Neutrophil activation in systemic capillary leak syndrome (Clarkson disease)

Intrinsic endothelial hyperresponsiveness to inflammatory mediators drives acute episodes in models of Clarkson disease

Clarkson disease, or monoclonal gammopathy-associated idiopathic systemic capillary leak syndrome (ISCLS), is a rare, relapsing-remitting disorder featuring the abrupt extravasation of fluids and proteins into peripheral tissues, which in turn leads to hypotensive shock, severe hemoconcentration, and hypoalbuminemia. The specific leakage factor(s) and pathways in ISCLS are unknown, and there is no effective treatment for acute flares. Here, we characterize an autonomous vascular endothelial defect in ISCLS that was recapitulated in patient-derived endothelial cells (ECs) in culture and in a mouse model of disease. ISCLS-derived ECs were functionally hyperresponsive to permeability-inducing factors like VEGF and histamine, in part due to increased endothelial nitric oxide synthase (eNOS) activity. eNOS blockade by administration of N(γ)-nitro-l-arginine methyl ester (l-NAME) ameliorated vascular leakage in an SJL/J mouse model of ISCLS induced by histamine or VEGF challenge. eNOS mislocalization and decreased protein phosphatase 2A (PP2A) expression may contribute to eNOS hyperactivation in ISCLS-derived ECs. Our findings provide mechanistic insights into microvascular barrier dysfunction in ISCLS and highlight a potential therapeutic approach.

Ultrasound findings and specific intrinsic blood volume expansion therapy for neonatal capillary leak syndrome: report from a multicenter prospective self-control study

OBJECTIVE

Capillary leak syndrome (CLS) is characterized by severe systemic edema without specific treatment, resulting in a high mortality rate. This study investigated whether there is organ edema in neonatal CLS patients and specific treatment strategies to improve patient prognosis.

METHODS

Thirty-seven newborns diagnosed with CLS were included in this study. (1) Routine point-of-care ultrasound (POCUS) was used to identify whether the patients had visceral edema or fluid collection. (2) All patients were treated with 3% NaCl intravenously, and the clinical manifestations, laboratory indices and outcomes were compared before and after treatment.

RESULTS

(1) Diffuse severe edema was found in 92.0% of the patients. (2) The POCUS examination revealed that CLS patients exhibited significant visceral edema in addition to diffuse severe edema, which included pulmonary edema in 67.6%, cerebral edema in 37.8%, severe intestinal edema in 24.3%, severe myocardial edema in 8.1%, pericardial effusion in 5.4%, pleural effusion in 29.7% and peritoneal effusion in 18.9%. Two patients (5.45%) had only myocardial edema without other manifestations. (3) Before and after the intravenous injection of 3% NaCl, there were no significant differences in the serum sodium or potassium levels of CLS patients, while the hemoglobin and hematocrit levels were significantly lower after treatment (p < 0.01). Her plasma ALB concentration and arterial pressure returned to normal levels after the treatment was completed. (4) All the patients survived, and no side effects or complications were observed during or after treatment with 3% NaCl.

CONCLUSIONS

(1) In addition to diffuse severe edema, visceral edema and effusion are common and important clinical manifestations of neonatal CLS and need to be detected by routine POCUS. (2) The intravenous injection of 3% NaCl is a safe, effective and specific treatment strategy for neonatal CLS, with a survival rate of 100% and no adverse effects.

A ligand-independent Tie2-activating antibody reduces vascular leakage in models of Clarkson disease

Vascular dysfunction resulting from endothelial hyperpermeability is a common and important feature of critical illness due to sepsis, trauma, and other conditions associated with acute systemic inflammation. Clarkson disease [monoclonal gammopathy-associated idiopathic systemic capillary leak syndrome (ISCLS)] is a rare, orphan disorder marked by spontaneous and recurrent episodes of hypotensive shock and peripheral edema due to widespread vascular leakage in peripheral tissues. Mortality from acute flares approaches 30% due to lack of effective therapies. We evaluated a monoclonal antibody (4E2) specific for the endothelial receptor tyrosine kinase Tie2 in ISCLS models. 4E2 activated Tie2 in ISCLS patient-derived endothelial cells and reduced baseline and proinflammatory mediator-induced barrier dysfunction. 4E2 also reduced mortality and/or vascular leakage associated with systemic histamine challenge or influenza infection in the SJL/J mouse model of ISCLS. These findings support a critical role for Tie2 dysregulation in ISCLS and highlight a viable therapeutic approach to this catastrophic disorder.

Markers of endothelial glycocalyx dysfunction in Clarkson disease

BACKGROUND

Clarkson disease (monoclonal gammopathy-associated idiopathic systemic capillary leak syndrome, ISCLS) is a rare idiopathic condition marked by transient, relapsing-remitting episodes of systemic microvascular hyper-permeability, which liberates plasma fluid and macromolecules into the peripheral tissues. This pathology manifests clinically as the abrupt onset of hypotensive shock, hemoconcentration, and hypoalbuminemia.

