Involvement of Extracellular Vesicles in the Proinflammatory Response to Clozapine: Implications for Clozapine-Induced Agranulocytosis.

Most idiosyncratic drug reactions (IDRs) appear to be immune-mediated, but mechanistic events preceding severe reaction onset remain poorly defined. Damage-associated molecular patterns (DAMPs) may contribute to both innate and adaptive immune phases of IDRs, and changes in extracellular vesicle (EV) cargo have been detected post-exposure to several IDR-associated drugs. To explore the hypothesis that EVs are also a source of DAMPs in the induction of the immune response preceding drug-induced agranulocytosis, the proteome and immunogenicity of clozapine- (agranulocytosis-associated drug) and olanzapine- (non-agranulocytosis-associated drug) exposed EVs were compared in two preclinical models: THP-1 macrophages and Sprague-Dawley rats. Compared with olanzapine, clozapine induced a greater increase in the concentration of EVs enriched from both cell culture media and rat serum. Moreover, treatment of drug-naïve THP-1 cells with clozapine-exposed EVs induced an inflammasome-dependent response, supporting a potential role for EVs in immune activation. Proteomic and bioinformatic analyses demonstrated an increased number of differentially expressed proteins with clozapine that were enriched in pathways related to inflammation, myeloid cell chemotaxis, wounding, transforming growth factor-ß signaling, and negative regulation of stimuli response. These data indicate that, although clozapine and olanzapine exposure both alter the protein cargo of EVs, clozapine-exposed EVs carry mediators that exhibit significantly greater immunogenicity. Ultimately, this supports the working hypothesis that drugs associated with a risk of IDRs induce cell stress, release of proinflammatory mediators, and early immune activation that precedes severe reaction onset. Further studies characterizing EVs may elucidate biomarkers that predict IDR risk during development of drug candidates. SIGNIFICANCE STATEMENT: This work demonstrates that clozapine, an idiosyncratic drug-induced agranulocytosis (IDIAG)-associated drug, but not olanzapine, a safer structural analogue, induces an acute proinflammatory response and increases extracellular vesicle (EV) release in two preclinical models. Moreover, clozapine-exposed EVs are more immunogenic, as measured by their ability to activate inflammasomes, and contain more differentially expressed proteins, highlighting a novel role for EVs during the early immune response to clozapine and enhancing our mechanistic understanding of IDIAG and other idiosyncratic reactions.

Fatal pulmonary hemorrhage, pneumothorax and skin necrosis caused by IRIS to an Aspergillus flavus infection in a young patient with metamizole associated agranulocytosis.

We report the case of a young female with steroid-dependent ulcerative colitis (UC) who developed a complex systemic infection with Aspergillus flavus. This occurred following a UC relapse while vacationing in the Middle East, leading to extended use of metamizole and subsequent agranulocytosis. On her return to Germany, she was hospitalized for neutropenic sepsis and later transferred to our hospital due to persistent cytopenia and suspected Hemophagocytic Lymphohistiocytosis (HLH). Despite initial stabilization with targeted treatment for pulmonary Aspergillus flavus infection, her condition rapidly deteriorated following the onset of an Immune Reconstitution Inflammatory Syndrome (IRIS), which manifested as skin necrosis and pneumothorax after the replenishment of neutrophil granulocytes. The patient eventually died from an unmanageable pulmonary hemorrhage. Microscopy of skin necroses showed a massive presence of Aspergillus flavus, but tissue culture remained negative, suggesting effective antifungal treatment yet delayed phagocytosis due to agranulocytosis. This case underscores the need to consider IRIS in immunosuppressed patients who worsen despite aggressive and appropriately targeted treatment, highlighting its potential beyond the commonly recognized context in HIV-positive patients.

Genetic susceptibility to breast cancer increases the risk of neutropenia and agranulocytosis: insights from Mendelian randomization.

