Morphological and immunofenotypic features of the monoclonal population of B-lymphocytes in chronic lymphocytic leukemia

Purpose of the study. To evaluate the features of morphological and immunophenotypic characteristics of the lymphoid population with different restriction of light chains of immunoglobulins in patients with chronic lymphocytic leukemia (CLL).

Materials and methods. The study included 30 CLL patients aged 47–79 years (20 men and 10 women). All patients underwent a General clinical blood test (SysmexXE 2100, Japan), morphological examination of the bone marrow (BioVision; Micros, Austria), immunophenotyping of bone marrow and peripheral blood by flow cytofluorometry (Navios10/3, Beckman Coulter, USA). B-cell clonality established by detection of restriction of light chains of surface immunoglobulins kappa or lambda. Morphological analysis of lymphocytes that differ in the expression of light chains of surface immunoglobulins: kappa (k) — group I (22 people — 73,3%), lambda (λ) — group II (8 people — 26,7%).

Results. Determination of cell types by values of direct (FSC) and lateral (SSC) light scattering during immunophenotyping of peripheral blood and bone marrow samples showed that in patients of group I (CD19k+/CD5+/CD23+) on the light scattering diagram, the lymphoid population had low parameters: on the FSC scale — from 200 to 400, on the SSC — from 10 to 160 units, which indicates morphological uniformity of cells. In group II (CD19λ+/CD5+/CD23+), on the contrary, on the light scattering sketogram, the lymphoid zone was heterogeneous and stretched: on the FSC scale — from 200 to 1000, on the SSC — from 10 to 400 units, which indicates morphological polymorphism of cells. There were also differences in the expression of the common leukocyte antigen CD45. In group I, the expression is higher: the population of B-lymphocytes in terms of fluorescence intensity is on the dot graph on the CD45 scale in the second half of the third decade and in the fourth decade — to the right, than in group II, in which B-lymphocytes lie in the third decade. The data indicate that the CD19k+/CD5+/CD23+ population is represented by Mature cells, while the Cd19k+/CD5+/CD23+ population is represented by less Mature and / or intermediate forms. Significant morphological differences in lymphocyte populations were also observed in microscopic studies of blood and bone marrow preparations.

Conclusion. The established immunophenotypic and morphological differences in lymphoid populations expressing either kappa — or lambda-light chains of immunoglobulins may be important for identifying risk groups among patients with biologically heterogeneous variants of chronic lymphocytic leukemia.

1. Voitsekhovskii VV, Zabolotskikh TV, Tseluiko SS, Landyshev YuS, Grigorenko AA. Chronic lymphocytic leukemia. Blagoveshchensk, 2015, 178. (In Russian).

2. Stadnik EA, Strugov VV, Virts YuV, Zaritskey AYu. Guideline for diagnosis and first-line treatment in cll. Bulletin of the Almazov Federal center for heart, blood and endocrinology. 2012;(6):5–15. (In Russian).

3. Voitsekhovskii VV, Landyshev YuS, Esenin VV, Skripkina NS, Esenina TV. Some aspects of diagnosis and treatment of B-cell chronic lymphocytic leukemia. Siberian Medical Journal (Irkutsk). 2007;68(1):72–75. (In Russian).

4. Bennet JM, Catovsky D, Daniel MT, Flandrin G, Galton DA, Gralnick HR, et al. Proposals for the classification of chronic (mature) B and T lymphoid leukaemias. French-AmericanBritish (FAB) Cooperative Group. J Clin Pathol. 1989 Jun;42(6):567–584. https://doi.org/10.1136/jcp.42.6.567

5. Shibinskaya AV. Immunological characteristics of morphological variants of B-cell chronic lymphocytic leukemia. Dissertation. Мoscow, 2010, 122 p. (In Russian).

6. Kravchenko DV, Svirnovsky AI. Chronic lymphocytic leukemia: clinic, diagnosis, treatment. Gomel: GU "RNPC RM and EC", 2017, 117 p.

7. Craig FE, Foon KA. Flow cytometric immunophenotyping for hematologic neoplasms. Blood. 2008 Apr 15;111(8):39413967. https://doi.org/10.1182/blood-2007–11–120535

8. Kataeva EV, Golenkov AK, Mitina TA, Klinushkina EF, Trifonova EV, Vysotskaya LL, et al. Clinical aspects of determining free light chains of serum immunoglobulins in patients with chronic lymphocytic leukemia. Hematology and Transfusiology. 2017;62(3):153–157. https://doi.org/10.18821/0234–5730–2017–62–3–153–157

9. Maurer MJ, Cerhan JR, Katzmann JA, Link BK, Allmer C, Zent CS, et al. Monoclonal and polyclonal serum free light chains and clinical outcome in chronic lymphocytic leukemia. Blood. 2011 Sep 8;118(10):2821–2826. https://doi.org/10.1182/blood-2011–04–349134

10. Katzman JA, Clark RJ, Abraham RS, Bryant S, Lymp JF, Bradwell AR, et al. Serum reference intervals and diagnostic ranges for free kappa and free lambda immunoglobulin light chains: relative sensitivity for detection of monoclonal light chains. Clin Chem. 2002 Sep;48(9):1437–1444.

11. Pratt G, Harding S, Holder R, Fegan C, Pepper C, Oscier D, et al. Abnormal serum free light chain ratios are associated with poor survival and may reflect biological subgroups in patients with chronic lymphocytic leukaemia. Br J Haematol. 2009 Jan;144(2):217–222. https://doi.org/10.1111/j.1365–2141.2008.07456.x

12. Maurer MJ, Micallef INM, Cerhan JR, Katzmann JA, Link BK, Colgan JP, et al. Elevated serum free light chains are associated with event-free and overall survival in two independent cohorts of patients with diffuse large B-cell lymphoma. J Clin Oncol. 2011 Apr 20;29(12):1620–1626. https://doi.org/10.1200/JCO.2010.29.4413

13. Marti GE, Rawstron AC, Ghia P, Hillmen P, Houlston RS, Kay N, et al. Diagnostic criteria for monoclonal B-cell lymphocytosis. Br J Haematol. 2005 Aug;130(3):325–332. https://doi.org/10.1111/j.1365–2141.2005.05550.x

14. Hallek M, Cheson BD, Catovsky D, Caligaris-Cappio F, Dighiero G, Döhner H, et al. Guidelines for the diagnosis and treatment of chronic lymphocytic leukemia: a report from the International Workshop on Chronic Lymphocytic Leukemia updating the National Cancer Institute-Working Group 1996 guidelines. Blood. 2008 Jun 15;111(12):5446–5456. https://doi.org/10.1182/blood-2007–06–093906

15. Gavrilina OA, Zvonova EE, Sudarikov AB, Nikulina EE, Sidorova YuV, Biderman BV, et al. Detection of bone marrow B-cell clonality in diffuse large B-cell lymphoma. Hematology and Transfusiology. 2015;60(2):26–31.

16. Lugovskaya SA, Pochtar ME. Hematological Atlas. 4th edition, additional. Moscow: Triada Publishing house, 2016, 434 p.