Fig. 3.

Psoriasis tonsils have smaller germinal centres and larger mantle zones. The germinal centre occupies a smaller part of the follicle in the psoriasis tonsils (PST, c) compared with the hypertrophic (HT, a, P = 0·005) and the recurrently infected tonsils (RT, b, P = 0·02) (a–d). Conversely, the mantle zone is the larger portion of the follicle in the PST tonsils compared with the HT (e, P = 0·019) and the RT tonsils (e, P = 0·012). The RT and HT tonsils appeared to be proportionally similar (d,e). Although the tonsils differed in the size of their follicles, there was no difference in follicle number (f). Evaluation of the total tissue area covered by follicles revealed that the HT tonsils had a significantly larger follicle area than both the PST and the RT tonsils (g, P = 0·0004 and P = 0·014, respectively). Germinal centres (GC) and mantle zones (MZ) were analysed further to distinguish which was the influencing factor. HT tonsils had both a larger GC and MZ than both the PST (h, P < 0·0001; i, P = 0·018) and the RT tonsils (h, P = 0·017; i, P = 0·08). However, the difference between RT and PST tonsils was present only for the GC (h) that was significantly smaller in the PST tonsils (P = 0·02). Data points represent average measurements of all follicles in each tonsil in mm² at ×25 magnification in two to four visual fields for each tonsil. Statistical significance was determined using Student's t-test or Mann–Whitney U-tests as appropriate and indicated on each panel. Follicles shown at ×100 magnification.