Identification of GAD65 AA 114-122 reactive 'memory-like' NK cells in newly diagnosed Type 1 diabetic patients by HLA-class I pentamers

Flow cytometry immune profiling of recurrent and newly diagnosed growth hormone secreting pituitary neuroendocrine tumors: comparison of two clinical cases

Early detection of aggressive pituitary neuroendocrine tumors (PitNETs) remains challenging due to the absence of reliable markers that can predict disease progression. Aggressive tumors are typically identified through long-term observation. Tumor immune microenvironment (TIME) is crucial for understanding PitNETs' heterogeneity and identifying potential predictors of tumor aggressiveness. In this study, we analyzed immune profile of micro- and macroenvironment in two somatotropinomas (aggressive and non-aggressive) using flow cytometry. We observed lymphopenia and elevated neutrophil levels in the periphery in the patient with tumor recurrence. The aggressive TIME showed greater leukocyte infiltration, with lymphoid cells predominating over myeloid cells along with a higher proportion of CD4 + T cells over CD8 + T cells. We detected double-positive CD4 + CD8 + population, high level of regulatory T cells and a sharp increase in PD-1 + expressing T cells over six months during recurrence. In the blood of the patient with tumor recurrence, we observed reduced granule-mediated cytotoxicity of CD8 + T cells and NK-cells. In the aggressive TIME the number of effector cells producing perforin and granzyme B-both independently and simultaneously was significantly lower. The proportion of CD3-CD20- NK cells and CD3-CD56 + NK cells was low after the first recurrence but increased sharply after six months. The ratio of monocyte subpopulations in tumor differed from that in blood, with CD16 + expressing monocytes predominating in the TIME of both patients. M2 macrophages in TIME rose sharply to 60.8% over six months during recurrence. In several immunological parameters, the patient with tumor recurrence exhibited a more pronounced immunosuppressive profile.

Monitoring islet specific immune responses in type 1 diabetes clinical immunotherapy trials

The number of immunotherapeutic clinical trials in type 1 diabetes currently being conducted is expanding, and thus there is a need for robust immune-monitoring assays which are capable of detecting and characterizing islet specific immune responses in peripheral blood. Islet- specific T cells can serve as biomarkers and as such can guide drug selection, dosing regimens and immunological efficacy. Furthermore, these biomarkers can be utilized in patient stratification which can then benchmark suitability for participation in future clinical trials. This review focusses on the commonly used immune-monitoring techniques including multimer and antigen induced marker assays and the potential to combine these with single cell transcriptional profiling which may provide a greater understanding of the mechanisms underlying immuno-intervention. Although challenges remain around some key areas such as the need for harmonizing assays, technological advances mean that multiparametric information derived from a single sample can be used in coordinated efforts to harmonize biomarker discovery and validation. Moreover, the technologies discussed here have the potential to provide a unique insight on the effect of therapies on key players in the pathogenesis of T1D that cannot be obtained using antigen agnostic approaches.

Lower percentages of natural killer cells in children with type 1 diabetes and their siblings

INTRODUCTION

One of the most common children's endocrine and autoimmune diseases in the world is type 1 diabetes mellitus (T1DM). The incidence of type 1 diabetes is constantly increasing, and according to current estimates, the number of children with T1DM in the world has exceeded 542,000. There are 3 main components emphasized in the pathogenesis: genetic and environmental factors, and the patient's immune system. Many publications have confirmed the role of natural killer cells (NK) in the pathogenesis of type 1 diabetes and other autoimmune diseases.

AIM

The aim of the study was to evaluate the population of NK cells and pancreatic β cell autoantibodies in a group of children with T1DM and their healthy siblings in comparison with children from families with no history of autoimmune diseases.

MATERIAL AND METHODS

The research included 76 children with T1DM, 101 children from the sibling group, and 30 children from the control group. Peripheral blood was analysed on a FACSCalibur flow cytometer (Becton Dickinson) to evaluate the NK cell population. The results were presented as the percentage of NK cells among lymphocytes. Statistical analysis was performed using STATIS-TICA 10 PL software.

RESULTS

The mean percentage of NK cells in children with T1D (10.59 ±5.37) and in the sibling group (11.93 ±5.62) was statistically reduced in comparison to the control group (14.89 ±7.78) in sequence (Student's t -test: t = -3.24; df = 103; p = 0.002) (Stu-dent's t -test: t = -2.30; df = 128; p = 0.02). There was no statistically significant difference in the percentage of NK cells be-tween the group of children with T1DM and their siblings (Student's t -test: t = -1.59; df = 173; p = 0.11). In the group of sib-lings, the younger the child, the lower the reported percentage of NK cells. This relationship was statistically significant (test for the Pearson correlation coefficient t = 3.41; p = 0.0009; r = 0.33). In the group of children with type 1 diabetes, a similar relationship was not found. The concentration of anti-IA2 and anti-Znt8 antibodies was statistically significantly higher in the sibling group compared to the control group (anti-IA2 p = 0.0000001; anti-ZnT8 p = 0.00001), and the concentration of anti-GAD antibodies was comparable in both groups. In the group of children with type 1 diabetes, a positive correlation was demonstrated between the reduced percentage of NK cells and the coexistence of anti-GAD and anti-ZnT8 antibodies (Mann-Whitney U test Z = -2.02; p = 0.04). There was no similar relationship in the group of siblings.

CONCLUSIONS

The reduced percentage of NK cells in children with T1DM and in their siblings compared to the control group suggests the role of NK cells in the pathogenesis of T1DM. Genetic predisposition and dysfunction of NK cells probably underlie the pathogenesis of T1DM.

Type 1 Diabetes and Its Multi-Factorial Pathogenesis: The Putative Role of NK Cells

Type 1 diabetes (T1D) affects millions of people worldwide and is the prevalent form of all pediatric diabetes diagnoses. T1D is recognized to have an autoimmune etiology, since failure in specific self-tolerance mechanisms triggers immune reactions towards self-antigens and causes disease onset. Among all the different immunocytes involved in T1D etiopathogenesis, a relevant role of natural killer cells (NKs) is currently emerging. NKs represent the interface between innate and adaptive immunity; they intervene in the defense against infections and present, at the same time, typical features of the adaptive immune cells, such as expansion and generation of memory cells. Several recent studies, performed both in animal models and in human diabetic patients, revealed aberrations in NK cell frequency and functionality in the peripheral blood and in damaged tissues, suggesting their possible redirection towards affected tissues. NKs oscillate from a quiescent to an activated state through a delicate balance of activating and inhibitory signals transduced via surface receptors. Further accurate investigations are needed to elucidate the exact role of NKs in T1D, in order to develop novel immune-based therapies able to reduce the disease risk or delay its onset.