Increased expression of CD69 on T cells as an early immune marker for human cytomegalovirus reactivation in chronic lymphocytic leukemia patients

Immune checkpoint analysis of T-cell responses to pp65 and IE-1 antigens in end-stage lung diseases

Lung transplant (LTX) patients are at high risk of cytomegalovirus (CMV) infection, which is often associated with high mortality and morbidity. Reactivation of CMV causes cell injury due to the cytopathic effect of viral replication and triggering of T cell immunity. The aim of this study was to compare expression of immune checkpoints (ICs) (PD-1, CTLA-4, LAG-3 and TIGIT) in CD4, CD8 and CD56 and activation markers CD137, CD154 and CD69 of end-stage patients awaiting lung transplant. Eighteen pre-LTX positive for anti-CMV IgG titres and 18 healthy subjects were enrolled. IC and activation markers have been evaluated through flow cytometric analysis in HC and pre-LTX patients. Reactive (QF+) and unreactive (QF-) patients were stratified according to QuantiFERON-CMV assays. ICs' and activation markers' expression were determined before and after in vitro stimulation with pp-65 and IE-1 antigens. Lower expression of PD-1 was observed in CD4 and CD8 cells of pre-LTX patients than controls, whereas CTLA4 appeared upregulated in CD56 and CD8 cells. TIGIT is increased on the surface of CD4, CD8 and NK cells after peptide stimulation in QF-negative patients and PD-1 is only downregulated after stimulation in the QF-positive patients. This study provides new evidence of immune dysregulation in patients with end-stage lung disorders, particularly in relation to immune checkpoint cell biology. The change in QF+ mostly happens on cytotoxic cells NK and CD8, while the changes in QF- were observed in adaptive immune cells, including CD4 and CD8.

[Significance of evaluation of CD69 expression by peripheral blood lymphocytes for predicting pregnancy outcome in women with recurrent pregnancy loss]

The aim of this work was to characterize phenotypically peripheral blood T- and NK lymphocytes expressing an early marker of activation, CD69, and assess the significance of CD69 expression for predicting pregnancy outcome in women with idiopathic reccurent pregnancy loss (IRP) before and after immunocytotherapy (ICT). The study group consisted of 36 patients with IRP who became pregnant after pre-gestational allimmunization, in 30 patients the pregnancy was prolonged to the full term and ended with the birth of a viable baby, in 6 - it was terminated before 12 weeks of gestation. In the control group, 15 fertile women outside pregnancy and 11 women at 12 weeks of physiological pregnancy were examined. Assessment of the CD69 expression in women with prolonged pregnancy revealed the absence of significant differences with the control group in the content and proportion of activated lymphocytes (CD69+). In women with aborted pregnancy after pre-gestational ICT, an increase in the number of almost all analyzed lymphocyte subpopulations responding to the activation stimulus, with a clear tendency to increase the proportion of activated T- but not NK-lymphocytes was found. At 5-6 weeks, the proportion of activated lymphocytes among a subpopulation of cytotoxic T-lymphocytes (CD3+CD8+/CD3+CD8+CD69+) in these women was significantly higher than in women with prolonged pregnancy, which confirms the leading role of effector cytotoxic T-lymphocytes in rejection reactions. Thus, the studies showed the promise of evaluating the expression of the early activation marker CD69 as an additional laboratory criterion for the personable appointment of immunocytotherapy to women with a common reccurent pregnancy loss.

Pregnant women infected with pandemic H1N1pdm2009 influenza virus displayed overproduction of peripheral blood CD69+ lymphocytes and increased levels of serum cytokines

The first pandemic of the 21^st century occurred in 2009 and was caused by the H1N1pdm influenza A virus. Severe cases of H1N1pdm infection in adults are characterized by sustained immune activation, whereas pregnant women are prone to more severe forms of influenza, with increased morbi-mortality. During the H1N1pdm09 pandemic, few studies assessed the immune status of infected pregnant women. The objective of this study was to evaluate the behavior of several immune markers in 13 H1N1pdm2009 virus-infected pregnant (PH1N1) women, in comparison to pregnant women with an influenza-like illness (ILI), healthy pregnant women (HP) and healthy non-pregnant women (HW). The blood leukocyte phenotypes and the serological cytokine and chemokine concentrations of the blood leukocytes, as measured by flow cytometry, showed that the CD69+ cell counts in the T and B-lymphocytes were significantly higher in the PH1N1 group. We found that pro-inflammatory (TNF-α, IL-1β, IL-6) and anti-inflammatory (IL-10) cytokines and some chemokines (CXCL8, CXCL10), which are typically at lower levels during pregnancy, were substantially increased in the women in the ILI group. Our findings suggest that CD69 overexpression in blood lymphocytes and elevated levels of serum cytokines might be potential markers for the discrimination of H1N1 disease from other influenza-like illnesses in pregnant women.

Functional deficits of pertussis-specific CD4+ T cells in infants compared to adults following DTaP vaccination

Understanding the immune responses that explain why infants require multiple doses of pertussis vaccine to achieve protection against infection is a high priority. The objective of this study was to compare the function and phenotypes of antigen-specific CD4(+) T cells in adults (n=12), compared to infants (n=20), following vaccination with acellular pertussis (DTaP) vaccine. Peripheral blood mononuclear cells (PBMCs) were stimulated with pertussis toxoid (PT), pertactin (PRN) and filamentous haemagglutinin (FHA). Multi-parameter flow cytometry was used to delineate CD4(+) T cell populations and phenotypes producing interferon (IFN)-γ, interleukin (IL)-2, tumour necrosis factor (TNF)-α and IL-4. Based on surface CD69 expression, infants demonstrated activation of vaccine antigen-specific CD4(+) T cells similar to adults. However, among infants, Boolean combinations of gates suggested that type 1 (Th-1) CD4(+) T cell responses were confined largely to TNF-α(+) IL-2(+) IFN-γ(-) or TNF-α(+) IL-2(-) IFN-γ(-) . A significantly lower percentage of polyfunctional T helper type 1 (Th1) responses (TNF-α(+) IFN-γ(+) IL-2(+) ) and type 2 (Th2) responses (IL-4) were present in the infants compared to adults. Moreover, a significantly higher percentage of infants' functional CD4(+) T cells were restricted to CD45RA(-) CCR7(+) CD27(+) phenotype, consistent with early-stage differentiated pertussis-specific memory CD4(+) T cells. We show for the first time that DTaP vaccination-induced CD4(+) T cells in infants are functionally and phenotypically dissimilar from those of adults.