PURPOSE: The causal relationship between breast cancer and its estrogen receptor (ER) subtypes and neutropenia and agranulocytosis is unclear. METHODS: In two-sample Mendelian randomization (MR), we used inverse variance weighting (IVW), Bayesian weighted MR (BWMR), MR-Egger, weighted median, simple mode, and weighted mode methods to analyze causality for ER-positive breast cancer, ER-negative breast cancer, overall breast cancer, and drug-induced neutropenia and agranulocytosis. To validate the results, we performed the analysis again using GWAS data on neutropenia from different databases. In multivariable MR (MVMR), we assessed the independent effects of ER-positive and ER-negative breast cancer on causality. RESULTS: Two-sample MR analysis showed a causal relationship between ER-positive breast cancer (IVW odds ratio (OR) = 1.319, P = 7.580 × 10-10), ER-negative breast cancer (OR = 1.285, P = 1.263 × 10-4), overall breast cancer (OR = 1.418, P = 2.123 × 10-13), and drug-induced neutropenia and a causal relationship between ER-positive breast cancer (OR = 1.349, P = 1.402 × 10-7), ER-negative breast cancer (OR = 1.235, P = 7.615 × 10-3), overall breast cancer (OR = 1.429, P = 9.111 × 10-10), and neutropenia. Similarly, ER-positive breast cancer (OR = 1.213, P = 5.350 × 10-8), ER-negative breast cancer (OR = 1.179, P = 1.300 × 10-3), and overall breast cancer (OR = 1.275, P = 8.642 × 10-11) also had a causal relationship with agranulocytosis. MVMR analysis showed that ER-positive breast cancer remained causally associated with drug-induced neutropenia (OR = 1.233, P = 4.188 × 10-4), neutropenia (OR = 1.283, P = 6.363 × 10-4), and agranulocytosis (OR = 1.142, P = 4.549 × 10-3). Heterogeneity analysis and pleiotropy test showed that our results were reliable. CONCLUSION: Our study provides genetic evidence for a causal association between breast cancer and its estrogen receptor subtypes and neutropenia. In clinical practice, in addition to focusing on therapeutic factors, additional attention should be given to breast cancer patients to avoid severe neutropenia.

Severe Infection Mimicking AML due to Bone Marrow Suppression: a Diagnostic Challenge.

BACKGROUND: Infection may lead to agranulocytosis due to bone marrow suppression. However, a rare case with infection presented with morphological features of acute myeloid leukemia (AML). METHODS: We report a case of extreme agranulocytosis due to severe infection mimicking acute myeloid leukemia. The case was definitively diagnosed by subsequent morphology, flow cytometry, and bone marrow biopsy, and subsequent successful anti-infective treatment confirmed the diagnosis. CONCLUSIONS: To date, no case of a patient diagnosed with severe infection mimicking AML has been reported. The case emphasizes the importance of an integrated diagnostic work-up, especially careful clinical observation and differential diagnosis.

Dose-dependent incidence of agranulocytosis in patients treated with methimazole and propylthiouracil.

Agranulocytosis is a serious adverse effect of methimazole (MMI) and propylthiouracil (PTU), and although there have been reports suggesting a dose-dependent incidence in relation to both drugs, the evidence has not been conclusive. The objective of our study was to determine whether the incidences of agranulocytosis induced by MMI and PTU exhibit dose-dependency. The subjects were 27,784 patients with untreated Graves' disease, 22,993 of whom were on an antithyroid drug treatment regimen for more than 90 days. Within this subset, 18,259 patients had been treated with MMI, and 4,734 had been treated with PTU. The incidence of agranulocytosis according to dose in the MMI group was 0.13% at 10 mg/day, 0.20% at 15 mg/day, 0.32% at 20 mg/day, and 0.47% at 30 mg/day, revealing a significant dose-dependent increase. In the PTU group, there were 0 cases of agranulocytosis at doses of 125 mg/day and below, 0.33% at 150 mg/day, 0.31% at 200 mg/day, and 0.81% at 300 mg/day, also revealing a significant dose-dependent increase. The incidence of agranulocytosis at MMI 15 mg and PTU 300 mg, i.e., at the same potency in terms of hormone synthesis inhibition, was 0.20% and 0.81%, respectively, and significantly higher in the PTU group. Our findings confirm a dose-dependent increase in the incidence of agranulocytosis with both drugs, but that at comparable thyroid hormone synthesis inhibitory doses PTU has a considerably higher propensity to induce agranulocytosis than MMI does.

