Leukocyte Composition and Immunophenotype of the Blood Lymphocytes in Women with Type 2 Diabetes Mellitus and Obesity

Abstract

Background. There is an opinion that changes in some indicators of natural and adaptive immunity in patients with type 2 diabetes mellitus (DM) and overweight are caused by concomitant obesity, as the adipose tissue is the potent secretory organ that produces many cytokines, particularly adipokines playing a key role in various immune responses. It is known that the level of the main adipokines, which regulate the adipose tissue, in the human peripheral blood (PB) is determined on the basis of human sexual dimorphism. Purpose of the study — to elucidate the question of the extent, to which the observed changes in the leukocyte composition and lymphocyte immunophenotype in type 2 DM in women are determined by obesity, due to the significant sex differences in the secretion of some adipokines involved in controlling the function of the immune system. Materials and methods. The study included 24 women aged 40 to 65 years with newly diagnosed type 2 DM, who were divided into 2 subgroups: the first one — with a body mass index (BMI) < 25 kg/m2 and the second one — with BMI ≥ 30 kg/m2. The total number of leukocytes in the PB was counted using hematology analyzer. Leucocyte vomposition was determined in smears of the PB per 200 cells stained by Pappenheim. Surface antigens of lymphocytes against membrane antigens: CD3, CD4, CD8, CD20 and CD56 — were labelled by monoclonal antibodies marked with fluorescein isothiocyanate or phycoerythrin. Results. The increase in the total number of leukocytes in the PB of obese patients was more significant than in patients with a normal BMI, i.e. 23.1 versus 14.5 % (p < 0.05). The highest leukocytosis was observed in patients with DM type 2 and obesity, reached 7.61 × 109/L on the average. In the subgroup of healthy women and female patients with normal body mass, the absolute number of segmented neutrophils in the PB of patients with DM type 2 in relation to that of normoglycemic women had increased on average by 20.3 %, while in obese women this ratio was 29.1 % (p < 0.05). The absolute number of monocytes in the PB in these subgroups was increased by an average of 59.2 % in lean (p < 0.05) and 64 % in obese (p < 0.05). The majority of women with newly diagnosed DM type 2 and normal values of body weight have only a slight and statistically non-significant increase in the absolute number of CD4+T- and CD8+T-cells. The majority of patients with type 2 DM and obesity showed a statistically significant increase in the absolute number of natural killer cells (CD56+-cells) in the PB. Conclusions. In female patients with DM type 2 and obesity, there is a more significant change in the composition of leukocytes (increased number of neutrophils and monocytes) and immunophenotype of blood lymphocytes (increasing the number of CD4+Т- and CD56+-cells) than in women with DM 2 type and a normal BMI, which indicates a more significant low-grade chronic inflammation in them and explains the cause of a more severe course of DM type 2 in obesity. The findings are consistent with the recent data where efficiency of some oral hypoglycemic drugs, such as metformin, is largely due to their anti-inflammatory action.

Keywords

• type 2 diabetes mellitus
• obesity
• immunity
• leukocyte composition of the blood
• lymphocyte immunophenotype