Changes in immunoglobulin levels during clozapine treatment in schizophrenia.

BACKGROUND AND HYPOTHESIS: Use of clozapine in treatment-resistant schizophrenia is often limited due to risk of adverse effects. Cross-sectional associations between clozapine treatment and low immunoglobulin levels have been reported, however prospective studies are required to establish temporal relationships. We tested the hypothesis that reductions in immunoglobulin levels would occur over the first 6 months following initiation of clozapine treatment. Relationships between immunoglobulin levels and symptom severity over the course of clozapine treatment were also explored. DESIGN: This prospective observational study measured immunoglobulin (Ig) levels (A, M and G) in 56 patients with treatment-resistant schizophrenia at 6-, 12- and 24-weeks following initiation with clozapine. Clinical symptoms were also measured at 12 weeks using the positive and negative syndrome scale (PANSS). RESULTS: IgA, IgG and IgM all decreased during clozapine treatment. For IgA and IgG the reduction was significant at 24 weeks (IgA: ß = -32.66, 95% CI = -62.38, -2.93, p = 0.03; IgG: ß = -63.96, 95% CI = -118.00, -9.31, p = 0.02). For IgM the reduction was significant at 12 and 24 weeks (12 weeks: ß = -23.48, 95% CI = -39.56, -7.42, p = 0.004; 24 weeks: ß = -33.12, 95 %CI = -50.30, -15.94, p = <0.001). Reductions in IgA and IgG during clozapine treatment were correlated with reductions in PANSS-total over 12 weeks (n = 32, IgA r = 0.59, p = 0.005; IgG r = 0.48, p = 0.03). CONCLUSIONS: The observed reductions in immunoglobulin levels over six months of clozapine treatment add further evidence linking clozapine to secondary antibody deficiency. Associations between Ig reduction and symptom improvement may however indicate that immune mechanisms contribute to both desirable and undesirable effects of clozapine.

Risk of bleeding amongst warfarin and direct oral anticoagulant users prescribed immediate antibiotics for respiratory tract infection: Cohort study.

PURPOSE: Incidence of bleeding amongst warfarin and direct oral anticoagulant (DOAC) users is greater following a respiratory tract infection (RTI). It is unclear whether immediate antibiotics modify this association. We estimated the risk of bleeding amongst warfarin and DOAC users with RTI by antibiotic treatment. METHODS: This retrospective cohort study used data from the Clinical Practice Research Datalink (CPRD) GOLD for adults in England prescribed warfarin or a DOAC, who sought primary care for an RTI between 1st January 2011 and 31st December 2019. Outcomes were major bleeding (hospital admission for intracranial or gastrointestinal bleeding), and non-major bleeding (hospital admission or General Practice consult for epistaxis, haemoptysis, or haematuria). Cox models derived hazard ratios (HRs) and 95% confidence intervals (CIs) for each outcome, adjusting for confounders using inverse probability of treatment weighting. RESULTS: Of 14 817 warfarin and DOAC users consulting for an RTI, 8768 (59%) were prescribed immediate antibiotics and 6049 (41%) were not. Approximately 49% were female, and median age was 76 years. Antibiotics were associated with reduced risk of major bleeding (adjusted HR 0.38, 95% CI 0.25 to 0.58). This was consistent across several sensitivity analyses. Antibiotics were also associated with a reduced risk of non-major bleeding (adjusted HR 0.78, 95% CI 0.61 to 0.99). CONCLUSIONS: Immediate antibiotics were associated with reduced risk of bleeding amongst warfarin and DOAC users with an RTI. Further work is needed to understand mechanisms and confirm whether a lower threshold for antibiotic use for RTI in this population may be beneficial.

Mechanically Ventilated Patients Shed High-Titer Live Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) for Extended Periods From Both the Upper and Lower Respiratory Tract.

