CD4+CD25+ T lymphocytes in human tonsils suppress the proliferation of CD4+CD25- tonsil cells

Increased levels of S100A8/A9, IL-1ß and IL-18 as a novel biomarker for recurrent tonsillitis

Background

Acute tonsillitis represents one of the most frequent reasons patients seek primary medical care and otorhinolaryngology consultation. Therefore, recurrent episodes of acute tonsillitis (RAT), also called chronic tonsillitis, exhaust a substantial amount of medical and financial resources. Diagnosis of tonsillitis depends on a physical examination, which therefore does not allow for a reliable differentiation between viral and bacterial infection. However, the frequency of bacterial infections during the previous three years is currently being used as the major deciding factor in patient selection for tonsillectomy. The aim of the present study was to determine an objective biomarker to help in the identification of patients suffering from recurrent tonsillitis.

Results

By analyzing a panel of cytokines and chemokines in serum and saliva of patients with RAT compared to healthy controls, increased levels of IL-1ß (153.7 ± 48.5 pg/ml vs 23.3 ± 6.6 pg/ml, p = 0.021), IL-18 (120.2 ± 16.5 vs 50.6 ± 9.3 pg/ml, p = 0.007) and/or S100A8/A9 (996 ± 102 ng/ml vs 546 ± 86 ng/ml, p = 0.042) could be observed in patients suffering from RAT. Cut-off values of these parameters were determined and combined to a new RAT-score allowing for reliable identification of patients suffering from recurrent tonsillitis with a sensitivity of 95% and a specificity of 88%.

Conclusion

The RAT-score represents the first objective criterion as a tool for the diagnosis of recurrent tonsillitis and it also improves patient selection for tonsillectomy.

Effects of pepsin and pepstatin on reflux tonsil hypertrophy in vitro

There is evidence that pepsin can aggravate tonsil hypertrophy. Pepstatin is a potent inhibitor of pepsin activity and could protect patients against reflux tonsil hypertrophy by inhibiting pepsin. We examined the effects of pepstatin on the development of tonsil hypertrophy to investigate pepsin’s role in the pathogenesis of tonsil lesions. We investigated whether pepstatin suppresses pepsin-mediated lymphocyte proliferation in tonsil hypertrophy. Forty-nine children with tonsil hypertrophy and twenty-two adults with tonsillitis were recruited to the study prior to surgery. Tonsil tissue from each patient was harvested and assessed for changes in the number of lymphocytes and macrophages in the presence of pepsin and pepstatin. We found that the proportions of CD4- and CD14-positive cells were significantly lower (p < 0.05), but that the proportions of CD19- and CD68-positive cells were significantly higher (p < 0.05), in children than in adults. There were significantly more CD4-positive cells after pepsin treatment, but these numbers were reduced by pepstatin. The levels of both interleukin-2 (IL-2) and interferon gamma (IFN-γ) increased significantly in response to pepsin, but were reduced when pepsin was inhibited by pepstatin. The level of IL-10 is reduced in pepsin-treated CD4 cells and the level is restored by pepstatin. IL-2 blocking reduced the increased CD4 cell number by pepsin. But, an additive or a synergic effect is not founded in combined with IL-2 blocking and pepstatin. Pepsin-positive cells did not co-localize with CD20 and CD45 cells, but they were found surrounding CD20- and CD45-positive hypertrophic tonsil cells. Pepsin-positive cells co-localized with CD68-positive cells. It is probable that pepsin from extraesophageal reflux aggravates tonsil hypertrophy and pepstatin exerts a protective effect by inhibiting pepsin activity.

Neonatal regulatory T cells have reduced capacity to suppress dendritic cell function

Regulatory T cells (Treg cells) limit contact between dendritic cells (DCs) and conventional T cells (Tcons), decreasing the formation of aggregates as well as down-modulating the expression of co-stimulatory molecules by DCs, thus decreasing DC immunogenicity and abrogating T-cell activation. Despite the importance of this Treg-cell function, the capacity of Treg cells from term and preterm neonates to suppress DCs, and the suppressive mechanisms they use, are still undefined. We found that, relative to adult Treg cells, activated Treg cells from human neonates expressed lower FOXP3 and CTLA-4, but contained higher levels of cAMP. We developed an in vitro model in which Treg function was measured at a physiological ratio of 1 Treg for 10 Tcon and 1 monocyte-derived DC, as Treg target. Term and preterm Treg cells failed to suppress the formation of DC-Tcon aggregates, in contrast to naïve and memory Treg cells from adults. However, neonatal Treg cells diminished DC and Tcon activation as well as actin polymerization at the immunological synapses. In addition, CTLA-4 and cAMP were the main suppressive molecules used by neonatal Treg. Altogether, both preterm and term neonatal Treg cells appear less functional than adult Treg cells, and this defect is consistent with the general impairment of CD4 cell function in newborns.

