Peripheral white blood cell subtypes and the development/progression of diabetic macular edema in type 2 diabetic...

Inflammation and immune dysregulation are involved in the pathogenesis of diabetic macular edema (DME). The progressive increase of neutrophils in peripheral blood can lead to the increase of the number of neutrophils in the retina, thus leading to the sustained damage of the retinal vascular system and the destruction of the blood retinal barrier (BRB); lymphocytes play a protective role in vascular diseases caused by type 2 diabetes mellitus (T2DM). The purpose of this study was to study the relationship between the changes of leukocytes and their classification in peripheral blood and the occurrence and progression of DME in patients with T2DM.

A retrospective analysis was made on 81 patients with T2DM with DME (DME group) hospitalized in our hospital from January 2019 to December 2020. According to the morphological characteristics of macular edema in optical coherence tomography (OCT), they were divided into early DME group (n=33) and late DME group (n=48); 33 patients with diabetes retinopathy (DR) but without DME matched in age and course of disease served as the control group (NO-DME group). The clinical parameters assessed included eye examination, OCT results, WBCs and subtypes, blood glucose, and glycosylated hemoglobin.

Compared with NO-DME group (n=33), Neutrophils% in DME group (n=81) was higher (57.37±9.52 vs. 63.27±7.85; P=0.001); Monocyte% (7.63±1.77 vs. 6.88±1.83; P=0.047) and lymphocyte% (30.35±9.51 vs. 27.26±6.59; P=0.032) were decreased. The optimal model was obtained with R 4.0.5 software. With other relevant variables being the same, females had a significantly increased risk of DME (b=1.273, P=0.015), %neutrophils was significantly associated with increased risk of DME (b=0.152, P=0.0006), and %lymphocytes was significantly associated with a reduced risk of DME (b=-0.027, P=0.179). However, in the early and late DME groups, no significant differences in biological markers were found, and a high-quality model was not obtained.

In this preliminary study, %neutrophils is associated with increased risk of DME, whereas %lymphocytes is associated with a reduced risk of DME.