Pembrolizumab-induced agranulocytosis.

INTRODUCTION: With the widespread use of anti-programmed death-1 monoclonal antibodies, such as pembrolizumab, rare side effects appear in clinical practice. CASE REPORT: We report the case of a man diagnosed with non-keratinizing squamous lung carcinoma stage IVB with programmed death-ligand 1 70% who developed agranulocytosis 10 days after a single dose of pembrolizumab as monotherapy. MANAGEMENT AND OUTCOME: Pembrolizumab was discontinued immediately. Grade 4 neutrophil decrease is mentioned in the product information sheet as a rare side effect. The patient was admitted in poor physical condition with grade 4 neutropenic fever, mucositis and anemia. Agranulocytosis did not improve despite treatment with granulocyte colony-stimulating factor, intravenous corticosteroids and intravenous immunoglobulins. He experienced a rapid worsening and died 3 weeks after admission. The causal relationship between pembrolizumab and the appearance of agranulocytosis was determined as possible according to Naranjo's modified Karch and Lasagna's imputability algorithm. DISCUSSION: Hematologic immune-related adverse events are uncommon but important side effects among patients treated with immune checkpoint inhibitors. Agranulocytosis and neutropenia are infrequently reported but can be life-threatening. The main approach for agranulocytosis consists of intravenous corticosteroids, granulocyte colony-stimulating factors and blood products. Depending on bone marrow characteristics, treatments for refractory patients include intravenous immunoglobulins or cyclosporine. After an immune-related adverse event, benefits and risks must be considered before continuation with an immune checkpoint inhibitor. Detection and communication of adverse drug reactions to the Pharmacovigilance Systems have special relevance for rare side effects.

Escaping the Long Shadow Cast by Agranulocytosis: Reflections on Clozapine Pharmacovigilance Focused on the United Kingdom.

PURPOSE/BACKGROUND: A recent article in this journal presented a US perspective regarding the modernization of clozapine prescription and proposed an escape from the long shadow cast by agranulocytosis. METHODS: Here, an international group of collaborators discusses a point of view complementary to the US view by focusing on worldwide outcomes of clozapine usage that may be uneven in terms of frequency of clozapine adverse drug reactions. FINDINGS/RESULTS: Studies from the Scandinavian national registries (Finland and Denmark) did not find increased mortality in clozapine patients or any clear evidence of the alleged toxicity of clozapine. Data on clozapine-associated fatal outcomes were obtained from 2 recently published pharmacovigilance studies and from the UK pharmacovigilance database. A pharmacovigilance study focused on physician reports to assess worldwide lethality of drugs from 2010 to 2019 found 968 clozapine-associated fatal outcomes in the United Kingdom. Moreover, the United Kingdom accounted for 55% (968 of 1761) of worldwide and 90% (968 of 1073) of European fatal clozapine-associated outcomes. In a pharmacovigilance study from the UK database (from 2008 to 2017), clozapine was associated with 383 fatal outcomes/year including all reports from physicians and nonphysicians. From 2018 to 2021, UK clozapine-associated fatal outcomes increased to 440/year. IMPLICATIONS/CONCLUSIONS: The interpretation of fatal outcomes in each country using pharmacovigilance databases is limited and only allows gross comparisons; even with those limitations, the UK data seem concerning. Pneumonia and myocarditis may be more important than agranulocytosis in explaining the uneven distribution of fatal outcomes in clozapine patients across countries.

Clozapine-Associated Agranulocytosis: A Systematic Review. Is It Really So Frighteningly Common?