Human secondary lymphoid organs typically contain polyclonally-activated proliferating regulatory T cells

Immunomodulating regulatory T-cell (Treg) therapy is a promising strategy in autoimmunity and transplantation. However, to achieve full clinical efficacy, better understanding of in vivo human Treg biology is warranted. Here, we demonstrate that in contrast to blood and bone marrow Tregs, which showed a resting phenotype, the majority of CD4(pos)CD25(pos)CD127(neg)FoxP3(pos) Tregs in secondary lymphoid organs were proliferating activated CD69(pos)CD45RA(neg) cells with a hyperdemethylated FOXP3 gene and a broad T-cell receptor-Vβ repertoire, implying polyclonal activation. Activated CD69(pos) Tregs were distributed over both T-cell and B-cell areas, distant from Aire(pos) and CD11c(pos) cells. In contrast to the anergic peripheral blood Tregs, lymphoid organ Tregs had significant ex vivo proliferative capacity and produced cytokines like interleukin-2, while revealing similar suppressive potential. Also, next to Treg-expressing chemokine receptors important for a prolonged stay in lymphoid organs, a significant part of the cells expressed peripheral tissue-associated, functional homing markers. In conclusion, our data suggest that human secondary lymphoid organs aid in the maintenance and regulation of Treg function and homeostasis. This knowledge may be exploited for further optimization of Treg immunotherapy, for example, by ex vivo selection of Tregs with capacity to migrate to lymphoid organs providing an in vivo platform for further Treg expansion.

Regulatory T cells and liver pathology in a murine graft versus host response model

AIM

We have previously reported in mice the hepatic inflammatory in graft versus host response (GVHR) model due to the disparity of major histocompatibility complex class-II. The regulatory T (Treg) cells have been reported to control excessive immune response and prevent immune-related diseases. This study aimed to investigate the pathogenesis profiles of chronic GVHR progression, focusing on the Treg cells.

METHODS

GVHR mice induced by parental spleen CD4(+) T cell injection were sacrificed after 0, 2, 4, and 8 weeks (G0, G2, G4, G8). Further, one GVHR group received anti-IL-10 antibody in advance and were maintained for 2 weeks. Pathologic profiles of hepatic infiltrating inflammatory cells were evaluated by haematoxylin and eosin and immunohistochemistry staining with surface markers including Treg cell markers.

RESULTS

Remarkable hepatic inflammatory in G2 significantly and gradually improved over time up to G8. In immunohistochemical staining, the increased IL-10 receptor beta(+) Tr1 cells in G2 were maintained through to G8; although other inflammatory cells decreased from G2 to G8. By contrast, in the anti-IL-10 antibody received-GVHR mice, the Tr1 cells were not detectable with significant inflammatory aggravation, while FoxP3(+) Treg cells significantly enhanced.

CONCLUSIONS

These findings in the GVHR mice suggest that the expression and activity of Treg cells, especially the Tr1 cells, might be key factors for pathologic alteration in immune-related liver disease.

Evaluation of long-term impacts of tonsillectomy on immune functions of children: a follow-up study

OBJECTIVE

The purpose of this follow-up study was to investigate the long-term effects of tonsillectomy in comparison with their short-term results.

PATIENTS AND METHODS

We successfully retrieved 20 out of our previously reported 37 patients who underwent tonsillectomy in our clinic 54 months ago. The blood levels of CD3+, CD4+, CD8+, CD19+, CD25+ and CD16++56+ (cellular immunity), and IgG, IgA, IgM, C3 and C4 (humoral immunity) were determined and compared with their previously reported short-term respective values.

RESULTS

There were no statistically significant differences between the short-term (1 month) and long-term (54 months) values of IgA, IgG, IgM and C4 levels of the patients (P>0.05). There was a slight but statistically significant decrease in complement factor C3 value compared to its the early-stage value (P<0.05) but this was not significantly different from age-matched healthy controls (P>0.05). The levels of CD4+ and CD19+ were higher and the levels of CD16++56+ and CD25+ were lower in the late-stage (54 months) compared to their early-stage values (P<0.05). When the long-term immune parameters of the tonsillectomized patients were compared with aged-match healthy controls, there were no significant differences between the levels of immunoglobulins, complements and lymphocytes (IgA, IgG, IgM, C3, C4, CD3+, CD4+, CD8+, CD19+, CD25+, CD16++56+) (P>0.05).

