti-HHV-8 antibodies in various populations according to their risk of blood-, graft- or sexual transmission of viral infections by mean of a standardized serological test in order to determine the routes of transmission of HHV-8. Methods : Anti-HHV-8 antibodies were sought in 1431 samples using a commercial immunofluorescent assay (IgG IFA kit, Biotrin, Irland), using KS-1 cell line for the detection of antibodies directed to structural and non-structural HHV-8 antigens. Findings : The prevalence of anti-HHV-8 antibodies was : 6/399 (1.5 %) in French blood donors from the Paris area, 12/160 (7.5 %) in blood donors from the French West Indies, 9/183 (4.9 %) in pregnant women, 8/100 (8 %) in organ donors, 2/82 (2.4 %) in intravenous drug users, 26/215 (12 %) in multiply- transfused patients, 15/99 (15.2 %) in kidney recipients, 5/17 (30 %) in HIV-negative patients with sexual exposure, 106/176 (60.2 %) in patients infected with HIV by sexual route. In multiplytransfused patients, no correlation was found between the number of transfused packed red cells and the presence of HHV-8 antibodies. In HIV-infected patients, anti-HHV-8 antibodies were significantly more frequent in homosexuals than in heterosexuals (70 % versus 24 %, p < 0.0001). Conclusions : Our results are in keeping with HHV-8 being mainly transmitted by sexual route and do not suggest HHV-8 transmission in patients receiving white blood cell-reduced blood products. Thus, systematic screening of HHV-8-positive blood donors does not seem justified. However, the HHV-8 seroprevalence in organ donors and recipients raises the question of a systematic screening in this population.
S05-002 HIGH PREVALENCE OF TT VIRUS (TTV) INFECTION IN THREE DIFFERENT GROUPS FROM BRAZIL
BASSIT L., TAKEI K., HOSHINO-SHIMIZU S., NISHIYA A.S., BASSITT R.P., D AMICO E., FOCACCIA R., CHAMONE D.F., RIBEIRO-DOSSANTOS G PRÓ-SANGUE HEMOCENTRO DE SÃO PAULO BLOOD BANK ; SCHOOL OF PHARMACEUTICAL SCIENCES, UNIVERSITY OF SÃO PAULO/USP, INSTITUTE OF INFECTOLOGY « EMÍLIO RIBAS », SÃO PAULO, BRAZIL. [email protected] The prevalence of TT virus (TTV) infection was investigated in low- and high-risk groups from São Paulo, Brazil, by PCR-based amplification of the untranslated region (UTR) ; no data on this subject are so far available. The study included (i.) children without history of blood transfusion or of liver disease, (ii.) blood donors, and (iii.) hemophiliacs. The prevalence (see table) found for these groups was very high (> 81 %). The distribution of TTV infection according to the age groups showed no significant difference, except for the group of children, which displayed an interesting profile. The prevalence was remarkably high, 95 %, in children aging 2 to 4 years, decreasing continuously thereafter and reaching a lower prevalence of 62 % (P < 0.05) in young people aging 15 to 17 years, suggesting the influence of immunological factors among others. Prevalence of TTV Infection by PCR (UTR) in Three Different Groups from Brazilian (São Paulo) Population Group Age (Years) Total no. TTV-positive Children Blood donors Hemophiliacs
2-17 16-61 0.6-81
138 191 130
112 (81 %) 168 (85 %) 127 (98 %)
The findings show that the TTV infection based on the PCR-UTR is widespread among Brazilians. Also, the parenteral route of transmission does not seem to play a major role for this infection. Moreover, the high
11s
S04-002 WBC-REDUCTION AND COUNTING LOW LEVEL OF WBC : UNRESOLVED PROBLEMS AND NEED FOR STANDARDISATION / HARMONISATION SEGHATCHIAN J., KRAILADSIRI P.
