Case report: low-titre anti-Yo reactivity in a female patient with psychotic syndrome and frontoparieto-cerebellar atrophy.

BACKGROUND: Autoimmune and inflammatory mechanisms in psychotic disorders have attracted increasing scientific attention in recent years. In this regard, we performed routine cerebrospinal fluid (CSF) basic diagnostics and CSF/serum analyses for antibodies directed against neuronal intracellular and surface antigens in psychotic patients. In this context, the patient presented in this paper was diagnosed. CASE PRESENTATION: We present the case of a 20-year-old female patient with a first episode of a drug-induced psychotic syndrome but without neurological deficits. Further investigations showed a reproducible low-titre positive anti-Yo reactivity in the CSF and serum with two independent immunoblot assays. Magnetic resonance imaging showed frontoparietal and cerebellar atrophy. On [(18)F]fluorodeoxyglucose positron emission tomography, a mild cerebellar hypometabolism was found. No underlying tumor was detected. CONCLUSION: Despite the presence of anti-Yo reactivity, the diagnostic criteria for a paraneoplastic neurological syndrome were not fulfilled. Previously published data indicate the possible association between low-titer antibodies against intracellular localized, onconeural antigens, and psychotic disorders. Large prospective studies that investigate the prevalence and clinical significance of antibodies against intracellular onconeural antigens in psychiatry are needed.

Immune system: a possible nexus between cannabinoids and psychosis.

BACKGROUND: Endocannabinoid system is involved in the regulation of the brain-immune axis. Cannabis consumption is related with the development, course, and severity of psychosis. The epidemiological evidence for increased occurrence of immunological alterations in patients with psychosis has not been sufficiently addressed. The aim of this review is to establish whether there is any scientific evidence of the influence of cannabinoids on aspects of immunity that affect susceptibility to psychotic disorder induction. METHODS: A comprehensive search of PubMed/MEDLINE, EMBASE and ISI Web of Knowledge was performed using combinations of key terms distributed into three blocks: "immune", "cannabinoid", and "endocannabinoid receptor". Studies were considered to be eligible for the review if they were original articles, they reported a quantitative or qualitative relation between cannabinoid ligands, their receptors, and immune system, and they were carried out in vitro or in mammals, included humans. All the information was systematically extracted and evaluated. RESULTS: We identified 122 articles from 446 references. Overall, endocannabinoids enhanced immune response, whereas exogenous cannabinoids had immunosuppressant effects. A general change in the immune response from Th1 to Th2 was also demonstrated for cannabinoid action. Endogenous and synthetic cannabinoids also modulated microglia function and neurotransmitter secretion. CONCLUSION: The actions of cannabinoids through the immune system are quite regular and predictable in the peripheral but remain fuzzy in the central nervous system. Despite this uncertainty, it may be hypothesized that exposure to exocannabinoids, in particular during adolescence might prompt immunological dysfunctions that potentially cause a latent vulnerability to psychosis. Further investigations are warranted to clarify the relationship between the immunological effects of cannabis and psychosis.

Anti-SS-A (Ro) antibody is positively associated with steroid-induced psychiatric events in systemic lupus erythematosus patients.

Forty-five systemic lupus erythematosus (SLE) patients who had steroid at a prednisolone dose of 0.8 mg/kg/day or more were retrospectively studied for psychiatric events that developed after the therapy. Simple insomnia was excluded. Their age, sex, dose, and duration of steroid, autoantibodies, and prophylactic heparin use were examined. Seventeen patients (female/male: 16/1, 36.7 ± 10.7 years old) developed psychiatric events 18.2 ± 10.2 days after steroid start, whereas 28 patients (27/1, 37.9 ± 13.1) did not. Anti-SS-A (Ro) antibody was more prevalent in patients with the events (15/17 vs. 14/28, p = 0.009). When heparin was administered concurrently with steroid, psychiatric events developed less frequently either in all of the patients (2/17 vs. 11/28, p = 0.048) or in patients positive for the anti-SS-A antibody (2/15 vs. 7/14, p = 0.041). SLE patients positive for the anti-SS-A (Ro) antibody would much more likely develop psychiatric events after a substantial-dose steroid therapy, and a concurrent prophylactic heparin administration might reduce the risk.