Low-dose cyclosporine A therapy increases the regulatory T cell population in patients with atopic dermatitis

Background:  Atopic dermatitis (AD) is a T cell dependent chronic relapsing inflammatory skin disorder successfully treated with cyclosporine A (CsA). Clinical observations indicate that even low-dose CsA therapy is successful in severely affected AD patients. We studied the impact of low-dose CsA therapy on the ability of T helper cells to be activated, and examined whether regulatory T (Treg) cells are increased in these patients.
Methods:  Peripheral T cells were activated in a whole blood sample and interleukin-2 producing cells were measured by intracellular cytokine staining. Regulatory T cells were analyzed by intracellular FoxP3 staining. Regulatory T cells (CD4⁺CD25⁺CD127^low) and effector T cells (CD4⁺CD25⁻CD127⁺) were sorted by flow cytometry and used for suppression assays.
Results:  A group of AD patients treated with low-dose CsA had a significantly larger Treg cell population than a healthy control subject group. In individual patients, onset of low-dose CsA therapy reduced the ability of T cells to be activated to 42 ± 18% ( P  <   0.005) and significantly increased Treg cells, both in absolute numbers (1.6-fold change) and frequencies (1.7-fold change). Treg cells from AD patients showed similar suppressive capacities as Treg cells from healthy donors. Furthermore, Treg cells from AD patients had skin homing properties.
Conclusion:  Our results indicate that the therapeutic effect of low-dose CsA therapy in AD patients might be not only mediated by the inhibition of T cell hyperactivity but also by an increased population of Treg cells.     

Variation in Gut-Homing CD27-Negative Lymphocytes in Inflammatory Colon Disease

Prolonged antigenic stimulation results in lymphocyte shedding of CD27, a member of the tumour necrosis factor receptor (TNFR) family, and transformation to a stable phenotype capable of synthesizing interleukin-4 (IL-4). Co-expression of α4β7 identifies those cells with gut-homing potential. We have investigated these cell populations in patients with inflammatory colonic disease. Circulating and lamina propria mononuclear cells were isolated from patients with Crohn's disease (CD), ulcerative colitis (UC), non-inflammatory bowel disease (non-IBD) colonic inflammation and healthy controls. Double and triple colour flow cytometry for CD3, CD4, CD27, α4β7 and intracellular cytokines was performed. Circulating CD4+CD27– populations were increased in patients with CD (8.8 ± 0.8%, P  < 0.001), UC (12.2 ± 1.9%, P  < 0.001) and non-IBD colitis (10.5 ± 1.3%, P  < 0.01) as compared with controls (6.1 ± 0.5%). CD4⁺CD27⁻α4β7⁺ cells were increased in CD ( P  < 0.01). Lamina propria CD4⁺CD27⁻ populations were depressed significantly in CD ( P  < 0.05), UC ( P  < 0.02) and non-IBD colitis ( P  < 0.03). Mucosal CD4⁺CD27⁻ cells synthesized IL-4 in preference to interferon-γ. Thus, colonic inflammation is associated with alterations in gut-tropic circulating and mucosal populations of differentiated memory T cells with the phenotype of predominantly IL-4-synthesizing cells.     

Comparative Analysis of Peripheral Natural Killer Cells in the Two Phases of the Ovarian Cycle

Changes in endometrial Natural Killer (NK) cells during the luteal phase of the ovarian cycle are important in initiating/maintaining a subsequent pregnancy. In the present study it was investigated whether during the menstrual cycle changes occur also in peripheral blood (PB) NKs.

Method of study

Blood samples during the follicular and the luteal phase were collected from 30 women without fertility problems. Samples were analyzed by flow-cytometry for: (1) NK cells (CD3⁻CD16⁺CD56⁺) and (2) intracellular production of interferon-γ (IFN-γ) by NK cells. For the comparison and correlation of the two populations between the two phases, Wilcoxon signed-rank test and Spearman's Coefficient were used.