METHODS

We analysed endothelial glycocalyx (eGCX)-related markers in plasma from patients with ISCLS during acute disease flares and convalescence by ELISA and comprehensive proteomic profiling. We evaluated eGCX-related components and gene expression in cultured endothelial cells using RNA-sequencing, real-time PCR, and fluorescence staining.

RESULTS

Serum levels of eGCX-related core components including hyaluronic acid (HA) and the core proteoglycan soluble syndecan-1 (sCD138) were elevated at baseline and during acute ISCLS flares. Serial measurements demonstrated that sCD138 levels peaked during the recovery (post-leak) phase of the illness. Proteomic analysis of matched acute and convalescent ISCLS plasma revealed increased abundance of eGCX-related proteins, including glypicans, thrombospondin-1 (TSP-1), and eGCX-degrading enzymes in acute compared to remission plasma. Abundance of endothelial cell damage markers did not differ in acute and baseline plasma. Expression of several eGCX-related genes and surface carbohydrate content in endothelial cells from patients with ISCLS did not differ significantly from that observed in healthy control cells.

CONCLUSIONS

eGCX dysfunction, but not endothelial injury, may contribute to clinical symptoms of acute ISCLS. Serum levels of of eGCX components including sCD138 may be measured during acute episodes of ISCLS to monitor clinical status and therapeutic responses.

New-Onset Systemic Capillary Leak Syndrome in an Adult Patient with COVID-19

Systemic capillary leak syndrome (SCLS) is a rare disorder manifesting as shock, hemoconcentration, and hypoalbuminemia, which may be either idiopathic or secondary to an underlying disease process. We report a case of an adult with COVID-19 infection associated with new onset SCLS. Our case joins only two other cases of new SCLS associated with COVID-19 infection reported in the literature. The clinical and laboratory findings in this case are distinct from findings seen in COVID-19 cytokine storm syndrome. Whether our therapeutic approach was efficacious is unknown. Further research into causes and therapies for these syndromes is urgently indicated.

Hypoalbuminemia in COVID-19: assessing the hypothesis for underlying pulmonary capillary leakage

BACKGROUND

Since the first observations of patients with COVID-19, significant hypoalbuminaemia was detected. Its causes have not been investigated yet.

OBJECTIVE

We hypothesized that pulmonary capillary leakage affects the severity of respiratory failure, causing a shift of fluids and proteins through the epithelial-endothelial barrier.

METHODS

One hundred seventy-four COVID-19 patients with respiratory symptoms, 92 admitted to the intermediate medicine ward (IMW) and 82 to the intensive care unit (ICU) at Luigi Sacco Hospital in Milan, were studied.

RESULTS

Baseline characteristics at admission were considered. Proteins, interleukin 8 (IL-8) and interleukin 10 (IL-10) in bronchoalveolar lavage fluid (BALF) were analysed in 26 ICU patients. In addition, ten autopsy ultrastructural lung studies were performed in patients with COVID-19 and compared with postmortem findings in a control group (bacterial pneumonia-ARDS and H1N1-ARDS). ICU patients had lower serum albumin than IMW patients [20 (18-23) vs 28 (24-33) g L^-1 , P < 0.001]. Serum albumin was lower in more compromised groups (lower PaO₂ -to-FiO₂ ratio and worst chest X-ray findings) and was associated with 30 days of probability of survival. Protein concentration was correlated with IL-8 and IL-10 levels in BALF. Electron microscopy examinations of eight out of ten COVID-19 lung tissues showed loosening of junctional complexes, quantitatively more pronounced than in controls, and direct viral infection of type 2 pneumocytes and endothelial cells.

CONCLUSION

Hypoalbuminaemia may serve as severity marker of epithelial-endothelial damage in patients with COVID-19. There are clues that pulmonary capillary leak syndrome plays a key role in the pathogenesis of COVID-19 and might be a potential therapeutic target.

Capillary Leak Syndrome From Rituximab Therapy of Lymphoma

Capillary leak syndrome (CLS) is characterized by plasma extravasation into the interstitium with resultant hypotension, anasarca, hemoconcentration, and hypoalbuminemia in the absence of albuminuria. Initially reported in Clarkson’s disease (systemic capillary leak syndrome), CLS has been observed in multiple disease settings, the most common being sepsis. In oncology, CLS has been reported more often as a complication from therapy, and less often from malignancy. In this case study, we documented clinical manifestation, laboratory features, and radiological findings of CLS from rituximab therapy when employed in combination with a multi-agent chemotherapy regimen (EPOCH-R). Differentiating drug-induced CLS from sepsis, which presents with the same clinical features, is important in avoiding further exposure to rituximab, which could be fatal to the patient.

