Table 6. Rosetting of P. falciparum clone IT/R29 by ABO genotype.

IT/R29 rosette size
N	Genotype	Mean rosette size	95% CI	p value
23	OO	2.89	2.77–3.01	-
18	AO	2.92	2.78–3.05	0.737
2	AA	3.36	2.95–3.78	0.030
9	BO	2.92	2.73–3.11	0.773
1	BB	2.52	1.93–3.11	0.229
7	AB	3.28	3.06–3.50	0.003
37	Non-O	3.00	2.92–3.11	0.157
Frequency of IT/R29 large rosettes
N	Genotype	% of large rosettes (>4 uninfected RBCs/rosette)	95% CI	p value
23	OO	8.49	5.75–1.22	-
18	AO	9.36	6.27–12.22	0.674
2	AA	20.55	11.20–29.91	0.016
9	BO	8.45	4.09–12.81	0.988
1	BB	1.29	-12.01–14.59	0.296
7	AB	18.23	13.19–23.28	0.001
37	Non-O	11.27	8.89–13.66	0.143

Differences in IT/R29 rosette size or frequency of large rosettes by ABO genotype were tested using multivariate regression analysis with adjustment for confounding by HbAS. 60 RBC donor samples were tested once in duplicate over two successive experimental days (day 1 n = 30 and day 2 n = 30), therefore, experimental day was included as a co-variate to account for day-to-day variation.