Figure 1

Histopathological features of bone marrow in patients with arthritis and T-cell large granular lymphocyte (T-LGL) lymphocytosis. (a) Patient 1 with rheumatoid arthritis (RA) and T-LGL leukemia. Staining for CD57 demonstrates intrasinusoidal linear arrays and interstitial clusters of T cells (EnVision stain, ×100). (b) Granzyme B highlights cytotoxic granules in these cells (EnVision stain, ×200). (c) Patient 10 with polyclonal T-LGL lymphocytosis. Staining for CD8 shows dispersed T cells (EnVision stain, ×200). (d) Patient 9 with unclassified arthritis, T-LGL leukemia, and IGKV and IGLV gene rearrangements. CD3 staining shows interstitial and nodular infiltration of T cells (EnVision stain, ×100). (e) Patient 9. The lymphoid nodule contains few CD20⁺ B cells (EnVision stain, ×200). (f) Patient 7 with RA and T-LGL leukemia. A decreased count of granulocytic precursors (myeloperoxydase⁺) is shown (EnVision stain, ×200). IGKV, immunoglobulin kappa variable; IGLV, immunoglobulin lambda variable