Immunological and viral features in patients with overactive bladder associated with human T‐cell lymphotropic virus type 1 infection

The majority of patients infected with human T‐cell lymphotropic virus‐type 1 (HTLV‐1) are considered carriers, but a high frequency of urinary symptoms of overactive bladder, common in HTLV‐1 associated myelopathy/tropical spastic paraparesis (HAM/TSP) have been documented in these patients. The aim of this study was to determine if immunological and viral factors that are seen in HAM/TSP are also observed in these patients. Participants were classified as HTLV‐1 carriers (n = 45), HTLV‐1 patients suffering from overactive bladder (n = 45) and HAM/TSP (n = 45). Cells from HTLV‐1 overactive bladder patients produced spontaneously more proinflammatory cytokines than carriers. TNF‐α and IL‐17 levels were similar in HAM/TSP and HTLV‐1 overactive bladder patients. High proviral load was found in patients with overactive bladder and HAM/TSP and correlated with proinflammatory cytokines. In contrast with findings in patients with HAM/TSP, serum levels of Th1 chemokines were similar in HTLV‐1 overactive bladder and carriers. Exogenous addition of regulatory cytokines decreased spontaneous IFN‐γ production in cell cultures from HTLV‐1 overactive bladder patients. The results show that HTLV‐1 overactive bladder and HAM/TSP patients have in common some immunological features as well as similar proviral load profile. The data show that HTLV‐1 overactive bladder patients are still able to down regulate their inflammatory immune response. In addition, these patients express levels of chemokines similar to carriers, which may explain why they have yet to develop the same degree of spinal cord damage as seen in patients with HAM/TSP. These patients present symptoms of overactive bladder, which may be an early sign of HAM/TSP. J. Med. Virol. 84:1809–1817, 2012. © 2012 Wiley Periodicals, Inc.