Table. Treatment protocol for each group of mice (n = 6).

Variable	i.p. sensation	Metformin injection (i.p.)	SCIT treatment	Challenge
NC	5 µg HDM/alum, × 3	PBS, × 3	PBS, × 3	PBS
PC	5 µg HDM/alum, × 3	PBS, × 3	PBS, × 3	25 µg HDM, × 5
Met(100)	5 µg HDM/alum, × 3	100 mg/kg metformin, × 9	PBS, × 3	25 µg HDM, × 5
Met(300)	5 µg HDM/alum, × 3	300 mg/kg metformin, × 9	PBS, × 3	25 µg HDM, × 5
HDM-SCIT	5 µg HDM/alum, × 3	PBS, × 3	250 µg HDM, × 3	25 µg HDM, × 5
SCIT-Met(100)	5 µg HDM/alum, × 3	100 mg/kg metformin, × 9	250 µg HDM, × 3	25 µg HDM, × 5
SCIT-Met(300)	5 µg HDM/alum, × 3	300 mg/kg metformin, × 9	250 µg HDM, × 3	25 µg HDM, × 5

i.p., intraperitoneal; SCIT, subcutaneous immunotherapy; NC, negative control; HDM, house dust mite; alum, aluminum hydroxide; PBS, phosphate-buffered saline; PC, positive control; Met(100), 100 mg/kg metformin; Met(300), 300 mg/kg metformin; SCIT-Met(100), subcutaneous immunotherapy combined with 100 mg/kg metformin; SCIT-Met(300), subcutaneous immunotherapy combined with 300 mg/kg metformin.