Pattern of cytokine expression in circulation CD57+ T cells from long-term renal allograft recipients

Inflammatory process of CD8+ CD28- T cells in induced sputum from asthmatic patients

Previously unreported CD8⁺CD28⁻ and CD8⁺CD28⁺ T-cell subsets occur in healthy individuals and expand in patients suffering from autoimmune disease. Here we studied, for the first time, the expression of CD8⁺CD28⁺, CD8⁺CD28⁻, and CD8⁺CD56⁺ subpopulations in induced sputum from asthmatics. Using sputum samples, purified CD8⁺ T cells were stained for surface antigen CD28, CD56, FITC-conjugated anti-perforin, and anti-IFN-γ. Cytotoxic activity was evaluated in a chromium releasing test. Induced sputum CD8⁺CD28⁻ T cells were found to be more expanded and expressed low levels of IFN-γ in severe asthmatics than mild asthma and age-matched healthy controls. The predominance of CD8⁺CD28⁻ T cells can be in part explained by the expansion of CD8⁺CD56⁺. CD8⁺CD28⁻ T cells from severe asthmatics produced high intracytoplasmic perforin and exerted a potent cytotoxic activity. Considering their phenotyping and functional properties, the CD8⁺CD28⁻ T-cell subset may constitute an intermediate phenotype in the process of CD8⁺ T-cell differentiation of effector-type cells in severe asthmatics. Functional studies showed that CD8⁺CD28⁻ T cells had cytotoxic function.

Anti-inflammatory role of interleukin-15 in Crohn's disease

BACKGROUND

Interleukin (IL)-15 is overexpressed in intestinal tissue with active Crohn's disease (CD). However, its role in the pathogenesis of the disease remains uncertain. We studied the effects of IL-15 on colonic mucosal proinflammatory cytokine response in vitro using organ culture of human colonic explants.

METHODS

Colonic tissue was obtained from (1) resections in pediatric CD patients (inflamed and noninflamed) and (2) rectal biopsies in patients with CD undergoing colonoscopy (n = 31) and controls (n = 9). In preliminary experiments, explants from the resections were cultured in the presence or absence of a simulated T(H)1 stimulation using ionomycin (Io) and phorbol-myristate-acetate (PMA), with or without IL-15, or in medium alone. Rectal biopsies were cultured in the same conditions as above, with or without adding a monoclonal anti-IL-15 neutralizing antibody (mAb). Levels of interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha, and IL-2R alpha were measured by enzyme-linked immunosorbent assay.

RESULTS

IL-15, in the absence of Io + PMA, did not induce the expression of IFN-gamma, TNF-alpha, or IL-2R alpha. Only inflamed explants from resections stimulated with Io + PMA expressed IFN-gamma, TNF-alpha, and IL-2R alpha. This T(H)1 stimulatory effect was inhibited by IL-15 in a dose-dependent fashion. In rectal biopsy explants, inflamed, noninflamed CD, and control tissue responded to stimulation with Io + PMA (P < 0.05) with increased IFN-gamma and TNF-alpha (P < 0.05). This response was again inhibited by IL-15. The inhibitory effect of IL-15 was specifically reversed by anti-IL-15 mAb (P < 0.05). The data for the CD group were also analyzed according to the severity of colonic inflammation and medication use.

CONCLUSIONS

Our results suggest a possible anti-inflammatory role for IL-15 in CD. We postulate that its overexpression in CD potentially represents a protective mechanism against the exaggerated T(H)1 immune response.

Effect of dietary ribonucleotides on infant immune status. Part 2: Immune cell development