BACKGROUND: Clozapine is a very effective therapeutic option for schizophrenic disorders that have been refractory to most other therapies. This extremely positive aspect clashes easily with an adverse effect of the drug that is deemed to be a very dangerous one: agranulocytosis. We asked whether the mandatory strict hematological follow-up prescribed in the black box warning of clozapine's label is proportioned to the actual incidence of agranulocytosis, considering that is the main reason that such a drug is often used only late in the treatment course. METHODS: We carried out a systematic review of reports examining clozapine administration and agranulocytosis incidence. We specifically selected those where mild and moderate neutropenia was not used as a trigger to stop administration of clozapine, to better estimate the sheer incidence of agranulocytosis when clozapine was continued even with mild hematological effect, where detected. We used PubMed, MEDLINE, EMBASE, Cochrane, and ScienceDirect databases to identify clinical studies conducted between January 1975 and April 2023. RESULTS: We included 14 studies, mostly retrospective ones, that examined the incidence of hematological adverse effects in patients using clozapine. A total of 2354 subjects were included. The mean age of the subjects was 33.5 years. The mean duration of observation of subjects who took clozapine was 800 days, with a mean daily dose of 319.5 mg per day. Of the 2354 subjects examined, we found that 11 of them experienced agranulocytosis (0.47%). CONCLUSIONS: These results suggest the evidence of a lower incidence of agranulocytosis than previously estimated and are in line with more recent meta-analyses. We may therefore think that clinical practice may demand a revision of the approach that both psychiatrists and supervising organizations often take when talking about clozapine.

Outcome of COVID-19 mRNA Vaccination in Patients Treated With Clozapine WHO Previously Went Through SARS-COV-2 Infection.

BACKGROUND: The outbreak of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic had multiple consequences for the health care system, especially for patients with mental illnesses. Schizophrenia patients particularly appear to have a higher risk of complications due to coronavirus-19 (COVID-19). Clozapine remains the gold standard for treatment-resistant schizophrenia (TRS). However, the COVID-19 pandemic had an important negative impact on clozapine treatment, mainly because of its administration protocol, which was very difficult to follow during the restrictions imposed in the pandemic, and its side effects in patients with COVID-19 infection. Vaccination is an effective method of avoiding SARS-CoV-2 infection or its severe complications, especially in susceptible populations. Data on adverse events after vaccination against COVID-19 are limited, both in the general population and in schizophrenia patients. STUDY QUESTION: The study aimed to investigate the safety of COVID-19 vaccination in patients treated with clozapine for hematological parameters. STUDY DESIGN: We conducted an analytical cross-sectional study between July 1, 2021, and June 30, 2022. We compared 2 groups of COVID-19 vaccinated patients who had previously experienced SARS-CoV-2 infection: The first group was treated with clozapine, whereas the second group was treated with other antipsychotics. MEASURES AND OUTCOMES: The primary objective was to identify granulocytopenia, leukocytopenia, and lymphocytopenia. The results were measured after the second dose of the Pfizer-BioNTech vaccine. RESULTS: This study included 100 patients. White blood cell count changes were limited to a few cases of mild granulocytopenia (8.16% in the clozapine group and 3.92% in the nonclozapine group, P = 0.37) with no cases of severe granulocytopenia or agranulocytosis. CONCLUSIONS: As far as leukocyte counts are concerned, mRNA COVID-19 vaccination seems to be safe in patients treated with clozapine who previously had SARS-CoV-2 infection. Leukocyte changes had no clinical implications.

Detection of drug safety signal of drug-induced neutropenia and agranulocytosis in all-aged patients using electronic medical records.

