Detection of clinical and neurological signs in apparently asymptomatic HTLV-1 infected carriers: Association with high proviral load.

Several studies suggest that HTLV-1 infection may be associated with a wider spectrum of neurologic manifestations that do not meet diagnostic criteria for HAM/TSP. These conditions may later progress to HAM/TSP or constitute an intermediate clinical form, between asymptomatic HTLV-1 carriers and those with full myelopathy. Our aim was to determine the prevalence of HTLV-1-associated disease in subjects without HAM/TSP, and the relationship between these findings with HTLV-1 proviral load (PVL). METHODS: 175 HTLV-1-infected subjects were submitted to a careful neurological evaluation, during their regular follow up at the HTLV outpatient clinic of the Institute of Infectious Diseases "Emilio Ribas", São Paulo city, Brazil. Clinical evaluation and blinded standardized neurological screening were performed for all the subjects by the same neurologist (MH). RESULTS: After the neurological evaluation, 133 patients were classified as asymptomatic and 42 fulfilled the criteria for intermediate syndrome (IS). The mean age of the enrolled subjects was 46.3 years and 130 (74.3%) were females. Clinical classification shows that neurological symptoms (p<0.001), visual disorders (p = 0.001), oral conditions (p = 0.001), skin lesions (p<0.001), bladder disorders (p<0.001), and rheumatological symptoms (p = 0.001), were strongly associated to IS, except for disautonomy (p = 0.21). A multivariate analysis revealed that HTLV-1 proviral load, oral conditions, bladder disorders and rheumatological symptoms were independently associated with the IS. CONCLUSIONS: We found some early alterations in 42 patients (24%), particularly the presence of previously not acknowledged clinical and neurological symptoms, among subjects previously classified as "asymptomatic", who we reclassified as having an intermediate syndrome.

Detection of clinical and neurological signs in apparently asymptomatic HTLV-1 infected carriers: Association with high proviral load

Several studies suggest that HTLV-1 infection may be associated with a wider spectrum of neurologic manifestations that do not meet diagnostic criteria for HAM/TSP. These conditions may later progress to HAM/TSP or constitute an intermediate clinical form, between asymptomatic HTLV-1 carriers and those with full myelopathy. Our aim was to determine the prevalence of HTLV-1-associated disease in subjects without HAM/TSP, and the relationship between these findings with HTLV-1 proviral load (PVL). METHODS: 175 HTLV-1-infected subjects were submitted to a careful neurological evaluation, during their regular follow up at the HTLV outpatient clinic of the Institute of Infectious Diseases "Emilio Ribas", São Paulo city, Brazil. Clinical evaluation and blinded standardized neurological screening were performed for all the subjects by the same neurologist (MH). RESULTS: After the neurological evaluation, 133 patients were classified as asymptomatic and 42 fulfilled the criteria for intermediate syndrome (IS). The mean age of the enrolled subjects was 46.3 years and 130 (74.3%) were females. Clinical classification shows that neurological symptoms (p<0.001), visual disorders (p = 0.001), oral conditions (p = 0.001), skin lesions (p<0.001), bladder disorders (p<0.001), and rheumatological symptoms (p = 0.001), were strongly associated to IS, except for disautonomy (p = 0.21). A multivariate analysis revealed that HTLV-1 proviral load, oral conditions, bladder disorders and rheumatological symptoms were independently associated with the IS. CONCLUSIONS: We found some early alterations in 42 patients (24%), particularly the presence of previously not acknowledged clinical and neurological symptoms, among subjects previously classified as "asymptomatic", who we reclassified as having an intermediate syndrome

Risk factors associated with HTLV-1 vertical transmission in Brazil: longer breastfeeding, higher maternal proviral load and previous HTLV-1-infected offspring.

HTLV-1 is transmitted primarily either through sexual intercourse or from mother to child. The mother/child pairs were classified as seroconcordant or serodiscordant. We analyzed mother to child transmission (MTCT) according to sociodemographic, clinical and epidemiological characteristics of the mother, child's gender and duration of breastfeeding. Between June 2006 and August 2016 we followed 192 mothers with HTLV-1 infection (mean age 41 years old), resulting in 499 exposed offspring, 288 (57.7%) of whom were tested for HTLV-1, making up the final sample for the study, along with their 134 respective mothers. Among the tested mother/child pairs, 41 (14.2%) were HTLV-1 positive, highlighted that seven of 134 family clusters concentrated 48.8% of positive cases. Variables associated with a positive child: breastfeeding duration ≥12 months, maternal PVL ≥100 copies/104 PBMC, mother's age at delivery >26 years old, and HTLV-1 in more than one child of the same mother. In a multiple logistic regression, breastfeeding ≥12 months, higher maternal PVL and ≥2 previous HTLV-1-infected children remained independently associated with the outcome. Thus, high maternal PVL and breastfeeding beyond 12 months were independently associated with MTCT of the HTLV-1 infection. Our results reinforce the need for both prenatal HTLV screening in endemic areas and for advising mothers on breastfeeding.