CONCLUSION

The results of this long-term follow-up study indicate that tonsillectomy do not compromise the immune functions of children as humoral and cellular immunity of patients recovered compared to their early-stage immune status (1 month), as they have similar immune capacity compared to their age-matched healthy controls at both early- and late-stages. Although a small sample of patients enrolled, our results are of importance with respect to the reassuring in settling the widely held urban myth that tonsillectomy compromises life long immunity.

T-regulatory lymphocytes and chronic viral hepatitis

Both hepatitis B virus (HBV) and hepatitis C virus (HCV) can cause persistent viral infection in humans. Chronic infection is associated with a risk of cirrhosis and hepatocellular carcinoma. The cause of chronic infection is unknown. A large body of evidence suggests that a failure of the adaptive immune response is critical in the establishment of chronic infection. Recently a new group of T cells (T-regulatory cells), that express CD4(+)CD25(+) and Foxp3, which can inhibit the cellular (CD4(+)/CD8(+)) immune response have been described. In this review the authors explore the thoughts regarding immune responses to HBV and HCV infections and the role of these T-regulatory cells in relation to the pathogenesis of chronic HBV and HCV infection and the potential for therapeutic intervention.

Differential pathogenesis of primary CCR5-using human immunodeficiency virus type 1 isolates in ex vivo human lymphoid tissue

In the course of human immunodeficiency virus (HIV) disease, CCR5-utilizing HIV type 1 (HIV-1) variants (R5), which typically transmit infection and dominate its early stages, persist in approximately half of the infected individuals (nonswitch virus patients), while in the other half (switch virus patients), viruses using CXCR4 (X4 or R5X4) emerge, leading to rapid disease progression. Here, we used a system of ex vivo tonsillar tissue to compare the pathogeneses of sequential primary R5 HIV-1 isolates from patients in these two categories. The absolute replicative capacities of HIV-1 isolates seemed to be controlled by tissue factors. In contrast, the replication level hierarchy among sequential isolates and the levels of CCR5(+) CD4(+) T-cell depletion caused by the R5 isolates seemed to be controlled by viral factors. R5 viruses isolated from nonswitch virus patients depleted more target cells than R5 viruses isolated from switch virus patients. The high depletion of CCR5(+) cells by HIV-1 isolates from nonswitch virus patients may explain the steady decline of CD4(+) T cells in patients with continuous dominance of R5 HIV-1. The level of R5 pathogenicity, as measured in ex vivo lymphoid tissue, may have a predictive value reflecting whether, in an infected individual, X4 HIV-1 will eventually dominate.

Replicative senescence of CD8 T cells: effect on human ageing

Elderly persons have been exposed to a myriad of pathogens over their lifespan. This life-long immunological history leads, in some cases, to the generation of expanded populations of memory CD8 T cells that have reached the end stage of replicative senescence. In cell culture, CD8 T cells that are subjected to repeated rounds of antigen-driven proliferation eventually show irreversible cell cycle arrest, permanent and complete loss of CD28 gene expression, apoptosis resistance, reduced gene transcription of the major stress protein in response to heat shock, and shortened telomeres compared to their CD28-expressing progenitors. Clinical studies have documented that high proportions of CD8 T cells that lack CD28 are correlated with reduced antibody response to influenza vaccination and are also an immune marker of increased risk of mortality in persons greater than 80 years of age. In addition, CD8 T cells lacking CD28 expression have been documented to have suppressive influences on immune function. Thus, senescent CD8 T cells may affect immune function both directly and indirectly by modulating other immune cell types. The potential role of senescent T cells in bone homeostasis is suggested as a potentially fruitful area for future investigation. The patterns of cytokine changes observed during the progression to senescence in cell culture are consistent with this possibility, and T cells producing these same cytokines have, in fact, been identified within the bone marrow in murine models of osteoporosis. Interestingly, CD8 T cells with markers of replicative senescence are correlated with increased osteoporotic fractures in the elderly. Thus, senescent CD8 T cells are associated with a variety of deleterious health-related outcomes, suggesting that these cells may exert pleiotropic negative effects on both immune and non-immune organ systems during ageing.