PURPOSE: We explored the adverse drug reaction signals of drug-induced neutropenia (DIN) and drug-induced agranulocytosis (DIA) in hospitalized patients and evaluated the novelty of these correlations. METHOD: A two-step method was established to identify the relationship between drugs and DIN or DIA using 5-year electronic medical records (EMRs) obtained from 242 000 patients at Qilu Hospital of Shandong University. First, the drugs suspected to induce DIN or DIA were selected. The associations between suspected drugs and DIN or DIA were evaluated by a retrospective cohort study using unconditional logistic regression analysis and multiple linear regression model. RESULTS: Twelve suspected drugs (vancomycin, meropenem, voriconazole, acyclovir, ganciclovir, fluconazole, oseltamivir, linezolid, compound borax solution, palonosetron, polyene phosphatidylcholine, and sulfamethoxazole) were associated with DIN, and six suspected drugs (vancomycin, voriconazole, acyclovir, ganciclovir, fluconazole, and oseltamivir) were associated with DIA. The multivariate linear regression model revealed that nine drugs (vancomycin, meropenem, voriconazole, ganciclovir, fluconazole, oseltamivir, compound borax solution, palonosetron, and polyene phosphatidylcholine) and four drugs (vancomycin, voriconazole, ganciclovir, and fluconazole) were found to be associated with DIN and DIA, respectively. While logistic regression analysis revealed that palonosetron and ganciclovir were associated with DIN and DIA, respectively. CONCLUSION: Palonosetron and ganciclovir were found to be correlated with drug-induced granulocytopenia. The results of this study provide an early warning of drug safety signals for drug-induced granulocytopenia, facilitating a quick and appropriate response for clinicians.

Impact of rhG-CSF on Clinical Efficacy and Immune Cell Subsets after Initial Induction Chemotherapy in AML.

BACKGROUND: The impact of recombinant human granulocyte colony-stimulating factor (rhG-CSF) in acute myeloid leukemia (AML) is still controversial. The purpose of this study is to explore the impact of rhG-CSF administration on clinical efficacy and immune cell subsets after initial induction chemotherapy in AML. METHODS: The clinical efficacy and immune cell subsets were compared in the newly diagnosed patients with AML according to whether rhG-CSF was used after initial induction chemotherapy. Next, rhG-CSF stimulation experi-ments on leukemia cell lines and primary leukemia blasts were performed in vitro. RESULTS: There was no statistical difference between control group and rhG-CSF therapy group in complete remission rate and relapse free survival. The duration of agranulocytosis was significantly shortened in rhG-CSF therapy group compared with control group. The percentage of circulating monocytic myeloid-derived suppressor cells (M-MDSCs) and regulatory T cells (Tregs) were significantly increased after the administration of rhG-CSF. Furthermore, it was found that rhG-CSF did not promote the proliferation of leukemia cell lines and primary leukemia blasts, but increased the proportion of M-MDSCs and Tregs in vitro. CONCLUSIONS: Administration of rhG-CSF after initial induction therapy of AML does not affect the clinical remission and relapse rate, but reduces the duration of agranulocytosis and increases the proportion of M-MDSCs and Tregs.

[A case of ulcerative colitis with mesalazine intolerance complicated with agranulocytosis and septic shock during salazosulfapyridine administration].

A 73-year-old woman developed ulcerative colitis with mesalazine intolerance a year ago. She relapsed 10 months later. Although she was in clinical remission with salazosulfapyridine (SASP) and prednisolone administration, she developed agranulocytosis 53 days following SASP administration. She went into septic shock;however, she recovered with antibiotics, granulocyte colony-stimulating factor, and cardiotonic agents. Drug-induced lymphocyte stimulation test was positive for both mesalazine and SASP. Drug selection should be carefully determined in patients with 5-aminosalicylic acid intolerance.

Diamond-Blackfan anaemia with iron overload: A serious issue.

Transfusion-dependent Diamond-Blackfan anaemia (DBA) patients rapidly develop iron overload and frequently experience cardiac complications. The report by Lecornec and colleagues offers useful details on indications and the management of deferiprone, a highly efficient chelator in removing excess cardiac iron but associated with a high risk of agranulocytosis in DBA patients. Commentary on: Lecornec et al. Agranulocytosis in patients with Diamond-Blackfan anaemia (DBA) treated with deferiprone for post-transfusion iron overload: A retrospective study of the French DBA cohort. British Journal of Haematology 2022;199:285-288.

