Circulating lymphocyte subsets linked to intracellular cytokine profiles in normal humans

Chemokine receptors expressed on T cells in packed red blood cell units change over storage time

The transfusion of blood products is associated with adverse events that are related to the leukocytes in stored units of blood. These leukocytes have been shown to promote the elaboration of inflammatory cytokines. However, the status of a set of key inflammatory mediators, chemokine receptors, expressed on T lymphocytes in stored red blood cell (RBC) units is largely unknown. We investigated the expression pattern of selected chemokine receptors on T cells from non-leukocyte-reduced RBC units over storage time. Selecting segments from stored RBC units, we evaluated the T-cell subsets for the chemokine receptors CXCR3 and CCR4 by flow cytometry. Statistical analysis was performed by regression analysis. We analysed 30 samples stored between 5 and 38 days. The CD4+ T cells expressing CXCR3 increased by 0.27% daily (P= 0.02), whereas the expression of CCR4 declined by 0.40% daily (P < 0.001). Though the expression of the chemokine receptors on CD8+ cells followed the same trend, the changes were statistically nonsignificant. This study suggests that a longer duration of storage is associated with a higher expression of chemokine receptor CXCR3 and a lower expression of CCR4 on T cells in RBC units, suggesting a pro-inflammatory Th1 bias. The clinical significance of these changes in the setting of adverse transfusion events needs further evaluation.

NKG2A and CD56 are coexpressed on activated TH2 but not TH1 lymphocytes

NKG2A is commonly expressed on cytotoxic cells but has been found on activated T helper (TH) cells. In identifying novel markers differentiating between TH1 and TH2 lymphocytes, we focused on NKG2A expression. TH1 and TH2 cells were negatively isolated from healthy volunteers for microarray analysis and reverse transcription polymerase chain reaction (RT-PCR). Flow cytometry of quiescent and activated TH1 and TH2 cells was performed. Isolates were >95% pure CD3+CD4+ cells (TH1=90.3% and TH2=84.1%). Microarrays revealed differential expression of NKG2A and NKG2C isoforms between TH1 and TH2 cells. RT-PCR indicated greater expression of NKG2A in TH2 cells (4-fold) and NKG2C in TH1 cells (3-fold). Flow studies revealed tripling of TH2 NKG2A with activation to 10.76+/-4.01% (p=0.05), a 23-fold increase in CD56 to 35+/-14.54% (p=0.03), and an increase in NKG2A+CD56+ double-positive cells to 3.04+/-1.38% (p=0.04). TH1 lymphocytes did not differ with activation. We identified co-induction of NKG2A and CD56 on activation of TH2 cells. These cells would likely bind more HLA-E and exhibit increased effector inhibition. Given that certain viruses are known to decrease MHC class I and thus HLA-E production by antigen-presenting cells, activated TH2 cells would bind less HLA-E in this scenario. This would likely result in less effector inhibition and a relatively robust TH2 response.

Intracellular cytokines in peripheral blood leucocytes in children with chronic renal failure

We have previously shown that children with mild renal impairment show significant changes in leucocyte subsets and circulating cytokines, indicating that these patients show an increased inflammatory state. We hypothesised that measurement of intracellular cytokine production by lymphocytes and monocytes would more precisely define the immunological mechanism associated with the inflammatory state in children with pre-dialytic chronic renal failure. Blood was collected from children with chronic renal failure (CRF) who were not yet on dialysis and an age-matched control group. Leucocyte subsets and intracellular cytokine production were determined using flow cytometry. Children with CRF showed increased production of interleukin (IL)-12 by monocytes accompanied by decreased production of interferon (IFN)-gamma and increased production of IL-4 by T cells. There were no significant changes in the production of IL-8, IL-10, IL-6, IL-1alpha or tumour necrosis factor (TNF)-alpha by monocytes or in IL-2 or TNF-alpha production by T cells. There were no significant differences in total white cell count or lymphocyte count. There was a significant decrease in both B and NK cells. This study examines intracellular cytokine production in children with CRF in detail. It is the first to show that children with relatively mild renal failure display significant immunological changes of lymphocyte subsets and leucocyte cytokine production. These data provide a more accurate understanding of the immunological changes that may contribute to the clinical manifestations and progression of the disease.

Cytokine/Chemokine HLDA8 Workshop panel report: analysis of receptors on lymphocytes from cord blood, normal and asthmatic subjects, and HIV positive patients

Chemokines and cytokines are involved in many processes, both physiological and pathological, particularly the recruitment, differentiation, activation, and proliferation of immune cells taking part in ontogenesis, inflammation, and cancer. It was assumed that chemokines and cytokines receptors are expressed in a regulated manner by human lymphocytes during ontogeny and later on, under the environmental stimulation of antigens they contribute to organogenesis, angiogenesis, and tissue remodeling, as well as modulating leukocyte effector functions. Using monoclonal antibodies classified by the Cytokine/Chemokine section of the 8th International Workshop on Human Leukocyte Differentiation Antigens, we analyzed human lymphocytes in blood samples drawn from the umbilical cord, normal adults, allergic and non-allergic asthma patients, HIV infected, and AIDS positive subjects. The main differences noted between adult and cord blood lymphocytes were related to CCR7 and CXCR4 receptors, which were more strongly expressed on cord blood lymphocytes, confirming the important role of these chemokines during development of the immune system. As with the HIV, CXCR4, and CCR5 co-receptors, we found no differences in CXCR4 expression between HIV and AIDS patients. However CCR5 was more strongly expressed in AIDS patients, which is likely to be associated with the evolution of disease. Further studies are needed to gain a better understanding of the functions of these molecules in the underlying pathogenesis of many diseases and to probe the use of the chemokine receptors as targets for therapeutic intervention.

