Macrophage Activation Syndrome Research Articles

Paradoxical tuberculous reaction to anti-tnfα discontinuation: a complex case of miliary tuberculosis and macrophagic activation syndrome with hepatic manifestations

Tuberculosis reactivation during anti-TNF-alpha therapy paradoxically worsened following reconstitution of pathogen-specific immune responses after cessation of TNFα antagonist treatment and initiation of anti-bacillary therapy. We report the case of a 46-year-old woman who was prescribed a tumor necrosis factor blocker (anti-TNF) for a relapse of Behçet's disease. The patient developed pulmonary miliary tuberculosis following the reactivation of latent tuberculosis, despite a normal pre-therapeutic work-up. Discontinuation of anti-TNF and initiation of anti-bacillary drugs triggered a paradoxical tubercular reaction (PTR). The diagnosis of paradoxical reaction to anti-tuberculosis drugs was evoked by the clinical and biological deterioration and the appearance of miliary cerebral tuberculosis and cerebral venous thrombosis after a period of clinical improvement. Although this phenomenon has been documented, it represents a major challenge for clinicians. The peculiarity of this case lies in its association with a macrophagic activation syndrome (MAS) with hepatic involvement, retained on clinical-biological and histological criteria. The overlap between MAS and PTR makes it difficult to diagnose these two entities with certainty. The patient responded favorably to moderate-dose systemic corticosteroid therapy with progressive degression, and the reintroduction of anti-tuberculosis drugs.This work aims to highlight the importance of close monitoring of TB patients on anti-TNFα therapy for early diagnosis and management of complications to improve the prognosis of these complex patients.

Efficacy and safety of tumor necrosis factor inhibitors for systemic juvenile idiopathic arthritis: a systematic review.

This systematic review assessed the efficacy and safety of tumor necrosis factor (TNF) inhibitors in patients with systemic juvenile idiopathic arthritis (JIA). Studies were searched using PubMed, Embase, Cochrane, Ichushi-Web, and clinical trial registries (from 2000 to 2021). The risk of bias was assessed using the Cochrane Risk of Bias version 2 for randomized controlled trials (RCTs) and the manual for development clinical practice guidelines by Minds, a project promoting evidence-based medicine in Japan, for observational studies. One RCT and 22 observational studies were included. In the RCT on infliximab, the American College of Rheumatology pediatric (ACR Pedi) 30/50/70 responses at 14 weeks were 63.8%/50.0%/22.4%, with relative risks of 1.30 (95% confidence interval [CI]: 0.94-1.79)/1.48 (95% CI: 0.95-2.29)/1.89 (95% CI: 0.81-4.40), respectively. In the observational studies, ACR Pedi 30/50/70 responses for etanercept at 12 months were 76.7%/64.7%/46.4%, respectively. Infliximab treatment caused anaphylaxis in 17% and an infusion reaction in 23% of patients. The incidence of macrophage activation syndrome, serious infection and malignancy caused by TNF inhibitors was 0%-4%. Thus, although TNF inhibitors were relatively safe, they were unlikely to be preferentially administered in patients with systemic JIA because of their inadequate efficacy. Further studies, particularly well-designed RCTs, are necessary to confirm the efficacy and safety of TNF inhibitors for systemic JIA.

Blinatumomab-induced macrophage activating syndrome (MAS) in adult with B-cell acute lymphoblastic leukemia (B-ALL).

Blinatumomab as a single agent has demonstrated superiority over salvage chemotherapy in patients with relapsed and refractory B-cell acute lymphoblastic leukemia (B-ALL), with manageable safety and efficacy. Though known to have anticipated drug toxicities including cytokine release syndrome (CRS) and neurotoxicity, there is only one prior report of macrophage activating syndrome (MAS) due to blinatumomab. Case Presentation: We report the first case of blinatumomab-induced MAS in an adult. The patient presented with fever, cough, and weakness on the second cycle of blinatumomab. Complete blood count was notable for severe leukopenia, with comprehensive metabolic panel notable for elevated alkaline phosphatase, AST, ALT, LDH, and hyperferritinemia consistent with MAS. The patient was already in MRD-negative remission at presentation with MAS. She responded rapidly to withholding the drug and administration of both tocilizumab and dexamethasone. She was able to restart therapy with blinatumomab dosed at 9 mcg/day with no recurrence of symptoms. Though MAS is not an expected association with blinatumomab, the risk for CRS is. Secondary MAS in this case likely shares a mechanism with other hyperinflammatory conditions. Management includes holding the offending agent, like blinatumomab, and administering tocilizumab and dexamethasone. Future research will be needed to predict which patients are at highest risk to develop MAS after similar T-cell therapies.

