35 - TENASCIN-C EXPRESSION IN THE CERVICAL LYMPH NODE OF A PATIENT EXPERIENCING THE THIRD EPISODE OF KAWASAKI DISEASE

Background: The clinical signs of Kawasaki disease(KD) independently manifest across multiple organs, particularly appearing around the border between keratinized stratified squamous epithelium (skin, cornea) and non-keratinized epithelium(oral mucosa, conjunctiva). Among the clinical diagnostic criteria for KD, only an enlarged cervical lymph node(LN) presents unilaterally, while other manifestations exhibit no laterality. The node-first KD (NFKD) showcases a LN sign preceding other organ manifestations. As LN is enveloped in a capsule, we tried to identify spatiotemporally ongoing pathologic findings of KD, focusing on the borderline between the capsule and the subcapsular area.

Methods: Pathologic findings were examined using various staining methods on a biopsy specimen of cervical LN collected 10 years ago from a 6-year-old boy with NFKD during his third episode of KD.

Results: H&E staining and Masson trichrome staining of the LN biopsy specimens reveal a significantly thickened capsule with increased collagen (fibrosis), along with reactive fibroblasts and inflammatory cells, leading to the obliteration of the subcapsular sinus. The subcapsular area exhibits necrosis, while follicular areas remain unaffected. Additionally, linear aggregation of RBCs along the subcapsular area is observed, with vasculitis present in the medullary arterioles. Tenascin-C, a matricellular protein known to be re-expressed in a spatiotemporally-restricted manner in KD, stains specifically around the subcapsular sinus and interfollicular area, while sparing the lymphoid follicles.

To specify the aggregated RBCs in the subcapsular area, we attempted to stain the LN biopsy specimen with CD71+ (transferrin receptor 1 & premature RBC marker) antibodies. The expression of CD71+ in RBCs was found to be increased compared to an adult LN specimen diagnosed with non-specific hyperplasia. However, the staining was not localized; instead, it was scattered non-specifically, including in the subcapsular area.

Conclusion: LN in NFKD exhibits a thick capsule with increased inflammation, more reactive fibroblasts, and necrosis in the subcapsular area, aligning with findings from previous studies. We highlight the recruitment of RBCs around the subcapsular area toward ongoing necrosis and the fibrogenic area, spatiotemporally defined by tenascin-C staining.

 We recommend further studies with more specialized staining strategies using additional tissue specimens to better define the pathogenesis of KD.