Risk factors associated with HTLV-1 vertical transmission in Brazil: longer breastfeeding, higher maternal proviral load and previous HTLV-1-infected offspring

HTLV-1 is transmitted primarily either through sexual intercourse or from mother to child. The mother/child pairs were classified as seroconcordant or serodiscordant. We analyzed mother to child transmission (MTCT) according to sociodemographic, clinical and epidemiological characteristics of the mother, child's gender and duration of breastfeeding. Between June 2006 and August 2016 we followed 192 mothers with HTLV-1 infection (mean age 41 years old), resulting in 499 exposed offspring, 288 (57.7%) of whom were tested for HTLV-1, making up the final sample for the study, along with their 134 respective mothers. Among the tested mother/child pairs, 41 (14.2%) were HTLV-1 positive, highlighted that seven of 134 family clusters concentrated 48.8% of positive cases. Variables associated with a positive child: breastfeeding duration ≥12 months, maternal PVL ≥100 copies/104 PBMC, mother's age at delivery >26 years old, and HTLV-1 in more than one child of the same mother. In a multiple logistic regression, breastfeeding ≥12 months, higher maternal PVL and ≥2 previous HTLV-1-infected children remained independently associated with the outcome. Thus, high maternal PVL and breastfeeding beyond 12 months were independently associated with MTCT of the HTLV-1 infection. Our results reinforce the need for both prenatal HTLV screening in endemic areas and for advising mothers on breastfeeding

Polymorphisms in HLA-C and KIR alleles are not associated with HAM/TSP risk in HTLV-1-infected subjects

INTRODUCTION: Several genetic polymorphisms may be related to susceptibility or resistance to viral disease outcomes. Immunological or genetic factors may act as major triggers of the immune pathogenesis of HAM/TSP. This study investigated the association of immune related genetic polymorphisms with viral and immunological markers. METHODS: 247 HTLV-1-infected volunteers, drawn from a larger group of HTLV-infected subjects followed at the Institute of Infectious Diseases "Emilio Ribas" (IIER) for up to 19 years, participated in this study, which ran from June 2011 to July 2016. The subjects were classified according to their neurological status into two groups: Group 1 (160 asymptomatic individuals) and Group 2 (87 HAM/TSP patients). Samples were tested for spontaneous lymphocyte proliferation (LPA) and HTLV-1 proviral load (PVL) and for IFN-λ4, HLA-C and KIR genotypes using qPCR. RESULTS: We found associations between LPA (p=0.0001) with HAM/TSP and confirmed the IFN-λ4 polymorphism rs8099917, allele GG, as a protective factor using a recessive model (OR=3.22, CI=1.10-9.47). Polymorphisms in HLA-C and KIR alleles were not associated with risk of developing HAM/TSP. CONCLUSION: We demonstrated that age, LPA and an IFN-λ4 polymorphism were associated with progression to HAM/TSP. Understanding HAM/TSP pathogenesis can provide important markers of prognostic value for clinical management, and contribute to the discovery of new therapeutic interventions in the future

Polymorphisms in HLA-C and KIR alleles are not associated with HAM/TSP risk in HTLV-1-infected subjects.

INTRODUCTION: Several genetic polymorphisms may be related to susceptibility or resistance to viral disease outcomes. Immunological or genetic factors may act as major triggers of the immune pathogenesis of HAM/TSP. This study investigated the association of immune related genetic polymorphisms with viral and immunological markers. METHODS: 247 HTLV-1-infected volunteers, drawn from a larger group of HTLV-infected subjects followed at the Institute of Infectious Diseases "Emilio Ribas" (IIER) for up to 19 years, participated in this study, which ran from June 2011 to July 2016. The subjects were classified according to their neurological status into two groups: Group 1 (160 asymptomatic individuals) and Group 2 (87 HAM/TSP patients). Samples were tested for spontaneous lymphocyte proliferation (LPA) and HTLV-1 proviral load (PVL) and for IFN-λ4, HLA-C and KIR genotypes using qPCR. RESULTS: We found associations between LPA (p=0.0001) with HAM/TSP and confirmed the IFN-λ4 polymorphism rs8099917, allele GG, as a protective factor using a recessive model (OR=3.22, CI=1.10-9.47). Polymorphisms in HLA-C and KIR alleles were not associated with risk of developing HAM/TSP. CONCLUSION: We demonstrated that age, LPA and an IFN-λ4 polymorphism were associated with progression to HAM/TSP. Understanding HAM/TSP pathogenesis can provide important markers of prognostic value for clinical management, and contribute to the discovery of new therapeutic interventions in the future.