Mutational status and gene repertoire of IGHV-IGHD-IGHJ rearrangements in Serbian patients with chronic lymphocytic leukemia

Gastric DLBCL clonal evolution as function of patient age

Diffuse large B cell lymphoma (DLBCL) is the most common type of NHL, accounting for about 40% of NHL cases, and is one of the most aggressive lymphomas. DLBCL is widespread in individuals aged more than 50 years old, with a maximum incidence in the seventh decade, but it may also occur in younger patients. DLBCL may occur in any immune system tissue, including those around the gastrointestinal tract, and even in the stomach, though gastric DLBCL has yet to be sufficiently investigated. This study aimed to understand changes in gastric Diffuse Large B cell lymphoma (gastric DLBCL) development with age. Immunoglobulin (Ig) heavy chain variable region genes were amplified from sections of nine preserved biopsies, from patients whose age varied between 25 and 89 years, sequenced and analyzed. We show first that identification of the malignant clone based on the biopsies is much less certain than was previously assumed; and second that, contrary to expectations, the repertoire of gastric B cell clones is more diverse among the elderly DLBCL patients than among the young.

The signs of negative selection in IGHV framework regions are associated with worse overall survival of chronic lymphocytic leukemia patients

The mutational status of the variable region of the immunoglobulin heavy chain (IGHV) genes remains the most significant prognostic factor in chronic lymphocytic leukemia (CLL) patients. However, the groups of mutated (M) and unmutated (UM) patients are also heterogeneous, and additional markers are used for a more accurate prognosis. The aim of our work was to determine the prognostic value of the signs of antigen selection determined by BASELINe statistics in M IGHV sequences of CLL patients. Clinical data, IGHV gene configuration, TP53, NOTCH1, SF3B1 mutations were analyzed in 127 CLL patients with M IGHV sequences. The median OS of patients with negative selection in the framework regions (FWRs) of IGHV genes was 120 months compared to 202 month in other CLL patients (P = 0.016). In multivariate Cox regression analysis Binet stage C vs A + B (P < 0.0001), SF3B1 mutations (P < 0.0001), negative selection in the FWRs (HR P = 0.007), and age ≥65 years (P = 0.034) were powerful adverse prognostic factors for OS in CLL patients with M IGHV genes. These preliminary data suggest that the signs of antigen-driven selection may be used as a prognostic factor in CLL patients with M IGHV genes in combination with other markers.

Matrix-assisted laser desorption ionization mass spectrometry profiling of plasma exosomes evaluates osteosarcoma metastasis

Osteosarcoma is the most common primary sarcoma of bone among adolescents, often characterized by early lung metastasis resulting in high mortality. Recently, exosomes have been used in liquid biopsy to monitor tumors. Herein, we used matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to profile human plasma exosomes for the evaluation of osteosarcoma lung metastasis. Forty patients with osteosarcoma with (n = 20) or without (n = 20) lung metastasis as well as 12 heathy controls were recruited. Exosomes were isolated from human plasma for MALDI-TOF MS analysis. Multivariate statistical analyses were performed based on the MALDI-TOF mass spectra. The strategy can efficiently differentiate osteosarcomas from healthy controls and further discriminate osteosarcoma lung metastasis from non-lung metastasis. We identified seven exosomal proteins as potential biomarkers of osteosarcoma lung metastasis. The proposed method holds great promise to clinically diagnose osteosarcoma and monitor osteosarcoma lung metastasis.

