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ScienceDirect www.sciencedirect.com Transfusion Clinique et Biologique 21 (2014) 139–142
Letter to the editor Prevalence of HTLV-I virus in blood donors and transfusion in Mali: Implications for blood safety Prévalence du virus HTLV-I chez les donneurs de sang et les transfusés au Mali : conséquences pour la sécurité transfusionnelle
Keywords: HTLV-1; Multi-transfused patients; Blood donors Mots clés : HTLV-1 ; Patients polytransfusés ; Donneurs de sang
1. Introduction Human T-lymphotropic virus type 1 (HTLV-1) is the first oncogenic retrovirus discovered in humans in 1980 by American from a culture of CD4+ T cells. These cells were from the peripheral blood of a patient with hematologic malignancy initially considered as cutaneous T cell lymphoma with a leukemic [1,3] phase. It is the etiologic agent of two severe diseases: adult T cell leukemia/lymphoma (ATL) and HTLV-1 associated myelopathy also known as tropical spastic paraparesis (HAM/TSP). HTLV1 is also transmitted through sexual contact, by transfusion of contaminated blood products and by injection drug use. HTLV-1 endemic areas include the Caribbean region, Japan, the southern United States, Northern Latin America, sub-Saharan Africa and Seychelles [4,5]. Sub-Saharan Africa is considered one of the greatest centers of HTLV-1 infection, with about two to four million people infected [6]. In France, HTLV-1 screening of blood donors has been in place since July 15, 1991 [7,8]. This is not the case in Africa where we observe the biggest focus of HTLV-1. In Mali, few studies have been conducted on HTLV-1 related to blood safety, especially in the population of blood donors and among multiple transfusions. Three ATL cases have been previously characterized among Malian patients [9,10]. Despite these data indicating the presence of HTLV-1 in Mali, HTLV-1 antibody screening is not routinely done at the National Blood Transfusion Centre (CNTS) of Bamako. We undertook this study on the seroprevalence of HTLV-1 infection in blood donors and in multi-transfused patients to assess the risk of transmission by blood products and to improve blood safety in Mali. 2. Methods 2.1. Study sites The study was done at the National Blood Transfusion Centre (CNTS), the Departments of Hematology-Oncology and http://dx.doi.org/10.1016/j.tracli.2014.05.002 1246-7820/© 2014 Elsevier Masson SAS. All rights reserved.
Nephrology at University Teaching Hospital of Point G (CHU Point G) and at the Sickle Cell Disease Research and Control Centre (CRLD). The CNTS is the reference center for the collection, processing and distribution of blood products in Mali. In 2010, 36,873 units of blood bags were collected and 28,946 blood components distributed. CHU Point G is one of the two biggest hospitals in Mali both in terms of bed capacity and the number of specialized services, and it is the national reference structure for the management of hematologic and kidney diseases in Mali. The CRLD is a regional reference research center for sickle cell disease and is located near CHU Point G. 2.2. Study period and populations We conducted two cross-sectional studies from January to December 2011. The first study enrolled blood donors at the CNTS. We applied blood donors selection criteria in Mali as described by Diarra et al. [11]. We excluded from blood donation persons with chronic illnesses, women currently breast-feeding or menstruating, vaccination within the three weeks before donation and persons at risk of sexually transmitted diseases. The second study included multi-transfused patients (those with at least two transfusion episodes documented in their medical records) recruited from the nephrology and hematologyoncology departments at the CHU Point G and at the CRLD. 2.3. Laboratory procedures Anti-HTLV-1 antibodies were determined by Elisa using the Murex HTLV-1 +2 (Abbott, France) kit. This test has a sensitivity and specificity of 97.2 and 99.7% respectively compared to PCR [12] in patients from Argentina. Three milliliters of blood were collected in tubes without additives from the blood bag tubing for blood donors and by venipuncture in patients. 2.4. Statistical tests Data were entered and analyzed using SPSS software version 19.1. Chi2 and Fisher’s exact tests were used to compare proportions using a level of significance of P ≤ 0.05.
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Letter to the editor / Transfusion Clinique et Biologique 21 (2014) 139–142
Table 1 Characteristics of blood donors enrolled in the study. Variable Age groups (n = 799) 18–25 ans 26–35 ans 36–45 ans 46–60 ans Gender (n = 799) Female Male Type of donors (n = 799) Volunteers Family/replacement
3.2. HTLV-1 prevalence in multi-transfused patients
n
%
402 212 121 63
50 27 15 8
105 694
13 87
290 509
36 64
The majority of the 156 multi-transfused patients in our study were aged under 35 years (56.4%) and female (59%). Most of patients had received at least three predominantly blood transfusions. Seroprevalence was 4.7 and 7.6% respectively for male and female patients (Table 2; P = 0.5). HTLV-1 seroprevalence was 2.8% among patients who received two transfusions and 7.5% in those who received at least three transfusions (P = 0.31). A single case of co-infection with HVB was found among the 10 HTLV-1 positive patients compared to three HIV, 13 HVB and six HCV positives among the HTLV-1 negative patients.
