T and B Cell Composition and Cytokine Producing Capacity Before and After Bariatric Surgery

Morbid obesity is associated with a chronic state of low-grade inflammation, which may lead to accelerated differentiation of T and B cells. These differentiated immune cells are strongly cytotoxic and have an increased pro-inflammatory cytokine producing capacity. Furthermore, the anti-inflammatory function of the T and B cells decreases. The aim of this study was to evaluate the effect of morbid obesity on the subset profile and cytokine producing capacity of T and B cells. Subsequently, we assessed whether bariatric surgery affected the subset profile and cytokine producing capacity of these cells. We determined the proportion of T and B cell subsets and their cytokine producing capacity in peripheral blood collected from 23 morbidly obese patients before and three months after bariatric surgery using flow-cytometry. We compared this with the results of 25 lean controls. Both CD4+ and CD8+ T cells showed a more differentiated subset profile in morbidly obese patients as compared to lean controls, which was not recovered three months after bariatric surgery. The B cell composition of morbidly obese patients after bariatric surgery adjusted towards the profile of lean controls. However, the IL-2 and IFN-γ producing capacity of CD8+ T cells and the IL-2, IFN-γ, TNF-α and IL-10 producing capacity of B cells was not restored three months after bariatric surgery. In conclusion, the data suggest that the immune system has the capacity to recover from the detrimental effects of morbid obesity within three months after bariatric surgery in terms of cell composition; however, this was not seen in terms of cytokine producing capacity. The full restoration of the immune system after bariatric surgery may thus take longer.

CD4+ CD28null T cells are not alloreactive unless stimulated by interleukin-15

Proinflammatory, cytotoxic CD4⁺ CD28^null T cells can be substantially expanded in patients with end-stage renal disease. These cells have been associated with the risk for rejection, but their alloreactive potential is unknown. CD4⁺ CD28^null T cells were stimulated with HLA-mismatched antigen presenting cells in the absence/presence of exogenous cytokines. Alloreactive potential was evaluated based on proliferation, degranulation, cytotoxicity, and cytokine production. Further, their suppressive capacity was assessed by measuring inhibition of proliferating alloreactive CD28⁺ T cells. CD4⁺ CD28^null T cells contained alloreactive (CD137⁺ ) T cells but did not proliferate in response to allogeneic stimulation, unless interleukin (IL)-15 was added. However, they could proliferate on stimulation with cytomegalovirus antigen without exogenous cytokines. IL-15 increased the frequency of proliferating alloreactive CD4⁺ CD28^null T cells to 30.5% without inducing CD28 expression (P < .05). After allogeneic stimulation together with IL-15 and IL-21, frequency of degranulating CD107a⁺ CD4⁺ CD28^null T cells increased significantly from 0.6% to 5.8% (P < .001). Granzyme B and perforin positivity remained similar, but production of interferon-γ and tumor necrosis factor-α increased by the combination of IL-15 and IL-21 (P < .001 and P < .05, respectively). Finally, CD4⁺ CD28^null T cells did not show significant suppression. Thus, CD4⁺ CD28^null T cells represent a population with absent alloreactivity unless IL-15 is present.

Lymph node and circulating T cell characteristics are strongly correlated in end-stage renal disease patients, but highly differentiated T cells reside within the circulation

Ageing is associated with changes in the peripheral T cell immune system, which can be influenced significantly by latent cytomegalovirus (CMV) infection. To what extent changes in circulating T cell populations correlate with T cell composition of the lymph node (LN) is unclear, but is crucial for a comprehensive understanding of the T cell system. T cells from peripheral blood (PB) and LN of end-stage renal disease patients were analysed for frequency of recent thymic emigrants using CD31 expression and T cell receptor excision circle content, relative telomere length and expression of differentiation markers. Compared with PB, LN contained relatively more CD4⁺ than CD8⁺ T cells (P < 0·001). The percentage of naive and central memory CD4⁺ and CD8⁺ T cells and thymic output parameters showed a strong linear correlation between PB and LN. Highly differentiated CD28^null T cells, being CD27^- , CD57⁺ or programmed death 1 (PD-1⁺ ), were found almost exclusively in the circulation but not in LN. An age-related decline in naive CD4⁺ and CD8⁺ T cell frequency was observed (P = 0·035 and P = 0·002, respectively) within LN, concomitant with an increase in central memory CD8⁺ T cells (P = 0·033). Latent CMV infection increased dramatically the frequency of circulating terminally differentiated T cells, but did not alter T cell composition and ageing parameters of LN significantly. Overall T cell composition and measures of thymic function in PB and LN are correlated strongly. However, highly differentiated CD28^null T cells, which may comprise a large part of circulating T cells in CMV-seropositive individuals, are found almost exclusively within the circulation.

