The Role of Human T-Cell Lymphotropic Virus Type 1 (HTLV-1) Infections in Haematological Malignancies

Abstract

Background: The Human T-Cell Lymphotropic Virus (HTLV) was first recognized in the 1980s by Poiesz et al and was the first retrovirus identified in human. HTLVs are human retroviruses identified as the causative agents of Adult T-Cell Leukemia/Lymphoma (ATLL), a lymphoproliferative malignancy of CD4+ activated cells and HTLV-1 associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP), a demyelinating disease. There is a significant association of HTLV 1 with lymphoid malignancies. Worldwide, about 10 to 20 million persons are estimated to be living with HTLV-1 infection; a greater part of these infections are not symptomatic. Approximately, 5% of these infections progress to cause diseases, which are exceptionally severe (Confidence et al., 2018; Gessain & Cassar, 2012; Gross & Thoma-kress, 2016; Verdonck et al., 2007). The main transmission routes of the virus are by mother to child (mainly through breastfeeding), sexual intercourse, sharing of infected needles among drug users and by blood transfusion. In Ghana, reported seroprevalence of HTLV-1 is between 0.5-4.2% among different study groups mainly among blood donors and pregnant women (Ampofo et al., 2002; Armah et al., 2006; Sarkodie et al., 2001) but none of the studies included malignant haematological disorders. Current evidence with regards to the role of HTLV-1 in hematological malignancies in Ghana is scarce. Aim: To determine the role of Human T-cell Lymphotropic Virus type 1 (HTLV-1) infections in haematological malignancies among patients diagnosed at the Department of Haematology, Korle-Bu Teaching Hospital. Methods: This was a cross-sectional study involving 200 study participants randomly selected. Data abstraction forms were used to obtain demographic data and clinical history from the study participants. A blood sample of 5mls was collected from the antecubital fossa into a sterile, plain tube. The sera was then be separated into sterile cryovials and stored in aliquots at -70°C prior to analysis. Sera from study participants were tested using commercial immunoassays for Anti-HTLV-1 specific for HTLV-1 by ELISA method using anti HTLV (MP Diagnostics HTLV ELISA 4.0). The testing was done in duplicates. Analysis of the data was done using Excel and SPSS software version 23.0. Results: A total of 200 respondents were tested with median age of 49.50 years. There were more females (54.5%) than males. Out of the 200 samples, 14 of them were seropositive for HTLV-1 infection comprising 3 males and 11 females resulting in an overall seroprevalence of 7.0%. This research found no statistically significant association between haematological malignancies, gender and transfusion history and HTLV-1 infection in the study population (P-value = 0.081, 0.061 and 0.551 respectively). This study also did not show significant association between Hb (P-value = 0.941), TWBC (P-value = 0.924), PLT (P-value = 0.281) and LYM (P-value = 0.496) and HTLV-1 infection. Conclusion: The findings of this current study show the seroprevalence of HTLV-1 of 7.0% among patients with haematological malignancies. The HTLV-1 seroprevalence obtained in this study is high. Consequently, it is possible to consider HTLV-1 screening during clinical and laboratory workup of patients with haematological malignancies in Ghana. However, there was no significant association between HTLV-1 infection and haematological malignancies, previous history of blood transfusion as well as some haematologic parameters (Hb, lymphocyte count, total WBC and platelet count) studied.