Table 5 Mother−child similarity score—Mean sequence similarity matching (SSM) score and risk of systemic lupus erythematosus (SLE) among mothers

From: Mother−child histocompatibility and risk of rheumatoid arthritis and systemic lupus erythematosus among mothers

Histocompatibility per SSM score (Quartile)

SLE

n (%)

Controls

n (%)

OR (95% CI)a

p for linear trend

HLA Class I

 A

Least (4th)

26 (22)

222 (24)

Reference

 

Most (1st)

31 (27)

229 (25)

1.2 (0.7–2.2)

0.46

 B

Least (4th)

23 (20)

231 (25)

Reference

 

Most (1st)

37 (32)

231 (25)

1.5 (0.9–2.7)

0.23

 C

Least (4th)

30 (26)

209 (23)

Reference

 

Most (1st)

26 (22)

227 (25)

0.8 (0.4–1.4)

0.19

HLA Class II

 DPB1

Least (4th)

26 (22)

220 (24)

Reference

 

Most (1st)

19 (16)

244 (27)

0.7 (0.3–1.2)

0.04

 DQA1

Least (4th)

26 (22)

218 (24)

Reference

 

Most (1st)

19 (16)

221 (24)

0.7 (0.4–1.4)

0.25

 DQB1

Least (4th)

29 (25)

295 (32)

Reference

 

Most (1st)

18 (15)

221 (24)

0.8 (0.4–1.5)

0.89

 DRB1

Least (4th)

14 (12)

210 (23)

Reference

 

Most (1st)

28 (24)

244 (27)

1.7 (0.9–3.3)

0.42

  1. OR odds ratio, 95% CI confidence interval
  2. aAdjusted for number of live births. The SSM score estimates degree of similarity between two alleles. A lower score indicates increased similarity relative to a higher score; therefore, the fourth quartile of scores is intended to represent the least histocompatible group and the first quartile the most