Uremia-Associated Premature Aging of T Cells Does Not Predict Infectious Complications After Renal Transplantation

Patients with end-stage renal disease have prematurely aged T cell systems. We tested whether T cell aging parameters were associated with the risk of infections after renal transplantation (RTx). We studied 188 patients over 1 year. Peripheral T cells were analyzed before and at 3 and 6 mo after RTx for frequency of recent thymic emigrants, relative telomere length and differentiation status. These parameters were related to the occurrence of opportunistic and serious infections. Overall, 84 patients developed an infection. In this group, 50 developed an opportunistic infection and 53 developed a serious infection. T cell aging parameters assessed before RTx were not associated with infection risk. The memory T cells showed a decrease within the first 3 mo in both groups (p < 0.001). The CD4(+) memory T cells increased between 3 and 6 mo within the infection group (p = 0.015). The number of CD8(+) memory T cells increased in both groups (p < 0.001) but reached baseline levels only in the infection group. In the infection group, the CD8(+) CD28(null) T cell percentage increased between 3 and 6 mo (p = 0.024), tending to be higher than at baseline (p = 0.061). These differences in post-RTx dynamics resulted from infections. Parameters of uremia-associated premature aging of peripheral T cells do not predict posttransplant infections.

Abstract P1-10-07: Phase 3 comparison of APF530 versus ondansetron, each in a guideline-recommended 3-drug regimen for prevention of chemotherapy-induced nausea and vomiting due to anthracycline + cyclophosphamide (AC)–based highly emetogenic chemotherapy (HEC) regimens: A post hoc subgroup analysis of the MAGIC trial

Background:Managing delayed chemotherapy-induced nausea and vomiting (CINV) associated with HEC is an unmet need. AC-based HEC is often administered to breast cancer patients (pts), a mostly female, high-CINV-risk population. APF530, an extended-release formulation of granisetron, demonstrated superior complete response (CR; no emesis [vomiting, retching] + no rescue medication use) in delayed-phase (&gt;24-120 h) CINV with HEC (ASCO criteria) vs ondansetron (Ond) (65% vs 57%, P=0.014), each combined with a neurokinin-1 antagonist and dexamethasone (Dex) (NCT02106494). This post hoc analysis evaluated efficacy and safety of APF530 in pts receiving AC-based therapy.

Methods: In this randomized, double-blind, multicenter trial, pts scheduled to receive single-day HEC were stratified by cisplatin ≥50 mg/m2 yes/no and randomized 1:1 to APF530 500 mg SC (granisetron 10 mg) or Ond 0.15 mg/kg IV. Pts received concomitant Dex 12 mg IV and fosaprepitant 150 mg IV on day 1 and oral Dex on days 2-4. The primary end point was CR in the delayed phase. Secondary and other end points included CR in acute (0-24 h) and overall (0-120 h) phases, and complete control (CC; CR and no more than mild nausea) and total response (TR; CR and no nausea) in acute, delayed, and overall phases. Rates were compared using 95% confidence intervals (CIs) for treatment differences; post hoc analysis was not powered to detect treatment differences in the AC subgroup. Safety assessments included adverse events (AEs), injection-site reactions (ISRs), laboratory parameters, and vital signs.

Results: A total of 589/902 pts (65%) in the modified intent-to-treat population received AC-based HEC (APF530 291, Ond 298). Baseline demographics were balanced between treatment arms. The majority of pts in the AC subgroup were female (APF530 99%, Ond 98%). Delayed-phase CR was higher with APF530 vs Ond, approaching statistical significance (APF530 64%, Ond 56%; P=0.062) in the AC subgroup, similar to the benefit seen in the larger study. No appreciable benefit of APF530 vs Ond was observed in the acute phase, and trends favorable to APF530 were observed in the overall phase (Table). APF530 was well tolerated. Most AEs were ISRs, generally mild or moderate, and resolved by end of study.

