Relation Between Unconjugated Bilirubin and Peripheral Biomarkers of Inflammation Derived From Complete Blood Counts in Patients With Acute Stage of Schizophrenia

Differences in Blood Leukocyte Subpopulations in Schizophrenia: A Systematic Review and Meta-Analysis

Importance

This study aims to provide robust evidence to support or challenge the immune hypothesis of schizophrenia.

Objective

To conduct a meta-analysis of reports on blood leukocyte subpopulations in schizophrenia vs healthy controls, examining disease- and treatment-related differences as well as potential confounders.

Data Sources

Systematic database search for English and non-English peer-reviewed articles in PubMed, Web of Science, Scopus, and Cochrane Library databases, with the last search in January 2024.

Study Selection

Cross-sectional, case-control, and longitudinal studies comparing leukocyte numbers in patients with schizophrenia and healthy controls. After duplicates were removed, 3691 studies were identified for screening.

Data Extraction and Synthesis

Data extraction and quality assessment were conducted following PRISMA and MOOSE guidelines. Data were independently extracted by 2 authors and pooled using random-effects models.

Main Outcomes and Measures

The planned primary outcomes were differences in leukocyte subpopulation counts between individuals with schizophrenia and healthy controls to increase our understanding of the immune system dysfunction in schizophrenia.

Results

Sixty-four relevant articles were identified (60 cross-sectional/case-control studies and 4 longitudinal studies) with data on leukocyte numbers from 26 349 individuals with schizophrenia and 16 379 healthy controls. Neutrophils (g = 0.69; 95% CI, 0.49 to 0.89; Bonferroni-adjusted P < .001; n = 40 951 [47 between-group comparisons]) and monocytes (g = 0.49; 95% CI, 0.24 to 0.75; Bonferroni-adjusted P < .001; n = 40 513 [44 between-group comparisons]) were higher in schizophrenia compared with control participants. Differences were greater in first-episode vs chronic schizophrenia and in patients who were not treated vs treated with antipsychotic medication. There were no significant differences in eosinophils (g = 0.02; 95% CI, -0.16 to 0.20; Bonferroni-adjusted P > .99; n = 3277 [18 between-group comparisons]), basophils (g = 0.14; 95% CI, -0.06 to 0.34; Bonferroni-adjusted P = .85; n = 2614 [13 between-group comparisons]), or lymphocytes (g = -0.08; 95% CI, -0.21 to 0.06; Bonferroni-adjusted P > .99; n = 41 693 [59 between-group comparisons]). Neutrophils decreased longitudinally (g = -0.30; 95% CI, -0.45 to -0.15; Bonferroni-adjusted P < .001; n = 896 [4 within-group comparisons]) and eosinophils increased longitudinally (g = 0.61; 95% CI, 0.52 to 0.71; Bonferroni-adjusted P < .001; n = 876 [3 within-group comparisons]) after successful treatment of acute psychosis.

Conclusions and Relevance

Our findings of increased blood neutrophils and monocytes support the immune hypothesis of schizophrenia, particularly highlighting the role of innate immune activation. As these effects were more pronounced in early disease stages and also reflected clinical improvement, they may pave the way for innovative treatment strategies based on immunological and inflammatory pathways and help revolutionize the treatment landscape for schizophrenia.

Predictors of clozapine concentration and psychiatric symptoms in patients with schizophrenia

Clozapine has superior efficacy to other antipsychotics, especially in patients with treatment-resistant schizophrenia. However, its pharmacokinetics and pharmacodynamics vary largely among patients. We aimed to evaluate the clinical and genetic factors associated with the pharmacokinetics and pharmacodynamics of clozapine in patients with schizophrenia. Blood samples for clozapine pharmacokinetic assessment were collected from patients with schizophrenia at weeks 2 (visit 2), 8 (visit 3), and 18 (visit 4) from the initiation of clozapine treatment. The Positive and Negative Syndrome Scale (PANSS) score was assessed at baseline (visit 1) and visits 3 and 4. Linear mixed models were used to identify the clinical and genetic variables associated with the clozapine concentration and total PANSS score. A total of 45 patients were included in the pharmacogenomic analysis. Owing to the small sample size, we categorized concomitant medications into four groups. However, individual drugs may have different effects on clozapine concentration. Clozapine concentration was significantly associated with smoking status and cumulative clozapine dose. Clozapine concentration was significantly associated with five single nucleotide polymorphisms (SNPs) in three genes (rs28371726 and rs202102799 in CYP2D6, rs4148323 and rs34946978 in UGT1A1, and rs2011404 in UGT1A4). Furthermore, follow-up time, body mass index, and total bilirubin levels were significantly associated with the total PANSS scores. The PANSS score was significantly associated with four SNPs in two genes (rs7787082 and rs10248420 in ABCB1 and rs2133251840 and rs762502 in DRD4). This study suggests potential clinical and genetic predictors of clozapine concentration and psychiatric symptoms in patients with schizophrenia treated with clozapine. With further investigations in diverse populations, our findings may provide important information on variables to be considered in individualized clozapine treatment.

