Both rejection and tolerance of allografts can occur in the absence of secondary lymphoid tissues.
Kant CD, Akiyama Y, Tanaka K, Shea S, Yamada Y, Connolly SE, Marino J, Tocco G, Benichou G. Both rejection and tolerance of allografts can occur in the absence of secondary lymphoid tissues. J Immunol. 2015 Feb 01; 194(3):1364-71.