Gluten sensitivity and relationship to psychiatric symptoms in people with schizophrenia.

The relationship between gluten sensitivity and schizophrenia has been of increasing interest and novel mechanisms explaining this relationship continue to be described. Our study in 100 people with schizophrenia compared to 100 matched controls replicates a higher prevalence of gluten sensitivity and higher mean antigliadin IgG antibody levels schizophrenia (2.9 ± 7.7 vs. 1.3 ± 1.3, p = 0.046, controlled for age). Additionally, we examined symptoms within the schizophrenia group and found that while positive symptoms are significantly lower in people who have elevated antigliadin antibodies (AGA; 4.11 ± 1.36 vs. 6.39 ± 2.99, p = 0.020), no robust clinical profile differentiates between positive and negative antibody groups. Thus, identifying people in schizophrenia who may benefit from a gluten-free diet remains possible by blood test only.

Analytical and clinical comparison of two fully automated immunoassay systems for the diagnosis of celiac disease.

OBJECTIVE: Here we compared analytical and clinical performance characteristics of two novel automated assay systems for the detection of celiac disease (CD) specific antibodies: QUANTA Flash (INOVA Diagnostics, Inc.) and EliA (Thermo Scientific). METHODS: A total of 74 biopsy-proven CD patients (2 with IgA deficiency) and 138 controls were tested by both methods. RESULTS: Sensitivities of QUANTA Flash assays ranged from 35.1% to 90.5% and specificities from 96.4% to 99.3%, while sensitivities for EliA assays ranged from 37.8% to 90.5% (equivocal considered positive) and specificities from 97.1% to 100.0%. Good qualitative agreement was found between all assays. Thirty-four (50.0%) of the 68 QUANTA Flash h-tTG IgA positive results were higher than 10 times the upper limit of normal (ULN). In contrast, only 22.8% of the EliA tTG IgA positive samples were >10x ULN. Seventy-three (98.6%) biopsy-proven CD patients were correctly identified with the QUANTA Flash h-tTG IgA+DGP IgG combination, while 64 (86.5%) and 72 (97.3%) (depending on equivocal range) were identified with the same combination of EliA assays. CONCLUSION: The QUANTA Flash CD assays have outstanding clinical performance. Of particular clinical significance, in light of proposals to decrease the absolute necessity of biopsy, was the demonstration that 50% of the QUANTA Flash h-tTG IgA results were >10x ULN.

Relationships between serum leptin level and severity of positive symptoms in schizophrenia.

The adipocytokine leptin is a key mediator of energy homeostasis. Recent papers have suggested that leptin may also have roles in the brain however it is unclear whether leptin is connected to symptoms of mental disorders. In this study, we sought to clarify the relationships between serum leptin level and psychopathology in schizophrenia (SZ) patients. The severity of positive symptoms inversely correlated with the serum leptin levels among SZ patients. There was no correlation between leptin levels and negative symptoms or neurocognition. Our data suggest a role of leptin in SZ positive symptoms.

Increased prevalence of transglutaminase 6 antibodies in sera from schizophrenia patients.

Gluten can cause extraintestinal manifestations with or without gastrointestinal symptoms and elevated antitissue transglutaminase 2 (tTG2) autoantibodies. Organ-specific gluten reaction involves immune response toward other transglutaminase (TG) isoforms including tTG3 (expressed in the skin, leading to dermatitis herpetiformis) and tTG6 (expressed in the brain, causing gluten ataxia). This analysis focuses on tTG6 antibodies, which have never been studied before in schizophrenia (SZ) and its relationships to tTG2 and to antigliadin antibodies. We previously showed an increased prevalence of tTG2 antibodies in gluten sensitive SZ patients compared with healthy controls (HC) that was not paralleled by an increased prevalence of antiendomysial antibody. To elucidate this discrepancy, we examined those tTG2 positive SZ patients for the presence of tTG6 antibody. We also searched for tTG6 antibodies in our sample of antigliadin (AGA) positive and AGA and tTG2 negative SZ patients. Seventy-four tTG2 positive SZ patients were compared with 148 age and gender-matched HC. Of the 74 tTG2 positive SZ patients, 16 were positive for tTG6 IgA for a prevalence of 22%. Only 4 HC were positive for tTG6 IgA for a prevalence of 2.7%. Among the AGA positive SZ patients, the prevalence of tTG6 IgA was 21.3% while 13.1% of the AGA and tTG2 negative SZ patients were positive for tTG6 IgA. The HC had a prevalence of 6%. Our results indicate a higher prevalence of tTG6 antibodies in SZ that may represent a biomarker useful to identify SZ patients who would benefit from a gluten-free diet.