Blind verification of elevated platelet autoantibodies in serum of schizophrenic patients--part I: young subjects.

BACKGROUND It has been hypothesized that the etiology of schizophrenia, in a distinct group of patients, originates from an autoimmune reaction against platelets. Previous open screenings have recorded significantly higher blood titers of platelet-associated autoantibodies (PAA) in schizophrenic patients as compared to normal healthy subjects. In addition, young schizophrenic patients at the early stages of their disorder displayed higher PAA titers than older patients with a longer duration of the disorder. A blood test based on these observations was proposed. AIM To verify by a blind test a significant difference in PAA between young schizophrenic patients and matched healthy control subjects, for the validation of a blood test for schizophrenia. METHODS A total of 36 young schizophrenic patients in an active psychotic state, aged 13-20 years (mean +/- SD: 16.2 +/- 2.1 years) with an average PANSS score of 115.6 +/- 14.5 and illness duration of 9.5 +/- 9.4 months, were examined. The control group consisted of 49 healthy young subjects between the ages of 13 and 21 years (16.2 +/- 2.2 years). The blood titers of PAA were evaluated blindly using an optimized ELISA test, expressed by a linear optical density (OD) scale. The blood samples of all participants were tested anonymously, and were scored under a code number. A test recording above 1.3 OD units was defined as positive. RESULTS The PAA titers of schizophrenia patients (1.6 +/- 0.4 OD units, range: 0.7-2.3 OD units) were significantly higher than those of the control group (1.0 +/- 0.4 OD units, range: 0.4-1.8 OD units; p < 0.0001). In 61% of the young schizophrenic patients (22 out of the 36 patients), a positive result (OD >1.3 units) was recorded. In the control group, only 12.2% (6 of the 49 subjects) displayed a positive result (p < 0.0001). CONCLUSIONS These findings support further assessment of PAA titers as a potential biomarker for patients with clinical signs and symptoms of schizophrenia.