BACKGROUND: SARS-CoV-2 infection can lead to severe acute respiratory distress syndrome needing intensive care admission and may lead to death. As a virus that transmits by respiratory droplets and aerosols, determining the duration of viable virus shedding from the respiratory tract is critical for patient prognosis, and informs infection-control measures both within healthcare settings and the public domain. METHODS: We prospectively examined upper and lower airway respiratory secretions for both viral RNA and infectious virions in mechanically ventilated patients admitted to the intensive care unit (ICU) of the University Hospital of Wales. Samples were taken from the oral cavity (saliva), oropharynx (subglottic aspirate), or lower respiratory tract (nondirected bronchoalveolar lavage [NBAL] or bronchoalveolar lavage [BAL]) and analyzed by both quantitative PCR (qPCR) and plaque assay. RESULTS: 117 samples were obtained from 25 patients. qPCR showed extremely high rates of positivity across all sample types; however, live virus was far more common in saliva (68%) than in BAL/NBAL (32%). Average titers of live virus were higher in subglottic aspirates (4.5 × 107) than in saliva (2.2 × 106) or BAL/NBAL (8.5 × 106) and reached >108 PFU/mL in some samples. The longest duration of shedding was 98 days, while most patients (14/25) shed live virus for ≥20 days. CONCLUSIONS: ICU patients infected with SARS-CoV-2 can shed high titers of virus both in the upper and lower respiratory tract and tend to be prolonged shedders. This information is important for decision making around cohorting patients, de-escalation of personal protective equipment, and undertaking potential aerosol-generating procedures.

Development of a high-sensitivity ELISA detecting IgG, IgA and IgM antibodies to the SARS-CoV-2 spike glycoprotein in serum and saliva.

Detecting antibody responses during and after SARS-CoV-2 infection is essential in determining the seroepidemiology of the virus and the potential role of antibody in disease. Scalable, sensitive and specific serological assays are essential to this process. The detection of antibody in hospitalized patients with severe disease has proven relatively straightforward; detecting responses in subjects with mild disease and asymptomatic infections has proven less reliable. We hypothesized that the suboptimal sensitivity of antibody assays and the compartmentalization of the antibody response may contribute to this effect. We systematically developed an ELISA, optimizing different antigens and amplification steps, in serum and saliva from non-hospitalized SARS-CoV-2-infected subjects. Using trimeric spike glycoprotein, rather than nucleocapsid, enabled detection of responses in individuals with low antibody responses. IgG1 and IgG3 predominate to both antigens, but more anti-spike IgG1 than IgG3 was detectable. All antigens were effective for detecting responses in hospitalized patients. Anti-spike IgG, IgA and IgM antibody responses were readily detectable in saliva from a minority of RT-PCR confirmed, non-hospitalized symptomatic individuals, and these were mostly subjects who had the highest levels of anti-spike serum antibodies. Therefore, detecting antibody responses in both saliva and serum can contribute to determining virus exposure and understanding immune responses after SARS-CoV-2 infection.

High-throughput STELA provides a rapid test for the diagnosis of telomere biology disorders.

Telomere biology disorders are complex clinical conditions that arise due to mutations in genes required for telomere maintenance. Telomere length has been utilised as part of the diagnostic work-up of patients with these diseases; here, we have tested the utility of high-throughput STELA (HT-STELA) for this purpose. HT-STELA was applied to a cohort of unaffected individuals (n = 171) and a retrospective cohort of mutation carriers (n = 172). HT-STELA displayed a low measurement error with inter- and intra-assay coefficient of variance of 2.3% and 1.8%, respectively. Whilst telomere length in unaffected individuals declined as a function of age, telomere length in mutation carriers appeared to increase due to a preponderance of shorter telomeres detected in younger individuals (< 20 years of age). These individuals were more severely affected, and age-adjusted telomere length differentials could be used to stratify the cohort for overall survival (Hazard Ratio = 5.6 (1.5-20.5); p < 0.0001). Telomere lengths of asymptomatic mutation carriers were shorter than controls (p < 0.0001), but longer than symptomatic mutation carriers (p < 0.0001) and telomere length heterogeneity was dependent on the diagnosis and mutational status. Our data show that the ability of HT-STELA to detect short telomere lengths, that are not readily detected with other methods, means it can provide powerful diagnostic discrimination and prognostic information. The rapid format, with a low measurement error, demonstrates that HT-STELA is a new high-quality laboratory test for the clinical diagnosis of an underlying telomeropathy.

