Connexin 43 Communication Channels in Follicular Dendritic Cell Development and in Follicular Lymphomas

Figure 4

Connexin 43 expression in follicular lymphomas (FL); lymph node localization ((a)–(f)); and bone marrow involvement ((g)–(j)). Large and irregular follicles dominated by CD10 positive FL B cells (a) and fragmented CD21 positive FDC meshwork (b). Cx43 ((c), red) reaction colocalizes with that of CD21 ((d), green) in yellow (arrowheads). Insets show a binuclear FDC with highly upregulated Cx43 ((c), green),and colocalization of Cx43 (red) and CD10 (green) as yellow dots (d). Elevated tumor cell proliferation detected with Ki67 reaction (green) is seen in FL follicles either with dense FDC and Cx43 reactions ((e); red) or with fragmented FDC and Cx43 staining ((f); circled area highlights broken or missing FDC). In the bone marrow involvement of FL NGFR (g) and CD21 (inset) positive follicles (arrowhead: LNGFR positive hyperplastic stromal cells) show the most of Cx43 reaction ((h), red) and proliferating tumor cells (Ki67-green). Strong Cx43 staining ((i), red) is accompanied with only fragmented CD21 reaction (green) in another follicle. Significantly more Cx43 (red) but less Ki67 (green) is detected within a bone marrow FL infiltrate than in the rest of bone marrow (j). Arrowheads in the inset show Cx43 within the boxed area. Graphs reveal linear correlation between Cx43 and CD21 levels in FL (k) and Cx43 (l) or Ki67 (m) expression in FDC rich and FDC poor FL areas. Immunoperoxidase ((a), (b), and (g)) and immunofluorescence staining ((c)–(f) and (h)–(j)). Blue nuclear staining using hematoxylin ((a), (b), and (g)) or Hoescht ((c)–(f) and (h)–(j)). Significance: and . Scale bar on (a) shows 150 µm on (a) and (b); 30 µm on (c) and (d); 120 µm on (e), (f), (g), (i), and (j); and 100 µm on (h).