Localization
of macrophages and AFB in resected lungs. Macrophages, stained with
CD68 (A, C, and E) and AFB stained with carbolfuchsin (B, D, and F) in
the left upper-lobe cavity wall of the open lesion of patient 1 are
shown. CD68 staining is seen at the cavity (cav) surface (A and C),
within the necrotic area (nec) (A and C), and in the granulomatous area
below the necrotic area (E). AFB are seen predominantly within
macrophages at the cavity surface (D) and not in the Langhans
cells or macrophages of the granulomatous tissue (F). The inset in
panel D shows AFB in cells at the luminal surface of the
right-lower-lobe cavity of patient 2. AFB are also seen in macrophages
within the liquefied (liq) material adjacent to the necrotic area
(H) of the left-lower-lobe fibrotic nodule undergoing
breakdown (liquefaction) in patient 3. Magnifications,
×10 (A and B), ×40 (C, E, F, and G), ×80 (D,
inset), and ×200 (D and
H).