S04-001
NATIONAL BLOOD SERVICE, LONDON, UK [email protected] The key unresolved questions in universal WBC-reduction are how counting with different technologies influences WBC-reduction statistical monitoring, the performance of various filters or other WBC-reduction processes over time. Earlier investigation in our laboratories revealed that the cause of WBC-reduction failure is multifactoral and can be donor, operational, filter or WBC-reduction process design, frequency of donation and counting technology dependent. Regarding WBC counting, the unresolved issues are : (i) variability in gating strategy used by flow cytometry ; (ii) aggressive nature of some reagent leading to rapid shredding of WBC and presence of some aggregates/debris in some samples ; (iii) effects of the presence of apoptotic cells and some bacteria colonies. These can affect WBC results to variable degrees, depending on the types of blood products, filters and counting technologies. We have employed several methods to solve these issues. Both the analyses of apoptotic cells and WBC subsets by monoclonal antibodies are found to be useful in identifying the cause of discrepancy between counting methods. Adjusting the gate on flow cytometry often help in making the results interchangeable. Re-filtering the failed WBC-reduced products and recovering WBC from the used filter by back-flushing with AB plasma was also found to be a useful approach for apportioning the cause of WBC-reduction failure as well as the discrepancy in WBC results. When channelling or cracked filters are seen, large numbers of platelet as well as all sub-population of WBC are detected. Furthermore, Often debris are enriched by the refiltering process and sometimes identifiable by ICAM-3. Harmonisation and standardisation of WBC counting is pre-requisite in order to understand and identify the cause as well as to provide a cure.
QUALITY MANAGEMENT PROJECT FOR BLOOD TRANSFUSION
S04-003
Quality improvement and risk management Chair: Marcel Joussemet, FRA – Danièle Sondag-Thull, BEL S124678200100146X/MIS
DHINGRA N., EMMANUEL J.C., VERCAUTEREN G., NOEL L.
BLOOD TRANSFUSION SAFETY TEAM, BLOOD SAFETY AND CLINICAL TECHNOLOGY, WORLD HEALTH ORGANIZATION, GENEVA, SWITZERLAND [email protected] Objective : Quality management in all areas of blood transfusion is crucial for provision of safe blood. WHO has developed an innovative global project « Quality Management Project (QMP) for Blood Transfusion Services » in order to assist and support countries in the development of quality management systems for blood transfusion services. Methods : QMP has been developed as a long term project in collaboration with WHO Regions, Collaborating Centres and Experts in Transfusion Medicine. The 4 major components of QMP are : identification and strengthening of regional quality training centres, organization of Quality Management Training (QMT) courses with specially developed training materials, establishment of external quality assessment schemes (EQAS) and creation of effective quality networks. The 1st QMT course was held for the WHO African Region in 2000. Activities in this project will be carried out in most of the WHO regions in 2001. Results : Consultations for planning and evaluation of QMP were held in 2000. Global endorsement and support was obtained from WHO Regions as well as from the Experts. Implementation of QMP will include training of blood transfusion staff as quality managers working in networks and responsible for quality management systems at national level. Regional quality training centres each with dedicated QMT coordinators have been identified as focal points for this network. 2 Conclusion : Development and implementation of quality management system in blood transfusion services through this collaborative project will lead to improvement in safety, adequacy and quality of blood for all the patients requiring blood transfusion. This would help in achieving the ultimate goal of global blood safety.
