ANTIRETROVIRAL SEROREACTIVITIES WITHOUT EPIDEMIOLOGIC CLUSTERING IN AMYOTROPHIC-LATERAL-SCLEROSIS

Of 25 male and 13 female patients diagnosed as sporadic cases of amyot rophic lateral sclerosis between 1989 and 1992, 17 had reproducible se rum antibodies against human foamy virus (HFV = human spuma retrovirus , HSRV). HFV-positive ALS patients had higher IgG3 concentrations than HFV-negatives (P < 0.05) and competed better on maedi-visna retrovira l antigen than HFV-negatives or controls (P < 0.05), but did not diffe r otherwise. Two HFV-positive patients were living in the same buildun g: two other ALS patients lived within 300 m of one another, and three HFV gag reactive men (2 ALS, 1 control) were living in neighbouring v illages. These were the closest geographic clusters found among curren t patients. We summarize recent findings compatible with a pathogeneti c role for endogenous and/or exogenous retrovir sequences in adult mot or neuron disease, and confirm a male preponderance as well as an inve rse correlation between survival time and age at onset.