Lymphocyte populations in human lymph nodes. Alterations in CD4+ CD25+ T regulatory cell phenotype and T-cell receptor Vbeta repertoire

Here we provide a description of lymphocyte populations in human lymph nodes (LN) with a special emphasis on the CD4+ lymphocyte population constitutively expressing CD25 at a high level and endowed with immunoregulatory properties [T regulatory (Treg) cells]. Lymph nodes were analysed by multicolour flow cytometry in parallel with correspondent peripheral blood (PB). Immunomagnetically purified Treg cells were tested for anergy and suppressive activity in a CD3/T-cell receptor (TCR)-driven proliferation assay. Compared to PB, there was a reduced T/B lymphocyte ratio in LN. Both LN and PB contained a similar proportion of CD4+ lymphocytes but, conversely, CD8+ lymphocytes were less represented in PB, with a consequent increase in the ratio of CD4+/CD8+ natural killer cells were <2% (PB range 6-22%). No significant differences existed in the frequency of the other lymphocyte subpopulations examined (naïve-type CD4+ and CD8+ lymphocytes, activated B and CD4+ lymphocytes, and effector-type CD8+ lymphocytes). LN and PB contained similar percentages of CD4+ lymphocytes constitutively expressing intermediate or high levels of CD25. CD4+ CD25++ cells constitutively coexpressed high levels of CD152 and were therefore identified as Treg cells. Treg cells in LN and PB differed in terms of CD45RB, HLA-DR, CD45RO, and CD62L expression. Also the TCRVbeta repertoire diverged between Treg cells from LN and PB. Similar to Treg cells from PB, Treg cells from LN were anergic and efficiently inhibited other CD4+ and CD8+ lymphocyte proliferation. This study extends the information on the diversities in lymphocyte composition between human LN and PB, and reports for the first time a description of the phenotypic and functional characteristics of Treg cells in human LN, highlighting the importance of the LN microenvironment in shaping the surface phenotype of Treg cells.

Early stage impacts of tonsillectomy on immune functions of children

OBJECTIVE

The purpose of this study was to investigate the changes in the humoral and cellular immunity of patients with chronic tonsillitis before and 1 month after tonsillectomy.

PATIENTS AND METHODS

37 patients scheduled for tonsillectomy were enrolled in this study. The levels of CD3+, CD4+, CD8+, CD19+, CD25+ and CD16+ + 56+ were measured for cellular immunity, and levels of IgG, IgA, IgM, C3 and C4 were measured for humoral immunity in blood samples taken from these patients before and 1 month after the operation.

RESULTS

The levels of CD3+, CD8+ and CD19+ were reduced in post-operative period as compared to pre-operative period but this was not statistically significant (P > 0.05). However it was found that the level of CD4+ was significantly increased while the level of CD25+ was reduced (P < 0.05) in the post-operative period. There were statistically significant differences between pre- and post-operative levels of immunoglobulins, C3 and C4, which were decreased after tonsillectomy (P < 0.05), but these levels were comparable with those of the control group.

CONCLUSION

The results from the present study indicate that humoral and cellular immunity of patients undergoing tonsillectomy were decreased in the early period and came to normal later. The cellular and humoral immune responses are stimulated in patients with tonsillitis, and tonsillectomy removes this stimulus without negatively affecting the patient's immune functions.

Evidence for Naturally Acquired T Cell-Mediated Mucosal Immunity toNeisseria meningitidis

Naturally acquired protective immunity against Neisseria meningitidis is thought to partially explain the disparity between the high levels of carriage in the human nasopharynx and the rare incidence of disease. To investigate this immunity to Neisseria meningitidis at the mucosal level, in vitro cellular responses to outer membrane vesicle preparations derived from this pathogen were examined using mononuclear cells from the palatine tonsils of adults and children. Characterization of these responses was achieved by depletion of CD45RA(+), CD45RO(+), and CD19(+) populations and outer membrane vesicles derived from isogenic mutants expressing different serosubtypes of the major outer membrane protein, porin A (PorA), no PorA and membrane preparations from a mutant with no LPS (LpxA(-)). The magnitude of cellular proliferative responses against the outer membrane vesicles were strongly associated with age and were largely T cell mediated, involving both CD45RO(+) and CD45RA(+) T cell phenotypes. Responses were not dependent on LPS but consisted of both PorA cross-specific and non-PorA-dependent responses. Cellular immunity against Neisseria meningitidis was found to be frequently associated with systemic IgG Abs but was not associated with serum bactericidal Abs. For the first time our results demonstrate an age-associated acquisition of mucosal T effector/memory cell responses to Neisseria meningitidis. This mucosal cellular immunity can be present in the absence of serum bactericidal Abs, a classical marker of protective immunity.