Combined Predictors for the Diagnostic Transition from Acute and Transient Psychotic Disorder to Schizophrenia: A Retrospective Study

Purpose

Acute and transient psychotic disorder (ATPD), a psychosis frequently diagnosed, can potentially evolve into chronic conditions like schizophrenia (SCZ) and other mental disorders. This study aimed to develop a predictive model based on clinical data to forecast the transition from ATPD to SCZ and to identify the predictive factors.

Methods

According to the diagnostic criteria issued by the International Statistical Classification of Diseases and Related Health Problems 10th Revision (ICD-10), 396 inpatients diagnosed with ATPD were collected in this study. The Cox proportional-hazards regression model was performed using demographic data, clinical characteristics, and inflammatory markers to identify independent predictors for subsequent diagnostic transition (SDT) to SCZ.

Results

During the follow-up period, 43.69% (n = 173) of ATPD patients had their diagnoses revised to SCZ. The multivariate Cox regression analysis identified post-treatment monocyte count, post-treatment monocyte/lymphocyte ratio (MLR), and the presence of schizophreniform symptoms as significant predictors for the diagnostic revision. Time-dependent receiver operating characteristic (TimeROC) analyses were developed. The AUC value at the 5-year follow-up was 0.728 for combined predictors, 0.702 for post-treatment monocyte count, 0.764 for post-treatment MLR, and 0.535 for the presence of schizophreniform symptoms.

Conclusion

The combined predictors had good predictive ability for the diagnostic transition from acute and transient psychotic disorder to schizophrenia.

The potential predictive value and relationship of blood-based inflammatory markers with the clinical symptoms of Han Chinese patients with first-episode adolescent-onset schizophrenia

Background

Inflammation is associated with the pathophysiology of schizophrenia. The blood markers for systemic inflammation include neutrophil-lymphocyte ratio (NLR), systemic immune-inflammation index (SII), lymphocyte-monocyte ratio (LMR), system inflammation response index (SIRI), and platelet-lymphocyte ratio (PLR). However, these inflammation markers and their relationships with clinical phenotypes among Han Chinese patients with first-episode adolescent-onset schizophrenia (AOS) is unclear. This investigation aimed to elucidate the impact of inflammation on Han Chinese AOS patients as well as the association of blood-based inflammation markers with clinical symptoms.

Methods

Altogether, 203 Han Chinese individuals participated in this study, 102 first-episode AOS patients and 101 healthy controls. The assessment of inflammatory indices was based on complete blood cell count. Furthermore, schizophrenia-related clinical symptoms were evaluated using the five-factor model of the Positive and Negative Syndrome Scale (PANSS).

Results

In Han Chinese first-episode AOS patients, levels of SIRI, PLR, SII, and NLR were significantly increased (p < 0.001), while LMR decreased (p < 0.001) compared to healthy controls. Furthermore, multivariate logistic regression showed that LMR, NLR, SII, and SIRI (all p < 0.05) were independently associated with AOS. Moreover, Receiver operating characteristics assessment indicated that NLR, SIRI, LMR, and SII could effectively distinguish AOS patients from healthy controls. Their areas under the curves were 0.734, 0.701, 0.715, and 0.730 (all p < 0.001). In addition, Correlation analysis revealed that LMR was negatively correlated with the PANSS total, negative, and cognitive factor scores (all p < 0.05); NLR was positively correlated with the cognitive factor score (p < 0.01); SII was negatively correlated with the positive factor score and positively with the negative and cognitive factor scores (all p < 0.05); SIRI was positively correlated with the PANSS total and cognitive factor scores (all p < 0.01).

