Multiparameter Phenotypical Characterisation of Human Blood Monocyte Subpopulations in Suspected Chronic Lymphocytic Leukemia

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Laboratorinė medicina. 2016,
t. 18,
Nr. 4,
p. 159 -
167

Background. B-CLL is one of the most common types of leukemia. Leukemic B cells are resistant to apoptosis, and microenvironment has large impact on their survival. In this microenvironment, an important role is played by monocyte derived macrophages and the substances they secrete (e. g. cytokines). Monocytes are the pregenitors of macrophages. According to genetic and immunophenotypic differences, monocytes are categorized into 3 subpopulations.

The aim of this study was to evaluate peripheral monocyte subpopulation changes in the blood of patients with B-cell chronic lymphocytic leukemia (CLL).

Materials and methods. We retrospectively analysed laboratory test results of 243 people treated and investigated at Vilnius University hospital, Santariskiu klinikos from 2013 to 2015. The participants were divided into 3 groups: group 1 (No pathology), group 2 (Reactive changes) and group 3 (CLD - chronic lymphoproliferative disorder). All participants had received a flow cytometric evaluation of blood leukocytes, using fluorochromes marked with antibodies against CD markers.

Results. Group 3 (CLD) had a significantly lower peripheral monocyte percentage than the other groups, while groups 1 (No pathology) and 2 (Reactive changes) both had a similar percentage. When investigating subpopulations, it was found that group 1 had a higher percentage of classical monocytes than the other groups, which had similar percentages. Intermediate monocyte percentages didn’t differ much befween groups; however, group 1 had a slightly lower per cent age. Non-classical monocyte percentage didn’t differ significantly between groups, however variation befween the highest and lowest values was quite high in groups 2 and 3. Group 3 also had a slightly elevated percentage of non-classical monocytes, in comparison to group 1. CD38, CD4, HLA-DR and CD56 expression wasn’t significantly different between groups.

Conclusions. When no pathology is present, classical monocytes are certainly the largest monocyte subpopulation, while intermediate and non-classical monocytes take only a small part. These monocytes express CD38, HLA-DR, CD4, don’t express or have a low expression of CD2 and CD56. If there is reactive changes to another pathology, the intermediate monocyte fraction increases, but the expression of markers doesn’t change much. In case of CLD, monocyte subpopulations changes and expression of CD markers are similar to reactive changes. Persistant increase in intermediate monocytes shows an active inflammatory process in the body, which can be a prognostic sign for disease. It is recommended to perform a more detailed analysis of different monocyte subpopulations, to evaluate their diagnostic significance in cases of acute or chronic cancer.

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