Chronic lymphocytic leukemia (CLL) patients with differential somatic hypermutation status of the immunoglobulin heavy variable genes, namely mutated or unmutated, display fundamental clinico-biological differences. Considering this, we assessed prognosis separately within mutated (M-CLL) and unmutated (U-CLL) CLL in 3015 patients, hypothesizing that the relative significance of relevant indicators may differ between these two categories. Within Binet A M-CLL patients, besides TP53 abnormalities, trisomy 12 and stereotyped subset #2 membership were equivalently associated with the shortest time-to-first-treatment and a treatment probability at five and ten years after diagnosis of 40% and 55%, respectively; the remaining cases exhibited 5-year and 10-year treatment probability of 12% and 25%, respectively. Within Binet A U-CLL patients, besides TP53 abnormalities, del(11q) and/or SF3B1 mutations were associated with the shortest time-to-first-treatment (5- and 10-year treatment probability: 78% and 98%, respectively); in the remaining cases, males had a significantly worse prognosis than females. In conclusion, the relative weight of indicators that can accurately risk stratify early-stage CLL patients differs depending on the somatic hypermutation status of the immunoglobulin heavy variable genes of each patient. This finding highlights the fact that compartmentalized approaches based on immunogenetic features are necessary to refine and tailor prognostication in CLL. Copyright © 2019 Ferrata Storti Foundation.

• MeSH
• Time-to-Treatment MeSH
• Chromosome Aberrations MeSH
• Leukemia, Lymphocytic, Chronic, B-Cell * MeSH
• Immunogenetics MeSH
• Kaplan-Meier Estimate MeSH
• Humans MeSH
• Mutation MeSH
• Disease Susceptibility * MeSH
• Biomarkers, Tumor * MeSH
• Prognosis MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Neoplasm Staging MeSH
• Check Tag
• Humans MeSH
• Male MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Female MeSH

Nuext generation sequencing studies in Homo sapiens have identified novel immunoglobulin heavy variable (IGHV) genes and alleles necessitating changes in the international ImMunoGeneTics information system (IMGT) GENE-DB and reference directories of IMGT/V-QUEST. In chronic lymphocytic leukaemia (CLL), the somatic hypermutation (SHM) status of the clonotypic rearranged IGHV gene is strongly associated with patient outcome. Correct determination of this parameter strictly depends on the comparison of the nucleotide sequence of the clonotypic rearranged IGHV gene with that of the closest germline counterpart. Consequently, changes in the reference directories could, in principle, affect the correct interpretation of the IGHV mutational status in CLL. To this end, we analyzed 8066 productive IG heavy chain (IGH) rearrangement sequences from our consortium both before and after the latest update of the IMGT/V-QUEST reference directory. Differences were identified in 405 cases (5 % of the cohort). In 291/405 sequences (71.9 %), changes concerned only the IGHV gene or allele name, whereas a change in the percent germline identity (%GI) was noted in 114/405 (28.1 %) sequences; in 50/114 (43.8 %) sequences, changes in the %GI led to a change in the mutational set. In conclusion, recent changes in the IMGT reference directories affected the interpretation of SHM in a sizeable number of IGH rearrangement sequences from CLL patients. This indicates that both physicians and researchers should consider a re-evaluation of IG sequence data, especially for those IGH rearrangement sequences that, up to date, have a GI close to 98 %, where caution is warranted.

• MeSH
• Alleles MeSH
• Leukemia, Lymphocytic, Chronic, B-Cell * genetics   immunology   pathology   MeSH
• Complementarity Determining Regions * genetics   MeSH
• Humans MeSH
• Mutation MeSH
• Prognosis * MeSH
• Amino Acid Sequence genetics   MeSH
• Sequence Alignment MeSH
• Check Tag
• Humans MeSH