Discriminating minor and major forms of drug reaction with eosinophilia and systemic symptoms: Facial edema aligns to the severe phenotype

BACKGROUND

Drug reaction with eosinophilia and systemic symptoms (DRESS) is a cutaneous and systemic drug allergy disorder. Patients exist on a severity spectrum, with some experiencing a mild form of the disorder that fails to meet the Registry of Severe Cutaneous Adverse Reactions (SCAR) to Drugs diagnostic criteria for DRESS.

OBJECTIVE

We sought to determine whether there were any cutaneous or dermatopathologic features that discriminate between the mild form of DRESS (DRESS minor) and the severe phenotype (DRESS major).

METHODS

Hospitalized patients from a single center with a diagnosis of DRESS were prospectively recruited over a 7-year period. Clinical and dermatopathologic features were analyzed to discriminate between DRESS minor and DRESS major.

RESULTS

Forty-five patients were included, of whom 19 had a Registry of Severe Cutaneous Adverse Reactions (SCAR) to Drugs score of ≤3 (DRESS minor) and 26 had a score of ≥4 (DRESS major). The mean latency period (P = .001), fever >38.5 °C (P = .001), and a reaction lasting >15 days (P = .010) discriminated DRESS major from DRESS minor. Facial edema was the sole discerning cutaneous feature (P = .025). Discriminating histopathologic features included basal squamatization (P = .005), dermal red blood cell extravasation (P = .009), and interface inflammation (P = .005).

CONCLUSION

We propose a new classification system-DRESS minor-to distinguish the milder illness from the severe form, DRESS major. Facial edema and certain histopathologic features can help discriminate between major and minor versions.

[Idiopathic systemic capillary leak syndrome: 2 cases with misleading presentation]

INTRODUCTION

Idiopathic systemic capillary leak syndrome (ISCLS) also known as Clarkson syndrome is a rare and sudden life-threatening entity. Three consecutive phases are described. A first non-specific prodromal phase often manifests as "flu-like" symptoms and precedes capillary leak phase with major hypovolemic and distributive shock leading to serious and frequent multiorgan dysfunction syndrome (MODS). Severe hypovolemia contrasts with edema, and hemoconcentration with hypoalbuminemia. ISCLS is characterized by these two clinical and biological paradoxes. Subsequent recovery phase exhibits organ function restoration along with interstitial/intravascular volumes normalization. The latter occurs spontaneously and systematically in patients surviving from leak phase.

OBSERVATIONS

We report here two ISCLS cases admitted in intensive care unit (ICU) both enhancing initial misdiagnosis possibly lowering prognosis and outcome. Our first 28-year-old female patient was admitted for « polycythemia vera » although hemoconcentration was attributable to hypovolemia. She presented circulatory arrest during the second bloodletting session and complicated with MODS. In and out ICU favorable outcome was noted on intravenous immunoglobulin therapy. A second 57-year-old male patient was admitted in ICU for severe "myositis" (myalgia and rhabdomyolysis) although rectified diagnosis retained compartment syndrome (muscular severe edema following capillary leak). Rapid and refractory hypovolemic shock appeared with subsequent MODS leading to death.

CONCLUSION

ISCLS pathophysiology remains unknown but certainly implies transitory endothelial dysfunction. Impossibility of randomized controlled trial for this exceptional disease led to based-on-experience therapeutic guidelines implying symptomatic care (cardiac output surveillance, nephroprotection, prudent fluid intake, prudent vasoactive amine use) and specific therapies (intravenous aminophylline during severe flares). Although enhancing controversial and even deleterious effects during the acute phase, polyvalent immunoglobulins are effective for relapse prevention. Syndromic diagnosis is difficult, but its precocious finding constitutes a key-element in better outcome before organ failure.

Plasmacytoid Dendritic Cells Depletion and Elevation of IFN-γ Dependent Chemokines CXCL9 and CXCL10 in Children With Multisystem Inflammatory Syndrome

Background

SARS-CoV-2 occurs in the majority of children as COVID-19, without symptoms or with a paucisymptomatic respiratory syndrome, but a small proportion of children develop the systemic Multi Inflammatory Syndrome (MIS-C), characterized by persistent fever and systemic hyperinflammation, with some clinical features resembling Kawasaki Disease (KD).

Objective

With this study we aimed to shed new light on the pathogenesis of these two SARS-CoV-2-related clinical manifestations.

Methods

We investigated lymphocyte and dendritic cells subsets, chemokine/cytokine profiles and evaluated the neutrophil activity mediators, myeloperoxidase (MPO), and reactive oxygen species (ROS), in 10 children with COVID-19 and 9 with MIS-C at the time of hospital admission.

