Table 1.

Width of the collagen VII layer of the BMZ

Treatment	Age, mo	n	Collagen VII, μm	Height, μm	Circumference, mm
Filtered air (FA)	1	3	0.02 ± 0.04	44.0 ± 4.2	8.5 ± 0.9
	3	6	0.61 ± 0.12	45.0 ± 5.2	9.1 ± 0.3
	6	6	1.28 ± 0.34*	49.3 ± 5.2	11.3 ± 0.9
	12	4	2.15 ± 0.13†	54.5 ± 4.2	13.3 ± 1.5
House dust mite	3	6	0.48 ± 0.20	43.6 ± 3.9	9.4 ± 0.5
	6	6	0.74 ± 0.15‡	47.3 ± 2.6	11.6 ± 0.6
Recovery in FA	12	4	1.68 ± 0.11§	58.0 ± 6.6	13.2 ± 2.1

Values are means ± SD.

^*Greater than 3 mo, P < 0.05.

^†Greater than 6 mo, P < 0.05.

^‡Less than 6-mo FA, P < 0.05.

^§Less than 12-mo FA, P < 0.05. BMZ, basement membrane zone.