According to the World Health Organization classification system, the major diagnostic criterion for bone marrow involvement by systemicmastocytosis (SM) is the presence of dense aggregates (>15 cells) of mast cells. Expression of CD25, a low-affinity receptorfor interleukin-2 (IL-2), is a reliable diagnostic tool for distinguishing neoplastic mast cell aggregates from reactive proliferations, and has therefore recently become a minor criterion for the diagnosis of SM. Hahn et al. demonstrated that aberrant staining of mast cell clusters by anti-CD25 antibody in GI biopsies was essentially diagnostic of SM. Anti-CD25 antibody has also been useful in identifying mast cells in skin biopsies in the setting of urticaria pigmentosa, which is predictive of systemic mastocytosis. Quantitation of regulatory T cells (Treg) in the setting of hepatocellular carcinoma (HCC) has been used as an independent predictive factor of tumor recurrence after hepatic resection for HCC. Also, the percentage of tumor infiltrating CD25+FOXP3+ regulatory T cells among tumor cells, inside tumor parenchyma and at its periphery, is significantly higher in recurrent cutaneous melanoma than in non-recurrent melanoma.
According to the World Health Organization classification system, the major diagnostic criterion for bone marrow involvement by systemicmastocytosis (SM) is the presence of dense aggregates (>15 cells) of mast cells. Expression of CD25, a low-affinity receptorfor interleukin-2 (IL-2), is a reliable diagnostic tool for distinguishing neoplastic mast cell aggregates from reactive proliferations, and has therefore recently become a minor criterion for the diagnosis of SM. Hahn et al. demonstrated that aberrant staining of mast cell clusters by anti-CD25 antibody in GI biopsies was essentially diagnostic of SM. Anti-CD25 antibody has also been useful in identifying mast cells in skin biopsies in the setting of urticaria pigmentosa, which is predictive of systemic mastocytosis. Quantitation of regulatory T cells (Treg) in the setting of hepatocellular carcinoma (HCC) has been used as an independent predictive factor of tumor recurrence after hepatic resection for HCC. Also, the percentage of tumor infiltrating CD25+FOXP3+ regulatory T cells among tumor cells, inside tumor parenchyma and at its periphery, is significantly higher in recurrent cutaneous melanoma than in non-recurrent melanoma.
