PARP1 and B-cell non-Hodgkin lymphoma: Demonstrated in the B-cell lymphoma mouse cell line I.29μ and splenic B cells, PARP inhibition increased IgA switching (Shockett & Stavnezer 1993), while B cells of PARP-1−/− mice exhibit aberrant recombination and subsequent immunoglobulin class switching following LPS stimulation, as well as impaired T-cell dependent responses (Ambrose et al., 2009).