Results

The differences in percentages of CD3⁻CD16⁺CD56⁺ cells and that of CD3⁻CD16⁺CD56⁺/IFN-γ⁺ cells between the follicular and the luteal phase were not statistically significant (10.61 ± 5.11 versus 9.76 ± 4.57 and 6.48 ± 7.90 versus 7.30 ± 6.77, respectively, P  > 0.05). The correlation between the two variables (NK% and NK/IFN-γ%) was weakly positive ( P  = 0.07) only in the follicular phase.

Conclusion

The study did not reveal menstrual cycle-depended changes in PB NK cells. Thus, a suggestion to measure these cells in a specific phase of the cycle in order to predict the outcome of a subsequent pregnancy in women with fertility problems is objected.     

Effects of Peritoneal Fluid from Endometriosis Patients on Interferon-γ-Induced Protein-10 (CXCL10) and Interleukin-8 (CXCL8) Released by Neutrophils and CD4+ T Cells

Problem  Intraperitoneal immuno-inflammatory changes may be associated with the pathogenesis of endometriosis. We evaluated the effects of peritoneal fluid obtained from patients with endometriosis (ePF) on the release of interferon-γ-induced protein-10 (IP-10/CXCL10) and interleukin-8 (IL-8/CXCL8) by neutrophils, CD4⁺ T cells, and monocytes.
Method of study  Neutrophils, CD4⁺ T cells, and monocytes were cultured with ePF and the chemokine levels in the supernatants were then measured using enzyme-linked immunosorbent assay.
Results  The addition of ePF to cultures of CD4⁺ T cells led to a significant increase in the release of IP-10 when compared with control PF without endometriosis (cPF). There was a positive correlation between the levels of IL-8 and IP-10 in ePF ( R  = 0.89, P  =   0.041), but not between the levels of IP-10 and IL-8 released by neutrophils, CD4⁺ T cells, and monocytes. The levels of IP-10 in ePF were positively correlated with the release of IP-10 by ePF-treated neutrophils ( R  = 0.89, P  <   0.001), CD4⁺ T cells ( R  = 0.93, P  <   0.001), and monocytes ( R  = 0.70, P  =   0.01). Moreover, the addition of ePF significantly enhanced the interferon-γ-induced release of IP-10 by nuetrophils and CD4⁺ T cells.
Conclusion  These findings suggest that neutrophils and T cells release differential levels of IP-10 and IL-8 in response to stimulation with ePF, and that these cells are a major source of IP-10 in the PF of endometriosis patients.     

Mifepristone as an Anti-Implantation Contraceptive Drug: Roles in Regulation of Uterine Natural Killer Cells during Implantation Phase

Problem  To investigate the immunological mechanism of low-dose mifepristone acting as a contraceptive at the level of the endometrium.
Method of study  Endometrial explants were cultured in vitro with or without mifepristone treatment for 24 hr. Some tissues were fixed and immunostained for CD56, while other tissues were dissociated and cells analysed by three colour flow cytometry for CD3, CD56 and CD16.
Results and conclusion  Results showed a significant increase in the number of CD56⁺ natural killer (NK) cells and the percentages of CD3⁻ CD56⁺ CD16⁻ NK cell subset in the tissue treated with mifepristone, while the percentage of CD3⁻ CD56⁺ CD16⁺ NK cell subset remained unaffected. It shows that low-dose mifepristone increases the number of CD56⁺ NK cells and the percentage of CD3⁻ CD56⁺ CD16⁻ NK subset in receptive endometrium and provides new insights into the immunological mechanism of low-dose mifepristone as an anti-implantation contraceptive drug.     

CD 127- and FoxP3+ expression on CD25+CD4+ T regulatory cells upon specific diabetogeneic stimulation in high-risk relatives of type 1 diabetes mellitus patients

