Does helminthic infection alter the clinical course of HTLV-1 infection?

Introduction

HTLV-1 is associated with the development of HAM/TSP and overactive bladder (OB). A higher prevalence of helminthic coinfection has been observed among those infected with HTLV-1. Because helminthic infection may modify the immune response and influence clinical outcomes in HTLV-1 infection, we investigated the development of HAM/TSP and OB in HTLV-1 positive individuals with and without helminthic coinfection.

Methods

HTLV-1 patients enrolled in a cohort study between 2004-2010 were classified as coinfected and non-coinfected based on stool samples. All patients were followed at least two years from initial evaluation, with yearly clinical assessments. Disease-free survival for OB was estimated using the Kaplan-Meier method, and the relationship between helminthic infection and development of OB was assessed by Cox proportional hazard modeling.

Results

Seventy-four coinfected and 79 non-coinfected patients were followed. A total of 92 helminthic infections were observed in the coinfected group. One patient from each group developed HAM/TSP during followup. Fourteen and 17 patients developed OB from the coinfected and non-coinfected groups, respectively. There was no association between helminthic infection and risk of OB (hazard ratio 0.91, 95% CI 0.43-1.89, p = 0.79, adjusted for sex).

Discussion

We found no difference in the risk of development of OB in HTLV-1 and helminthic coinfected and non-coinfected patients. The incidence of HAM/TSP was low in each group. These data indicate that general helminthic infection does not modify development of HAM/TSP or OB. Future studies should address the potential association between specific helminthic infections and risk of neurologic disease in HTLV-1 infection.