Pharmacogenomics of Clozapine-induced agranulocytosis: a systematic review and meta-analysis.

Although clozapine is the most effective pharmacotherapy for treatment-resistant schizophrenia, it is under-utilized, and initiation is often delayed. One reason is the occurrence of a potentially fatal adverse reaction, clozapine-induced agranulocytosis (CIA). Identifying genetic variations contributing to CIA would help predict patient risk of developing CIA and personalize treatment. Here, we (1) review existing pharmacogenomic studies of CIA, and (2) conduct meta-analyses to identify targets for clinical implementation. A systematic literature search identified studies that included individuals receiving clozapine who developed CIA and controls who did not. Results showed that individuals carrying the HLA-DRB1*04:02 allele had nearly sixfold (95% CI 2.20-15.80, pcorrected = 0.03) higher odds of CIA with a negative predictive value of 99.3%. Previously unreplicated alleles, TNFb5, HLA-B*59:01, TNFb4, and TNFd3 showed significant associations with CIA after multiple-testing corrections. Our findings suggest that a predictive HLA-DRB1*04:02-based pharmacogenomic test may be promising for clinical implementation but requires further investigation.

Clozapine Rechallenge or Continuation Despite Neutropenia, an Extended Follow-up of a Consecutive Quebec Case Series.

BACKGROUND: Clozapine is the most efficacious antipsychotic for treatment-resistant schizophrenia. However, clozapine-induced neutropenia may warrant treatment discontinuation, hindering recovery. Several case reports describe clozapine rechallenge or continuation despite neutropenia, although many are subject to selective reporting, with incomplete information and short follow-up periods. Thus, consecutive case series, devoid of such bias, with long-term comprehensive follow-up are needed to better assess this practice. This study aimed to describe consecutively the evolution of every patient in the Québec City catchment area for whom clozapine was either reintroduced after neutropenia during a previous clozapine trial or was maintained despite a first neutropenia. METHODS: Patients were identified through clozapine's national hematological monitoring database and their medical records between January 1, 2000, and October 22, 2017. RESULTS: Twenty-three patients were identified, 8 continued clozapine despite neutropenia, while 15 discontinued clozapine and attempted rechallenge; among the latter, 4 patients were successfully rechallenged after agranulocytosis without the use of granulocyte colony-stimulating factors, which is the largest published consecutively. A total of 6 patients experienced further neutropenia episodes. Every patient who had a neutropenia recurrence also had a possible explanation for neutropenia other than exposure to clozapine. After a median follow-up of 4.8 years, 16 patients were still on clozapine and 3 cases discontinued because of a hematological event. CONCLUSIONS: This study adds further data on the subject of clozapine rechallenge or continuation despite neutropenia. Clozapine rechallenge after agranulocytosis may be less perilous than first thought, but a systematic review on this specific subject is needed.

Current challenges of hematologic complications due to immune checkpoint blockade: a comprehensive review.

Immune checkpoint blockade has demonstrated durable clinical benefits in a variety of malignancies. These immune checkpoint inhibitors (ICIs) produce unwanted autoimmune reactions due to an impaired self-tolerance. Hematologic immune-related adverse events (heme-irAEs) have been increasingly reported in the literature with a reported fatality rate of 12%. In this review, we illustrate 3 cases treated at Johns Hopkins Hospital for ICI-induced agranulocytosis, aplastic anemia, and thrombocytopenia. We then summarize the available evidence regarding the incidence and prevalence of heme-irAEs. We identified immune thrombocytopenia and hemolytic anemia as the most commonly reported heme-irAEs which are more commonly observed with nivolumab therapy. Median time to onset of heme-irAEs varies between patients but occurs earlier with CTLA-4 inhibitors than with anti-PD-L1/PD-1 agents. We also describe the current challenges regarding the recurrence of heme-irAEs despite immune checkpoint blockade termination. We provide the available evidence supporting a mixed T-cell and B-cell immune-mediated response. Finally, we review the treatment algorithm of these complications and provide treatment alternatives to steroid-refractory cases.

