. Author manuscript; available in PMC: 2014 Dec 1.

Published in final edited form as: J Immunol. 2014 Apr 28;192(11):5069–5073. doi: 10.4049/jimmunol.1400577

Table 2.

Maternal KIR2DS1 significantly increases birth weight when the fetus has more HLA-C2 epitopes than the mother (Table 2A) and when a single fetal C2 is paternally but not maternally derived (Table 2B).

A. Maternal KIR2DS1 significantly increases birth weight when the fetus has more HLA-C2 epitopes than the mother.
Categorical analysis^*
Subjects	Maternal KIR2DS1 genotype	Median birth weight (6 – 89th centile)	High birth weight (>89th centile)	Effect of KIR2DS1 on birth weight
Subjects	Maternal KIR2DS1 genotype	Median birth weight (6 – 89th centile)	High birth weight (>89th centile)	OR	95% CI		p value
Less C2 in fetus than mother (n=280)	Positive	n = 76 (35.3%)	n = 25 (38.5%)	1.25	0.70	2.26	0.45
Less C2 in fetus than mother (n=280)	Negative	n = 139 (64.7%)	n = 40 (61.5%)
Equal C2 in fetus and mother (n=725)	Positive	n = 215 (39.6%)	n = 75 (41.2%)	1.10	0.78	1.55	0.59
Equal C2 in fetus and mother (n=725)	Negative	n = 328 (60.4%)	n = 107 (58.8%)
More C2 in fetus than mother (n=304)	Positive	n = 95 (40.8%)	n = 47 (66.2%)	2.93	1.66	5.18	0.0002
More C2 in fetus than mother (n=304)	Negative	n = 138 (59.2%)	n = 24 (33.8%)

Continuous analysis^**
Subjects	Effect of KIR2DS1 on birth weight (g)			p
Subjects	n	Mean increase (g)	SE	p
Less C2 in fetus than mother	280	55	70	0.43
Equal C2 in fetus and mother	725	43	46	0.35
More C2 in fetus than mother	304	245	66	0.0002

B. Maternal KIR2DS1 significantly increases birth weight when a single fetal C2 is paternally but not maternally derived.
Categorical analysis^*
Subjects	Maternal KIR2DS1 genotype	Median birth weight (6 – 89th centile)	High birth weight (≥90th centile)	Effect of KIR2DS1 on birth weight
Subjects	Maternal KIR2DS1 genotype	Median birth weight (6 – 89th centile)	High birth weight (≥90th centile)	OR	95% CI		p value
Single fetal C2 paternal (n=204)	Positive	n = 61 (38.9%)	n = 29 (61.7%)	2.65	1.34	5.26	0.005
Single fetal C2 paternal (n=204)	Negative	n = 96 (61.1%)	n = 18 (38.3%)
Single fetal C2 maternal (n=102)	Positive	n = 28 (37.3%)	n = 9 (33.3%)	0.81	0.31	2.11	0.67
Single fetal C2 maternal (n=102)	Negative	n = 47 (62.7%)	n = 18 (66.7%)

Continuous analysis^**
Subjects	Effect of KIR2DS1 on birth weight (g)			p
Subjects	n	Mean increase (g)	SE	p
Single fetal C2 paternal	204	196	81	0.016
Single fetal C2 maternal	102	42	130	0.75

Presence versus absence of KIR2DS1 was tested for effect on birth weight as a categorical variable by logistic regression. UK and Norway cohorts were combined and then analysed in groups defined by combinations of maternal and fetal HLA-C type (Table 3). Cohort and sex of the baby were included as covariates. n = number of pregnancies, OR = odds ratio and CI = confidence interval.

^**

Presence versus absence of maternal KIR2DS1 was tested for an effect on birth weight as a continuous variable in linear regression models of subsets of pregnancies >5th birth weight centile defined by maternal/fetal HLA-C genotype (Table 3). Cohort and sex of the baby were included as covariates. n = number of pregnancies analysed, mean = the average increase in birth weight (in grams) conferred by presence of KIR2DS1 and SE = standard error.