Broad national specialist-centre coverage
The survey includes 117 patients from 25 of 34 adult UK Clinical Immunology and Allergy centres, providing substantial national coverage for an exceptionally rare disorder.
↳ Methods, “Data collection”
Abstract
BACKGROUND: Acquired angioedema due to C1-inhibitor deficiency (AAE-C1-INH) is very rare compared to its prototype, hereditary angioedema. An updated characterization of the AAE-C1-INH cohort in the UK is required to inform management. OBJECTIVES: To describe the disease burden of AAE-C1-INH, long-term prophylaxis (LTP) and the clinical, immunochemical, and treatment profiles of AAE-associated diseases in the UK. METHOD: Retrospective data on 117 AAE-C1-INH patients were collected using a national survey proforma across 25/34 Adult Clinical Immunology and Allergy centres in the UK. Other European cohorts were compared. RESULTS: The median age at AAE-C1-INH diagnosis was 65 years with 3.4% of patients diagnosed below 40 years. The median delay in diagnosis was 1 year. Antifibrinolytics and attenuated androgens showed comparable efficacy to LTP, at 88.9% and 89.5%, respectively. A haematological disorder was identified in 83.8% of AAE-C1-INH patients compared to 3.4% of autoimmune diseases. The predominant haematological disorders were splenic marginal zone lymphoma 34% followed by MGUS 16%. The severity of angioedema did not depend on the associated disease. Anti-C1INH-autoantibodies testing was limited to 23.1%. Rituximab monotherapy was effective in treating 9/9 splenic marginal zone lymphoma and 1/2 MGUS-associated AAE-C1-INH. Rituximab efficacy was independent of anti-C1INH-autoantibodies detection with response in 3/3 seronegative and 4/4 seropositive patients. CONCLUSION: The diagnosis of AAE-C1-INH should not be overlooked below the age of 40 years. The choice of oral LTP should be informed by the propensity to side effects. B cell depletion could be considered in treating monoclonal B cell disorder-associated-AAE-C1-INH in the absence of haematological indications. Further studies are required to address the clinical utility of anti-C1INH-autoantibodies.
Key Claims
Primary findingSupported
Antifibrinolytics and attenuated androgens showed comparable efficacy to LTP, at 88.9% and 89.5%, respectively.
Fragile — the claim's weakest requirement is that the effect exists at all. Experimental. Every point below is traceable to a quoted passage, but this forecast has not yet been validated against known replication outcomes.
retrospective clinician-assessed comparison without random allocation or confounder adjustment
Abstract; Results, “Comparison of the efficacy of androgens and antifibrinolytics”; Table 4
SecondaryWell-supported
The median age at AAE-C1-INH diagnosis was 65 years with 3.4% of patients diagnosed below 40 years.
direct descriptive frequencies from the full 117-patient cohort
Abstract; Results, “Demographic and clinical profile”; Table 1
SecondaryWell-supported
A haematological disorder was identified in 83.8% of AAE-C1-INH patients compared to 3.4% of autoimmune diseases.
direct cohort counts reported consistently in the abstract and Table 3
Abstract; Results, “The profile of AAE-associated disorders”; Table 3
SecondaryWell-supported
The predominant haematological disorder in the UK cohort was SZL followed by MGUS.
consistent full-cohort percentages in the abstract and Table 3 despite one denominator typo in the text
Conclusion; Table 3
SecondaryTentative
Rituximab monotherapy was effective in treating 9/9 splenic marginal zone lymphoma and 1/2 MGUS-associated AAE-C1-INH.
small selected treatment groups within an uncontrolled retrospective audit
Abstract; Results, “Effect of treatment of AADs on AAE symptoms”; Table 5A
Derived from the full evaluation — not a separate score.
Strengths · Limitations
Strengths
Systematic European cohort comparison
Tables 3–6 compare disease associations, prophylaxis, rituximab experience, and immunochemical testing across five European cohorts, allowing UK-specific patterns to be distinguished from recurring findings.
↳ Tables 3–6; Discussion
Transparent reporting of study constraints
The Methods and Limitations sections identify retrospective clinician reporting, cross-centre assay variation, small subgroups, and unavailable chronological biomarker data. Missing denominators are also reported in the tables.
↳ Methods, “Variables”; Table 1; Limitations
Limitations
Treatment inference exceeds observational design
The recommendation to consider B-cell depletion without haematological indications rests on small, selected, uncontrolled treatment groups with clinician-assessed outcomes. These observations are hypothesis-generating rather than comparative evidence of effectiveness.
