IL13 and systemic mastocytosis: There were significant positive associations between Sm infection and PPD-specific cytokine and antibody responses, as observed for PPD-specific IL-13 (aGMR 1.75 [1.19, 2.56], p = .007) and IgG4 responses (aGMR 1.12 [1.00, 1.26], p = .046) [Table 3B].