4. Discussion 3. Results 4.1. HTLV-1 seroprevalence in blood donors. 3.1. HTLV-1 seroprevalence in blood donors The 799 blood donors were mostly aged 18 to 35 years and male (sex ratio = 6.6; Table 1). Blood group O was the most frequent followed by group B and groups A and AB. Family replacement donors were more common than voluntary donors. Over 95% of donors were Rhesus (Rh) positive. A total of 11 (1.4%) blood donors were seropositive for HTLV-1; 0.9% and 4.8% among men and women respectively (Table 2; P < 0.01). Seroprevalence was 2.4% in voluntary donors and 0.8% in family replacement donors (P > 0.05). The seroprevalence of HTLV-1 was higher among donors with blood group AB (5.7%) compared with blood groups A (1.7%), B (0.47%) and O (0.87%) (P = 0.019). All HTLV-1 positive donors were Rh positive. Most HTLV-1 positive blood donors did not have other infection markers. Among HTLV-1 positives, there was one donor who was also HbsAg positive.
We found moderate HTLV-1 seroprevalence among blood donors in Mali, with patterns consistent with previous studies. HTLV-1 seroprevalence was elevated among multi-transfused patients, especially those receiving more transfusions, suggesting HTLV-1 transmission by blood transfusion however the difference observed did not reach statistical significance. The overall seroprevalence of HTLV-1 infection in blood donors was 1.4%. This prevalence is higher than that reported in Senegal by Diop et al. in 2002 who observed 0.16% HTLV-1 positive blood donors [2]. A lowest seroprevalence of 0.7% was also observed in blood donors in Ghana [1]. This variation could be related to differences in HTLV-1 testing methods used in these studies, populations or region. However, it has been reported that Sub-Saharan Africa is an area of high endemicity and the seroprevalence may be underestimated by studies of blood donors [6,13,14].
Table 2 HTLV-1 seroprevalence in blood donors and transfused patients by sex, number of blood transfusions and other viral markers, Bamako, Mali. Blood donors
All subjects Age, years 18–25 26–35 36–45 46–60 Sex Male Female Number of transfusions
ScienceDirect www.sciencedirect.com Transfusion Clinique et Biologique 21 (2014) 139–142
Letter to the editor Prevalence of HTLV-I virus in blood donors and transfusion in Mali: Implications for blood safety Prévalence du virus HTLV-I chez les donneurs de sang et les transfusés au Mali : conséquences pour la sécurité transfusionnelle
Keywords: HTLV-1; Multi-transfused patients; Blood donors Mots clés : HTLV-1 ; Patients polytransfusés ; Donneurs de sang
1. Introduction Human T-lymphotropic virus type 1 (HTLV-1) is the first oncogenic retrovirus discovered in humans in 1980 by American from a culture of CD4+ T cells. These cells were from the peripheral blood of a patient with hematologic malignancy initially considered as cutaneous T cell lymphoma with a leukemic [1,3] phase. It is the etiologic agent of two severe diseases: adult T cell leukemia/lymphoma (ATL) and HTLV-1 associated myelopathy also known as tropical spastic paraparesis (HAM/TSP). HTLV1 is also transmitted through sexual contact, by transfusion of contaminated blood products and by injection drug use. HTLV-1 endemic areas include the Caribbean region, Japan, the southern United States, Northern Latin America, sub-Saharan Africa and Seychelles [4,5]. Sub-Saharan Africa is considered one of the greatest centers of HTLV-1 infection, with about two to four million people infected [6]. In France, HTLV-1 screening of blood donors has been in place since July 15, 1991 [7,8]. This is not the case in Africa where we observe the biggest focus of HTLV-1. In Mali, few studies have been conducted on HTLV-1 related to blood safety, especially in the population of blood donors and among multiple transfusions. Three ATL cases have been previously characterized among Malian patients [9,10]. Despite these data indicating the presence of HTLV-1 in Mali, HTLV-1 antibody screening is not routinely done at the National Blood Transfusion Centre (CNTS) of Bamako. We undertook this study on the seroprevalence of HTLV-1 infection in blood donors and in multi-transfused patients to assess the risk of transmission by blood products and to improve blood safety in Mali. 2. Methods 2.1. Study sites The study was done at the National Blood Transfusion Centre (CNTS), the Departments of Hematology-Oncology and http://dx.doi.org/10.1016/j.tracli.2014.05.002 1246-7820/© 2014 Elsevier Masson SAS. All rights reserved.