↳ Results, Table 5; Conclusion
Biomarker independence claim is underpowered
The abstract describes rituximab efficacy as independent of anti-C1INH-autoantibody detection, but the comparison comprises only 3/3 seronegative and 4/4 seropositive patients. The Results section itself acknowledges that the sample was small.
↳ Abstract; Results, “Anti-CINH-autoantibodies as a marker for AAE response to Rituximab”; Table 5B
Incomplete and heterogeneous outcome measurement
Anti-C1INH-autoantibodies were tested in only 27 of 117 patients without an explained selection mechanism, while complement and antibody findings were reduced to binary categories across varying assays and eras.
↳ Methods, “Variables”; Results, “Immunochemical profile”; Table 6
Nabu Commentary
The strongest evidence is descriptive: the national cohort counts, demographic profile, and associated-disease frequencies are directly reported and extensively compared with European series. The retrospective multicentre design is suitable for characterisation, but clinician-judged efficacy, non-random treatment allocation, missing outcomes, and very small rituximab subgroups limit treatment-effect inference. The wording of prophylaxis effectiveness and antibody-status independence therefore lowers Methodological Rigour and Reporting despite the paper's generally coherent organisation. Extensive cross-cohort engagement and a concrete limitations section support the higher Positioning and Contribution assessments.
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Author Note / Field Feedback
Nabu’s assessment, alongside the field’s view.
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Dimension breakdown
Study Quality
Sound3.2
Confidence mediumContribution
3.6
The 117-patient, 25-centre cohort updates the UK evidence base and places national clinical and treatment patterns beside five European cohorts. The advance is meaningful for a rare disease but remains predominantly descriptive and incremental.
Introduction; Results, Tables 3–6; Discussion
“We place these results in comparison to the five recently published European cohorts of AAE.”
Methodological Rigour
2.8
The multicentre retrospective design, standardised proforma, explicit outcome definition, and reported denominators are suitable for national description. Small uncontrolled treatment groups, clinician-assessed outcomes, selectively available antibody tests, and heterogeneous assays materially limit treatment-effect inference.
Methods, “Data collection” and “Variables”; Results, Tables 4–5; Limitations
“The data on AAE localization, severity, and efficacy of treatment were reported retrospectively by the medical practitioners.”
Reporting
3.3
The paper follows a coherent progression and makes extensive use of tables to expose cohort and subgroup counts. However, statements that rituximab efficacy was independent of antibody status and that both prophylactic classes are effective convey more certainty than the underlying observational evidence supports.
Abstract; Conclusion; Tables 4 and 5B
“Rituximab efficacy was independent of anti-C1INH-autoantibodies detection.”
Positioning
3.7
The findings are repeatedly compared with French, German, Spanish, Italian, Hungarian, and earlier UK cohorts, including discussion of discordant disease associations and prescribing patterns. The limitations section identifies several concrete constraints, although treatment-selection limitations could be integrated more directly into clinical recommendations.
Introduction; Discussion; Tables 3–6; Limitations
“androgens were prescribed as LTP only after the failure of antifibrinolytics in the Italian series”
Reliability
Caveats4 of 4 checks
Internal CoherenceNoted
The principal descriptive results are coherent across the abstract and tables, but several treatment-response statements require caution because of small or unclear denominators. A denominator notation error in the associated-disorders Results paragraph does not alter the corresponding figures in the abstract or Table 3.
Research ConductClean
Ethical handling of the anonymised retrospective audit is declared, conflicts and funding are disclosed, and data availability is stated. No text-grounded research-conduct inconsistency was identified.
Flags: 3 declared / 5 total
Reference IntegrityClean
13 of 13 checkable references verified
13 references in manuscript
Post-Publication RecordClean
No retraction notice found in Retraction Watch.
Last checked: 18 Sep 2026
Sources: Retraction Watch ✓
Readiness
Where this paper’s evidence sits on the path from initial observation to real-world use.
Demonstrated
The findings can inform audit, diagnostic vigilance, and research prioritisation but do not validate a deployment-ready treatment strategy. Prospective studies are explicitly requested for prophylaxis risks, biomarkers, and other treatments.
Recommendations; Conclusion
“Prospective studies on the side effects of LTP might inform the risk of LTP in AAE.”
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