Single center clinical analysis of macrophage activation syndrome complicating juvenile rheumatic diseases

BackgroundMacrophage activation syndrome (MAS), an example of secondary hemophagocytic lymphohistiocytosis, is a potentially fatal complication of rheumatic diseases. We aimed to study the clinical and laboratory characteristics, treatment schemes, and outcomes of different rheumatic disorders associated with MAS in children. Early warning indicators of MAS have also been investigated to enable clinicians to make a prompt and accurate diagnosis.MethodsFifty-five patients with rheumatic diseases complicated by MAS were enrolled between January 2017 and December 2022. Clinical and laboratory data were collected before disease onset, at diagnosis, and after treatment with MAS, and data were compared between patients with systemic juvenile idiopathic arthritis (sJIA), Kawasaki disease (KD), and systemic lupus erythematosus (SLE). A random forest model was established to show the importance score of each variable with a significant difference.ResultsMost (81.8%) instances of MAS occurred during the initial diagnosis of the underlying disease. Compared to the active stage of sJIA, the platelet count, erythrocyte sedimentation rate, and fibrinogen level in sJIA-MAS were significantly decreased, whereas ferritin, ferritin/erythrocyte sedimentation rate, aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, and D-dimer levels were significantly increased. Ferritin level, ferritin/erythrocyte sedimentation rate, and platelet count had the greatest predictive value for sJIA-MAS. The level of IL-18 in the sJIA-MAS group was significantly higher than in the active sJIA group, whereas IL-6 levels were significantly lower. Most patients with MAS were treated with methylprednisolone pulse combined with cyclosporine, and no deaths occurred.ConclusionsThrombocytopenia, ferritin levels, the ferritin/erythrocyte sedimentation rate, and elevated aspartate aminotransferase levels can predict the occurrence of MAS in patients with sJIA. Additionally, our analysis indicates that IL-18 plays an important role in the pathogenesis of MAS in sJIA-MAS.

The NLRP3 inflammasome is essential for IL-18 production in a model of macrophage activation syndrome.

Hyperinflammatory disease is associated with an aberrant immune response resulting in cytokine storm. One such instance of hyperinflammatory disease is known as macrophage activation syndrome (MAS). The pathology of MAS can be characterised by significantly elevated serum levels of interleukin (IL)-18 and interferon (IFN)-γ. Given the role for IL-18 in MAS, we sought to establish the role of inflammasomes in the disease process. Using a murine model of CpG-DNA induced MAS, we discovered that the expression of the NLRP3 inflammasome was increased and correlated with IL-18 production. Inhibition of the NLRP3 inflammasome, or downstream caspase-1, prevented MAS-mediated upregulation of plasma IL-18 but interestingly did not alleviate key features of hyperinflammatory disease including hyperferritinaemia and splenomegaly. Furthermore IL-1 receptor blockade with IL-1Ra did not prevent the development of CpG-induced MAS, despite being clinically effective in the treatment of MAS. These data demonstrate that in the development of MAS, the NLRP3 inflammasome was essential for the elevation in plasma IL-18, a key cytokine in clinical cases of MAS, but was not a driving factor in the pathogenesis of CpG-induced MAS.