Clozapine and COVID-19 Vaccination: Effects on blood levels and leukocytes. An observational cohort study.

OBJECTIVE: To investigate the safety of COVID-19 vaccination in patients on clozapine as regards plasma clozapine concentration and haematological parameters. METHODS: We conducted a multicentre observational cohort study from 22 February 2021 to 2 September 2021. Primary outcomes were clinically relevant increase in clozapine blood levels (>100 µg/L increase compared to baseline) and clozapine alert levels (>1000 µg/L). Secondary outcomes were granulocytopenia, leukocytopenia and lymphocytopenia. Outcomes were measured approximately 5 days after the first and (where applicable) second dose of COVID-19 vaccine. RESULTS: This study included 139 patients. Compared to baseline, clozapine blood levels increased significantly (ES = 0.28, p = 0.003) after the second vaccination. Clinically relevant increases in clozapine blood levels occurred in 20/92 patients (22%) and in 16/56 patients (29%) during the first and second phases, respectively. Clozapine alert levels developed in one patient (1%) following the first dose and in three patients (5%) after the second dose. In both phases, changes in white blood cells (WBC) were limited to mild granulocytopenia (3% and 5%), moderate granulocytopenia (1% and 0%) and leukocytopenia (2% and 3%) without cause for extra monitoring according to the guideline. CONCLUSION: In general, as regards WBC counts COVID-19 vaccination seems to be safe in patients with SMI. Changes in WBC had no clinical implications. Psychoeducation on the symptoms of clozapine intoxication is recommended, especially in patients with clozapine blood levels approaching the upper limit of the therapeutic range. Increase in the C-reactive protein (CRP) level can signal inflammation rapidly and help to prevent clozapine intoxication following vaccination.

Predictive role of blood eosinophils in adult varicella patients.

The study aimed to explore the relationship between eosinophils and the prognosis of varicella in adults. We retrospectively reviewed the medical records of patients who were hospitalised in The Fifth People's Hospital of Suzhou with a diagnosis of adult varicella during the period between 1 January 2012 and 31 December 2020. Of the 359 patients, 228 (63.51%) had eosinopenia. The proportion of patients with mild type disease was significantly lower in the eosinopenia group than that in the non-eosinopenia group (50.44% vs. 65.65%, P = 0.006). The proportion of the patients with common type disease was significantly higher in the eosinopenia group than that in the non-eosinopenia group (39.47% vs. 28.24%, P = 0.039). The proportion of the patients with severe type disease was higher in the eosinopenia group, although the difference did not reach statistical significance (10.09% vs. 6.11%, P = 0.243). The rates of high fever (47.81% vs. 32.82%, P = 0.008; relative risk (RR) 1.296, 95% confidence interval (CI) 1.091-1.540), headache (43.42% vs. 22.14%, P < 0.001; RR 1.415, 95% CI 1.233-1.623), anorexia (53.51% vs. 35.88%, P = 0.001; RR 1.367, 95% CI 1.129-1.655) and complications (82.89% vs. 64.12%, P < 0.001; RR 2.106, 95% CI 1.460-3.038) were also significantly higher in the eosinopenia group. Among the complications, the liver injury and skin infection were more serious in the eosinopenia group. The disease course was significantly longer in the eosinopenia group than that in the non-eosinopenia group (9.43 ± 1.89 days vs. 8.73 ± 1.25 days, P < 0.001). The improvement rate of liver injury in the recovery period was lower in the eosinopenia group than that in the non-eosinopenia group (35.38% vs. 50%, P = 0.012). The study found that adult varicella patients with eosinopenia had a more serious condition, a higher morbidity of complications and a slower recovery. Blood eosinophils can be used as a new predictor of the severity of adult varicella.

