Human T-Lymphotropic Virus Type I (HTLV-1) Infection among Iranian Blood Donors: First Case-Control Study on the Risk Factors

Abstract

Human T-cell lymphotropic virus type 1 (HTLV-1) infection is an endemic condition in Northeast Iran and, as such, identification of risk factors associated with the infection in this region seems to be a necessity. All the possible risk factors for HTLV-1 seropositivity among first-time blood donors were evaluated in Mashhad, Iran, during the period of 2011–2012. Blood donation volunteers were interviewed for demographic data, medical history, and behavioral characteristics and the frequencies of risk factors were compared between HTLV-1 positive (case) and HTLV-1 negative (control) donors. The data was analyzed using Chi square and t-tests. Logistic regression analysis was performed to identify independent risk factors for the infection. Assessments were carried out on 246 cases aged 17–60 and 776 controls aged 17–59, who were matched based on their ages, gender, and date and center of donation. Logistic analysis showed low income (OR = 1.53, p = 0.035), low educational level (OR = 1.64, p = 0.049), being born in the cities of either Mashhad (OR = 2.47, p = 0.001) or Neyshabour (OR = 4.30, p < 0001), and a history of blood transfusion (OR = 3.17, p = 0.007) or non-IV drug abuse (OR = 3.77, p < 0.0001) were significant predictors for infection with HTLV-1. Lack of variability or small sample size could be reasons of failure to detect some well-known risk factors for HTLV-1 infection, such as prolonged breastfeeding and sexual promiscuity. Pre-donation screening of possible risk factors for transfusion-transmissible infections should also be considered as an important issue, however, a revision of the screening criteria such as a history of transfusion for more than one year prior to donation is strongly recommended.

Prevalence and risk factors for Human T-Lymphotropic Virus Type 1 (HTLV-1) among maintenance hemodialysis patients

“…The association between HTLV-1 infection and blood transfusion is well established and has been confirmed in several studies using blood donors in different countries [ 39 – 41 ], including Brazil [ 38 ]. Blood transfusions among MHD patients were much more common before the advent of recombinant human erythropoietin (rhEPO) [ 42 , 43 ]; indeed, this might help explain the high prevalence of HTLV-1 in the MHD population of some Japanese studies published before the advent of rhEPO [ 25 , 26 ].…”

“…Our initial hypothesis was that the prevalence of HTLV-1 in the MHD population would be greater than that observed in the general population. This hypothesis was based on older literature data from other countries [ 27 – 29 , 35 ] and on the following postulates: a) ESRD could be a risk factor for HTLV-1, mediated by anemia and greater frequency of blood transfusion or due to the risk of acquiring the virus during the hemodialysis procedure, as it is known to happen with HBV and HCV [ 36 , 37 ]; b) HTLV-1 and end stage renal disease (ESRD) could share risk factors, such as poverty and health illiteracy [ 38 , 39 ]; c) HTLV-1 could be a risk factor for ESRD as the urological manifestations of the virus, such as neurogenic bladder, can lead to post-renal kidney failure [ 9 ]. Nevertheless, the overall prevalence of HTLV-1 seropositivity in our sample of 605 MHD patients was 2.48% (95% CI 1.22–3.74%), which is only marginally higher than that observed by Dourado et al in a population-based study in the city of Salvador (1.7; 95% CI 1.1–2.5%) [ 24 ].…”

Thioredoxin reductase gene expression and activity among human T‐cell lymphotropic virus type 1–infected patients

“…The study was performed in a university hospital in Mashhad, northeastern Iran, where HTLV-1 is endemic. 15,16 It has been previously reported that reduced total antioxidant capacity during HTLV-1 infection was correlated with the clinical status of the patients. 13 Oxidative stress is the main result of inconsistency between oxidants and antioxidants of different sources in a way that hampers cellular organization and functions.…”

“…To our knowledge, the present research is one of the first reports on TrxR activity in HTLV‐1 infection and HAM‐TSP patients. The study was performed in a university hospital in Mashhad, northeastern Iran, where HTLV‐1 is endemic . It has been previously reported that reduced total antioxidant capacity during HTLV‐1 infection was correlated with the clinical status of the patients .…”

Risk factors associated with HTLV-1 vertical transmission in Brazil: longer breastfeeding, higher maternal proviral load and previous HTLV-1-infected offspring

“…Human T-cell lymphotropic virus type 1 (HTLV-1), a virus infecting humans since ancient times, is the causative agent of a lymphoproliferative malignancy named Adult T-cell Leukemia/Lymphoma (ATLL), as well as of the HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP); HTLV-1 has also been associated with uveitis, infective dermatitis, and other inflammatory disorders 1 – 4 . This infection is endemic in many parts of the world, including southwestern Japan, South America, some of the Caribbean islands, western and central Africa, Australo-Melanesia and some areas of Middle-East, such as regions of Iran 5 . There are at least an estimated five to 10 million HTLV-1 carriers worldwide 3 , but screening of the population for the presence of the virus is performed for only one third of the endemic areas.…”