Spider bite presenting as fever, macrophage activation syndrome and a skin ulcer

Introduction: Fever of unknown origin (FUO) refers to a condition of prolonged increased body temperature, without identified causes. The most common cause of FUO worldwide are infections; arthropod bites (loxoscelism) should be considered in view of the spread of the fiddleback spider. Loxoscelism can present in a cutaneous form (a necrotic cutaneous ulcer) or in a systemic form with fever, haemolytic anaemia, rhabdomyolysis and, rarely, macrophage activation syndrome (MAS). For this suspicion, it is important to have actually seen the spider. Case description: A 71-year-old man was admitted to our department because of intermittent fever, arthralgia and a necrotic skin lesion on his right forearm that appeared after gardening. Laboratory tests were negative for infectious diseases, and several courses of antibiotics were administered empirically without clinical benefit. Whole-body computed tomography showed multiple colliquative lymphadenomegalies, the largest one in the right axilla, presumably of reactive significance. A shave biopsy of the necrotic lesion was performed: culture tests were negative and histological examination showed non-specific necrotic material, so a second skin and lymph node biopsy was performed. The patient developed MAS for which he received corticosteroid therapy with clinical/laboratory benefit. Cutaneous and systemic loxoscelism complicated by MAS was diagnosed. Subsequently, the second biopsy revealed morphological and immunophenotypic findings consistent with primary cutaneous anaplastic large cell lymphoma (PC-ALCL). Conclusions: Skin lesions and lymphadenomegalies of unknown origin should always be biopsied. It is very common to get indeterminate results, but this does not justify not repeating the procedure to avoid misdiagnosis.

Macrophage Activation Syndrome Presents as Initial Manifestation of Lupus in an Adult Female

Macrophage Activation Syndrome Presents as Initial Manifestation of Lupus in an Adult Female

Lysinuric protein intolerance with novel mutations in solute carrier family 7A member 7 in a Chinese family

ABSTRACTIntroductionLysinuric protein intolerance (LPI) is a rare genetic disorder caused by mutations in the solute carrier family 7A member 7 (SLC7A7) gene.Case presentationWe presented two siblings with LPI, carrying novel mutations of c.776delT (p.L259Rfs*18) and c.155G>T (p.G52V) in SLC7A7. The younger sibling, preferring protein‐rich foods, showed severe symptoms, including alveolar proteinosis, macrophage activation syndrome, severe diarrhea, and disturbance of consciousness with involuntary movements. In contrast, the elder sibling only had mild symptoms, likely due to aversion to protein‐rich food since toddler age.ConclusionLPI is a congenital genetic metabolic disease with multi‐system involvement. Initiating appropriate protein‐restricted diet therapy as soon as possible could help prevent the progression of LPI.

Efficacy and safety of abatacept for systemic juvenile idiopathic arthritis: a systematic review.

This systematic review assessed the efficacy and safety of abatacept in patients with systemic juvenile idiopathic arthritis (JIA). Studies published between 2000 and 2021 were searched using PubMed, Embase, Cochrane, Ichushi-Web and clinical trial registries. The risk of bias was assessed according to the manual for development clinical practice guidelines by Minds, a project to promote evidence-based medicine in Japan. Seven observational studies were included. American College of Rheumatology pediatric 30/50/70 responses at 3, 6 and 12 months were 64.8%/50.3%/27.9%, 85.7%/71.4%/42.9% and 80.0%/50.0%/40.0%, respectively. Outcomes on systemic symptoms, joint symptoms and activities of daily living were not obtained. No macrophage activation syndrome or infusion reaction occurred. Serious infection occurred in 2.6% of cases. Abatacept improved the disease activity index. In addition, abatacept was as safe as interleukin-6 (IL -6) and IL-1 inhibitors. However, both the efficacy and safety data in this systematic review should be reviewed with caution because their quality of evidence is low or very low. Further studies are needed to confirm the efficacy and safety of abatacept for systemic JIA, especially its efficacy on joint symptoms.

An unusual case of adult-onset still’s disease complicated with anti-complement factor H antibodies associated atypical haemolytic uraemic syndrome