Abnormalities in CD4⁺CD25⁺ regulatory T cells (Treg) may contribute to type 1 diabetes (T1D) development. First-degree relatives of T1D patients are at increased risk especially when they carry certain HLA II haplotypes. Using two novel markers of CD4⁺CD25⁺ Treg (CD127⁻ and FoxP3⁺ respectively), we evaluated number and function of Treg after specific stimulation with diabetogeneic autoantigens in 11 high-risk (according to HLA-linked risk) relatives of T1D patients and 14 age-matched healthy controls using a cytokine secretion assay based on interferon- γ (IFN- γ ) production. High-risk relatives of T1D patients had significantly lower pre- and post-stimulatory number of CD127⁻ Treg than that of healthy controls ( P  < 0.05). Labelling Treg with FoxP3⁺ demonstrated similar trend but did not reach statistical significance. Although the stimulation with diabetogenic autoantigens did not lead to a significant change in number of Treg in both groups, the defective function of Treg was performed by significantly higher activation of diabetogeneic T cells in high-risk relatives of T1D patients compared to healthy controls ( P  ≤ 0.02). Individuals at increased HLA-associated genetic risk for T1D showed defects in Treg.     

CD3−4−8− Thymocyte Precursors with Interleukin-2 Receptors Differentiate Phenotypically in Coculture with Thymic Stromal Cells

CD3⁻4⁻8⁻ interleukin-2 receptor positive (IL-2R⁺) thymocyte precursors from adult mice were cocultured with thymic stromal cells from syngeneic adult mice. The IL-2R⁺CD3⁻4⁻8⁻ thymocytes were obtained by positive panning of IL-2R⁺ cells followed by either sorting or negative panning of triple negative cells, and they were cocultured with primary or secondary cultures of heterogeneous thymic stromal cells. Phenotypic maturation of these precursor cells was extremely rapid. Within 2½ days significant numbers of CD4⁺8⁺ and CD3⁺4⁺8⁻ cell populations developed, the latter expressing the αβ T-cell receptor (αβ-TCR). Thus heterogeneous stromal cell cultures support the development of IL-2R⁺ precursors and with these methods it will now be possible to isolate the particular stromal cells involved at each stromal-dependent step.     

CD8+CD28− T suppressor cells and the induction of antigen-specific, antigen-presenting cell-mediated suppression of Th reactivity

Summary: Human CD8⁺CD28⁻ suppressor T cells (Ts) are a subset of T cells generated in the course of in vitro and in vivo immunizations. Ts recognize MHC class I:peptide complexes and inhibit the reactivity of T helper cells (Th) with cognate antigen specificity. We have demonstrated for the first time that CD8⁺CD28⁻ Ts represent a unique subset of regulatory cells that induces the differentiation of tolerogenic antigen-presenting cells, initiating a suppressive loop which results in the induction and spreading of Th unresponsiveness.     

Timed Sexual Intercourse Facilitates the Recruitment of Uterine CD56bright Natural Killer Cells in Women with Infertility

Problem  The aim of this study was to investigate the influence of sexual intercourse on uterine NK cell subsets.
Method of study  Mid-secretory endometrial samples obtained from 56 women were submitted for flow cytometric analysis. Basal body temperature was used to determine the day of ovulation. A total of 27 women had sexual intercourse before ovulation (pre-ovulation group) and eight women had only after ovulation (post-ovulation group) without any contraceptive devices. A total of 21 women did not have sexual intercourse during the experimental cycle (abstinence group). Endometrial NK cells were analyzed for the expression of CD16 and CD56 using 3-color flow cytometry.
Results  CD16⁻/CD56^bright cells were markedly increased in the pre-ovulation group as compared with that of the post-ovulation group ( P  < 0.01) and the abstinence group ( P  < 0.01). CD16⁺/CD56^dim cells were significantly decreased in the pre-ovulation group as compared with that of the post-ovulation group ( P  < 0.01) and the abstinence group ( P  < 0.05).
Conclusion  It is suggested that seminal plasma participates in the recruitment of CD56^bright NK cells into endometrium.     

