CALGB 150905 (Alliance): rituximab broadens the antilymphoma response by activating unlicensed NK cells.


Journal Article

Natural killer (NK) cells contribute to clinical responses in patients treated with rituximab, but the rules determining NK-cell responsiveness to mAb therapies are poorly defined. A deeper understanding of the mechanisms responsible for antibody-dependent cellular cytotoxicity (ADCC) could yield useful biomarkers for predicting clinical responses in patients. Unlicensed NK cells, defined as NK cells lacking expression of an inhibitory KIR for self-HLA class I ligands, are hyporesponsive in steady state, but are potent effectors in inflammatory conditions. We hypothesized that antitumor antibodies such as rituximab can overcome NK-cell dependence on licensing, making unlicensed NK cells important for clinical responses. Here, we examined the influences of variations in KIR and HLA class I alleles on in vitro responses to rituximab. We tested the clinical significance in a cohort of patients with follicular lymphoma treated with rituximab-containing mAb combinations, and show that rituximab triggers responses from all NK-cell populations regardless of licensing. Neither IL2 nor accessory cells are required for activating unlicensed NK cells, but both can augment rituximab-mediated ADCC. Moreover, in 101 patients with follicular lymphoma treated with rituximab-containing mAb combinations, a "missing ligand" genotype (predictive of unlicensed NK cells) is associated with a higher rate of progression-free survival. Our data suggest that the clinical efficacy of rituximab may be driven, in part, by its ability to broaden the NK-cell repertoire to include previously hyporesponsive, unlicensed NK cells. A "missing ligand" KIR and HLA class I genotype may be predictive of this benefit and useful for personalizing treatment decisions in lymphomas and other tumors.

Full Text

Duke Authors

Cited Authors

  • Du, J; Lopez-Verges, S; Pitcher, BN; Johnson, J; Jung, S-H; Zhou, L; Hsu, K; Czuczman, MS; Cheson, B; Kaplan, L; Lanier, LL; Venstrom, JM

Published Date

  • September 2014

Published In

Volume / Issue

  • 2 / 9

Start / End Page

  • 878 - 889

PubMed ID

  • 24958280

Pubmed Central ID

  • 24958280

Electronic International Standard Serial Number (EISSN)

  • 2326-6074

Digital Object Identifier (DOI)

  • 10.1158/2326-6066.CIR-13-0158


  • eng

Conference Location

  • United States