Results

Patients with MIS-C showed higher plasma levels of C reactive protein (CRP), MPO, IL-6, and of the pro-inflammatory chemokines CXCL8 and CCL2 than COVID-19 children. In addition, they displayed higher levels of the chemokines CXCL9 and CXCL10, mainly induced by IFN-γ. By contrast, we detected IFN-α in plasma of children with COVID-19, but not in patients with MIS-C. This observation was consistent with the increase of ISG15 and IFIT1 mRNAs in cells of COVID-19 patients, while ISG15 and IFIT1 mRNA were detected in MIS-C at levels comparable to healthy controls. Moreover, quantification of the number of plasmacytoid dendritic cells (pDCs), which constitute the main source of IFN-α, showed profound depletion of this subset in MIS-C, but not in COVID-19.

Conclusions

Our results show a pattern of immune response which is suggestive of type I interferon activation in COVID-19 children, probably related to a recent interaction with the virus, while in MIS-C the immune response is characterized by elevation of the inflammatory cytokines/chemokines IL-6, CCL2, and CXCL8 and of the chemokines CXCL9 and CXL10, which are markers of an active Th1 type immune response. We believe that these immunological events, together with neutrophil activation, might be crucial in inducing the multisystem and cardiovascular damage observed in MIS-C.

Neutrophil-mediated immune response as a possible mechanism of acute unilateral vestibulopathy

OBJECTIVE

This study aimed to investigate the underlying pathogenesis of acute unilateral vestibulopathy (AUV) using gene expression profiling combined with bioinformatics analysis.

METHODS

Total RNA was extracted from the peripheral blood mononuclear cells of ten AUV patients in the acute phase and from ten controls. The differentially expressed genes (DEGs) between these two groups were screened using microarray analysis with the cut-off criteria (|fold changes| > 1.5 and p-value < 0.05). Functional enrichment analysis of DEGs was performed using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis, and the protein-protein interaction (PPI) network was constructed using the STRING (Search Tool for the Retrieval of Interacting Genes) database.

RESULTS

There were 57 DEGs (50 up-regulated and 7 down-regulated) identified in the AUV group. Functional enrichment analysis showed that most of the up-regulated DEGs were significantly enriched in terms related to the neutrophil-mediated immune pathway. From the PPI network, the top ten hub genes were extracted by calculating four topological properties, and most of them were related to the innate immune system, inflammatory processes and vascular disorders. The complete blood count tests showed that the neutrophil-to-lymphocyte ratio was significantly higher in the 72 AUV patients than in the age-matched controls (2.93±2.25 vs 1.54±0.61, p < 0.001).

CONCLUSIONS

This study showed that the neutrophil-mediated immune pathway may contribute to the development of AUV by mediating inflammatory and thrombotic changes in the vestibular organ.

Hydrochlorothiazide-induced systemic capillary leak

Hypersensitivity reactions to drugs may cause very rapid physiologic derangements that can be fatal in the absence of adequate compensatory mechanisms or definitive treatment. For the most part, adverse drug reactions that progress over the course of minutes are mediated either by mast cell or complement activation. If a patient survives the acute event, appropriate long-term management requires the identification and future avoidance of the inciting drug. Here, we describe a patient who experienced two life-threatening multisystem reactions with cardiopulmonary compromise minutes after taking hydrochlorothiazide (HCTZ). The reactions were associated with systemic vascular leak resulting in hypotension and non-cardiogenic pulmonary edema.

Neutrophil activation in systemic capillary leak syndrome (Clarkson disease)

Systemic capillary leak syndrome (SCLS; Clarkson disease) is a rare orphan disorder characterized by transient yet recurrent episodes of hypotension and peripheral oedema due to diffuse vascular leakage of fluids and proteins into soft tissues. Humoral mediators, cellular responses and genetic features accounting for the clinical phenotype of SCLS are virtually unknown. Here, we searched for factors altered in acute SCLS plasma relative to matched convalescent samples using multiplexed aptamer‐based proteomic screening. Relative amounts of 612 proteins were changed greater than twofold and 81 proteins were changed at least threefold. Among the most enriched proteins in acute SCLS plasma were neutrophil granule components including bactericidal permeability inducing protein, myeloperoxidase and matrix metalloproteinase 8. Neutrophils isolated from blood of subjects with SCLS or healthy controls responded similarly to routine pro‐inflammatory mediators. However, acute SCLS sera activated neutrophils relative to remission sera. Activated neutrophil supernatants increased permeability of endothelial cells from both controls and SCLS subjects equivalently. Our results suggest systemic neutrophil degranulation during SCLS acute flares, which may contribute to the clinical manifestations of acute vascular leak.