The prevalence of Systemic Mastocygtosis (SM) is diffi- cult to assess due to the possible absence of skin lesions and/or specific signs and symptoms. Aim of our study was to evaluate the role of flow cytometry (FC) in the identification of SM patients in com- parison to other techniques. We studied 47 adult patients with suspected SM. Among them, 16 cases had been diagnosed as cutaneous mastocytosis (CM), 27 had presented severe anaphylactic reactions after hymenoptera stings in association with high basal serum tryptase levels, and 4 patients had unspecific signs and symptoms. According to international consensus for diagnosis of SM, each patient was evaluated as follows: basal tryptase serum level, bone marrow (BM) aspirate and BM biopsy (anti-tryptase monoclonal antibody staining). The presence of mast cells (MCs) on BM aspirate was investigated using a specific five-color monoclonal antibody combination (CD25/CD2/CD45/CD34/CD117). In addition, we assessed the presence of D816V KIT mutation in BM mononuclear cells by restriction fragment length polymorphism analysis. Based on clinical, laboratory, immunophenotypic and molecular findings the definitive diagnosis was reached in 43.47 patients (32 SM, 8 Monoclonal MCs Activation Syn- drome,and 3 CM). By using FC we were able to identify cells with the SM features (i.e.CD11711/CD342/CD251 or CD21) infiltrat- ing the BM i 37/40 cases (93%). In contrast, 78% of cases resulted positive by molecular biology analysis and 61% by BM histology. In addition, FC analysis could detect MCs expressing aberrant phenotypes in the presence of low BM-infiltrating SM MCs (median 0.12% of CD451 cells; range 0.002%–1.46%). Therefore, FC shows a good efficiency in the identifi- cation of abnormal MCs compared with other techniques and could represent the tool of choice to diagnose patients with suspected SM.
Underdiagnosed systemic mastocytosis: The role of flow cytometry
PERBELLINI, Omar;ZANOTTI, ROBERTA;BONADONNA, PATRIZIA;CARUSO, BEATRICE;SCUPOLI, Maria;CHILOSI, Marco;PIZZOLO, Giovanni
2007-01-01
Abstract
The prevalence of Systemic Mastocygtosis (SM) is diffi- cult to assess due to the possible absence of skin lesions and/or specific signs and symptoms. Aim of our study was to evaluate the role of flow cytometry (FC) in the identification of SM patients in com- parison to other techniques. We studied 47 adult patients with suspected SM. Among them, 16 cases had been diagnosed as cutaneous mastocytosis (CM), 27 had presented severe anaphylactic reactions after hymenoptera stings in association with high basal serum tryptase levels, and 4 patients had unspecific signs and symptoms. According to international consensus for diagnosis of SM, each patient was evaluated as follows: basal tryptase serum level, bone marrow (BM) aspirate and BM biopsy (anti-tryptase monoclonal antibody staining). The presence of mast cells (MCs) on BM aspirate was investigated using a specific five-color monoclonal antibody combination (CD25/CD2/CD45/CD34/CD117). In addition, we assessed the presence of D816V KIT mutation in BM mononuclear cells by restriction fragment length polymorphism analysis. Based on clinical, laboratory, immunophenotypic and molecular findings the definitive diagnosis was reached in 43.47 patients (32 SM, 8 Monoclonal MCs Activation Syn- drome,and 3 CM). By using FC we were able to identify cells with the SM features (i.e.CD11711/CD342/CD251 or CD21) infiltrat- ing the BM i 37/40 cases (93%). In contrast, 78% of cases resulted positive by molecular biology analysis and 61% by BM histology. In addition, FC analysis could detect MCs expressing aberrant phenotypes in the presence of low BM-infiltrating SM MCs (median 0.12% of CD451 cells; range 0.002%–1.46%). Therefore, FC shows a good efficiency in the identifi- cation of abnormal MCs compared with other techniques and could represent the tool of choice to diagnose patients with suspected SM.
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