Distinct immunoglobulin heavy chain variable region gene repertoire and lower frequency of del(11q) in Taiwanese patients with chronic lymphocytic leukaemia

Chronic lymphocytic leukaemia (CLL) is the most common leukaemia in Western countries but very rare in Asia. Peripheral blood or bone marrow mononuclear cells obtained at initial diagnosis from 194 patients with CLL were analysed to determine the ethnic difference in genetic abnormalities. Mutated IGHV was detected in 71·2% of Taiwanese CLL and IGHV3‐23 was the most frequently used gene. Stereotyped BCR was present in 18·3% with subset 8 being the most frequent. All cases with subset 8 belonged to IGHV 4‐39 and were exclusively associated with un‐mutated IGHV and poor outcome. Mutation frequencies of SF3B1 (9·7%), NOTCH1 (8·6%), BIRC3 (1·1%), ATM (16·9%) or TP53 (8·1%), and frequencies of cytogenetic abnormalities including trisomy 12 (18·6%), del(17p) (10·4%), del(13q) (43·7%) and IGH translocation (10·1%) were comparable to those reported from Western countries, except del(11q) (6·9%) which was lower in our patients. Patients with un‐mutated IGHV, subset 8, disrupted TP53, trisomy 12, and SF3B1 mutations had a worse outcome compared to patients without these mutations. In conclusion, IGHV3‐23 usage, stereotyped subset 8 and lower frequency of del(11q) show an ethnicity‐dependent association in Taiwanese CLL patients.

UGT1A1 (TA)n Promoter Genotype: Diagnostic and Population Pharmacogenetic Marker in Serbia

The UGT1A1 enzyme is involved in the metabolism of bilirubin and numerous medications. Unconjugated hyperbilirubinemia, commonly presented as Gilbert syndrome (GS), is a result of decreased activity of the UGT1A1 enzyme, variable number of TA repeats in the promoter of the UGT1A1 gene affects enzyme activity. Seven and eight TA repeats cause a decrease of UGT1A1 activity and risk GS alleles, while six TA repeats contribute to normal UGT1A1 activity and non-risk GS allele. Also, the UGT1A1 (TA)_n promoter genotype is recognized as a clinically relevant pharmacogenetic marker. The aim of this study was to assess diagnostic value of UGT1A1 (TA)_n promoter genotyping in pediatric GS patients. Correlation of the UGT1A1 (TA)_n genotypes and level of unconjugated bilirubin at diagnosis and after hypocaloric and phenobarbitone tests in these patients was analyzed. Another aim of the study was to assess pharmacogenetic potential of UGT1A1 (TA)_n variants in Serbia. Fifty-one pediatric GS patients and 100 healthy individuals were genotyped using different methodologies, polymerase chain reaction (PCR) followed by acrylamide electrophoresis, fragment length analysis and/or DNA sequencing. Concordance of the UGT1A1 (TA)_n promoter risk GS genotypes with GS was found in 80.0% of patients. Therefore, UGT1A1 (TA)_n promoter genotyping is not a reliable genetic test for GS, but it is useful for differential diagnosis of diseases associated with hyperbilirubinemia. Level of bilirubin in pediatric GS patients at diagnosis was UGT1A1 (TA)_n promoter genotype-dependent. We found that the frequency of pharmacogenetic relevant UGT1A1 (TA)_n promoter genotypes was 63.0%, pointing out that UGT1A1 (TA)_n promoter genotyping could be recommended for preemptive pharmacogenetic testing in Serbia.

Immunoglobulin Heavy Chain Gene Rearrangements in Patients with Gaucher Disease

BACKGROUND

Several studies support the evidence of increased incidence of hematological complications in Gaucher disease including monoclonal and polyclonal gammopathies and blood malignancies, especially multiple myeloma.

METHODS

Serum concentrations of immunoglobulins and PCR analysis of the IGH gene rearrangements were performed. The clonal PCR products were directly sequenced and analyzed with the appropriate database and tools. Serum monoclonal proteins were detected and identified by electrophoresis.

RESULTS

Among 27 Gaucher patients, clonal IGH rearrangement was discovered in eight, with 5/8 having also serum monoclonal protein. Elevated immunoglobulins were detected in 9/27 patients. Follow-up data for 17 patients showed that the clonal rearrangement remained the same in four of them, however, in one patient it disappeared after the follow-up period. The remaining 12/17 patients were without previous IGH clonal rearrangement and remained so after the follow-up.

