HIV-associated motor neuron disease: HERV-K activation and response to antiretroviral therapy

OBJECTIVE:To determine whether there is activation of human endogenous retrovirus K (HERV-K) in amyotrophic lateral sclerosis in HIV infection and whether it might respond to treatment with antiretroviral drugs. METHODS:In this case series, we present 5 patients with HIV infection who subsequently developed motor neuron disease involving both upper and lower motor neurons. We monitored HERV-K levels in plasma of 4 of these patients. RESULTS:Three patients who received antiretroviral therapy had reversal of symptoms within 6 months of onset of neurologic symptoms and the other 2 had slow neurologic progression over several years. Three patients in whom the levels were measured at onset of neurologic symptoms showed elevated HERV-K levels that responded to optimization of antiretroviral therapy for CNS penetration. CONCLUSIONS:Thus, motor neuron disease in individuals with HIV infection may a treatable entity, but early treatment with CNS-penetrating antiretroviral therapy may be necessary. Monitoring of HERV-K levels may help guide treatment.