Evaluation of HTLV-1 activity in HAM/TSP patients using proviral load and Tax mRNA expression after In Vitro lymphocyte activation

Abstract

<em>Objective(s)</em>:HTLV-1 is the first human retrovirus that has been recognized and is associated with HAM/TSP and ATLL. Studies have shown that less than five percent of HTLV-1 infected carriers develop HAM/TSP or ATLL and about ninety-five percent remain asymptomatic. Therefore, the proviral load with Tax may affect cellular genes such as cytokines and oncogenes, as well as involve in pathogenicity. <em>Materials and Methods</em>:Thirty HAM/TSP patients, thirty HTLV-1 healthy carriers, and MT-2 cell line were evaluated for HTLV-1 activity. PBMCs were isolated and activated using PMA and ionomycine. Real-time PCR and TaqMan methods were performed using specific primers and fluorescence probes for Tax expression and proviral load assessment. Β2microglobulin (β₂m) and albumin were used as controls in Tax expression and in proviral load, respectively. <em>Results</em>: An insignificant increase in Tax expression was observed in rest PBMCs of HAM/TSP patients compared to healthy carriers. However, after lymphocyte activation there was a significant increase in Tax expression in HAM/TSP patients (<em>P</em>=0.042). The Proviral load in patients was significantly higher than in carriers. Moreover, there was a significant correlation between Tax mRNA expression in activated PBMCs and proviral load (R=0.37, <em>P</em>=0.012). <em>Conclusion</em>: Although proviral load had been addressed as a valuable index for monitoring HTLV-1 infected subjects, the results of this study demonstrated that Tax expression in activated PBMCs along with proviral load assessment in HAM/TSP patients are a more reliable factor for determining the prognosis and monitoring healthy carriers and HAM/TSP patients.