. 2012 Jan 25;24(3):175–182. doi: 10.1093/intimm/dxr123

Table 1.

Percentages of B cell subsets from young and elderly subjects before and after H1N1 vaccination

	Naive IgG−IgA−CD27−		IgM memory IgG−IgA−CD27+		Switched memory IgG+IgA+CD27−		Switched memory IgG+IgA+CD27+
Age (years)	t0	t28	t0	t28	t0	t28	t0	t28
20–64	58 ± 2	57 ± 2	36 ± 2	34 ± 2	3 ± 0.1	3 ± 0.4	3 ± 0.2	6 ± 0.4^a
≥65	71 ± 3^b	70 ± 2^b	26 ± 7	27 ± 5	2 ± 0.9	2 ± 0.5	1 ± 0.2^b	1 ± 0.3^b

One hundred microliter of blood from each subject were stained as described in Methods. Results refer to CD19+ cells.

P < 0.01, indicates the difference between t0 and t28. Total numbers and percentages of B cells decrease with age by about half to 120 cells μl^–1 and 6%, respectively, so although there is an increase in the % of naive cells in the elderly, the overall numbers are decreased. The t0 values here are consistent with those we have previously reported in 66 young and 46 elderly [see ref. (27)]

P < 0.01, indicates the difference between the young (20–64) and the elderly (≥65) individuals.