High circulatory titer of platelet-associated autoantibodies in childhood onset schizophrenia and its diagnostic implications

Effect of Clozapine and Other Antipsychotics on the Level of Platelet-Associated Autoantibodies in Children with Schizophrenia: A Longitudinal Follow-Up Study

BACKGROUND

Previous studies have demonstrated significantly higher blood titers of platelet-associated autoantibodies (PAA) in adult schizophrenia patients compared to normal healthy subjects. In addition, young adult schizophrenia patients at their early stages of the disorder displayed higher PAA titers than older patients with longer duration of the disorder.

AIM

To assess longitudinally the blood titers of PAA in inpatients with childhood-onset schizophrenia at admission, after short- and long-term follow-up, and the correlation of these titers with the response to clozapine and other antipsychotic treatments.

METHODS

Thirty children, age range of 6-12 (mean ± SD: 9.6 ± 1.5 years), with DSM-IV TR schizophrenia in active psychotic state were assessed 3 times: at baseline, after short-term (8-17 weeks; n = 26) and after long-term follow-up (33-170 weeks; n = 19). The blood titers of PAA were analyzed using ELISA and expressed by a linear optical density (OD) scale. A test recording >1.4 OD units was predefined as the positive cutoff value.

RESULTS

On long-term follow-up, 9 out of the 17 children who were PAA-positive at baseline became PAA-negative: 7 already after 2 months of clozapine treatment and 2 following 3 years of risperidone treatment. Eight children remained PAA-positive during the entire study period. There was no significant correlation between the clinical improvement (as assessed by change in the Positive and Negative Syndrome Scale score) and the alteration in PAA levels (n = 19, r = -0.4, p = 0.088).

CONCLUSIONS

High rates of positive PAA in COS patients may indicate an active autoimmune process in early-onset schizophrenia. It is concluded that PAA may serve as a biomarker for the diagnosis of COS, but does not predict the response to treatment. A transition to a PAA-negative status does not indicate an improvement in psychosis. © 2015 S. Karger AG, Basel.

The contribution of platelet studies to the understanding of disease mechanisms in complex and monogenetic neurological disorders

Platelets, known for their role in primary haemostasis, prevent excessive bleeding after injury. The study of platelets has, therefore, traditionally focused on bleeding disorders. It has recently become evident, however, that platelet research can contribute to unravelling the disease mechanisms that underlie neuropathological disorders that have a subtle subclinical platelet phenotype. Platelets and neurosecretory cells have common gene expression profiles and share several biological features. This review provides a literature update on the use of platelets as easily accessible cells to study neurological disorders. We provide examples of the use of different platelet-based tests to understand the underlying pathophysiological mechanisms for both complex and monogenetic neuropathological disorders. In addition to the well-studied regulated granule secretion and serotonin metabolism, more recent studies have shown that defects in transcription factors, membrane transporters, G-protein signal transduction, and cytoskeletal proteins can be investigated using platelets to gain information on their role in neuropathology.