The functional insufficiency of human CD4+CD25 high T-regulatory cells in allergic asthma is subjected to TNF-alpha modulation

Background:  Natural CD4⁺CD25^highFoxp3⁺ regulatory T (nTreg) cells are important in maintaining immunologic tolerance, but their role in the pathogenesis of allergic asthma is unclear. We studied the function of nTreg cells in allergic asthmatic children and assessed the factors which may relate to the functional insufficiency of nTreg cells.
Methods:  The percentage of CD4⁺CD25^high Treg cells, the expression of Foxp3, and the cell-induced suppressive activity of nTreg cells isolated from nonatopic controls, allergic asthmatics, and allergen-specific immunotherapy (AIT)-treated asthmatic patients were studied.
Results:  Although the percentage of nTreg in peripheral blood mononuclear cells was increased, the expression of Foxp3 and its cell-induced suppressive activity were significantly lower in Dermatophagoides pteronyssinus (Der p)-sensitive asthmatic children when compared to nonatopic controls. In contrast, the expression of Foxp3 and the functional activity of nTreg cells were reversed in allergic asthmatics who received AIT. The addition of recombinant tumor necrosis factor (TNF)-α directly downregulated Foxp3 expression and abrogated the cell-induced suppressive function of Treg cells. The anti-TNF-α reagent, etanercept, restored the functional activity and Foxp3 expression of CD4⁺CD25^high Treg derived from allergic asthmatics.
Conclusions:  The functional insufficiency of nTreg cells in patients with allergic asthma may be related to the enhanced production of TNF-α and its effect on the Foxp3 expression. These results may explain, in part, the effectiveness of anti-TNF-α therapy in the treatment of allergic asthma.     

Regulatory T cells in spontaneous autoimmune encephalomyelitis

Summary: Spontaneous experimental autoimmune encephalomyelitis (EAE) develops in 100% of mice harboring a monoclonal myelin basic protein (MBP)-specific CD4⁺αβ T-cell repertoire. Monoclonality of the αβ T-cell repertoire can be achieved by crossing MBP-specific T-cell receptor (TCR) transgenic mice with either RAG^−/− mice or TCR α^−/−/TCR β^−/− double knockout mice. Spontaneous EAE can be prevented by a single administration of purified CD4⁺ splenocytes or thymocytes obtained from wild-type syngeneic mice. The regulatory T cells (T-reg) that protect from spontaneous EAE need not express the CD25 marker, as effective protection can be attained with populations depleted of CD25⁺ T cells. Although the specificity of the regulatory T cells is important for their generation or regulatory function, T cells that protect from spontaneous EAE can have a diverse TCR α and β chain composition. T-reg cells expand poorly in vivo , and appear to be long lived. Finally, precursors for T-reg are present in fetal liver as well as in the bone marrow of aging mice. We propose that protection of healthy individuals from autoimmune diseases involves several layers of regulation, which consist of CD4⁺CD25⁺ regulatory T cells, CD4⁺CD25⁻ T-reg cells, and anti-TCR T cells, with each layer potentially operating at different stages of T-helper cell-mediated immune responses.     

Phenotypic Characterization of Macrophages in the Endometrium of the Pregnant Cow

Problem  Macrophages are recruited in large number to the interplacentomal endometrium of the cow during pregnancy. We evaluated whether endometrial macrophages also accumulate in placentomal regions of endometrium during pregnancy and whether endometrial macrophages are regionally differentiated.
Method of study  Interplacentomal endometrium and placentomes were subjected to dual-color immunofluorescence using CD68 as a pan-macrophage marker.
Results  CD68⁺ cells were abundant in stroma of the interplacentomal endometrium and caruncular septa of the placentomes. CD68⁺ cells were not present in fetal villi of the placentomes or in the interplacentomal chorion. Regardless of location, the majority of CD68⁺ cells also expressed CD14. In interplacentomal endometrium, CD68⁺CD11b⁺ cells were present in deeper areas of the stroma but not in shallow endometrial stroma. In caruncular septa of the placentome, CD68⁺ cells were negative for CD11b. CD68⁺ cells in the interplacentomal endometrium were negative for MHC class II while most CD68⁺ cells in caruncular septa were positive for MHC class II.
Conclusion  CD68⁺CD14⁺ macrophages present in the stroma of the interplacentomal endometrium and caruncular septa of the placentome are regionally differentiated with regard to expression of CD11b and MHC class II.     