Conclusions

This research established the involvement of peripheral blood inflammatory markers (LMR, NLR, SII, and SIRI) with the clinical manifestations and pathophysiology of schizophrenia, and these can serve as screening tools or potential indices of the inflammatory state and AOS symptoms severity.

Immune Cell Alterations in Psychotic Disorders: A Comprehensive Systematic Review and Meta-Analysis

BACKGROUND

A comprehensive meta-analysis on the composition of circulating immune cells from both the myeloid and the lymphoid lines including specialized subsets in blood and cerebrospinal fluid (CSF) of patients with psychotic disorders compared with healthy control participants has been lacking.

METHODS

Multiple databases (PubMed, EMBASE, Cochrane Library, Web of Science, ClinicalTrials.gov, and PsycINFO) were searched for eligible studies up until October 18, 2022. All studies investigating circulating immune cells in the blood and CSF from patients with psychotic disorders (ICD-10: F20 and F22-29) compared with healthy control participants were included.

RESULTS

A total of 86 studies were included in the meta-analysis. In the blood, the following categories of immune cells were elevated: leukocyte count (31 studies, standardized mean difference [SMD] = 0.35; 95% CI, 0.24 to 0.46), granulocyte count (4 studies, SMD = 0.57; 95% CI, 0.12 to 1.01), neutrophil granulocyte count (21 studies, SMD = 0.32; 95% CI, 0.11 to 0.54), monocyte count (23 studies, SMD = 0.40; 95% CI, 0.23 to 0.56), and B lymphocyte count (10 studies, SMD = 0.26; 95% CI, 0.04 to 0.48). Additionally, the neutrophil/lymphocyte ratio (23 studies, SMD = 0.40; 95% CI, 0.19 to 0.60), the monocyte/lymphocyte ratio (9 studies, SMD = 0.31; 95% CI, 0.04 to 0.57), and the platelet/lymphocyte ratio (10 studies, SMD = 0.23; 95% CI, 0.03 to 0.43) were elevated. The CSF cell count showed a similar tendency but was not significantly elevated (3 studies, SMD = 0.14; 95% CI, -0.04 to 0.32).

CONCLUSIONS

The results indicate a broad activation of the immune system in psychotic disorders, with cells from both the myeloid and the lymphoid line being elevated. However, CSF analyses were lacking in most of the studies, and many studies were hampered by insufficient adjustment for confounding factors such as body mass index and smoking.

The associations of psychopathology and metabolic parameters with serum bilirubin levels in patients with acute-episode and drug-free schizophrenia: a 5-year retrospective study using an electronic medical record system

BACKGROUND

The oxidative system plays an important role in the pathogenesis of schizophrenia. Inconsistent associations were found between hyperbilirubinemia and psychopathology as well as glycolipid metabolism in patients with schizophrenia at different episodes. This current study aimed to examine these associations in patients with acute-episode and drug-free (AEDF) schizophrenia.

METHODS

This is a retrospective study using 5 years of data from May 2017 to May 2022 extracted from the electronic medical record system of Chaohu Hospital of Anhui Medical University. Healthy controls (HCs) from the local medical screening center during the same period were also included. Participants' data of the bilirubin levels [total bilirubin (TB), conjugated bilirubin (CB), unconjugated bilirubin (UCB)], glycolipid metabolic parameters and the score of the Brief Psychiatric Rating Scale (BPRS) were collected.

RESULTS

A total of 1468 case records were identified through the initial search. After screening, 89 AEDF patients and 100 HCs were included. Compared with HCs, patients had a higher CB level, and lower levels of glycolipid metabolic parameters excluding high density lipoprotein-cholesterol (HDL-C) (all P < 0.001). Binary logistic regression analyses revealed that high bilirubin levels in the patients were independently associated with higher total and resistance subscale scores of BPRS, a higher HDL-C level, and lower total cholesterol and triglyceride levels (all P < 0.05).

