When is Helicobacter pylori acquired in populations in developing countries? A birth-cohort study in Bangladeshi children

Figures & data

Table 1. ELISA results to assess H. pylori status in mothers using cord blood from their children or breastmilk.

	Cord blood (n = 98)		Breast milk (n = 104)
Antigen detected	n	%	n	%
Whole cell antigen^*	69	70.4	40	38.5
CagA	77	78.6	38	36.5
Either	85	86.7	43	41.3

* WEWCA (water-extracted whole cell antigen), as reported.²⁰

^**recombinant CagA antigen, as reported.^5,83

Table 2. Serologic markers of H. pylori status in 105 birth-cohort children at 24 months of age.

Whole cell antigen^*		CagA antigen^**
IgA	IgG	IgG	Number of children in category	% of total
−	−	−	55	52.4
−	−	+	20	19.0
−	+	−	9	8.6
+	−	−	2	1.9
+	−	+	2	1.9
−	+	+	4	3.8
+	+	+	13	12.4

* WEWCA (water-extracted whole cell antigen), as reported.²⁰

** recombinant CagA antigen, as reported.^5,83

Table 3. Relationship between maternal H. pylori status and child's H. pylori status at 24 months of age.

Maternal H. pylori status^a		Number of mothers	% of children positive^b
Serum:	negative	13	54.8
	positive	85	47.1
Breast milk:	negative	61	47.5
	positive	43	46.5
Combined:	negative	7	42.9
	positive	91	48.4

^a Based on H. pylori-specific antibodies (serum IgG, or breastmilk IgA).

^b Based on H. pylori or CagA-specific antibodies (IgA and/or IgG).

Table 4. Response to H. pylori antigens in 105 Bangladeshi birth-cohort children, at 24 months of age.

		IgA	IgG
Seroconversion status	Number of children	WEWCA^*	WEWCA^*	CagA	Mean number of positive assays
Sero-positive^a	50	17	26	39	1.6 ± 0.4
Transient^b	8	1	3	5	1.1 ± 0.1
None	47	0	0	0	NA^c

* WEWCA: water-extracted whole cell antigen, as reported²⁰.

^a Among the 50 sero-positive children at 24 months of age, 32 (64%) seroconverted at 12 or 18 months, and 18 (36%) seroconverted at 24 months.

^b Among the 8 transiently-positive children, 4 seroconverted at 12 months and 4 serconverted at 18 months, but subsequent samples were negative.

^c NA, not applicable.

Table 5. Calculated seroconversion rates for H. pylori persistence in 105 Bangladeshi birth-cohort children during the first two years of life.

Age of child (months)	Number sero-negative children^*	Number becoming positive	Annualized seroconversion rate (%)^**
0	98	NA^***	NA^***
1-5	98	0	0.0
6-11	98	14	28.6
12-17	81	16	39.6
18-23	67	20	59.8

* Number of children enrolled at the start of the time period.

** Based on the number of IgG seroconversions to either WEWCA or CagA, divided by the total number of sero-negative children evaluable at the start of the particular six-month period; rate is annualized.

*** NA; Not applicable, because of maternal IgG interference with the serological determination.

Figure 1. Western blot of H. pylori antigen preparations with human and rabbit serum samples. Panel A. Whole cell preparation of H. pylori 26695; Panel B. Water extracted whole cell antigen (WEWCA), as described.²⁰ Panel C. Recombinant CagA protein, as described.⁸³ Sera are: Lane 1, H. pylori⁺/CagA⁺ patient (H, human serum), lane 2, H. pylori⁺/CagA⁻ patient. Lane 3, H. pylori⁻/CagA⁻ patient, and Lane 4, serum from rabbit immunized with purified H. pylori CagA antigen (R, rabbit).

Figure 2. Serum pepsinogen I (PGI) levels of 18 birth-cohort children. Panel A. PGI levels of samples (n = 20) from children who never seroconverted compared to children with seroconversion (split into samples from children before (n = 21) and after (n = 23) seroconversion). Horizontal bars indicate the mean.**p = 0.001; Panel B. Serum PGI levels over time (mean±SEM ng/ml) in five children who were persistently H. pylori sero-negative and were followed from birth; n = 5 per time point. Panel C. Changes in PGI levels (mean±SEM ng/ml) associated with H. pylori seroconversion in children who became persistently sero-positive. n = 9, 12, 13, 9, 3 for the indicated time points respectively;

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