A Reactive Metabolite of Clozapine Induces Hematopoietic Toxicity in HL-60 Cells Undergoing Granulocytic Differentiation through Its Effect on Glutathione Metabolism.

Clozapine is an atypical antipsychotic with several advantages over conventional antipsychotics, in addition to its well-known efficacy in treatment-resistant schizophrenia. However, the high risk of agranulocytosis associated with clozapine therapy limits its clinical application. Clozapine bioactivation to an unstable protein-reactive metabolite, identified as a nitrenium intermediate, has been implicated in cytotoxicity toward neutrophils. Clozapine affects myeloid precursor cells rather than neutrophils; however, the impact of its reactive metabolite on myeloid precursor cells undergoing granulocytic differentiation remains unclear. Herein, we used hydrogen peroxide (H2O2) to generate the reactive metabolite and compared reactive metabolite-induced cytotoxicity between HL-60 cells undergoing granulocytic differentiation and differentiated HL-60 cells. In addition, we examined the role of oxidative stress in this type of cytotoxicity. The reactive metabolite of clozapine induced rapid cytotoxicity in HL-60 cells undergoing granulocytic differentiation, but not in differentiated HL-60 cells, with the metabolite exhibiting more potent cytotoxicity than clozapine. No cytotoxicity was observed following incubation with olanzapine, a structural analog of clozapine, even after exposure of the drug to H2O2. The reactive metabolite of clozapine decreased the levels of reduced glutathione, while addition of reduced glutathione attenuated the reactive metabolite-induced cytotoxicity. These findings indicate that glutathione metabolism plays a role in the hematopoietic toxicity induced by the reactive metabolite of clozapine. Oxidative stress may potentially increase susceptibility to the hematopoietic toxicity induced by the reactive metabolite of clozapine.

A study to evaluate the role of eosinophil count as a prognostic marker for assessing the outcome in patients with COVID 19 infection.

The triaging of COVID 19 patients is of paramount importance to plan further management. There are several clinical and laboratory parameters that help in categorizing the disease severity, triaging, and prognostication. Little is known about the prognostic significance of eosinopenia in predicting the severity of COVID 19 from large hospital data especially from low- and middle-income countries. The objective of this study is to evaluate the level of eosinopenia as an early prognostic marker for assessing the outcomes in COVID 19 patients and to assess the superiority of eosinopenia as a prognostic marker for assessing the outcomes in COVID 19 patients compared to lymphopenia and neutrophil: lymphocyte ratio (NLR). MATERIAL: The study was carried out in a tertiary care hospital. A retrospective longitudinal approach was adopted wherein the hospital records of COVID 19 patients were analysed. Two separate groups of patients were included for analysis to describe the association between initial eosinophil counts of the patients and the clinical outcomes. In the first group, the disease severity in terms of clinical and radiological parameters was compared in patients of COVID 19 presenting with and without the presence of initial eosinopenia. Commonly used markers for triage namely lymphopenia and NLR were compared with the presence of initial eosinopenia among the patients who progressed to moderate and severe disease. In the second group, an analysis of eosinopenia was made among the patients who succumbed to the illness. OBSERVATION: It was seen that 29.6% of patients with eosinopenia had moderate and severe disease compared to those without eosinopenia where only 10.8 % had moderate disease, none had severe disease. It was seen that 19.7% of patients with eosinopenia but no lymphopenia had more severe disease compared to patients with lymphopenia but no eosinopenia where 10.8% of the patients had moderate disease, none had severe disease. In patients younger than 60 years who died of COVID 19, it was found that initial eosinopenia was found in 86 % whereas a high neutrophil: lymphocyte ratio >17 was seen in only 25.6% of patients who died. Thus, implying that is eosinopenia is an important marker of disease severity in COVID 19. CONCLUSION: Eosinopenia is an important parameter in the evaluation of COVID 19 and the presence of it should alert the clinicians regarding the further progression of the disease. It is not only an important marker but also an early marker for severe disease.