TOXOPLASMA ANTIBODY TITERS IN TREATMENT NAIVE FIRST
EPISODES OF SCHIZOPHRENIA
To explore the contribution of infectious exposure to
schizophrenia, we determined the levels of several antibodies to infectious
agents in blood samples collected in a randomized double-blind 52 week clinical
trial in China. The sample included 160 first-episode schizophrenia
patients and 60 normal controls balanced in distribution of age (28 ±7), gender
(53% male vs. 47% female) and birth place (48% urban vs 52% rural). The
levels of 9 antibodies, including IgG class antibodies to Herpes Simplex Virus
Type 1 and 2, Human Herpesvirus Type 6, Cytomegalovirus, Borrelia, Hantavirus,
as well as IgG, IgM and IgA class antibodies to the protozoan Toxoplasma
gondii (Toxo) were assayed with enzyme immunoassay. Toxo IgG was found
to be significantly elevated in schizophrenia patients compared to unaffected
controls (p=0.01). Furthermore, we found that patients with high Toxo IgG
had more severe negative symptoms at baseline shown by SNAS total score (p=0.01)
and its subscales on poverty of thought (p=0.04), apathy (p=0.03), and attention
deficit (p=0.02). For cognitive functioning measured by WAIS-R, Toxo IgA
correlated with poorer overall IQ (p=0.01) as with both performance IQ (p=0.01)
and verbal (p=0.03). This may suggest some first-episode patients
underwent infection with Toxoplasma in the recent past. We also explored
the relationship between antibody levels and treatment response.
Interestingly, high Toxo IgG levels significantly reduced the improvement in
BPRS total score (p=0.002), SNAS total score (p=0.002) in patients treated with
clozapine while the effectiveness of chlorpromazine was largely unaffected by
the Toxo IgG level. These findings area consistent with the known effects
of Toxoplasma gondii on brain development and provide the rationale for the
evaluation of specific medication regimens for individuals who have undergone
recent infection with this organism.