Recent reports have demonstrated that human T lymphotropic virus type 1 (HTLV-1) is associated with other neurological abnormalities in addition to HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). It has been well established that high HTLV-1 proviral loads are associated with the development of HAM/TSP. We now demonstrate, for the first time, to our knowledge, that HTLV-1 proviral loads in patients with other neurological abnormalities are also significantly higher than in asymptomatic HTLV-1 carriers.

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HIV-individuals are at risk for human T-lymphotropic virus (HTLV) coinfection and neurological diseases. Little is known about the impact of HAART among coinfected patients. In this study, 47 out of 428 HIV individuals were coinfected with HTLV (10.9%). Coinfection was an independent variable associated with neurological outcome (odds ratio 8.73). Coinfection was associated with myelopathy [chi square (X(2)) = 93, P < 0.001], peripheral neuropathy (X(2) = 6.5, P = 0.01), and hepatitis C virus infection (X(2) = 36.5, P < 0.001). HAART did not appear to protect against neurological diseases and had no impact on HTLV proviral load.

Although human T-lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is usually described as a chronic disabling disease, a rapid course over months or even weeks has been reported in some patients. The authors describe the clinical features of HAM/TSP in a Brazilian cohort and evaluate the prevalence of patients with a subacute progression of the disease. This was defined as the requirement of a wheelchair during the first 2 years after the onset of symptoms. Patients with this subacute course and patients with the chronic clinical course were compared in terms of their HTLV-I proviral loads (PLs) using real-time polymerase chain reaction (PCR). Seven out of 88 patients (7.9%) had a subacute progression. All patients were women and 5/7 acquired HTLV-I through sexual contact. There was no significant difference in the real-time PLs between the group with subacute evolution (mean 8.5 copies/100 cells, range 6.03 to 12.09) and those patients with a typical course of disease (mean 11.34 copies/100 cells, range 0.4 to 67.72) (P = .68), suggesting that factors other than the number of infected cells are implicated in the development of such an aggressive course of disease. Early recognition of this subgroup is important because immunosuppressive treatment might be beneficial if instituted promptly.

In Rio de Janeiro (RJ) most cases of paraparesis of obscure origin are associated with the human T‐cell lymphotropic virus type I (HTLV‐I). Thirty‐four consecutive patients with HTLV‐I‐associated myelopathy/tropical spastic paraparesis (HAM/TSP) from RJ were evaluated. Most patients came from low socio‐economic levels. There was no difference in terms of gender. The main affected racial group was white. A history of sexually transmitted diseases was a major risk factor for HAM/TSP and a positive serology for syphilis was found in 26.5% of the patients. The major clinical findings were of a spastic paraparesis with generalized brisk tendon jerks and bilateral Babinki's sign. Sensation was abnormal in 25 patients (73.5%) and five (14.7%) had a sensory level. Three patients (8.8%) had optic atrophy. The cerebrospinal fluid showed a lymphocytic pleocytosis with a mean total protein content of 0.4 g/litre, and an increased intrathecal IgG synthesis in 59.4% of patients. HAM/TSP and multiple sclerosis (MS) occur indigenously in RJ and some HAM/TSP cases can be sometimes confused with MS. Therefore we propose that, in places where MS coexist with HAM/TSP, HTLV‐I antibodies should be sought routinely in those MS suspected cases with prominent spastic paraparesis.

The prevalence of antibodies to HTLV-I and HIV-I in Brazil was determined by testing sera from: (a) 119 members of an isolated Amazonian community of African origin; (b) 100 voluntary blood donors in Rio de Janeiro; (c) 215 patients treated at the Hematology Service, National Cancer Institute, Rio de Janeiro, and (d) 44 Cebus apella New World monkeys, wild-caught in Amazonia. Anti-HTLV-I was detected in 1 (0.84%) of 119 Amazonians, in 8 (3.72%) of the 215 patients and in none of the blood donors or monkeys. The high prevalence found in patients included 4 (5.79%) of 69 with non-Hodgkin lymphoma, 2 (5.88%) of 34 with Hodgkin lymphoma, 1 (16.66%) of 6 patients with diagnosis of anemia and 1 (20%) of 5 with HIV-I infection. Anti-HIV-I was found in 7 (14.89%) of 47 patients and in none of the other groups. The high incidence of HTLV-I infection in the patient group suggests that this retrovirus is endemic in parts of Brazil.

Human T lymphotropic virus type 2 (HTLV-2) is characterized by a clinically asymptomatic persistent infection in the vast majority of infected individuals. In this study, we have characterized for the first time ex vivo specific CTL responses against the HTLV-2 Tax protein. We could detect CTL responses only against a single HLA-A*0201-restricted Tax2 epitope, comprising residues 11–19 (LLYGYPVYV), among three alleles screened. Virus-specific CTLs could be detected in most evaluated subjects, with frequencies as high as 24% of circulating CD8+ T cells. The frequency of specific CTLs had a statistically significant positive correlation with proviral load levels. The majority of virus-specific CD8+ T cells exhibited an effector memory/terminally differentiated phenotype, expressed high levels of cytotoxicity mediators, including perforin and granzyme B, and lysed in vitro target cells pulsed with Tax2(11–19) synthetic peptide in a dose-dependent manner. Our findings suggest that a strong, effective CTL response may control HTLV-2 viral burden and that this may be a significant factor in maintaining persistent infection and in the prevention of disease in infected individuals.

BackgroundHTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a progressive neurological and inflammatory disease, associated with HTLV-1 infection. HAM/TSP neurological disease is a consequence of an inflammatory reaction, and adaptive immune responses, through the secretion of anti-inflammatory and pro-inflammatory cytokines, play an important role in the outcome of infection and disease progression. Studies addressing the association between cytokines functional single nucleotide polymorphisms and HAM/TSP development are scarce.MethodsThe genetic polymorphisms of cytokine genes were evaluated in HAM/TSP patients (n = 68) and in asymptomatic HTLV-1 positive carriers (n = 83) from Rio de Janeiro, Brazil, in a case-control study. HTLV-1 infected patients were genotyped for SNPs in five cytokine genes: TNFA-308G/A, IL6-174G/C, IFNG + 874 T/A, TGFB at the codons + 10 T/C and + 25G/C, IL10-592C/A and -819C/T, and -1082A/G and proviral load (PVL) was quantified. Associations between genotypes, haplotypes, clinical outcome and pro viral load were evaluated.ResultsLack of association between the cytokine polymorphisms and disease outcome was observed. The genotypes TNFA-308GG, IL6-174GG/GC, IL10-592AA and -819CC and TGFb1 high producers phenotypes were correlated with higher PVL in HAM/TSP patients versus asymptomatic carriers.ConclusionsWe did not observe association between cytokine polymorphisms and risk for HAM/TSP development in Brazilian HTLV-1 infected individuals, regardless of differences in PVL between HAM/TSP versus asymptomatic carriers in specific cytokine polymorphisms.