The absolute and relative frequencies of pro- inflammatory cytokine (TNFα, IFNγ and IL-6) producing CCR4+CD7- cells (i.e. ‘ATL-like’ infected cells) was lower than in non-CCR4+CD7- CD4+ T cells (i.e. predominantly HTLV-1 uninfected memory cells, Fig 6F–6H) in AC and patients with HAM. Here, IL6 is linked to tropical spastic paraparesis.