The objective of this study was to determine whether dietary ribonucleotides alter immune cell phenotypes or function in the first year of life. Newborn term infants in a double-blind, 12-mo, multicenter trial were randomized to cow milk formula groups with (FN, n = 138) or without (F, n = 147) 72 mg/L supplemental ribonucleotides. A nonrandomized HMF cohort (n = 192) was concurrently enrolled. Eighty-eight immune blood cell types were characterized by flow cytometry. Data were analyzed by multivariate ANOVA (MANOVA), ANOVA, and repeated measures analysis (RMA), with adjustments made for multiple comparisons. Ribonucleotide feeding changed subpopulations of T and natural killer (NK) cells. FN had higher numbers and percentages of memory/effector (M/E) cytotoxic/suppressor (CD45R0(+)CD8(+), RMA) T, Fas(+) M/E (CD45R0(+)CD95(+)CD3(+), 6 mo) T, and CD56(+)CD16(-) NK cells (CD56(+)CD16(-)CD3(-)CD8(-), 12 mo), and higher percentages of M/E helper (CD45R0(+)CD4(+), RMA) T, Tc1 (IFN gamma(+)CD4(-)CD3(+), RMA), total interferon (IFN)gamma T (IFN gamma(+)CD4(+/-)CD3(+), RMA), Th2 (IL-4(+)CD4(+)CD3(+), 7 mo), and CD57(+) NK-T cells (CD57(+)CD56(-)CD3(+), 6 mo, 7 mo) compared with F. Percentages of naive helper T (CD45RA(+)CD4(+), 12 mo) and numbers and percentages of CD56(+) NK-T cells (CD56(+)CD16(-)CD3(+)CD8(-), 2 mo, 6 mo) were lower in FN than F. Percentages of M/E cytotoxic/suppressor, Th2, and CD56(+)CD16(-) NK cells in FN were significantly higher than F but were not different from HMF, whereas F was significantly lower than HMF. Ribonucleotide supplementation of infant formula supported increased T-cell maturation and affected immunoregulatory NK cell subsets. These FN-associated immune cell profiles either did not differ from those infants fed HMF or tended to be more like those fed HMF than those fed F.

Aberrant T-cell antigen receptor-mediated responses in autoimmune lymphoproliferative syndrome

Autoimmune Lymphoproliferative Syndrome (ALPS) is a disorder of defective lymphocyte apoptosis due to mutations of the Fas receptor and other molecules in the Fas signaling pathway. In addition to accumulation of CD4(-) CD8(-) double-negative (DN) T cells, many patients display a dysregulated cytokine pattern with dysfunctional T cells, suggesting Fas defects may impact pathways of T-cell activation/differentiation. Here, we report two novel mutations in the Fas receptor resulting in an ALPS phenotype. Utilizing flow cytometry, we found anti-CD3 activated CD4(+) T cells from these patients were incapable of fully upregulating activation markers (CD25, CD69, and CD40L) or producing interferon-gamma and IL-2. Additionally, DN T cells were unable to transduce proximal T-cell antigen receptor signals or produce cytokines. Furthermore, DN T cells overexpressed CD57 and phenotypically resembled end-stage effector cells. As DN T cells were essentially anergic, the clinical manifestations of autoimmunity are more likely to be a consequence of aberrant cytokine secretion within the CD4(+) T-cell subpopulation.

Transient stress lymphocytosis: an immunophenotypic characterization of the most common cause of newly identified adult lymphocytosis in a tertiary hospital

We prospectively evaluated 52 consecutive cases of newly identified absolute lymphocytosis to determine the hematologic and immunophenotypic features of transient stress lymphocytosis (TSL). The lymphocytosis in all cases was associated with an acute stressful event and ranged from 4,000 to 10,400/microL (4.0-10.4 x 10(9)/L). Compared with healthy individuals, patients with TSL showed an increase in the total WBC, absolute lymphocyte (ALC), absolute neutrophil (ANC), and platelet counts with no difference in hemoglobin levels. Immunophenotypic analyses of 38 cases revealed increases in absolute numbers of T B, and natural killer cells. Both CD4+ and CD8+ T cells were increased, predominantly accountedfor by an increase in memory cell subsets, with no change in gamma/delta T cells. Follow-up studies showed a significant reduction in the ALC with a concurrent increase in the ANC and reduction in hemoglobin values. The reduction in lymphocytes at resolution was accompanied by reduction in all broad Iymphocyte subsets. However, naive and memory subsets showed different patterns of alteration within the CD4+ and CD8+ populations, suggesting that acute stress differentially affects the in vivo distribution of these subsets.

Immune status of infants fed soy-based formulas with or without added nucleotides for 1 year: part 2: immune cell populations

BACKGROUND

Infants fed a soy protein isolate-based formula have immunization responses similar to breast-fed infants. However, cellular aspects of the immunologic development of soy-fed infants have not been studied extensively. Nucleotides added to milk-based formula benefit infant immune status, but reports of the immunologic effects of adding nucleotides to soy-based formula are not available. This study examines immune cell populations of infants fed soy protein isolate formulas with and without added nucleotides for 1 year.

METHODS

Newborn, term infants studied in a masked 12-month feeding trial were assigned randomly to soy formula groups with and without added nucleotides (n = 94, n = 92). A nonrandomized human milk/formula-fed cohort (n = 81), was concurrently enrolled. Blood samples were collected at 6, 7, and 12 months. Thirty-two immune cell populations were characterized using three-color flow cytometry. Cellular markers were chosen to assess general pediatric immune status, emphasizing maturation and activation of B, T, and NK lymphocytes.

