Electron micrographs of AKU salivary glands . A) Electron micrograph showing fine amyloid fibrils (A) approximately 10 nm in diameter located in close relation to the lamina (LP) of the secretory end-pieces as well as in the interstitial connective tissue stroma of AKU labial salivary gland. Pigment granules are visible amongst collagen fibrils in transverse and longitudinal section (black arrows). B-C) Electron micrographs of another AKU labial salivary gland showing a region of the interstitial glandular stroma that contains fine amyloid fibrils (A), approximately 10 nm in diameter, interspersed with bundles of collagen fibrils (C). Pigment deposits are present on broken collagen fibers (black arrows) and scattered between amyloid fibrils. To be note that amyloid fibrils appear superimposed to collagen fibers in different area of the tissue. D-F) Electron micrograph of a third AKU labial salivary gland showing the glandular stroma containing finely fibrillar amyloid material (A). In photo E) collagen fibers in transverse section are shown (arrowheads), many of which presenting electron dense ochronotic deposits located amongst fibers. In photos E-F), dark ochronotic pigment granules are indicated (arrowheads) scattered amongst the collagen fiber as well as amongst amyloid fibrils. Some deposits can be observed located within amyloid bundles of fibrils and bridging between collagen fibers (white arrows). A: amyloid; C: collagen; LP lamina propria. Photo A is from patient #2, photos B-C are from patient #5 and photos D-F are from patient #7. Bars, A: 5 μm, B, C and E: 2.5 μm, D and F: 1 μm.