Haematopoietic Stem Cell Transplant for Norovirus-Induced Intestinal Failure in X-linked Agammaglobulinemia.

Since the first clinical description in 1952, immunoglobulin replacement therapy remains the mainstay of treatment of patients with X-linked agammaglobulinemia (XLA). However, this therapy only replaces IgG isotype and does not compensate for the loss of Bruton tyrosine kinase in non-B-lymphocytes. Patients may still therefore develop complications despite current standard of care. Here, we describe an XLA patient with persistent chronic norovirus infection, refractory to treatment and causing intestinal failure. The patient underwent haematopoietic stem cell transplantation, curing XLA and allowed clearance of norovirus prior to humoral immunoreconstitution, suggesting non-humoral immunodeficiency in these patients.

Hematopoietic Stem Cell Transplantation Resolves the Immune Deficit Associated with STAT3-Dominant-Negative Hyper-IgE Syndrome.

Autosomal dominant hyper-IgE syndrome caused by dominant-negative loss-of-function mutations in signal transducer and activator of transcription factor 3 (STAT3) (STAT3-HIES) is a rare primary immunodeficiency with multisystem pathology. The quality of life in patients with STAT3-HIES is determined by not only the progressive, life-limiting pulmonary disease, but also significant skin disease including recurrent infections and abscesses requiring surgery. Our early report indicated that hematopoietic stem cell transplantation might not be effective in patients with STAT3-HIES, although a few subsequent reports have reported successful outcomes. We update on progress of our patient now with over 18 years of follow-up and report on an additional seven cases, all of whom have survived despite demonstrating significant disease-related pathology prior to transplant. We conclude that effective cure of the immunological aspects of the disease and stabilization of even severe lung involvement may be achieved by allogeneic hematopoietic stem cell transplantation. Recurrent skin infections and abscesses may be abolished. Donor TH17 cells may produce comparable levels of IL17A to healthy controls. The future challenge will be to determine which patients should best be offered this treatment and at what point in their disease history.

Burden of nosocomial COVID-19 in Wales: results from a multicentre retrospective observational study of 2508 hospitalised adults.

The burden of nosocomial SARS-CoV-2 infection remains poorly defined. We report on the outcomes of 2508 adults with molecularly-confirmed SARS-CoV-2 admitted across 18 major hospitals, representing over 60% of those hospitalised across Wales between 1 March and 1 July 2020. Inpatient mortality for nosocomial infection ranged from 38% to 42%, consistently higher than participants with community-acquired infection (31%-35%) across a range of case definitions. Those with hospital-acquired infection were older and frailer than those infected within the community. Nosocomial diagnosis occurred a median of 30 days following admission (IQR 21-63), suggesting a window for prophylactic or postexposure interventions, alongside enhanced infection control measures.

Quantification of human C1 esterase inhibitor protein using an automated turbidimetric immunoassay.