BackgroundAtypical haemolytic uremic syndrome (aHUS) is an uncommon form of thrombotic microangiopathy (TMA). However, it remains difficult to diagnose the disease early, given its non-specific and overlapping presentation to other conditions such as thrombotic thrombocytopenic purpura and typical HUS. It is also important to identify the underlying causes and to distinguish between primary (due to a genetic abnormality leading to a dysregulated alternative complement pathway) and secondary (often attributed by severe infection or inflammation) forms of the disease, as there is now effective treatment such as monoclonal antibodies against C5 for primary aHUS. However, primary aHUS with severe inflammation are often mistaken as a secondary HUS. We presented an unusual case of adult-onset Still’s disease (AOSD) with macrophage activation syndrome (MAS), which is in fact associated with anti-complement factor H (anti-CFH) antibodies related aHUS. Although the aHUS may be triggered by the severe inflammation from the AOSD, the presence of anti-CFH antibodies suggests an underlying genetic defect in the alternative complement pathway, predisposing to primary aHUS. One should note that anti-CFH antibodies associated aHUS may not always associate with genetic predisposition to complement dysregulation and can be an autoimmune form of aHUS, highlighting the importance of genetic testing.Case presentationA 42 years old man was admitted with suspected adult-onset Still’s disease. Intravenous methylprednisolone was started but patient was complicated with acute encephalopathy and low platelet. ADAMTS13 test returned to be normal and concurrent aHUS was eventually suspected, 26 days after the initial thrombocytopenia was presented. Plasma exchange was started and patient eventually had 2 doses of eculizumab after funding was approved. Concurrent tocilizumab was also used to treat the adult-onset Still’s disease with MAS. The patient was eventually stabilised and long-term tocilizumab maintenance treatment was planned instead of eculizumab following haematology review. Although the aHUS may be a secondary event to MAS according to haematology opinion and the genetic test came back negative for the five major aHUS gene, high titre of anti-CFH antibodies was detected (1242 AU/ml).ConclusionOur case highlighted the importance of prompt anti-CFH antibodies test and genetic testing for aHUS in patients with severe AOSD and features of TMA. Our case also emphasized testing for structural variants within the CFH and CFH-related proteins gene region, as part of the routine genetic analysis in patients with anti-CFH antibodies associated aHUS to improve diagnostic approaches.

Macrophage activation syndrome in patients with systemic juvenile idiopathic arthritis on anti-interleukin-1 or -6 therapy: more difficult to diagnose, not to control?

Macrophage activation syndrome in patients with systemic juvenile idiopathic arthritis on anti-interleukin-1 or -6 therapy: more difficult to diagnose, not to control?

Early identification of macrophage activation syndrome secondary to systemic lupus erythematosus with machine learning

ObjectiveThe macrophage activation syndrome (MAS) secondary to systemic lupus erythematosus (SLE) is a severe and life-threatening complication. Early diagnosis of MAS is particularly challenging. In this study, machine learning models and diagnostic scoring card were developed to aid in clinical decision-making using clinical characteristics.MethodsWe retrospectively collected clinical data from 188 patients with either SLE or the MAS secondary to SLE. 13 significant clinical predictor variables were filtered out using the Least Absolute Shrinkage and Selection Operator (LASSO). These variables were subsequently utilized as inputs in five machine learning models. The performance of the models was evaluated using the area under the receiver operating characteristic curve (ROC-AUC), F1 score, and F2 score. To enhance clinical usability, we developed a diagnostic scoring card based on logistic regression (LR) analysis and Chi-Square binning, establishing probability thresholds and stratification for the card. Additionally, this study collected data from four other domestic hospitals for external validation.ResultsAmong all the machine learning models, the LR model demonstrates the highest level of performance in internal validation, achieving a ROC-AUC of 0.998, an F1 score of 0.96, and an F2 score of 0.952. The score card we constructed identifies the probability threshold at a score of 49, achieving a ROC-AUC of 0.994 and an F2 score of 0.936. The score results were categorized into five groups based on diagnostic probability: extremely low (below 5%), low (5–25%), normal (25–75%), high (75–95%), and extremely high (above 95%). During external validation, the performance evaluation revealed that the Support Vector Machine (SVM) model outperformed other models with an AUC value of 0.947, and the scorecard model has an AUC of 0.915. Additionally, we have established an online assessment system for early identification of MAS secondary to SLE.ConclusionMachine learning models can significantly improve the diagnostic accuracy of MAS secondary to SLE, and the diagnostic scorecard model can facilitate personalized probabilistic predictions of disease occurrence in clinical environments.

Macrophagic Activation Syndrome Revealing Tuberculosis: A Case Report

We present a case involving an immunocompetent infant diagnosed with miliary tuberculosis complicated by macrophage activation syndrome. Macrophage activation syndrome (MAS), also known as bone marrow hemophagocytosis, presents as a non-specific clinical condition characterized by fever and hepatosplenomegaly. A 22-month-old infant from a non- consanguineous marriage, the only child in the family, was admitted to a regional hospital due to prolonged fever lasting 15 days. The syndrome can manifest as a primary disorder (familial HLH) due to various genetic mutations or as a sporadic secondary disorder triggered by infections, autoimmune diseases, or malignant conditions. The early initiation of antibacillary treatment in AMS complicating tuberculosis without the use of immunosuppressive drugs provides better management and improves the vital prognosis.

