MBL2 and systemic mastocytosis: Therefore, the objective of this study was to investigate the association between clinical factors (sex, upper gastrointestinal bleeding (UGB), specific treatment, and contact with focus area) and polymorphisms of the exon 1 region as well as the promoter regions (-550 and -221) of the MBL with PPF regression after specific treatment in patients with SM in populations of endemic areas in the state of Pernambuco, northeastern Brazil.