Nephrology at University Teaching Hospital of Point G (CHU Point G) and at the Sickle Cell Disease Research and Control Centre (CRLD). The CNTS is the reference center for the collection, processing and distribution of blood products in Mali. In 2010, 36,873 units of blood bags were collected and 28,946 blood components distributed. CHU Point G is one of the two biggest hospitals in Mali both in terms of bed capacity and the number of specialized services, and it is the national reference structure for the management of hematologic and kidney diseases in Mali. The CRLD is a regional reference research center for sickle cell disease and is located near CHU Point G. 2.2. Study period and populations We conducted two cross-sectional studies from January to December 2011. The first study enrolled blood donors at the CNTS. We applied blood donors selection criteria in Mali as described by Diarra et al. [11]. We excluded from blood donation persons with chronic illnesses, women currently breast-feeding or menstruating, vaccination within the three weeks before donation and persons at risk of sexually transmitted diseases. The second study included multi-transfused patients (those with at least two transfusion episodes documented in their medical records) recruited from the nephrology and hematologyoncology departments at the CHU Point G and at the CRLD. 2.3. Laboratory procedures Anti-HTLV-1 antibodies were determined by Elisa using the Murex HTLV-1 +2 (Abbott, France) kit. This test has a sensitivity and specificity of 97.2 and 99.7% respectively compared to PCR [12] in patients from Argentina. Three milliliters of blood were collected in tubes without additives from the blood bag tubing for blood donors and by venipuncture in patients. 2.4. Statistical tests Data were entered and analyzed using SPSS software version 19.1. Chi2 and Fisher’s exact tests were used to compare proportions using a level of significance of P ≤ 0.05.
140
Letter to the editor / Transfusion Clinique et Biologique 21 (2014) 139–142
Table 1 Characteristics of blood donors enrolled in the study. Variable Age groups (n = 799) 18–25 ans 26–35 ans 36–45 ans 46–60 ans Gender (n = 799) Female Male Type of donors (n = 799) Volunteers Family/replacement
3.2. HTLV-1 prevalence in multi-transfused patients
n
%
402 212 121 63
50 27 15 8
105 694
13 87
290 509
36 64
The majority of the 156 multi-transfused patients in our study were aged under 35 years (56.4%) and female (59%). Most of patients had received at least three predominantly blood transfusions. Seroprevalence was 4.7 and 7.6% respectively for male and female patients (Table 2; P = 0.5). HTLV-1 seroprevalence was 2.8% among patients who received two transfusions and 7.5% in those who received at least three transfusions (P = 0.31). A single case of co-infection with HVB was found among the 10 HTLV-1 positive patients compared to three HIV, 13 HVB and six HCV positives among the HTLV-1 negative patients.
4. Discussion 3. Results 4.1. HTLV-1 seroprevalence in blood donors. 3.1. HTLV-1 seroprevalence in blood donors The 799 blood donors were mostly aged 18 to 35 years and male (sex ratio = 6.6; Table 1). Blood group O was the most frequent followed by group B and groups A and AB. Family replacement donors were more common than voluntary donors. Over 95% of donors were Rhesus (Rh) positive. A total of 11 (1.4%) blood donors were seropositive for HTLV-1; 0.9% and 4.8% among men and women respectively (Table 2; P < 0.01). Seroprevalence was 2.4% in voluntary donors and 0.8% in family replacement donors (P > 0.05). The seroprevalence of HTLV-1 was higher among donors with blood group AB (5.7%) compared with blood groups A (1.7%), B (0.47%) and O (0.87%) (P = 0.019). All HTLV-1 positive donors were Rh positive. Most HTLV-1 positive blood donors did not have other infection markers. Among HTLV-1 positives, there was one donor who was also HbsAg positive.
We found moderate HTLV-1 seroprevalence among blood donors in Mali, with patterns consistent with previous studies. HTLV-1 seroprevalence was elevated among multi-transfused patients, especially those receiving more transfusions, suggesting HTLV-1 transmission by blood transfusion however the difference observed did not reach statistical significance. The overall seroprevalence of HTLV-1 infection in blood donors was 1.4%. This prevalence is higher than that reported in Senegal by Diop et al. in 2002 who observed 0.16% HTLV-1 positive blood donors [2]. A lowest seroprevalence of 0.7% was also observed in blood donors in Ghana [1]. This variation could be related to differences in HTLV-1 testing methods used in these studies, populations or region. However, it has been reported that Sub-Saharan Africa is an area of high endemicity and the seroprevalence may be underestimated by studies of blood donors [6,13,14].
Table 2 HTLV-1 seroprevalence in blood donors and transfused patients by sex, number of blood transfusions and other viral markers, Bamako, Mali. Blood donors
All subjects Age, years 18–25 26–35 36–45 46–60 Sex Male Female Number of transfusions