Tc1/Tc2 ratio in the inflammatory process in patients with Behçet's disease

BACKGROUND: Peripheral blood CD8+ T cells expressing interferon gamma and interleukin-4 (IL-4), and lacking CD28 molecules, were responsible for the dynamic interplay between peripheral blood and inflammatory sites. INTRODUCTION: The aim of the current study was to define in Behçet's disease (BD), CD8+ T-cell subsets using CD28 and CD11b monoclonal antibodies, and the characterization of the Tc1/Tc2 ratio and perforin expression. METHODS: Flow cytometry was used for intracytoplasmic cytokines and perforin expression. Effector cells were investigated by adhesion of CD8+ T cells to human microvascular endothelial cells and by chemotaxis using beta-chemokine. RESULTS: Interferon-gamma-producing CD8+ T cells in active and remission BD patients were increased, which induce a significant increase of the Tc1:Tc2 ratio in BD. CD8(+)CD28(-)CD11b+ T cells were found to be more expanded in BD patients than in age-matched healthy controls. The expression of CD11b molecules in active BD allowed to CD8(+)CD28+/CD8(+)CD28- subsets to adhere to human microvascular endothelial cells, with more efficiency in BD. Using MIP-1alpha, we observed that the migratory process of CD28(-)CD11b(+) is more important in BD. CD28(-)CD11b+ exhibited an increased perforin expression in BD patients. CONCLUSION: Taken together these results suggest the presence of immune activation, probably in response to a profound inflammation affecting BD patients. The physiopathological significance of these results were toward autoimmune diseases and/or infectious process.

Differences in systemic and central nervous system cellular immunity relevant to relapsing-remitting multiple sclerosis

In order to elucidate the differences between systemic and central nervous system (CNS) immunity that are relevant to exacerbations of multiple sclerosis (MS), paired peripheral blood and cerebrospinal fluid (CSF) samples obtained from 36 non-treated patients with relapsing-remitting MS (RRMS) were simultaneously examined using flow cytometry to determine the percentages of functional lymphocyte subsets, as well as enzyme-linked immunosorbent assays for measuring soluble immune mediators. Active RRMS patients (n = 27) were characterized by an increase in CD4+ CXCR3+ Th1 cells in blood as compared with inactive patients (n = 9), and this parameter was inversely correlated with plasma levels of IL-10 and IL- 12p70. In contrast, an increase in the percentage of CD4+ CD25+ cells and a decrease in the percentage of CD8+ CD11a(high) cells were features of CSF samples from those with active RRMS. Further, CSF CD4+ CD25+ cells had a close association with leukocyte counts as well as albumin and CXCL10 levels in the CSF, and, thus, could be useful as a measure for inflammatory reactions in the CNS. On the other hand, CD8+ CD11a(high) cells may function as immunoregulatory cells, as their percentage in the CSF showed a positive correlation with CSF levels of the anti-inflammatory cytokine IL-4. These findings suggest that MS relapses occur in a combination with altered cell-mediated immunity that differs between the peripheral blood and CSF compartments, while measurement of lymphocyte subsets may be helpful for monitoring disease status.

Abnormal expression of chemokine receptors in Behçet's disease: relationship to intracellular Th1/Th2 cytokines and to clinical manifestations

Dynamic interplay between cytokines and chemokines directs trafficking of peripheral blood mononuclear cells to tissues in autoimmune and/or viral diseases. The aim of the current study was to define the expression on CD3+ T cells of six chemokine receptors associated with inflammatory sites and the expression of intracellular cytokines, such as interferon-gamma (IFN-gamma) and interleukin-4 (IL-4), in Behcet's disease (BD). Flow cytometry was used to detect chemokine receptor and intracytoplasmic cytokines' expression. We observed that CD3+ T cells in the peripheral blood express a restricted array of inflammatory chemokine receptors, specifically, CCR5, CCR6 and CXCR3, but little CCR1-3. The highest expression of CXCR3 on CD3+ T cells is associated with the presence of central nervous system (CNS) manifestations or pulmonary involvement. CXCR3 is the principal inflammatory chemokine receptor involved in BD. CCR5 chemokine receptor is increased in BD regardless of clinical manifestations. The frequency of IFN-gamma-producing cells expressing CXCR3+ CD3+ cells is significantly increased in patients with BD compared with normal controls. IL-4-producing cells are decreased in BD. These results demonstrate the predominance of type 1 cytokine producing cells in CXCR3+ CD3+ T cells during BD. We hypothesize that CXCR3 is the principal inflammatory chemokine receptor involved in BD, particularly during CNS and pulmonary manifestations.

Immunomonitoring measures in relapsing-remitting multiple sclerosis

Forty-five patients with relapsing-remitting multiple sclerosis (MS) were examined to determine intracellular cytokine profiles and the surface phenotype of circulating lymphocytes during active, recovery, and stable stages. Active stage patients were characterized by decreases in CD4(+)IL-4(+) Th2 as well as CD4(+)IFN-gamma(+) Th1 cells, when compared with stable stage patients and 16 healthy controls. CCR4(+) Th2 cells were persistently decreased at every MS stage as compared to the controls. CD4(+)CD29(+) and CD4(+)CXCR3(+) cells were closely correlated with IFN-gamma-producing cells. These findings suggest that simultaneous flow cytometry for these two types of measurements can provide information concerning current immune status in MS.