Visceral leishmaniasis associated with macrophage activation syndrome: Case report

Visceral leishmaniasis associated with macrophage activation syndrome: Case report

A Case of Macrophage Activation Syndrome With Elderly Onset Still’s Disease Under Tocilizumab Treatment

A Case of Macrophage Activation Syndrome With Elderly Onset Still’s Disease Under Tocilizumab Treatment

Heterogeneity of macrophage activation syndrome and treatment progression.

Macrophage activation syndrome (MAS) is a rare complication of autoimmune inflammatory rheumatic diseases (AIIRD) characterized by a progressive and life-threatening condition with features including cytokine storm and hemophagocytosis. Predisposing factors are typically associated with microbial infections, genetic factors (distinct from typical genetically related hemophagocytic lymphohistiocytosis (HLH)), and inappropriate immune system overactivation. Clinical features include unremitting fever, generalized rash, hepatosplenomegaly, lymphadenopathy, anemia, worsening liver function, and neurological involvement. MAS can occur in various AIIRDs, including but not limited to systemic juvenile idiopathic arthritis (sJIA), adult-onset Still's disease (AOSD), systemic lupus erythematosus (SLE), Kawasaki disease (KD), juvenile dermatomyositis (JDM), rheumatoid arthritis (RA), and Sjögren's syndrome (SS), etc. Although progress has been made in understanding the pathogenesis and treatment of MAS, it is important to recognize the differences between different diseases and the various treatment options available. This article summarizes the cell types and cytokines involved in MAS-related diseases, the heterogeneity, and treatment options, while also comparing it to genetically related HLH.

Population Pharmacokinetics of the Anti-Interferon-Gamma Monoclonal Antibody Emapalumab: An Updated Analysis.

Emapalumab is a fully human monoclonal antibody that targets free and receptor-bound interferon-gamma (IFNγ), neutralizing its biological activity. IFNγ levels differ by orders of magnitude between patients with primary hemophagocytic lymphohistiocytosis (HLH) and macrophage activation syndrome (MAS; a form of secondary HLH) in systemic juvenile idiopathic arthritis (sJIA). Therefore, this study aimed to develop a population pharmacokinetic model for emapalumab across a patient population with a wide range of total (free and emapalumab-bound) IFNγ levels using observations from patients with primary HLH or MAS in sJIA in clinical trials. Pharmacokinetic data were pooled (n = 58; 2709 observations) from studies enrolling patients administered emapalumab for primary HLH or MAS in sJIA. Patients with primary HLH were administered emapalumab 1mg/kg (potentially increasing to 3, 6, and up to 10mg/kg based on clinical response) every 3days. Patients with MAS in sJIA were administered emapalumab 6mg/kg, followed by 3mg/kg every 3days until day 15 and twice weekly until day 28. An earlier population PK model was re-parameterized using this data. The final model for emapalumab comprised a 2-compartment model with first-order elimination. Emapalumab clearance remains constant when the total IFNγ concentration (free and emapalumab-bound) is < ~ 10,000pg/ml but increases proportionally to total IFNγ concentration above this threshold. Emapalumab clearance was estimated to be 0.00218, 0.00308, 0.00623 and 0.01718 l/h at total serum IFNγ concentrations of 103, 104, 105 and 106pg/ml, respectively, with corresponding terminal half-lives of 19.2, 13.8, 7.18 and 3.12days for a 1-year-old patient weighing 10kg with primary HLH. The median terminal half-life for emapalumab in patients with MAS in sJIA was estimated to be 24.0 (range, 6.13-32.4)days, which is similar to observations in healthy volunteers. Emapalumab pharmacokinetics in patients with primary HLH and MAS in sJIA were described by a two-compartment model with fixed allometric exponents and an age-related effect. Differences in total IFNγ levels between patients with primary HLH and MAS may affect emapalumab pharmacokinetics, suggesting that each indication may require different dosing to rapidly control hyperinflammation. Clinicaltrials.gov identifiers: NCT01818492, NCT03311854 and NCT02069899.

Predictors of disease course in systemic juvenile idiopathic arthritis.

