Immunophenotype and Immunoglobulin Variable Genes (IgVH) Mutation Status in Chronic Lymphocytic Leukemia (CLL). New Prognostic Patterns Detection and Target Therapy.
Authors: Gabus Raul , Pritsch Otto , Landoni Ana I. , Bianchi Sergio , Canessa Cecilia , Tiscornia Adriana , Borelli Gabriel , Uturbey Faride , Bodega Juan Enrique 
Published: April 2020

Introduction: The IgVH mutational profile ia a strong prognostic indicator in CLL patients (pts.), particularly in early stages, where clinical staging fails to accurately predict outcomes. Our center designed a prospective trial in newly diagnosed CLL pts; our aim was to evaluate peripheral blood inmunophenotype including CD38 and the IgVH and correlate these parameters with clinical evolution and treatment requirements.

Methods: Inclusion criteria were: below 75 years old and CLL diagnosed by inmunophenotype (Matutes-Moreau score) with 3 colors flow cytometry (fluorescence by triples markers and a predetermined ACMo panel). We did a recruited plan of 20 pts. with stage Binet A, 10 pts. Binet B and 10 pts. Binet C. Anti-CD38 FITC monoclonal was from Becton Dickinson (code 340927) and Ig nucleotide sequence was carried out at the Medicine Public University in Montevideo. A watch and wait attitude Binet A indolent Binet B was adopted whatever IgVH mutation status and fludarabine based regimen as standard first line therapy for progressive disease under NCI criteria Binet A, aggressive Binet B and C.

Results: From June 2003 to June 2006, we recruited 40 untreated CLL pts. Twenty-two males and 18 females entered the study, with a median age of 61 years (range: 38–73). The median lymphocytes counts at diagnosis was 53.100 per mm3 (range: 3.300–302.000); for Binet A 25.460 mm3, for Binet B 47.880 mm3 and for Binet C 113.820 mm3. Eight-five percent had typical immunophenotype pattern (score 4–5) and 15% had atypical one. Eighty percent were CD38 negative (cut off level: 30%). Among the 33 patients tested for IgVH: 48% (16/33) were mutated and 52% (17/33) were unmutated (cut off label ≤ 2% changes of näive pattern). IgVH mutation status by Binet are summarize in table n.1. All of the12 Binet A IgVH mutated pts. are in watch and wait strategy without signs of progression, but 5 over 6 Binet A IgVH unmutated pts. had criteria of progression and started into a Fludarabine regimen strategy. All aggresive Binet B and C patients received up-front therapy as scheduled. In contrast to other reports we failed to find a significant correlation between IgVH mutation status and CD38 expression, particularly in advanced stages of the disease. Median Progression Free Survival (PFS) in the untreated group (18 pts.) was 37 months and for the treated one (22 pts.) was 22 months. Median PFS for IgVH mutated and unmutated pts. were 39 and 22 months respectively; and median overall survival (OS) for IgVH mutated and unmutated pts were 45 and 28 months respectively. In Binet-A median OS for those mutated and untreated pts. was 47 months and for unmutated and treated pts. the median PFS and OS were 34 and 39 respectively. Median OS for Binet B and C were 23 and 21 months respectively.

Conclusion: Unmutated patients display a worse prognosis when compared to mutated ones. This is particularly true is early stages where the presence of an unmutated status results in short PFS and treatment requirement in most cases.

Table 1. IgVH mutation status by Binet stage BINET IgVH test performed Mutated, n (%) Unmutated, n(%) A n=18 12 (66) 6 (33) B n=7 2 (29) 5 (71) C n=8 2 (25) 6 (75)