Chronic lymphocytic leukemia (CLL) is uniquely characterized by the existence of subsets of cases with quasi-identical, 'stereotyped' B-cell receptors (BCRs). Herein we investigate this stereotypy in 2662 patients with CLL, the largest series yet, using purpose-built bioinformatics methods based on sequence pattern discovery. Besides improving the identification of 'stereotyped' cases, we demonstrate that CLL actually consists of two different categories, based on the BCR repertoire, with important biological and ontogenetic differences. The first ( approximately 30% of cases) shows a very restricted repertoire and is characterized by BCR stereotypy (clustered cases), whereas the second includes cases with heterogeneous BCRs (nonclustered cases). Eleven major CLL clusters were identified with antigen-binding sites defined by just a few critically positioned residues, regardless of the actual immunoglobulin (IG) variable gene used. This situation is closely reminiscent of the receptors expressed by cells participating in innate immune responses. On these grounds, we argue that whereas CLL cases with heterogeneous BCRs likely derive from the conventional B-cell pool, cases with stereotyped BCRs could derive from progenitor cells evolutionarily adapted to particular antigenic challenges, perhaps intermediate between a true innate immune system and the conventional adaptive B-cell immune system, functionally similar to what has been suggested previously for mouse B1 cells.

Purpose The general outlook for patients with diffuse large B-cell lymphoma (DLBCL) in first remission is important information for patients and for planning post-treatment follow-up. The purpose of this study was to evaluate the survival of patients with DLBCL in remission compared with a matched general population. Methods A total of 1,621 patients from the Danish Lymphoma Registry who were newly diagnosed with DLBCL between 2003 and 2011 were included in this study. All patients were ≥ 16 years of age at diagnosis and had achieved complete remission or complete remission unconfirmed after first-line rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) or R-CHOP-like therapy. Results The 5-year post-treatment DLBCL survival was inferior to survival in the matched general population (78%; 95% CI, 76 to 80; v 87%; standardized mortality ratio, 1.75; P < .001). Excess mortality was present but reduced for patients achieving post-treatment event-free survival for 24 months (pEFS24; standardized mortality ratio, 1.27; P < .001). In age-stratified analyses, the survival of patients < 50 years of age was normalized to the general population after achieving pEFS24 ( P = .99). During the first 8 years after pEFS24, the average loss of lifetime was 0.31 mo/y (95% CI, 0.11 to 0.50 mo/y). Excess mortality diminished when analyzing death from lymphoma as competing event to death from other causes, suggesting that early and late relapse is responsible for increased mortality in patients with DLBCL. Conclusion Although this population-based study does not support complete normalization of survival for patients with DLBCL achieving pEFS24, the estimated loss of residual lifetime was low for patients in continuous remission 2 years after ending treatment. Therefore, pEFS24 is an appealing and relevant milestone for patient counseling and could be a surrogate end point in clinical trials.