Figure 1. Proliferating Cells in LCH Granuloma are Mostly Endothelial Cells, Fibroblasts, and T Cells.

Paraffin-embedded and frozen sections were stained with antibodies against Ki-67 (which label proliferating cells), CD1a (LCs), CD3 (T cells), CD20 (B cells), CD68, CD31, and CD34 (endothelial cells).

(A) Double immunostaining of paraffin-embedded section from LCH eosinophilic granulomas with anti-Ki-67 Ab, (brown nuclear staining) and with anti-CD1a Ab (upper images, blue staining) or anti-CD3 Ab (lower images, blue staining). Open arrowheads indicate double-stained cells, black arrowheads indicate Ki-67⁺ cells with an endothelial morphology.

(B) Histogram represents percentage of CD1a⁺ cells and of CD3⁺ cells labeled with Ki-67 (n = 15).

(C) Histogram represents percentage of proliferating cells (Ki-67⁺) that express CD1a, CD3, CD20, or CD68 (n = 15).

(D) Histogram represents percentage of proliferating cells (Ki-67⁺) that are endothelial cells, interstitial cells (fibroblasts), and other types based on morphological examination.

(E) Immunolabeling of blood vessels on paraffin-embedded section from LCH eosinophilic granulomas with CD34 (left) and CD31 (right) antibodies.

(F) Proliferating Ki-67⁺ cells (brown nuclear staining) with a fibroblast-cell morphology in an eosinophilic granuloma.