SECONDARY OBJECTIVES: I. To evaluate the progression-free survival of subjects with B-cell NHL receiving maintenance therapy with lenalidomide and rituximab after ASCT. II. To examine whether potential effects of lenalidomide and rituximab on progression-free survival after ASCT, compared with historical controls, vary according to histologic subtype of B-cell NHL. III. To correlate potential associations between peripheral blood levels of lymphocyte subsets including NK, T, and B cells and progression-free survival after ASCT in enrolled subjects. IV. To evaluate potential associations between progression-free survival after ASCT and polymorphisms at position 158 of FCgammaRIIIa receptor in enrolled subjects.