Fig. 1

Linkage disequilibrium of investigated polymorphisms in region 2q33, which comprises genes CD28, CTLA4 and ICOS. The numbers within the squares represent the D’ value, expressed as per cent. Empty squares represent a D’ value of 1, which indicates complete linkage disequilibrium. Darker-shaded squares represent pairs with an LOD score = 2, light grey squares represent D’ = 1 and LOD < 2, and white squares represent LOD < 2 and D’ < 1. Two blocks were identified by means of the solid spine of linkage disequilibrium method [37]. Linkage Disequilibrium map was generated by Haploview 4.2