GD2 Ganglioside-Specific Monoclonal Antibody Reacts with Murine Cytotoxic T Lymphocytes Reactive with FBL-3N Erythroleukaemia

Ganglioside expression on cytotoxic T lymphocytes induced against the mouse erythroleukaemia line FBL-3N, was analysed, compared with that of naive T lymphocytes in the thymus, lymph nodes and spleen. Although normal uncultured and cultured T lymphocytes expressed no GD2, GD3 or GM2 gangliosides, cytotoxic T cells with CD4⁺ CD8⁻, CD4⁻CD8⁺, and CD4⁻CD8⁻ phenotypes reacted with anti-GD2 monoclonal antibody with various intensities. The reactivity with anti-GD2 was associated with the intensity of cytotoxic activity as analysed using cytotoxic T lymphocyte (CTL) clones established from the bulk CTLs of each phenotype. An increase of the mRNA expression of GM2/GD2 synthase gene was demonstrated by Northern blot hybridization using RNA extracted from thymocytes, spleen cells, Con A-treated spleen cells and various types of CTL cells. These results indicated that GD2 ganglioside expression might be associated with the functional differentiation of murine T lymphocytes.     

3, 3', 4, 4'-Tetrachlorobiphenyl Inhibits Proliferation of Immature Thymocytes in Fetal Thymus Organ Culture

The environmental pollutant 3, 3', 4, 4'-tetrachlorobiphenyl (TCB) leads to thymic atrophy and immuno-suppression, the former possibly causing the latter. TCB binds lo the cytosolic aryl-hydrocarbon receptor (AhR) and transforms it into a DNA-binding state. The development of fetal thymocyles is severely affected by TCB and other AhR-binding xenobiotics, leading to a skewed pattern of thymocyte maturation stages. Murine thymocyte proliferation after exposure to TCB was studied in fetal thymus organ culture (FTOC). C57BL/6 fetus thymic lobes from day 15 of gestation were explanted and grown for 2, 4, 6. and 8 days in organ culture in the presence or absence of 3.3 μM TCB. Subsets of thymocytes were defined by CD4 and CD8 surface markers, and their cell cycle was analysed by DNA staining with 7-amino-actinomycin D (7-AAD). Exposure of fetal thymi in vitro to 3.3 μM TCB significantly reduced the total number of thymocytes. and fewer thymocytes were in S/G₂M phase. The inhibition of cell proliferation induced by TCB treatment affected mainly the CD4⁻ CD8⁻ (double-negative, DN) and CD4⁻ CD8⁺ (single-positive, SP) subsets, and these inhibition appeared mainly in more immature thymocytes, i. e. DNCD3⁻ and CD8⁺CD3⁻ subpopulations, whereas no effect of TCB on CD4⁺CD8⁺ (double-positive, DP) cell proliferative activity was observed. Analysis of the relation of cell proliferation and development of subsets in differentiating fetal ihymocytes suggests that TCB enhanced thymocyte differentiation into mature CD8⁺ cells.     

Peripheral Lymphoid Hyperplasia and Central Lymphoid Depletion in Mice Treated with a Bacterial B-Cell Mitogen (F3'EP-Si/p90)

In order to further understand the mechanism mediating the mitogenic and immunosuppressor effects of p90, a protein produced by Streptococcus intermedius , flow cytometric studies were performed on peripheral and central lymphoid organs of mice treated with this protein. p90 induced a strong blastogenic B-cell response in the spleen and lymph nodes, followed by a slight but significant polyclonal T-cell activation. B-cell repertoire analysis indicated that polyclonal B-cell responses affected similarly both CD5⁺ and conventional (CD5⁻) B cells in the spleen. Repertoire analysis of T cells failed to reveal any preferential stimulation of the Vβ T-cell receptor (Vβ-TcR) families studied. Peripheral lymphoid hyperplasia was observed concomitantly with central lymphoid depiction. In the bone marrow, pre-B and B cells were profoundly depleted, with a more pronounced effect on small pre-B cells. In the thymus, double-positive (CD4⁺ CD8⁺) thymocytes were preferentially eliminated, with a relative enrichment of single positive (either CD4⁺ or CD8⁺) and double-negative (CD4⁻CD8⁻) thymocytes.     

