Interferon-gamma and perforin-positive T cells in acquired aplastic anemia: implication in therapeutic response.

Acquired aplastic anemia (aAA) is an autoimmune disease, characterized by infiltration of T lymphocytes in the bone marrow with destruction of hematopoietic stem cells by the effector cells. Interferon-gamma (IFN-γ) and perforin are important mediators of cell destruction. In this flow cytometry-based study, we have investigated the percentage of intracellular IFN-γ+ and perforin+ CD5+ T cells in peripheral blood of newly diagnosed aAA patients before and after immunosuppressive therapy (IST). Patients were categorized as per standard disease severity and response to IST. The median percentage of IFN-γ+ and perforin+ CD5+ T cells was higher in untreated patients compared to healthy controls. The percentage of these cells was also increased in untreated severe and very severe aplastic anemia when compared with non-severe aplastic anemia patients. In patients before and after IST the median percentage of T cells producing IFN-γ and perforin was elevated in non-responders as compared to partial plus complete responders. The higher percentage of IFN-γ+ and perforin+ CD5+ T cells may be useful as an early diagnostic marker for aberrant activation of immune system and predict poor response to IST in aAA patients, who will benefit from alternative therapy.

Increased Expression of NOTCH-1 and T Helper Cell Transcription Factors in Patients with Acquired Aplastic Anemia.

Background: Acquired aplastic anemia is an autoimmune disease in which auto-aggressive T cells destroy hematopoietic progenitors. T-cell differentiation is controlled by transcription factors that interact with NOTCH-1, which influences the respective T-cell lineages. Notch signaling also regulates the BM microenvironment. The present study aimed to assess the gene expressions of NOTCH-1 and T helper cell transcription factors in the acquired aplastic anemia patients. Methods: Using quantitative real-time PCR, we studied the mRNA expression level for NOTCH-1, its ligands (DLL-1 and JAG-1), and T helper cell transcription factors (T-BET, GATA-3, and ROR-γt) in both PB and BM of aAA patients and healthy controls. Further, patients of aplastic anemia were stratified by their disease severity as per the standard criteria. Results: The mRNA expression level of NOTCH-1, T-BET, GATA-3, and ROR-γT genes increased in aAA patients compared to healthy controls. There was no significant difference in the mRNA expression of Notch ligands between patients and controls. The mRNA expression level of the above-mentioned genes was found to be higher in SAA and VSAA than NSAA patients. In addition, NOTCH-1 and T helper cell-specific transcription factors enhanced in aAA. We also observed a significant correlation between the genes and hematological parameters in patients. Conclusion: The interaction between NOTCH-1, T-BET, GATA-3, and ROR-γT might lead to the activation, proliferation, and polarization of T helper cells and subsequent BM destruction. The mRNA expression levels of genes varied with disease severity, which may contribute to pathogenesis of aAA.

Old age-associated enrichment of peripheral T regulatory cells and altered redox status in pulmonary tuberculosis patients.

Aging influences the susceptibility and prognosis to various infectious diseases including tuberculosis (TB). Despite the impairment of T-cell function and immunity in older individuals, the mechanism for the higher incidence of TB in the elderly remains largely unknown. Here, we evaluated the age-associated immune alterations, particularly in effector and Treg responses in pulmonary TB patients. We also evaluated the impact of redox status and its modulation with N-acetyl-cysteine (NAC) in elderly TB. Higher frequency of Treg cells and reduced IFN-γ positive T cells were observed among older TB patients. The elevated number of Treg cells correlated tightly with bacillary load (i.e. disease severity); which declined significantly in response to successful anti-tubercular treatment. We could rescue Myobacterium tuberculosis-specific effector T cell (Th1) responses through various in vitro approaches, for example, Treg cell depletion and co-culture experiments, blocking experiments using antibodies against IL-10, TGF-ß, and programmed death-1 (PD-1) as well as NAC supplementation. We report old age-associated enrichment of Treg cells and suppression of M. tuberculosis-specific effector T (Th1) cell immune responses. Monitoring these immune imbalances in older patients may assist in immune potentiation through selectively targeting Treg cells and/or optimizing redox status by NAC supplementation.

Alterations in mitochondrial membrane potential in peripheral blood mononuclear cells in Parkinson's Disease: Potential for a novel biomarker.

BACKGROUND: Progressive apoptosis in the dopaminergic neurons of substantia nigra lead to Parkinson's disease. Since neurons require substantially higher supply of energy, their mitochondria have a pivotal status in neuronal survival. These organelles have a key role to play in apoptosis and any impairment thereof may lead to apoptosis mediated cell death. OBJECTIVES: To evaluate and compare the mitochondrial membrane potential (Δψ) in Parkinson's disease patients and healthy controls. METHODS: We evaluated the mitochondrial membrane potential (Δψ) in the peripheral blood mononuclear cells by Flow cytometry using a lipophillic cationic dye JC-1 in Parkinson's disease patients (N = 61) and healthy controls (N = 37). RESULTS: JC-1 fluorescence was measured and represented as percentage positivity i.e., Mean±SEM in FL-2 (representing non-apoptotic aggregates) and FL-1 (indicating apoptotic cell population having depolarized or damaged mitochondria) channels. The ratio of % FL-2 and % FL-1, which is an indicator of cellular mitochondrial membrane potential, was found to be significantly higher in healthy controls (Mean±SEM = 60.48±18.42) as compared to patients (Mean±SEM = 24.30±4.671) in both stimulated and unstimulated conditions. CONCLUSIONS: Mitochondrial membrane potential is altered and hence its evaluation in peripheral blood mononuclear cells may serve as an early marker of apoptosis in PD and, therefore, may pave way for early interventions. Since Δψ has a role in the maintenance of electrochemical gradient, the disruption of which may lead to neuronal apoptosis, Δψ is intricately nested within etiopathogenesis of PD and may prove to be useful in design of diagnostics, prognostics and therapeutics for PD.