Fig. 1

RA cohort divided into three synovial membrane histopathological subtypes which display different immune phenotypes, based on immune cell infiltrate. B cells and T cells were identified in duplex IHC by antibodies to CD20 (brown) and CD3 (red) (A, B). Macrophages/MLS identified by CD68 (brown) (C). Follicular: A (i) with many ectopic lymphoid structures (ELS) and T and B cell aggregates or B (i) small number of ELS and T- and B cells. Diffuse: A (ii) dominated by myeloid cells, T- and B-lymphocyte aggregates and scattered T and B cells; B (ii) small numbers of T- and B cell aggregates and scattered T- and B cells. Pauci-immune: A (iii) fibroblast dominated, with minimal inflammatory infiltrate areas of scattered T- and B cells; B (iii) very occasional T- and B cells. C CD68 + cells in (i) follicular, (ii) diffuse and (iii) pauci-immune subtypes. Arrows indicate the location of the inset (enlarged) images