Contributions
Abstract: PB2043
Type: Publication Only
Background
Mastocytosis considered as a subcategory of myeloid neoplasms based on World Health Organization (WHO) 2016 classification, is characterized by expansion and accumulation of abnormal clonal mast cells in one or more organs. KITD816V mutation and other KIT mutations play as driver mutations in the pathogenesis of disease. KITD816V mutation is positive in %80 of systemic mastocytosis patients. Recent studies show that high allele burden of KITD816V and high serum tryptase levels correlate with aggressive disease. Recently the importance of CD30 expression on neoplastic mast cells has been confirmed. CD30 is expressed aberrantly on neoplastic mast cells in patients with advanced systemic mastocytosis.
Aims
In this study we aimed to present demographic data, clinical follow-up and treatment of patients with mastocytosis and identify the impact of KIT D816V allele burden and expression of CD30 by mast cells in systemic mastocytosis.
Methods
We performed a retrospective study on 54 adult patients with mastocytosis (24 female, 30 male; mean age:44±13) who fullfilled WHO criteria between 2006 and 2016. These patients comprise cutaneous mastocytosis (CM) (n=10), ındolent systemic mastocytosis (ISM) (n=30), smoldering systemic mastocytosis (SSM) (n=2), aggressive systemic mastocytosis (ASM) (n=4), systemic mastocytosis associated hematologic neoplasm (SM-AHN) (n=3), mast cell leukemia (MCL) (n=4) and mast cell activation syndrome (MCAS)(n=1).
Results
At diagnosis, age of patients with advanced disease was higher than ISM and SSM group (p=0.001). Most frequent symptom of disease was skin lesion (urticaria pigmentosa) (%64). Skin lesions were significantly higher in patients with ISM and SSM than with advanced diasease (p=0.009). But B symptoms were significantly higher in advanced disease variant (p=0.013). Anemia, trombocytopenia, elevation of ALP and GGT, hypoalbuminemia were significantly higher in advanced disease than in ISM and in SSM. Osteopenia was higher in patients with ISM and SSM than with advanced disease, %56 and %18 respectively. KITD816V mutation was detectable in peripheral blood in 33 of 40 mastocytosis patients (%82) with a median Ct value 36±4. Median Ct value was significantly lower in advanced SM (Ct: 32±5 ) than in SM and SSM (Ct: 36±4 )(p=0.028) showing a significantly higher allele burden. Expression of CD30 on mast cells in bone marrow biopsies with immunohistochemistry investigation was detectable in 20 of 32 systemic mastocytosis patients (%62). There was no significant difference expression of C30 on mast cell between patients with ISM (%65) (13/20) and advanced SM (%87) (7/8) (p=0.371). There was no significant correlation between elevated serum tryptase level and CD30 expression (p=0.114).
Conclusion
The definition of disease subcategories in systemic mastocytosis is important for choosing the treatment modality (cytoreduction or allogeneic stem cell transplantation vs treatment of the mediator symptoms) for the individual patient. CD30 is a diagnostic marker and also a possible therapeutic target.
Session topic: 16. Myeloproliferative neoplasms - Clinical
Keyword(s): Mast cell disease, kit, CD30
Abstract: PB2043
Type: Publication Only
Background
Mastocytosis considered as a subcategory of myeloid neoplasms based on World Health Organization (WHO) 2016 classification, is characterized by expansion and accumulation of abnormal clonal mast cells in one or more organs. KITD816V mutation and other KIT mutations play as driver mutations in the pathogenesis of disease. KITD816V mutation is positive in %80 of systemic mastocytosis patients. Recent studies show that high allele burden of KITD816V and high serum tryptase levels correlate with aggressive disease. Recently the importance of CD30 expression on neoplastic mast cells has been confirmed. CD30 is expressed aberrantly on neoplastic mast cells in patients with advanced systemic mastocytosis.
Aims
In this study we aimed to present demographic data, clinical follow-up and treatment of patients with mastocytosis and identify the impact of KIT D816V allele burden and expression of CD30 by mast cells in systemic mastocytosis.
Methods
We performed a retrospective study on 54 adult patients with mastocytosis (24 female, 30 male; mean age:44±13) who fullfilled WHO criteria between 2006 and 2016. These patients comprise cutaneous mastocytosis (CM) (n=10), ındolent systemic mastocytosis (ISM) (n=30), smoldering systemic mastocytosis (SSM) (n=2), aggressive systemic mastocytosis (ASM) (n=4), systemic mastocytosis associated hematologic neoplasm (SM-AHN) (n=3), mast cell leukemia (MCL) (n=4) and mast cell activation syndrome (MCAS)(n=1).
Results
At diagnosis, age of patients with advanced disease was higher than ISM and SSM group (p=0.001). Most frequent symptom of disease was skin lesion (urticaria pigmentosa) (%64). Skin lesions were significantly higher in patients with ISM and SSM than with advanced diasease (p=0.009). But B symptoms were significantly higher in advanced disease variant (p=0.013). Anemia, trombocytopenia, elevation of ALP and GGT, hypoalbuminemia were significantly higher in advanced disease than in ISM and in SSM. Osteopenia was higher in patients with ISM and SSM than with advanced disease, %56 and %18 respectively. KITD816V mutation was detectable in peripheral blood in 33 of 40 mastocytosis patients (%82) with a median Ct value 36±4. Median Ct value was significantly lower in advanced SM (Ct: 32±5 ) than in SM and SSM (Ct: 36±4 )(p=0.028) showing a significantly higher allele burden. Expression of CD30 on mast cells in bone marrow biopsies with immunohistochemistry investigation was detectable in 20 of 32 systemic mastocytosis patients (%62). There was no significant difference expression of C30 on mast cell between patients with ISM (%65) (13/20) and advanced SM (%87) (7/8) (p=0.371). There was no significant correlation between elevated serum tryptase level and CD30 expression (p=0.114).
Conclusion
The definition of disease subcategories in systemic mastocytosis is important for choosing the treatment modality (cytoreduction or allogeneic stem cell transplantation vs treatment of the mediator symptoms) for the individual patient. CD30 is a diagnostic marker and also a possible therapeutic target.
Session topic: 16. Myeloproliferative neoplasms - Clinical
Keyword(s): Mast cell disease, kit, CD30