BACKGROUND: Impaired levels or function of C1 inhibitor (C1-INH) results in angioedema due to increased bradykinin. It is important to distinguish between angioedema related to C1-INH deficiency and that caused by other mechanisms, as treatment options are different. In hereditary (HAE) and acquired (AAE) angioedema, C1-INH concentration is measured to aid patient diagnosis. Here, we describe an automated turbidimetric assay to measure C1-INH concentration on the Optilite® analyzer. METHODS: Linearity, precision, and interference were established over a range of C1-INH concentrations. The 95th percentile reference interval was generated from 120 healthy adult donors. To compare the Optilite C1-INH assay with a predicate assay used in a clinical laboratory, samples sent for C1-INH investigation were used. The predicate results were provided to allow comparison. RESULTS: The Optilite C1-INH assay was linear across the measuring range at the standard sample dilution. Intra and interassay variability was <6%. The 95th percentile adult reference interval for the assay was 0.21-0.38 g/L. There was a strong correlation between the Optilite concentrations and those generated with the predicate assay (R2  = 0.94, P < 0.0001, slope y = 0.83x). All patients with Type I HAE (n = 24) and AAE (n = 3) tested had concentrations below the measuring range in both assays, while all patients with unspecified angioedema (UAE), not diagnosed with HAE or AAE had values within the reference range. CONCLUSION: The Optilite assay allows the automated and precise quantification of C1-INH concentrations in patient samples. It could therefore be used as a tool to aid the investigation of patients with angioedema.

Hyper-IgE in the allergy clinic--when is it primary immunodeficiency?

The 2017 International Union of Immunological Societies (IUIS) classification recognizes 3 hyper-IgE syndromes (HIES), including the prototypic Job's syndrome (autosomal dominant STAT3-loss of function) and autosomal recessive PGM3 and SPINK5 syndromes. Early diagnosis of PID can direct life-saving or transformational interventions; however, it remains challenging owing to the rarity of these conditions. This can result in diagnostic delay and worsen prognosis. Within increasing access to "clinical-exome" testing, clinicians need to be aware of the implication and rationale for genetic testing, including the benefits and limitations of current therapies. Extreme elevation of serum IgE has been associated with a growing number of PID syndromes including the novel CARD11 and ZNF341 deficiencies. Variable elevations in IgE are associated with defects in innate, humoral, cellular and combined immunodeficiency syndromes. Barrier compromise can closely phenocopy these conditions. The aim of this article was to update readers on recent developments at this important interface between allergy and immunodeficiency, highlighting key clinical scenarios which should draw attention to possible immunodeficiency associated with extreme elevation of IgE, and outline initial laboratory assessment and management.

Clozapine is associated with secondary antibody deficiency.

BACKGROUND: Schizophrenia affects 1% of the population. Clozapine is the only medication licensed for treatment-resistant schizophrenia and is intensively monitored to prevent harm from neutropenia. Clozapine is also associated with increased risk of pneumonia although the mechanism is poorly understood.AimsTo investigate the potential association between clozapine and antibody deficiency. METHODS: Patients taking clozapine and patients who were clozapine-naive and receiving alternative antipsychotics were recruited and completed a lifestyle, medication and infection-burden questionnaire. Serum total immunoglobulins (immunoglobulin (Ig)G, IgA, IgM) and specific IgG antibodies to haemophilus influenzae type B, tetanus and IgG, IgA and IgM to pneumococcus were measured. RESULTS: Immunoglobulins were all significantly reduced in the clozapine-treated group (n = 123) compared with the clozapine-naive group (n = 111). Odds ratios (ORs) for a reduction in clozapine:control immunoglobulin values below the fifth percentile were IgG, OR = 6.00 (95% CI 1.31-27.44); IgA, OR = 16.75 (95% CI 2.18-128.60); and IgM, OR = 3.26 (95% CI 1.75-6.08). These findings remained significant despite exclusion of other potential causes of hypogammaglobulinaemia. In addition, duration on clozapine was associated with decline in IgG. A higher proportion of the clozapine-treated group reported taking more than five courses of antibiotics in the preceding year (5.3% (n = 5) versus 1% (n = 1). CONCLUSIONS: Clozapine use was associated with significantly reduced immunoglobulin levels and an increased proportion of patients using more than five antibiotic courses in a year. Antibody testing is not included in existing clozapine monitoring programmes but may represent a mechanistic explanation and modifiable risk factor for the increased rates of pneumonia and sepsis-related mortality previously reported in this vulnerable cohort.Declaration of interestS.J. has received support from CSL Behring, Shire, LFB, Biotest, Binding Site, Sanofi, GSK, UCB Pharma, Grifols, BPL SOBI, Weatherden, Zarodex and Octapharma for projects, advisory boards, meetings, studies, speaker and clinical trials.

