By using static and dynamic light scattering (SLS and DLS), we investigate the effect of ion specificity and solution conditions on the solution behavior of monoclonal antibodies (mAbs). The extracted second virial coefficient, a global measure of the strength of protein-protein interactions, shows a complicated, nonmonotonic behavior. It can be connected on one side with the Hofmeister effect, and on the other with the interplay of screening and charge fluctuations in inhomogeneous, patchy charge distribution of these particular proteins. Although direct quantification in terms of the underlying long and short-range potentials is out of reach, the observed effects do point toward important features of mAbs solution aggregation processes that are governed by the identity of the solution ions as well as by details of the charge distribution of interacting proteins.