CONCLUSIONS

Although clonal expansion may occur relatively early in the disease course, at least judging by the IGH gene rearrangements in Gaucher patients, the detected clones may be transient. A careful clinical follow-up in these patients is mandatory, including monitoring for lymphoid neoplasms, especially multiple myeloma.

Immunoglobulin heavy chain variable region gene repertoire and B-cell receptor stereotypes in Indian patients with chronic lymphocytic leukemia

In chronic lymphocytic leukemia (CLL), the geographical bias in immunoglobulin heavy-chain variable (IGHV) gene usage lead us to analyze IGHV gene usage and B-cell receptor stereotypy in 195 patients from India. IGHV3, IGHV4, and IGHV1 families were the most frequently used. 20.5% sequences had stereotyped BCR and were clustered in 12 pre-defined and 6 novel subsets. Unmutated IGHV was significantly associated with reduced time to first treatment (p < 0.033) and poor overall survival (OS; p = 0.01). We observed a significant difference in OS between IGHV1, IGHV3, and IGHV4 family cases (p = 0.045) in early stage patients. Regarding subfamily usage, only IGHV1-69 expression was found to have statistically significant poor outcome (p = 0.017). Our results from the analysis of various molecular and clinical features suggest that the expression of specific IGHV gene influences the outcome in early stage CLL, and hence its assessment may be added to the clinical leukemia laboratory armamentarium.

Comprehensive characterization of immunoglobulin gene rearrangements in patients with chronic lymphocytic leukaemia

Previous studies have suggested a geographical pattern of immunoglobulin rearrangement in chronic lymphocytic leukaemia (CLL), which could be as a result of a genetic background or an environmental antigen. However, the characteristics of Ig rearrangements in the population from the South of France have not yet been established. Here, we studied CLL B-cell repertoire and mutational pattern in a Southern French cohort of patients using an in-house protocol for whole sequencing of the rearranged immunoglobulin heavy-chain genes. Described biased usage of variable, diversity and joining genes between the mutated and unmutated groups was found in our population. However, variable gene frequencies are more in accordance with those observed in the Mediterranean patients. We found that the third complementary-determining region (CDR) length was higher in unmutated sequences, because of bias in the diversity and joining genes usage and not due to the N diversity. Mutations found in CLL followed the features of canonical somatic hypermutation mechanism: preference of targeting for activation-induced cytidine deaminase and polymerase motifs, base change bias for transitions and more replacement mutations occurring in CDRs than in framework regions. Surprisingly, localization of activation-induced cytidine deaminase motifs onto the variable gene showed a preference for framework regions. The study of the characteristics at the age of diagnosis showed no difference in clinical outcome, but suggested a tendency of increased replacement and transition-over-transversion mutations and a longer third CDR length in older patients.

Mutation status and immunoglobulin gene rearrangements in patients from northwest and central region of Spain with chronic lymphocytic leukemia

The aim of this study was to investigate the frequency and mutation status of the immunoglobulin heavy variable chain (IGHV) in a cohort of 224 patients from northwest and central region of Spain diagnosed with chronic lymphocytic leukemia (CLL), and to correlate it with cytogenetic abnormalities, overall survival (OS) and time to first treatment (TTFT). 125 patients had mutated IGHV, while 99 had unmutated IGHV. The most frequently used IGHV family was IGHV3, followed by IGHV1 and IGHV4. The regions IGHV3-30, IGHV1-69, IGHV3-23, and IGHV4-34 were the most commonly used. Only 3.1% of the patients belonged to the subfamily IGHV3-21 and we failed to demonstrate a worse clinical outcome in this subgroup. The IGHV4 family appeared more frequently with mutated pattern, similar to IGHV3-23 and IGHV3-74. By contrast, IGHV1-69 was expressed at a higher frequency in unmutated CLL patients. All the cases from IGHV3-11 and almost all from IGHV5-51 subfamily belonged to the group of unmutated CLL.