BackgroundRenal involvement in hypereosinophilic syndrome (HES) occurs in 5-10% of patients but remains poorly characterized. Diagnostic overlap with IgG4-related kidney disease (IgG4-RKD) presents clinical challenges.ObjectiveTo characterize the clinicopathologic spectrum of histologically confirmed HES-related kidney disease, examine diagnostic differentiation from IgG4-RKD, and appraise therapeutic evidence.MethodsSystematic review with narrative synthesis following PROSPERO-registered protocol (CRD420261307200).
Six databases were searched from inception to February 27, 2026. Dual independent screening and domain-specific GRADE assessment were performed.
Due to uncontrolled study designs and high heterogeneity, narrative synthesis was conducted rather than quantitative meta-analysis.ResultsFrom 2, 247 records, 37 studies (42 cases) met inclusion criteria. Acute eosinophilic interstitial nephritis predominated (54.8%, 23/42), followed by thrombotic microangiopathy (19.0%, 8/42), chronic interstitial fibrosis (11.9%, 5/42), and glomerular lesions (14.3%, 6/42).
Nine cases (21.4%) exhibited IgG4-RKD-like features with IgG4+/IgG+ ratios below 40% (median 21%, IQR 14-30%). However, substantial technical heterogeneity limits clinical applicability.
Fourteen cases received anti-IL-5/IL-5Rα biologics; all reported improvement with no documented failures, suggesting publication bias.
Frontiers in Immunology published a clinical update in Infectious Disease on 23 Apr 2026.
The item focuses on Renal involvement in hypereosinophilic syndrome: a systematic review with narrative synthesis of pathology, diagnosis, and therapy.
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