STATISTICAL QUALITY CONTROL METHODS FOR THE MONITORING AND THE IMPROVEMENT OF THE VIRAL NAT (NUCLEIC ACID TESTING) PROCESS PERFORMANCES
REIFENBERG J.M.*, COSTE J*, CORNILLOT C.**, ASSAL A.***, MOREL P.****, BARLET V.***** * MONTPELLIER (FRANCE) ** EFS DIRECTION MÉDICALE ET SCIENTIFIQUE, PARIS (FRANCE) *** EFS CENTRE ATLANTIQUE, TOURS (FRANCE) **** EFS BOURGOGNE FRANCHE-COMTÉ, DIJON (FRANCE) ***** EFS RHÔNEALPES, GRENOBLE (FRANCE) [email protected] In the frame of the introduction of viral NAT in the screening of blood donations, quality control procedures are a part of the program. Indeed, in all processes it is necessary to monitor the extent to which the product or laboratory analysis results meet specifications. In general, two troublemakers may interfere in quality processes : (1) deviation from target specifications, and (2) extended variability around target specifications. Control Charting is one of the tools of Statistical Process Control (SPC) which allows to monitor an on-going production process. Among the different types of Control Charts, the more commonly used is the Shewhart Control Chart, which is designed to be applied on measurable variables. Such chart performs graphic representation of the process variability, allowing to distinguish the normal random causes of variability from the abnormal ones. This statistical method is an efficient preventive tool, which rapidly displays drifts in a process. When a trend emerges or when sample results fall outside the pre-specified limits, the process is notified to be out of control, and troubleshooting must be performed in order to identify the cause of the deviation. During the French Multicentric Feasibility Study of the introduction of viral NAT for HCV and HIV-1 in screening of blood donations, an experimental assay of x-bar and R Control Chart was conducted using the
12s
Communications
Relative Light Units (RLU) results, obtained with the Chiron-GenProbe Multiplex HIV-1/HCV TMA Assay, for the negative and HCV and HIV1 positive calibrator control specimens, and their related Internal Controls. In a first step, the assay was worked out with the results obtained by a single screening laboratory (EFS Pyrénées-Méditerranée, Montpellier) which performed TMA-screening on pool format Then, in a second phase, the study was extended to other sites such as EFS Rhône-Alpes, Grenoble, also working with pools and EFS Bourgogne Franche-Comté, Dijon which performed single testing. The results of this study demonstrated that SPC, combined with statistical methods for sampling inspection of reagents batches, can efficiently contribute to the monitoring of viral NAT technologies, which will become more and more automated in the coming years.
S04-004 QUALITY CONTROL OF BLOOD PRODUCTS REGULATORY ASPECTS IN FRANCE
PETERMANN R.*, DELESALLE N.*, GOUJON N.*, HUYGHE G.**, MOUILLOT L.*, TISSIER M.H
AFSSAPS - DLC, UNITÉ PRODUITS SANGUINS ET THÉRAPIE CELLULAIRE*, UNITÉ MICROBIOLOGIE**, SAINT-DENIS, FRANCE [email protected] In France, according to the law 98-535 of July 1st 1998 the « Agence Française de Sécurité Sanitaire des Produits de Santé » (AFSSaPS) organizes the control of blood products. The « Direction des Laboratoires et des Contrôles » has the responsability of the external quality control in order to supervise the quality of the blood components producted in blood banks in France [Red Blood Cells (RBC), platelet concentrates (PC) and fresh frozen plasma (FFP)]. This control includes not only a verification of transport conditions but also the check of labelling and biological assays (sterility, physical chemistry, virology and immuno-hematology). In 2000, seven operations of control have been conducted. The main problems corresponded principally to the PC and FFP transport conditions and the computerized mentions of labels. However, concerning the biological assays, different abnormalities were noted : the number of white cells (RBC), the pH, the level of VIII Factor (FFP), and a bacterial contamination by Propionebacterium acnes in a RBC. For 2001, the intensification of the control concern principally RBC and FFP, focusing on the count of white cells (RBC and FFP) and the level of VIII Factor (FFP) this being due to the introduction of procedures of removal potential presence of ATNC.
New and emerging viral infections relevant to blood transfusion Chair: Jean-Jacques Lefrere, FRA – Alfred Prince, USA S1246782001001471/MIS S05-001 SEROPREVALENCE OF ANTI-HUMAN HERPES VIRUS 8 IN POPULATIONS AT HIGH OR LOW RISK OF BLOOD, GRAFT OR SEXUAL TRANSMITTED VIRUSES : IS SYSTEMATIC VIRUS SCREENING NECESSARY ?
