Neither molecular diversity of the envelope, immunosuppression status, nor proviral load causes indeterminate HTLV western blot profiles in samples from human T‐cell lymphotropic virus type 2 (HTLV‐2)‐infected individuals

Abstract

Although human T-cell lymphotropic virus type 2 (HTLV-2) is considered of low pathogenicity, serological diagnosis is important for counseling and monitoring. The confirmatory tests most used are Western blot (WB) and PCR. However, in high-risk populations, about 50% of the indeterminate WB were HTLV-2 positives by PCR. The insensitivity of the WB might be due to the use of recombinant proteins of strains that do not circulate in our country. Another possibility may be a high level of immunosuppression, which could lead to low production of virus, resulting in low stimulation of antibody. We found one mutation, proline to serine in the envelope region in the position 184, presented at least 1/3 of the samples, independent the indeterminate WB profile. In conclusion, we found no correlation of immune state, HTLV-2 proviral load, or env diversity in the K55 region and WB indeterminate results. We believe that the only WB kit available in the market is probably more accurate to detect HTLV-1 antibodies, and some improvement for HTLV-2 detection should be done in the future, especially among high-risk population.

Human T Cell Lymphotropic Virus Type 2a Strains Among HIV Type 1-Coinfected Patients from Brazil Have Originated Mostly from Brazilian Amerindians

“…19 Still, the amino acid change S1909P in 100% of the env sequences was also previously reported in Brazilian strains, and could represent a molecular signature of HTLV-2a (variant 2c) strains from Brazil. 21,29 In relation to the tax sequences, the present results corroborated the previous reports that characterize the Brazilian HTLV-2c variant (often considered a molecular variant of -2a), highlighting the long Tax protein. 7,13,15 In addition, high similarity in tax was observed among isolates from the present study (99.9%) and also in relation to the Mo prototype (99.3%).…”

A New and Frequent Human T-Cell Leukemia Virus Indeterminate Western Blot Pattern: Epidemiological Determinants and PCR Results in Central African Inhabitants

“…The significance of these frequent indeterminate WB can be various but, in the majority of the cases, remains mostly unknown and a matter of discussion (24,28,57,69). Indeed, in rare cases, these patterns have been associated with (i) HTLV-1 but mostly HTLV-2 infection exhibiting an atypical HTLV serology (6,34,44,52,68,73,74), (ii) HTLV-1 seroconversion (17,45,46), and (iii) infection by a different HTLV, such as HTLV-3 or HTLV-4 (12,13,42,62,72). Furthermore, some have been considered the results of cross-reactivity against other microbial agents, especially Plasmodium falciparum in Central Africa and Indonesia (31,41,54).…”

Evaluation of two indigenous rapid and two ELISA assays for the diagnosis of HIV infection India

“…In our evaluation we did not see positive result in Enzaids Duet assay for some of these specimens for which we observed p24 band in western blot test. This could be due to false indeterminate in western blot, [15][16][17] further tests are required to resolve the conflicting serology of these specimens.…”