J

disease of uncertain etiology.  Previous studies have postulated that

retroviruses may contribute to the etiology of some cases of schizophrenia. 

We examined the possible relationship between retroviral infection and

schizophrenia by measuring antibodies to a number of different primate

retroviruses in the sera of individuals undergoing their first hospitalization

for this disease.  Sera from patients with first onset schizophrenia and

matched healthy controls were analyzed by immunoblot and enzyme linked

immunosorbent assays using purified retrovirus antigens to identify and quantify

antibodies reactive with retrovirus proteins.  A significantly increased

incidence of antibodies reactive to gag encoded proteins of Mason-Pfizer monkey

virus (MPMV), baboon endogenous virus (BaEV) and simian retrovirus type 5

(SRV-5) was observed in the sera of schizophrenia patients compared to controls. 

The reactivity of the cases and controls displayed the greatest differences in

terms of antibodies to the proteins of Mason-Pfizer monkey virus. 

Employing an algorithm of enzyme linked immunosorbent assay reactivity followed

by immunoblot confirmation, we found that MPMV antibodies in 28.9% of the

individuals with first episode schizophrenia patients as compared to 3.7% of the