Variability of PD-L1 expression in mastocytosis

Ellen W. Hatch, Mary Beth Geeze, Cheyenne Martin, Mohamed E. Salama, Karin Hartmann, Gregor Eisenwort, Katharina Blatt, Peter Valent, Jason Gotlib, Ji Hyun Lee, Lu Chen, Heather H. Ward, Diane S. Lidke, Tracy I. George

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


Mastocytosis is a rare disease with heterogeneous clinical manifestations and few effective therapies. Programmed death-1 (PD-1) and its ligands (PD-L1 and PD-L2) protect tissues from immune-mediated damage and permit tumors to evade immune destruction. Therapeutic antibodies against PD-1 and PD-L1 are effective in the treatment of a variety of neoplasms. In the present study,we sought to systematically analyze expression of PD-1 and PD-L1 in a large number of patients with mastocytosis using immunohistochemistry and multiplex fluorescence staining. PD-L1 showed membrane staining of neoplastic mast cells (MCs) in 77% of systemic mastocytosis (SM) cases including 3 of 3 patients with MC leukemia, 2 of 2 with aggressive SM, 1 of 2 with smoldering SM, 3 of 4 with indolent SM, and 9 of 12 with SM with an associated hematologic neoplasm (SM component only). Ninety-two percent (23 of 25) of cutaneous mastocytosis (CM) cases and 1 of 2 with myelomastocytic leukemia expressed PD-L1, with no expression found in 15 healthy/reactive marrows, 18 myelodysplastic syndromes (MDSs), 16 myeloproliferative neoplasms (MPNs), 5 MDS/MPNs, and 3 monoclonal MC activation syndromes. Variable PD-L1 expression was observed between and within samples, with PD-L1 staining of MCs ranging from 10% to 100% (mean, 50%). PD-1 dimly stained 4 of 27 CM cases (15%), with no expression in SM or other neoplasms tested; PD-1 staining of MCs ranged from 20% to 50% (mean, 27%). These results provide support for the expression of PD-L1 in SMand CM, and PD-1 expression in CM. These data support the exploration of agents with anti-PD-L1 activity in patients with advanced mastocytosis.

Original languageEnglish (US)
Pages (from-to)189-199
Number of pages11
JournalBlood Advances
Issue number3
StatePublished - Feb 14 2018

ASJC Scopus subject areas

  • Hematology


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