RESULTS

All cell populations, number and percentages, were within age-related normal ranges. The only significant difference found between soy formula and human milk/formula-fed infants was the percentage of CD57 + NK T cells at 12 months (human milk/formula > soy formula, P = 0.034). There were significant differences at some time points between human milk/formula-fed and nucleotide-supplemented soy formula-fed infants in populations of lymphocytes, eosinophils, total T, helper T, naive helper, memory/effector helper, CD57 - T, and CD11b + CD8 + NK cells. None of the cell populations differed between infants fed soy formula versus soy plus nucleotides.

CONCLUSIONS

Infants fed this commercial soy formula demonstrated immune cell status similar to human milk/formula-fed infants, consistent with normal immune system development. The addition of nucleotides to soy formula did not significantly change specific individual immune cell populations but tended to increase numbers and percentages of T cells and decreased numbers and percentages of NK cells.

TH1 cytokine response of CD57+ T-cell subsets in healthy controls and patients with alcoholic liver disease

Patients with chronic inflammatory diseases, including Crohn's disease and rheumatoid arthritis, as well as those with certain viral infections, and patients who are transplant recipients or who have certain hematologic malignancies have been observed to have CD57+ T cell expansion in both CD4+ and CD8+ subsets. We have reported previously that alcoholic patients also have CD57+ T cell expansion. Because many alcoholics become seriously deficient in cell-mediated immunity, it is of interest to determine whether the expanded CD57+ subsets can respond to stimulation with normal T helper cell subtype 1 (TH1) cytokine production. We report evaluation of the CD57 T-cell subsets of patients with alcoholic liver disease (ALD) with the use of cytoplasmic staining after stimulation through the T-cell receptor (TCR). The CD57+ subsets of the T cells of both healthy individuals and patients with ALD express significantly higher amounts of cytoplasmic tumor necrosis factor-alpha (TNF-) and interferon-gamma (IFN-) after 6 h of stimulation than do the CD57- subsets. This increased production can persist up to 46 h of continuous stimulation. Under these assay conditions, very little cytoplasmic interleukin (IL)-4 is observed in the T cells of either healthy control subjects or patients with ALD. Measurement of cytokine secretion by sort-purified CD57 T-cell subsets with the use of enzyme-linked immunosorbent assay (ELISA) shows that the CD57+ T-cell subset produces 18- to 30-fold more TNF- and IFN-, respectively, than does the CD57- subset in the first 12 h of stimulation. This response requires only stimulation through the TCR for the CD57+ subset, whereas significant secretion by the CD57- subset requires added IL-2 or anti-CD28 antibody. These results are consistent with the concept of the CD57+ T-cell subset as a differentiated effector cell and demonstrate that patients with ALD who are not drinking at the time of evaluation have normal or increased immediate TH1 T-cell responses.

Peripheral human CD8(+)CD28(+)T lymphocytes give rise to CD28(-)progeny, but IL-4 prevents loss of CD28 expression

At birth, virtually all peripheral CD8(+) T cells express the CD28 co-stimulatory molecule, but healthy human adults accumulate CD28(-)CD8(+) T cells that often express the CD57 marker. While these CD28(-) subpopulations are known to exert effector-type functions, the generation, maintenance and regulation of CD28(-) (CD57(+) or CD57(-)) subpopulations remain unresolved. Here, we compared the differentiation of CD8(+)CD28(bright)CD57(-) T cells purified from healthy adults or neonates and propagated in IL-2, alone or with IL-4. With IL-2 alone, CD8(+)CD28(bright)CD57(-) T cell cultures yielded a prevailing CD28(-) subpopulation. The few persisting CD28(dim) and the major CD28(-) cells were characterized by similar telomere shortening at the plateau phase of cell growth. Cultures from adults donors generated four final CD8(+) phenotypes: a major CD28(-)CD57(+), and three minor CD28(-)CD57(-), CD28(dim)CD57(-) and CD28(dim)CD57(dim). These four end-stage CD8(+) subpopulations displayed a fairly similar representation of TCR V(beta) genes. In cultures initiated with umbilical cord blood, virtually all the original CD8(+)CD28(bright) T cells lost expression of CD28, but none acquired CD57 with IL-2 alone. IL-4 impacted on the differentiation pathways of the CD8(+)CD28(bright)CD57(-) T cells: the addition of IL-4 led both the neonatal and the adult lymphocytes to keep their expression of CD28. Thus, CD8(+)CD28(bright)CD57(-) T cells can give rise to four end-stage subpopulations, the balance of which is controlled by both the cytokine environment, IL-4 in particular, and the proportions of naive and memory CD8(+)CD28(+) T cells.