As a high degree of homology exists between the proviral genomes of HTLV-I and HTLV-II, there is significant cross-reactivity. Therefore although detection of HTLV antibodies is characteristic of viral infection, it is not sufficient to confirm the presence of the viral type. Molecular tests used to diagnose the HTLV-I/II viruses are based on investigations of proviral genomic sequences, and allow for an infection to be diagnosed prior to the appearance of any sign or symptom. The HTLV proviral load in infected individuals can be determined using real-time PCR, a faster method with less risk of contamination than simple or nested PCR. We analyzed 63 samples from the Hemope Hospital, of which 33 were from HTLV seropositive individuals and 30 from blood donors, to determine the type of virus and the proviral load. The sensitivity of qualitative PCR in comparison to ELISA was 87.5% (95% IC: 70.1 - 95.9%) and the specificity was 100% (IC 95%: 85.9 - 100.0%). The sensitivity and specificity of real-time PCR in comparison to the serological test (ELISA) were 100% (95% IC: 86.7 - 100.0%) and 96.67% (95% IC: 80.9 - 99.8%) respectively. The proviral load in the seropositive individuals ranged from 13 to 343820 copies/106 PBMC cells. Our study also observed that individuals with TSP/HAM had a higher proviral load than those who showed no symptoms. The use of real time PCR for routine clinical testing of infected individuals will play a significant role in identifying the virus type and determining the proviral load, thereby providing more appropriate treatment.
Human T-cell lymphotropic virus; HTLV-I infections; molecular diagnosis; polymerase chain reaction