Phase, n (%)APF530OndansetronTreatment DifferenceN=291N=298(95% CI), %Complete responseDelayed185 (64)167 (56)8 (-0.4, 15.4)Overall163 (56)153 (51)5 (-3.4, 12.7)Acute205 (70)204 (69)1 (-5.4, 9.4)Complete controlDelayed171 (59)156 (52)7 (-1.6, 14.4)Overall149 (51)143 (48)3 (-4.9, 11.3 )Acute193 (66)191 (64)2 (-5.5, 9.9)Total responseDelayed119 (41)107 (36)5 (-2.9, 12.8)Overall100 (34)94 (32)2 (-4.8, 10.4)Acute164 (56)173 (58)-2 (-9.7, 6.3)

Conclusions: APF530 demonstrated an apparent clinical benefit in delayed-phase CR in pts receiving AC-based HEC, concordant with the statistically significant benefit seen in the overall study population. Prevention of CINV in this patient population continues to be a treatment challenge and further investigation is needed.

Citation Format: Schnadig I, Agajanian R, Dakhil S, Taylor C, Wilks S, Cooper W, Mosier M, Payne Y, Klepper M, Vacirca J. Phase 3 comparison of APF530 versus ondansetron, each in a guideline-recommended 3-drug regimen for prevention of chemotherapy-induced nausea and vomiting due to anthracycline + cyclophosphamide (AC)–based highly emetogenic chemotherapy (HEC) regimens: A post hoc subgroup analysis of the MAGIC trial. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-10-07.

Clinical rejection and persistent immune regulation in kidney transplant patients

We evaluated whether the regulatory function of CD4(+)CD25(high+)FoxP3(+) T-cells from patients on tacrolimus and mycophenolate mofetil (MMF) is affected by preceding steroid and anti-CD25 mAb induction therapy and whether this function is associated with rejection after kidney transplantation. Kidney recipients (N=15) were randomized to receive either anti-CD25 mAb induction (i.e., daclizumab) or steroids for 4 months. We analyzed the presence and suppressive activity of CD4(+)CD25(high+)FoxP3(+) peripheral T-cells in samples obtained at pre and 4-6 months after transplantation. Anti-CD25 mAb therapy and treatment with steroids did not significantly affect protein expression of FoxP3. However, at the functional level, significant differences were found in the regulatory activities of CD4(+)CD25(high+) T-cells from the anti-CD25 group vs those from the steroid group. At 4-6 months after transplantation, the regulatory activities of CD4(+)CD25(high+) T-cells were comparable to those before anti-CD25 mAb therapy; 49+/-13% (mean+/-SEM) vs 40+/-14% at a 1:20 ratio (CD25(high+):CD25(-/dim)), respectively. In contrast, the regulatory capacities of CD(+)D25(bright+) T-cells from the steroid patient group became significantly impaired. The percentage inhibition of the anti-donor response decreased from 57+/-12% before transplantation to 12+/-7% after transplantation (p<0.01). Five out of 15 patients experienced a rejection episode. At 4-6 months after transplantation, the CD25(high+) cells from these rejectors (who all received daclizumab induction therapy) had clear regulatory function, while suppression by CD25(high+) cells from non-rejectors (N=10) was significantly lower. The percentage inhibition of the anti-donor response was 48+/-14% (mean+/-SEM) vs 10+/-7%, respectively, p=0.02. Anti-CD25 mAb induction therapy does not negatively influence the regulatory function of CD4(+)CD25(high+)FoxP3(+) T-cells from kidney transplant recipients on tacrolimus and MMF. The majority of these patients experienced an acute rejection episode, which suggests that immune activation is required for persistent immunoregulatory function.

