Early Juvenile Human T-cell Lymphotropic Virus Type-1-Associated Myelopathy/Tropical Spastic Paraparesis: Study of 25 Patients.

Background: Human T-cell lymphotropic virus type-1 (HTLV-1) may cause severe diseases such as HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and infective dermatitis associated with HTLV-1 (IDH). The clinical characteristics and progression of 25 early onset HAM/TSP associated or not to IDH were described. Methods: Following-up 37 IDH patients with neurological examinations, 54% developed HAM/TSP. To these cases were added 5 cases of juvenile HAM/TSP. The patients were HTLV-1+ and were submitted to dermatological and neurological examinations. Diagnosis of HAM/TSP was performed according to Osame et al (1990) and Castro-Costa et al (2006) criteria. Results: Twenty-one patients were classified as definite HAM/TSP by both criteria, 3 as probable HAM/TSP by Osame et al, and another as probable HAM/TSP according to Castro-Costa et al Median age at onset of neurological manifestations was 9 years for the IDH/HAM/TSP group and 16 years for the HAM/TSP group (P = .045). In 12 patients, the onset of neurological manifestations occurred when they were less than 10 years of age. In the group IDH/HAM/TSP, the neurological symptoms always begun during the period of activity of IDH. The progression of HAM/TSP evaluated in 17 cases was heterogeneous, and 3 had rapid progressive course. Conclusions: The juvenile HAM/TSP may occur very early and also presents marked female predominance. Progression of IDH to HAM/TSP before 19 years of age is frequent (54%). Rapid progressive form may also occur in early HAM/TSP. As juvenile IDH and HAM/TSP are due to vertical transmission through breastfeeding, it is very important to avoid this pathway of infection.

HTLV-1 proviral load in infective dermatitis associated with HTLV-1 does not increase after the development of HTLV-1-associated myelopathy/tropical spastic paraparesis and does not decrease after IDH remission.

INTRODUCTION: Infective dermatitis associated with HTLV-1 (IDH) is a recurrent eczema which affects children vertically infected with HTLV-1. In Bahia, Brazil, we recently reported that 47% of IDH patients also develop juvenile HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), a progressive disabling disorder which is typically reported in adult HTLV-1 carriers. IDH may also predispose to adult T-cell leukemia/lymphoma, a neoplasm associated with HTLV-1. The factors relating to the development of HTLV-1-associated juvenile diseases have not yet been defined. HTLV-1 proviral load (PVL) is one of the main parameters related to the development of HTLV-1 associated diseases in adults. In the current study, we investigated the role of PVL in IDH and juvenile HAM/TSP. METHODOLOGY/PRINCIPAL FINDINGS: This is a cohort study that included fifty-nine HTLV-1 infected children and adolescents, comprising 16 asymptomatic carriers, 18 IDH patients, 20 patients with IDH and HAM/TSP (IDH/HAM/TSP) and five with HAM/TSP. These patients were followed-up for up to 14 years (median of 8 years). We found that PVL in IDH and IDH/HAM/TSP patients were similarly higher than PVL in juvenile asymptomatic carriers (p<0.0001). In those IDH patients who developed HAM/TSP during follow-up, PVL levels did not vary significantly. HAM/TSP development did not occur in those IDH patients who presented high levels of PVL. IDH remission was associated with an increase of PVL. Inter-individual differences in PVL were observed within all groups. However, intra-individual PVL did not fluctuate significantly during follow-up. CONCLUSIONS/SIGNIFICANCE: High PVL in IDH patients was not necessary indicative of progression to HAM/TSP. PVL did not decrease after IDH remission. The maintenance of high PVL after remission could favor early development of ATL. Therefore, IDH patients would have to be followed-up even after remission of IDH and for a long period of time.