Quantification of human complement C2 protein using an automated turbidimetric immunoassay.

BACKGROUND: The measurement of complement components is clinically useful where a deficiency is suspected, or where excessive activation and consumption are present in disease. C2 deficiency carries an increased risk of developing systemic lupus erythematosus, recurrent infections and atherosclerosis. In this study, we have evaluated The Binding Site's Human Complement C2 SPAPLUS® assay. METHODS: Linearity was tested using 13 sample dilutions covering the standard measuring range. Within- and between-assay variabilities were calculated using five samples with different C2 concentrations. The correlation between C2 concentrations in EDTA-plasma and serum was assessed, as was the correlation between C2 measurements by the automated assay and radial immunodiffusion. C2 concentrations were compared with CH50 activity, and quantified in individuals with homozygous or heterozygous C2 deficiency, acquired angioedema and patients with chronic inflammatory conditions. RESULTS: The assay was linear across the measuring range (3.8-42.3 mg/L). Intra- and interassay variability were 2.3%-3.8% and 0%-3.3%, respectively. Comparison between C2 measurements in EDTA-plasma and serum provided a strong correlation (p<0.0001, R2=0.82, slope 0.92), as did the correlation between the automated and radial immunodiffusion methods (p<0.0001, R2=0.89, slope 1.07). A positive correlation between C2 concentration and CH50 activity was demonstrated (p<0.0001, R2=0.48). Significant differences were observed between the median C2 concentrations obtained in healthy controls and the patient clinical samples, with homozygous C2-deficient patients giving below detectable results. CONCLUSIONS: This C2 SPAPLUS® assay allows the automated, rapid and precice quantification of complement C2 protein and could therefore be considered as a replacement for older, more time-consuming methods.

Sequestration and microvascular congestion are associated with coma in human cerebral malaria.

The pathogenesis of coma in severe Plasmodium falciparum malaria remains poorly understood. Obstruction of the brain microvasculature because of sequestration of parasitized red blood cells (pRBCs) represents one mechanism that could contribute to coma in cerebral malaria. Quantitative postmortem microscopy of brain sections from Vietnamese adults dying of malaria confirmed that sequestration in the cerebral microvasculature was significantly higher in patients with cerebral malaria (CM; n = 21) than in patients with non-CM (n = 23). Sequestration of pRBCs and CM was also significantly associated with increased microvascular congestion by infected and uninfected erythrocytes. Clinicopathological correlation showed that sequestration and congestion were significantly associated with deeper levels of premortem coma and shorter time to death. Microvascular congestion and sequestration were highly correlated as microscopic findings but were independent predictors of a clinical diagnosis of CM. Increased microvascular congestion accompanies coma in CM, associated with parasite sequestration in the cerebral microvasculature.

Atopic manifestations of inborn errors of immunity.

PURPOSE OF REVIEW: Allergy and atopic features are now well recognized manifestations of many inborn errors of immunity (IEI), and indeed may be the hallmark in some, such as DOCK8 deficiency. In this review, we describe the current IEI associated with atopy, using a comprehensive literature search and updates from the IUIS highlighting clinical clues for underlying IEI such as very early onset of atopic disease or treatment resistance to enable early and accurate genetic diagnosis. RECENT FINDINGS: We focus on recently described genes, their categories of pathogenic mechanisms and the expanding range of potential therapies. SUMMARY: We highlight in this review that patients with very early onset or treatment resistant atopic disorders should be investigated for an IEI, as targeted and effective therapies exist. Early and accurate genetic diagnosis is crucial in this cohort to reduce the burden of disease and mortality.