Clinicians often face significant challenges when managing histiocytic necrotizing lymphadenitis due to its diverse presentations. Recent research now classifies these variations into three distinct Kikuchi disease subtypes: febrile type, febrile lymphadenopathy (FebLAP), and afebrile lymphadenopathy (aLAP). Furthermore, understanding these specific categories helps practitioners predict clinical courses and potential recurrence rates more accurately.

Investigators recently utilized NanoString nCounter technology to analyze 35 lymph node specimens across these variations. Consequently, they discovered that the aLAP subtype exhibits significantly higher AICDA expression compared to the febrile type. However, traditional CD20 immunohistochemical staining did not reveal an increased total B-cell count in these specimens. This finding led researchers to hypothesize that specific, high-expressing cell populations drive these immunological differences rather than a general increase in B-lymphocytes.

Understanding Atypical B Cells in Kikuchi Disease Subtypes

Immunohistochemical analysis confirmed that IRTA1+ atypical memory B cells are prevalent in 64% of aLAP cases. In contrast, these cells appeared in only 18% of febrile cases and were entirely absent in the FebLAP group. These specific B cells likely contribute to the unique clinical heterogeneity observed in the condition. Therefore, IRTA1 serves as a potential biomarker to distinguish between these immunological variants, aiding in a more precise diagnostic approach for patients presenting with lymphadenopathy.

What are the primary Kikuchi disease subtypes?

Research categorizes the condition into the febrile type, febrile lymphadenopathy (FebLAP), and afebrile lymphadenopathy (aLAP) based on predominant symptoms and the presence of fever.

How do atypical memory B cells influence the disease?

Atypical memory B cells, characterized by IRTA1 and AICDA expression, are predominantly found in the aLAP subtype. These cells explain the distinct clinical profile of aLAP compared to the more systemic febrile variants.

Disclaimer: This content is for informational and educational purposes only. It does not constitute medical advice or a professional relationship between the reader and the author. Clinicians should use their professional judgment and refer to the latest local and national guidelines for clinical practice.

References

Yu SC et al. Immunological mechanisms underlying the clinical heterogeneity of Kikuchi disease: the potential role of atypical memory B cells. J Pathol. 2026 Apr 29. doi: 10.1002/path.70068. PMID: 42052902.

Masab M, Surmachevska N, Farooq H. Kikuchi-Fujimoto Disease. StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing. 2023 Oct 29.

Abdul Razak A, Shanmugasundaram S. Kikuchi-Fujimoto disease, a rare benign disease with atypical histomorphology: more than meets the eye. Pathology. 2024 Apr;56(3):382-390. doi: 10.1016/j.pathol.2023.10.017.