Vβ Usage and T Regulatory Cells in Children Following Partial or Total Thymectomy after Open Heart Surgery in Infancy

During open heart surgery in infants the thymus was usually removed, partly or completely. Our previous studies on 16 such children indicated reduced T-cell output later in life with signs of extrathymic maturation of the T cells, but no reduction in T regulatory cells (CD4⁺CD25⁺). The diversity of the T-cell repertoire in these children was examined to test if the extrathymic microenvironment could alter Vβ usage. The expression of Foxp3 and CD127 in CD4⁺CD25^high T cells was measured in order to determine whether the T regulatory cells had the phenotype of natural T regulatory cells. There was a wide distribution of Vβ usage in both study and control groups. Significant variability was found in Vβ usage for CD4⁺ and CD8⁺ T cells when the distribution of the percentage of T cells expressing each Vβ family was analysed between individuals within each group ( P  < 0.001; Kruskal–Wallis). Significant difference was also found in average usage of Vβ2, Vβ5.1 and Vβ14 chains within CD4⁺ T cells and Vβ2, Vβ8 and Vβ21.3 chains within CD8⁺ cells between the groups ( P  < 0.05; Student's t -test). There was no difference between the two groups with regard to the proportion of CD4⁺CD25^high T cells and no difference in the average expression of Foxp3 or CD127 within the CD4⁺CD25^high population. Our data provide evidence that cardiothoracic surgery in infants and total or partial thymectomy alters Vβ usage, suggesting more limited selection in such children than in the control group. The frequency of natural T regulatory cells seems to be unimpaired.     

Cytokine and chemokine expression in the skin from patients with maculopapular exanthema to drugs

Background:  Maculopapular exanthema (MPE) is the most frequent clinical manifestation of nonimmediate allergic reactions to drugs and T helper 1 (Th1) cytokines and CD4⁺ T cells have been shown to play an important role in its pathogenesis. We assessed the role of cytokines and chemokines and their receptors in the pathogenesis of MPE.
Methods:  We evaluated skin biopsies and peripheral CD4⁺ and CD8⁺ T cells from 27 patients during the acute phase of the reaction and 26 exposed controls. Semiquantitative real-time PCR was performed to determine the expression of cytokines and chemokines and their receptors and immunohistochemistry was used to determine the same chemokines and their receptor proteins in skin.
Results:  There was a high expression of the Th1 cytokines interferon-γ ( P  = 0.006) and tumor necrosis factor-α ( P  = 0.022) in skin and CD4⁺ T cells ( P  = 0.007 and P  = 0.005, respectively); and of the Th1 chemokines CXCL9 ( P  = 0.005) and CXCL10 ( P  = 0.028) in the skin, while their receptor CXCR3 was increased in skin ( P  = 0.006) and CD4⁺ T cells ( P  = 0.03). Homing chemokine receptors were also increased: CCR6 in skin ( P  = 0.026) and CD4⁺ T cells ( P  = 0.016), and CCR10 only in CD4⁺ T cells ( P  = 0.016), as well as their ligands, CCL20 and CCL27, in skin alone. Immunohistochemistry confirmed these results.
Conclusions:  These data show significant differences in the expression of chemokines and chemokine receptors, related with a Th1 profile, in both skin biopsies and peripheral CD4⁺ T cells in patients with drug-induced MPE.     

Decrease in Fine T-cell Subset ratio MT2/MT1 During Steroid Reduction of Asthmatic Patients

