Table 4. Estimated case-only interaction odds ratio between PTPN22 and HLA-DR genotypes on the risk of T1DM.

PTPN22 variants	HLA-DR variants	Frequency of cases	Case-only ORinteraction	95% CI	P-value
+	+	19	0.22	0.09–0.54	< 0.001
+	-	34
-	+	28
-	-	11

+: Refers to the presence of risk alleles;−: refer to the absence of risk alleles; OR: odds ratio; CI: confidence interval.