Absence of serological evidence for foamy virus infection in patients with amyotrophic lateral sclerosis.

Foamy virus (FV) infection has been implicated in the pathogenesis of sporadic motor neuron disease (MND) by means of serological assays. To confirm these results we tested serum and cerebrospinal fluid (CSF) samples from 23 cases of clinically verified non-familial MND and 11 cases of suspected non-familial MND for the presence of FV infection as determined by Western blot (WB) and indirect immunofluorescence assay (IFA). Using the same tests we also screened sera from 87 healthy chimpanzees for the presence of FV antibodies. None of the human samples in question tested positive. However, the testing revealed that 84 of 87 chimpanzees (96.6%) were seropositive for FV, indicating that combined WB and IFA are suitable methods for the serodiagnosis of FV infection. Given these results an association of FV infection and sporadic MND is highly improbable. Furthermore a suggested therapeutic trial with anti-retroviral drugs appears unjustified.