Combining inhaled long-acting β-2 agonist (LABA) and inhaled corticosteroid (ICS) seems to offer asthma control at a lower dose of ICS than achieved by ICS alone. Fine mapping of T-cell surface markers by flow cytometry offers a detailed status of the individual's inflammatory response. The frequency of MT2 (CD4⁺CD45RA^–CD62L⁺CD11adim) and MT1 (CD4⁺CD45RA^–CD62L^–CD11abright) cells in peripheral blood, and their ratio, has been shown to differ predictably in atopics and patients with leprosy, where MT2 correlates with a Th2 phenotype and MT1 with a Th1 phenotype. Stable asthmatics, requiring fluticasone propionate (FP) 750–1000 µg daily or equivalent, were randomized to receive, double-blinded, either Seretide^®[salmeterol and fluticasone propionate (SFC, n  = 16)] 50 µg/500 µg bd or FP 500 µg bd ( n  = 17). If asthma was controlled based on lung function and symptoms at clinic visits every 6 weeks, ICS dose was tapered until asthma exacerbated or 0 µg was reached. The frequency and ratio of MT2 and MT1 T cells of the patients was monitored at 6 week intervals. As treatment tapered, the frequency of MT2 cells decreased ( P =  0038 from first to final visit), whereas that of MT1 cells increased. The ratio of MT2/MT1 decreased ( P =  0049 from first to final visit). In patients receiving LABA + ICS, the fall in MT2/MT1 ratio appeared to be more pronounced than in patients receiving ICS alone. Thus, the MT2 phenotype may be associated with stable asthma, whereas an imminent exacerbation may associate with an increase in the MT1 phenotype. LABA may allow for a greater effect of FP on the MT ratio.     

Abnormal Pattern of Lymphocyte Subpopulations in the Endometrium of Infertile Women with Chronic Endometritis

Problem  Endometrial lymphocytes play a critical role in endometrial receptivity. This study aimed at evaluating the variations induced by chronic endometritis (CE) on endometrial lymphocyte subsets. We compared the results in infertile women diagnosed with CE with those in unexplained infertile women without any sign of CE.
Method of study  Twenty-three women referring for unexplained infertility had hysteroscopy and endometrial biopsy in the follicular phase; in nine women, CE was diagnosed (group CE+), while in 14 it was not (group CE−). All patients in the late secretory phase of the subsequent cycle underwent endometrial biopsy. By flow cytometry, the percentage and phenotype of the endometrial lymphocyte subpopulations were analyzed.
Results  The secretory endometrium of patients with CE displayed significantly lower percentage of CD56⁺ CD16⁻ and of CD56^bright CD16⁻ cells (47.8% ± 18.6 and 30.1% ± 20.5 versus 79.5% ± 3.9 and 67.3% ± 8.1, respectively; P  < 0.01) as compared with group CE(−), while the percentage of CD3⁺ cells was significantly higher (25% ± 12.2 versus 10.5 ± 5; P  < 0.01).
Conclusion  Infertile women with CE showed an abnormal percentage of endometrial lymphocyte subsets compared with unexplained infertile women suggesting that different mechanisms underlie the adverse pregnancy outcome of the two groups of patients.     

Effector and regulatory events during natural killer–dendritic cell interactions

Summary:  The different cell types of the innate immune system can interact with each other and influence the quality and strength of an immune response. The cross talk between natural killer (NK) cells and myeloid dendritic cells (DCs) leads to NK cell activation and DC maturation. Activated NK cells are capable of killing DCs that fail to undergo proper maturation ('DC editing'). Encounters between NK cells and DCs occur in both inflamed peripheral tissues and lymph nodes, where both cell types are recruited by chemokines released in the early phases of inflammatory responses. Different NK cell subsets (CD56^brightCD16⁻ versus CD56⁺CD16⁺) differ in their homing capabilities. In particular, CD56^brightCD16⁻ NK cells largely predominate the lymph nodes. In addition, these two subsets display major functional differences in their cytolytic activity, cytokine production, and ability to undergo proliferation. NK cell functions are also greatly influenced by the presence of polarizing cytokines such as interleukin (IL)-12 and IL-4. The cytokine microenvironment reflects the presence of different cell types that secrete such cytokines in response to microbial products acting on different Toll-like receptors (TLRs). Moreover, NK cells themselves can respond directly to microbial products by means of TLR3 and TLR9. Thus, it appears that the final outcome of a response to microbial infection may greatly vary as a result of the interactions occurring between different pathogen-derived products and different cell types of the innate immunity system. These interactions also determine the quality and strength of the subsequent adaptive responses. Remarkably, NK cells appear to play a key role in this complex network.