CONCLUSION

Bilirubin levels are elevated in patients with AEDF schizophrenia. Patients with high bilirubin levels have more severe psychopathology and relatively optimized glycolipid metabolism. In clinical practice, regular monitoring of bilirubin levels in this patient population should be carried out.

Hematological and inflammatory markers in Han Chinese patients with drug-free schizophrenia: relationship with symptom severity

Background

There is a growing amount of evidence suggesting that immunity and inflammation play an important role in the pathophysiology of schizophrenia. In this study, we aimed to examine the relationship between hematological and inflammatory markers with symptom severity in Han Chinese patients with drug-free schizophrenia.

Methods

This retrospective study was conducted at Chaohu Hospital of Anhui Medical University and data were extracted from the electronic medical record system over a 5-year period (May 2017 to April 2022), including participants' general and clinical information as well as Brief Psychiatric Rating Scale (BPRS) scores and hematological parameters.

Results

A total of 2,899 patients with schizophrenia were identified through the initial search. After screening, 91 patients and 141 healthy controls (HCs) were included. The patients had a higher value of neutrophils/lymphocytes ratio (NLR), monocyte/lymphocyte ratio (MLR), and platelet/lymphocyte ratio (PLR) than HCs (all P < 0.001). MLR was positively correlated with BPRS total score (r = 0.337, P = 0.001) and resistance subscale score (r = 0.350, P = 0.001). Binary logistic regression analyses revealed that severely ill was significantly associated with being male and a higher value of MLR (Natural Logaruthm, Ln) (all P < 0.05), and the receiver operating characteristic (ROC) analysis showed good performance of a regression model with an area under the curve (AUC) value of 0.787.

Conclusion

Patients with drug-free schizophrenia have an unbalanced distribution of peripheral blood granulocytes, and elevated NLR, MLR and PLR. Patients with higher value of MLR tend to have more psychotic symptoms, especially those symptoms of hostility, uncooperativeness, and suspiciousness. Our study gives a preliminary indication that MLR is a potential predictor of disease severity in patients with drug-free schizophrenia.

Albumin and Associated Biomarkers in Severe Neuropsychiatric Disorders: Acute-Phase Schizophrenia and Bipolar Disorder

Background

Inflammation is relevant to the pathophysiology of severe neuropsychiatric disorders, schizophrenia (SCZ) and bipolar disorders (BD). Multiple pathophysiological biomarkers are valuable for the study of inflammatory processes. This study investigated albumin-related biomarkers in SCZ and BD to explore their roles in disease.

Methods

A total of 5,577 SCZ, 3442 BD-manic (BD-M) and 1405 BD-depression (BD-D) in acute stage and 5000 health controls (HCs) were enrolled. The differences in these biomarker levels among different groups were compared, and the contributing factors for the occurrence of SCZ, BD, and subgroups of BD were analyzed.

Results

Both SCZ and BD exhibit lower prognostic nutritional index (PNI), but higher neutrophil percentage-to-albumin ratio (NPAR) and creatinine-albumin ratio (CRA) compared with HC. Compared with BD-D, BD-M had higher NPAR and platelet-to-albumin ratio (PAR) and lower CRA. In logistic regression, lower prognostic nutritional index (PNI) and higher CRA were associated with both SCZ and BD, while higher NPAR was associated with BD. In the subgroup of BD, higher NPAR, CRA and lower PNI were associated with BD-M; lower PAR, PNI and higher CRA were associated with BD-D.

Conclusion

Our study reaffirmed the role of inflammation in the pathophysiology of SCZ and BD. Diagnostic value has been demonstrated in NPAR, PAR, PNI and CRA for BD and SCZ.

Microglia and Other Cellular Mediators of Immunological Dysfunction in Schizophrenia: A Narrative Synthesis of Clinical Findings

Schizophrenia is a complex psychiatric condition that may involve immune system dysregulation. Since most putative disease mechanisms in schizophrenia have been derived from genetic association studies and fluid-based molecular analyses, this review aims to summarize the emerging evidence on clinical correlates to immune system dysfunction in this psychiatric disorder. We conclude this review by attempting to develop a unifying hypothesis regarding the relative contributions of microglia and various immune cell populations to the development of schizophrenia. This may provide important translational insights that can become useful for addressing the multifaceted clinical presentation of schizophrenia.