Low-density lipoprotein ( LDL ) receptor-related protein-associated protein 1 ( LRPAP1 ) had been identified by B-cell receptor ( BCR ) expression cloning and subsequent protein array screening as a frequent and proliferation-inducing autoantigen of mantle cell lymphoma ( MCL ). Of interest, high-titered and light chain–restricted LRPAP1 autoantibodies were detected in 8 of 28 patients with mantle cell lymphoma.
A study has analyzed LRPAP1 autoantibodies in sera of patients treated within the Younger and Elderly trials of the European MCL Network regarding frequency, association with disease characteristics, and prognostic impact.
LRPAP1 autoantibodies were detected in 41 ( 13% ) of 312 evaluable patients with mantle cell lymphoma.
These LRPAP1 autoantibodies belonged predominantly to the immunoglobulin G ( IgG ) class and were clonally light chain restricted ( 27 with κ light chains, 14 patients with λ light chains ). Titers ranged between 1:400 and 1:3200.
The presence of LRPAP1 autoantibodies was not significantly associated with any baseline clinical characteristic, however, it was associated with a superior 5-year probability for failure-free survival ( FFS ) of 70% ( 95% confidence interval [ CI ], 57% to 87% ) vs 51% ( 95% CI, 44% to 58% ), P = 0.0052; and for overall survival ( OS ) of 93% ( 95% CI, 85% to 100% ) vs 68% ( 95% CI, 62% to 74% ), P = 0.0142.
LRPAP1-seropositive patients had a Mantle Cell Lymphoma International Prognostic Index–adjusted hazard ratio for FFS of 0.48 ( 95% CI 0.27-0.83, P = 0.0083 ) and for OS of 0.47 ( 95% CI 0.24-0.94, P = 0.032 ).
LRPAP1 autoantibodies were frequently detected in a large cohort of patients with mantle cell lymphoma treated within prospective multicenter clinical trials.
These results suggest better outcomes for LRPAP1-autoantibody seropositive patients. ( Xagena )
Thurner L et al, Blood 2021; 137: 3251–3258