To identify potential predictors of the disease course of systemic juvenile idiopathic arthritis (sJIA) at the time of diagnosis. This retrospective observational study was conducted in patients diagnosed with sJIA in our hospital between April 2009 and October 2023. The relationship between the disease course of sJIA patients and demographic, clinical, laboratory findings and complications were analyzed. Of the 51 patients diagnosed with sJIA, 26 (51%) patients had monocyclic, 7 (13.7%) polycyclic and 18 (35.2%) persistent disease course. 3 (5.8%) patients had a persistent disease course with persistent arthritis developed flares with systemic manifestations during follow-up. The presence of arthritis, polyarticular involvement, and hip involvement at the time of diagnosis were associated with persistent disease course (p=0.009, p=0.003, p=0.003). Serositis and higher white blood cell and neutrophil counts at the time of diagnosis were associated with a monocyclic disease course (p=0.034, p=0.002, p=0.008). However, no significant correlation was found between macrophage activation syndrome (MAS) and disease course (p=1). Systemic JIA patients with polyarthritis and hip involvement at disease onset may develop a persistent course. Although MAS is an important complication of sJIA, its effect on the course of the disease was not found in this study.

Investigation on the relationship between serum periostin, MMP-7, TGF-β, and IL-18 levels and the clinical course and prognosis of COVID-19.

Cytokines are involved in the inflammatory/anti-inflammatory balance and have been shown to play an important role in the course of COVID-19. This study aimed to evaluate the relationship of periostin, transforming growth factor-beta (TGF-β), interleukin-18 (IL-18), and matrix metalloproteinase 7 (MMP-7) levels with clinical course and mortality in patients with early COVID-19 pneumonia. A total of 150 hospitalized patients were diagnosed with COVID-19 between June and October 2021, and a control group of 30 healthy individuals were included in our study. The COVID-19 patients were divided into those who developed macrophage activation syndrome (MAS) in Group 1 and those who did not in Group 2. Serum periostin, MMP-7, TGF-β, and IL-18 levels were measured from blood samples obtained at admission using enzyme-linked immunosorbent assay (ELISA). Periostin, MMP-7, and IL-18 levels were significantly higher in COVID-19 patients compared to the control group (p<0.001 for all). Periostin and MMP-7 levels were also significantly higher in Group 1 than in Group 2 (p<0.001 for both). Periostin, MMP-7, IL-18, and TGF-β levels were significantly higher in non-surviving patients compared to survivors (p=0.04, p<0.001, p<0.001, and p<0.001, respectively). In the receiver operating characteristic (ROC) curve analysis, MMP-7 was found to have high sensitivity (90%) at a predictive value of 2.66 ng/mL. It is still not possible to predict which patients with early COVID-19 pneumonia will go on to develop MAS despite receiving standard treatment. The results of our study suggest that elevation of periostin and MMP-7 levels in the early period may predict the development of macrophage activation syndrome.

The landscape of hot topics and research frontiers in Kawasaki disease: Scientometric analysis

PurposeKawasaki disease(KD) is a vascular inflammatory disease that was first identified in 1967. Numerous studies have been conducted on KD and have yielded valuable recent insights. This current bibliometric analysis aimed to determine the intellectual landscape of research interest in KD. MethodsPublications were collected from the Web of Science Core Collection. Bibliometric tools such as CiteSpace and VOSviewer were utilized to analyze the research focus, emerging trends, frontiers, and hot topics in this specific field. ResultsA total of 6122 articles on KD were retrieved. Pediatric Cardiology, Pediatrics International, and Pediatric Infections Disease Journal were the three most productive journals reporting KD development. The University of California San Diego was the most productive institution, with 230 publications. The USA was the most productive country, with 1661 articles in KD. SARS-CoV-2, diagnostic serum biomarkers, and risk factor prediction models for coronary arterial lesions and subtypes of KD are popular topics in KD research. Factors that induce smooth muscle cell transition to myofibroblastic cell, potentially halting the subacute/chronic vasculitis process and endothelial dysfunction in macrophage activation syndrome associated with KD were the frontiers in the study of KD. ConclusionKD has attracted widespread attention worldwide that has continued to increase since 1974. The most productive institution and country are the University of California San Diego and the USA, respectively. SARS-CoV-2, serum biomarkers, and prediction models are hot topics in this field.