Figure 1.
Histopathological review of periprosthetic tissues from hip joint M-M revision surgery.
Histopathological appearances in formalin fixed sections showing group 1: diffuse lymphocyte infiltrate (A), group 2: T cell aggregate (C), and group 3: organised lymphoid aggregate with central follicular area (E). Immunohistochemistry with CD3 shows diffuse (B), T cells in an aggregate (D) and T cells mixed with B cells (not stained) in a follicular type of aggregate (F). Images taken at 10X magnification.
Figure 2.
Lymphoid follicles resembling ectopic tertiary lymphoid organs occurs in a distinct subset of patients with lymphoid-like aggregates.
A) Immunofluorescence (IF) from tissues of M-M implants with lymphoid follicles show central B cell rich area (red) surrounded by T cells (blue) and reticular pattern of podoplanin expression in the B cell area (green). (B, b). IF images showing co-localisation of CD21+ FDC network (red) with podoplanin (green). FDC network stained with CD21 and podoplanin are largely excluded from T cell area (blue).
Figure 3.
Presence of HEVs in ectopic lymphoid follicles.
Paraffin sections of periprosthetic tissues having large lymphoid-like aggregates were stained with marker for B cell, CD20 (pink) and marker for HEVs, PNAd (cyan). Shown are representative images from the group containing large lymphoid aggregates. Plump HEVs expressing PNAd were detected in the periphery of lymphoid aggregates, in the T cell area (A, inset a).
Figure 4.
Expression of the chemokine CCL21 and CXCL13 in ectopic lymphoid follicles.
Photomicrographs of 5 µm thick sections with immunohistochemical staining of CCL21 and CXCL13 show scarce expression of CCL21 outside the germinal centre, in the T cell area (red in A) and intense CXCL13 staining in the B cell rich areas (red in D). Double immunohistochemistry show minimal expression of CCL21 (red in B, inset b) with PNAd+ HEVs (brown in B, inset b). Positive CCL21 expression is detected in control tonsil (red in C). CXCL13 expression (red in E, F) is detected in the CD20+ B cell-rich areas (brown in E) and CD21+ follicular dendritic cell network (brown in F). Images taken at 10× magnification.
Figure 5.
Expression of the B cell survival factors BAFF and April in ectopic lymphoid follicles and the presence of plasma cells in ectopic lymphoid follicles.
Immunofluorescence images of staining of BAFF (red) and April (green) detected in the CD21+ follicular dendritic cell network (blue) (A) Paraffin sections of tissues showing organised lymphoid aggregates were also stained with a marker for plasma cells, CD138 (cyan), and B cells (CD20) (red) by double immunofluorescence (B). Abundant plasma cells were detected at the periphery of the aggregates as well as in the surrounding tissue. Shown are representative images from the group of cases containing organised lymphoid aggregates.
Figure 6.
Co-localisation of implant derived metallic elements, Co and Cr, with TLO structures.
Confocal nuclear density map (A) and overlaid X-ray fluorescence maps for Co (B) and Cr (C) measured at a 50 μm resolution demonstrate a strong co-localisation of Cr with the B and T cell infiltrate. Scales refer to fluorescence intensity in arbitrary units. (D) is an immunofluorescence image taken from the boxed region in (A) showing B cells (red) and T cells (blue). Micro-focus X-ray fluorescence maps of the same region (5 μm resolution) demonstrates Co to be more evenly dispersed (E) with Cr well co-localised with the immune cell infiltrate (F).