CHALLINE D., ROUDOT F., MERCIER B., BROSSARD Y., GIROT R., GIRARD D., MARIOTTI M., PAWLOTSKY JM., LEFRERE JJ. CHALLINE D, ROUDOT F, MERCIER B, BROSSARD Y, GIROT R, GIRARD D, MARIOTTI M, PAWLOTSKY JM, LEFRERE JJ. HOPITAL HENRI-MONDOR, CRETEIL ; EFS ; CHP, PARIS ; HOP. TENON, PARIS ; INTS, PARIS, FRANCE. [email protected]
Background : Sexual transmission of HHV-8 has been suggested, whereas its transmission by blood products and organ transplantation remains controversial. Molecular biology techniques and in-house serological tests were not suitable for large-scale screening and the results obtained with these non-standardized assays were difficult to compare because of various performances in terms of sensitivity, specificity and reproducibility. The objective of this study was to determine the prevalence of anti-HHV-8 antibodies in various populations according to their risk of blood-, graft- or sexual transmission of viral infections by mean of a standardized serological test in order to determine the routes of transmission of HHV-8. Methods : Anti-HHV-8 antibodies were sought in 1431 samples using a commercial immunofluorescent assay (IgG IFA kit, Biotrin, Irland), using KS-1 cell line for the detection of antibodies directed to structural and non-structural HHV-8 antigens. Findings : The prevalence of anti-HHV-8 antibodies was : 6/399 (1.5 %) in French blood donors from the Paris area, 12/160 (7.5 %) in blood donors from the French West Indies, 9/183 (4.9 %) in pregnant women, 8/100 (8 %) in organ donors, 2/82 (2.4 %) in intravenous drug users, 26/215 (12 %) in multiply- transfused patients, 15/99 (15.2 %) in kidney recipients, 5/17 (30 %) in HIV-negative patients with sexual exposure, 106/176 (60.2 %) in patients infected with HIV by sexual route. In multiplytransfused patients, no correlation was found between the number of transfused packed red cells and the presence of HHV-8 antibodies. In HIV-infected patients, anti-HHV-8 antibodies were significantly more frequent in homosexuals than in heterosexuals (70 % versus 24 %, p < 0.0001). Conclusions : Our results are in keeping with HHV-8 being mainly transmitted by sexual route and do not suggest HHV-8 transmission in patients receiving white blood cell-reduced blood products. Thus, systematic screening of HHV-8-positive blood donors does not seem justified. However, the HHV-8 seroprevalence in organ donors and recipients raises the question of a systematic screening in this population.
S05-002 HIGH PREVALENCE OF TT VIRUS (TTV) INFECTION IN THREE DIFFERENT GROUPS FROM BRAZIL
BASSIT L., TAKEI K., HOSHINO-SHIMIZU S., NISHIYA A.S., BASSITT R.P., D AMICO E., FOCACCIA R., CHAMONE D.F., RIBEIRO-DOSSANTOS G PRÓ-SANGUE HEMOCENTRO DE SÃO PAULO BLOOD BANK ; SCHOOL OF PHARMACEUTICAL SCIENCES, UNIVERSITY OF SÃO PAULO/USP, INSTITUTE OF INFECTOLOGY « EMÍLIO RIBAS », SÃO PAULO, BRAZIL. [email protected] The prevalence of TT virus (TTV) infection was investigated in low- and high-risk groups from São Paulo, Brazil, by PCR-based amplification of the untranslated region (UTR) ; no data on this subject are so far available. The study included (i.) children without history of blood transfusion or of liver disease, (ii.) blood donors, and (iii.) hemophiliacs. The prevalence (see table) found for these groups was very high (> 81 %). The distribution of TTV infection according to the age groups showed no significant difference, except for the group of children, which displayed an interesting profile. The prevalence was remarkably high, 95 %, in children aging 2 to 4 years, decreasing continuously thereafter and reaching a lower prevalence of 62 % (P < 0.05) in young people aging 15 to 17 years, suggesting the influence of immunological factors among others. Prevalence of TTV Infection by PCR (UTR) in Three Different Groups from Brazilian (São Paulo) Population Group Age (Years) Total no. TTV-positive Children Blood donors Hemophiliacs
2-17 16-61 0.6-81
138 191 130
112 (81 %) 168 (85 %) 127 (98 %)
The findings show that the TTV infection based on the PCR-UTR is widespread among Brazilians. Also, the parenteral route of transmission does not seem to play a major role for this infection. Moreover, the high