Fig. 4.

The number of CD68⁺ macrophages correlate with the size of the follicle. CD68⁺ tingible body macrophages were counted within the germinal centre (GC) (a, see arrow). The circumference of the follicle and the GC were measured and macrophages per square mm of either follicle or GC evaluated. A clear correlation is present between the number of CD68⁺ macrophages in the germinal centre and its size as well as the size of the whole follicle, regardless of pathology (b, r² = 0·71). A positive correlation is also observed when analysed separately for psoriasis tonsils (PST) (c, r² = 0·74) and recurrently infected tonsils (RT) (d, r² = 0·72). A similar correlation is observed when the number of macrophages is analysed in regard to the size of the germinal GC alone, although the correlation is stronger for the psoriasis tonsils (e, r² = 0·74 versus f, r² = 0·74). The number of CD68 macrophages per mm² area of GC was evaluated for both the GC (g) and the whole follicle (h). Macrophages were more numerous per mm² of both areas in the recurrently infected tonsils. A total of five PST tonsils and 15 RT tonsils were analysed with, on average, four follicles being measured per tonsil. Statistical significance was determined using linear regression, t-test or Mann–Whitney U-test with P < 0·05 considered significant.