Donor-specific immune regulation by CD8 lymphocytes expanded from rejecting human cardiac allografts

To assess whether regulatory T cells are present in rejecting human cardiac allografts, we performed functional analyses of graft lymphocytes (GLs) expanded from endomyocardial biopsies (EMB; n = 5) with histological signs of acute cellular rejection. The GL cultures were tested for their proliferative capacity and regulatory activity on allogeneic-stimulated peripheral blood mononuclear cells (PBMC) of the patient (ratio PBMC:GLs = 5:1). Three of these GL cultures were hyporesponsive to donor antigens and suppressed the antidonor proliferative T-cell response of PBMC, but not the anti-third-party response. Interestingly, it was the CD8(+) GL subset of these cultures that inhibited the antidonor response (65-91% inhibition of the proportion of proliferating cells); the CD4(+) GLs of the expanded GL cultures were not suppressive. In conclusion, CD8(+) GLs expanded from rejecting human cardiac allografts can exhibit donor-specific immune regulatory activities in vitro. We suggest that during acute cellular rejection, GLs may not only consist of graft-destructing effector T cells, but also of cells of the CD8(+) type with the potential to specifically inhibit antidonor immune reactivity.

FoxP3+ T Cells Can Be Expanded From Rejecting Cardiac Allografts

A specific subset of T cells, the FoxP3+ regulatory T cells, control effector T-cell responses to self and foreign antigens. In transplant patients, we and others have shown that high intragraft FOXP3 mRNA levels are associated with acute rejection, suggesting that immune regulation is dependent on immune activation. To study whether transplanted grafts harbor FoxP3+ T cells and to functionally analyze them, graft infiltrating lymphocytes (GILs) must be propagated from the transplanted tissue. In the present study, we analyzed whether FoxP3+ T cells can be grown from endomyocardial biopsies (EMBs; n = 5) from patients after heart transplantation during acute cellular rejection. After 18 to 21 days of culture, 0.5 to 1.0 x 10(6) GILs were cultured from the EMBs. Of these GILs, 10.6% (median; range, 1.6%-17.1%) stained positive for FoxP3. Thus Foxp3+ T cells can be grown from EMBs, providing the tools to functionally characterize these cells in depth in forthcoming studies.

Vitamin E-coated dialyzer membranes downregulate expression of monocyte adhesion and co-stimulatory molecules

BACKGROUND

In patients on chronic hemodialysis leukocyte activation has been related to the impaired function of the immune system. In this study we investigated if the vitamin E-coated dialyzer membrane could reduce monocyte activation thereby improving cellular immunity.

METHODS

This hypothesis was tested in a prospective crossover trial in which 14 stable hemodialysis patients were switched from the baseline hemophane dialyzer to a vitamin E-coated and thereafter a polysulphone dialyzer membrane or vice versa.

RESULTS

Monocyte MHC class I, CD54 and ICAM-1 expression was significantly downregulated when a vitamin E-coated or polysulphone dialyzer was used. The use of a vitamin E membrane specifically decreased monocyte CD40 and CD86 expression. Lectin induced T cell proliferation increased with the use of the vitamin E-coated membrane as compared to polysulphone and hemophane dialyzers.

CONCLUSION

Vitamin E-coated dialyzers induced a less-activated phenotype of monocytes and may improve cellular immunity.

A case of chronic mountain sickness diagnosed by routine pulmonary function tests

In summary, this is a patient who presented with respiratory acidosis and cor pulmonale. The major diagnostic challenge was in differentiating primary cardiopulmonary disease from a central abnormality of ventilatory drive. The arterial blood gases showed a normal A-a gradient suggesting hypoventilation as the etiology of his hypoxemia. Pulmonary function testing showed air trapping, but a relatively normal FEV1/FVC and airways resistance. The literature suggests that most altitude natives have depressed hypoxemic and hypercapnic drives with a distinct subset demonstrating a profoundly depressed drive to ventilation. This latter group has been labeled as having chronic mountain sickness or Monge's disease. As one might expect, ventilatory control during sleep is also abnormal in these patients with CMS. Our patient indeed showed typical frequent severe desaturations with hypopnea. The diagnosis of CMS in our patient was made with routine arterial blood gases and standard pulmonary function tests. Additional tests of ventilatory responsiveness to oxygen and carbon dioxide could have been performed, but are not necessary to make the diagnosis.

