Belatacept prophylaxis against organ rejection in adult kidney-transplant recipients

High Inflammatory Tendency Induced by Malignant Stimulation Through Imbalance of CD28 and CTLA-4/PD-1 Contributes to Dopamine Neuron Injury

Background

Parkinson’s disease is a common neurodegenerative disease in the elderly. The incidence of various cancers in Parkinson’s disease patients is significantly lower than in healthy people. Parkinson’s disease patients are individuals with a high tendency for inflammation, whose peripheral immune system is represented in an activated state. We hypothesized that the hyperinflammatory predisposition of Parkinson’s disease patients is pathogenic.

Methods

DBA/1 mice were used to simulate “highly inflammatory individuals”, and the carcinogen DEN was used to induce malignancy. Hematoxylin & eosin (H&E) staining was used to observe the formation of lung tumors. Apoptosis of neurons was observed by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining. Immunohistochemistry and flow cytometry were used to observe CD4, CD28, major histocompatibility complex II (MHCII), cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4), and programmed death 1 (PD-1). The ionized calcium binding adaptor molecule-1 (IBA-1) + inducible nitric oxide synthase (iNOS) was used to label M1 microglia, and IBA-1 + arginase 1 (Arg1) was used to label M2 microglia by immunofluorescence. The expression of pro-inflammatory cytokines tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and anti-inflammatory cytokines IL-10 and IL-4 was detected by ELISA.

Results

DBA/1 mice with high inflammatory tendency showed a continuous increase of peripheral inflammation, promoting intracranial inflammation, decreasing the tumor incidence and increasing the neurodegeneration under induction of malignant change. CD28 and CTLA-4/PD-1 reduced the T-cell-dominated inflammatory response, reduced the intracerebral inflammatory response, protected from neurodegeneration, and increased the incidence of tumor. Combination of CTLA-4 and PD-1 blocker can overactivate T cells, worsen peripheral and intracranial inflammation, reduce the incidence of tumor, cause damage to dopamine neurons, and promote the occurrence of neurodegeneration.

Conclusion

High inflammatory tendency induced by malignant stimulation through the imbalance of CD28 and CTLA-4/PD-1 leads to dopamine neuron injury.

First report of expansion of CD4+/CD28 null T-helper lymphocytes in adult patients with idiopathic autoimmune hemolytic anemia

CD28 null T helper (T_h) cells are rare in healthy individuals, but they are increased in various inflammatory and immune-mediated diseases. In this study, we determined the size of the CD4⁺/CD28 null T lymphocyte compartment in the peripheral blood of 40 autoimmune hemolytic anemia (AIHA) patients (idiopathic and secondary) and 20 healthy control subjects, using tri-color flow cytometry. The frequency and absolute count of CD4⁺/CD28 null T helper (T_h) cells was significantly higher in idiopathic AIHA patients, compared to healthy controls (p = 0.001 and 0.001, respectively) and to patients with secondary AIHA (p = 0.04 and 0.01, respectively). The percentage of CD4⁺/CD28 null T_h cells was also negatively correlated to the hemoglobin (Hb) level (p = 0.03). These findings demonstrate, for the first time, the expansion of this phenotypically-defined population of T lymphocytes in patients with idiopathic AIHA and indicate that it likely plays an etiological role in the development of this disease. However, establishing the use of this marker for diagnosis or monitoring treatment of such patients needs further studies.

T Follicular Regulatory Cells and Antibody Responses in Transplantation

De novo donor-specific antibody (DSA) formation is a major problem in transplantation, and associated with long-term graft decline and loss as well as sensitization, limiting future transplant options. Forming high-affinity, long-lived antibody responses involves a process called the germinal center (GC) reaction, and requires interaction between several cell types, including GC B cells, T follicular helper (Tfh) and T follicular regulatory (Tfr) cells. T follicular regulatory cells are an essential component of the GC reaction, limiting its size and reducing nonspecific or self-reactive responses.An imbalance between helper function and regulatory function can lead to excessive antibody production. High proportions of Tfh cells have been associated with DSA formation in transplantation; therefore, Tfr cells are likely to play an important role in limiting DSA production. Understanding the signals that govern Tfr cell development and the balance between helper and regulatory function within the GC is key to understanding how these cells might be manipulated to reduce the risk of DSA development.This review discusses the development and function of Tfr cells and their relevance to transplantation. In particular how current and future immunosuppressive strategies might allow us to skew the ratio between Tfr and Tfh cells to increase or decrease the risk of de novo DSA formation.