Table 1.

Variation in Helicobacter pylori- and CagA-specific immune responses in study subjects, over a 21-year period.

Category		Paired Samplesb		Control subjectsc (n=24)
Assay	Number of subjects studieda	Absolute log 10 variation in titerf or % variationg	p value	Absolute log 10 variation in titerf or % variationg	p value
H. pylori IgG d	64	0.23+0.15f	NS	0.41+0.27f	0.008
H. pylori IgA d	42	0.20+0.17f	0.0008	0.38+0.30f	0.02
CagA IgG e	55	24.1+15g	0.002	47.1+40g	<0.0001

^aIncludes only those subjects who were seropositive in the indicated assay in both 1973 and 1994.

^bp values determined using Student's t-test; NS, p>0.05

^cSingle 1994 sample from an unrelated H. pylori-positive subject; p-values compare with samples from 24 subjects in 1973

^dMeasured as reciprocal titer

^eMeasured as OD value.

^fVariation measured as absolute difference between the two studied samples, and shown as Mean ± SD log₁₀

^gVariation measured as absolute percent difference between the two studied samples, and shown as Mean+SD.