Nicotinic cholinergic modulation of voltage-dependent calcium current in bovine adrenal chromaffin cells

1. The effects of cholinergic agonists on voltage-dependent calcium current (ICa) were studied in cultured chromaffin cells from bovine adrenal medulla. 2. Application of both acetylcholine (ACh) and nicotine resulted in inward nicotinic current from a holding potential of -90 mV, and at the same time reversible decreases in depolarization-activated ICa. Both of these effects were blocked by d-tubocurarine, while atropine pre-treatment was ineffective. 3. Internal accumulation of neither Na+ nor Ca2+ seems likely to explain the nicotinic-agonist-dependent decrease in ICa, as the modulation was observed with symmetrical Na+ solutions, with Ca2(+)-free Ba2(+)-containing external solutions, from holding potentials of both -90 and -40 mV, and when the internal Ca2+ buffer capacity was increased. 4. Isodihydrohistrionicotoxin, an open-channel blocker which does not compete for the agonist binding site, completely inhibited inward cholinergic currents while the agonist-dependent decrease in ICa was seen in only two of fifteen cells. 5. The nicotinic agonist-mediated decreases in ICa were not voltage-dependent. 6. No changes in voltage-dependent INa were seen with the nicotinic agonists. 7. Muscarine, with or without GTP in the pipette solution, produced neither modulation of ICa nor any changes in steady holding currents. The nicotinic current and the reversible decrease in ICa induced by ACh and nicotine were not affected by including GTP, or the guanine nucleotide analogues GDP-beta-S and GTP-gamma-S, in the pipette solution. 8. A 10 min pre-incubation of the cells in a high-K+ solution optimal for catecholamine secretion did not affect the nicotinic agonist-mediated decreases in ICa.

Modulation of secretion by dopamine involves decreases in calcium and nicotinic currents in bovine chromaffin cells

1. Catecholamine secretion from cultured bovine adrenal chromaffin cells was decreased in a dose-dependent manner by the D2 dopamine agonists apomorphine and LY 17 1555. 2. 45Ca2+ uptake was similarly inhibited and whole-cell Ca2+ currents were reduced by apomorphine. 3. These inhibitory effects of D2 agonists depended on the secretagogue used, being much more pronounced for nicotine-evoked responses compared to high K+ stimulation, indicating another possible site of action of apomorphine up-stream of Ca2+ entry. 4. Inhibition by apomorphine of nicotine-evoked responses could not be explained by competitive antagonism against nicotine or DMPP (1,1-dimethyl-4-phenyl-piperazinium iodide). 5. Apomorphine caused reductions of inward whole-cell nicotinic current evoked by ACh and nicotine. 6. Inhibition of nicotine-evoked secretion and 22Na+ influx by apomorphine were not affected by tetrodotoxin, and voltage-dependent, whole-cell Na+ currents were unaltered by apomorphine. 7. No evidence was obtained for increases in K+ conductance by apomorphine. 8. Action potentials recorded in whole-cell current clamp were blocked by apomorphine when they were triggered by nicotinic depolarization but not when they were elicited by direct electrical stimulation. 9. Inclusion of GDP-beta-S in the pipette internal solution did not affect apomorphine-dependent inhibition of nicotinic-evoked responses, while the decrease in whole-cell Ca2+ current induced by apomorphine was completely inhibited in the presence of GDP-beta-S. 10. Increases in cyclic AMP caused by cholera toxin and forskolin did not change the apomorphine-dependent inhibitory effects on nicotine-evoked secretion, indicating that changes in cyclic AMP levels caused by dopamine receptor stimulation are probably not involved.

Voltage-dependent and agonist-activated ionic currents in vascular endothelial cells: a review

Vascular endothelial cells produce a variety of substances known to modulate the tone of surrounding smooth muscle, but the initial steps involved in receptor-response coupling are poorly characterized in these cells. Because the stimulated release of endothelium-derived relaxing factor depends on the presence of external calcium, ion channel-mediated calcium influx might represent an essential first link. Furthermore, agonist-induced endothelial cell hyperpolarization has been widely described, although the ion channels involved and the functional significance of this response remain uncertain. A review of the available literature to date concerning voltage-dependent and agonist-activated ionic currents obtained using patch clamp techniques in vascular endothelial cells is presented here. A discussion of the possible functional roles of the underlying ion channels is included.