Abstract
The second-order alpha corrections in QED, in particular the two-photon exchange corrections, are investigated by the line profile approach. The expressions for equal-energy 'reference state' corrections and for the unequal-energy Coulomb-transverse corrections are given. The numerical calculations for the latter corrections of 'box' and 'cross' type in the case of (1s1/2)22s1/2 and (1s1/2)22p1/2 states of Li-like heavy ions are presented.