Therapy with infliximab decreases the CD4+CD28? T cell compartment in peripheral blood in patients with rheumatoid arthritis

Topical application of simvastatin acid sodium salt and atorvastatin calcium salt in vitiligo patients. Results of the randomized, double-blind EVRAAS pilot study

Contemporary treatment of vitiligo remains a great challenge to practitioners. The vast majority of currently conducted clinical trials of modern therapeutic methods are focused on systemic medications, while there is only a very limited number of reports on new topical treatment in vitiligo. With their pleiotropic activities statins turned out to be efficient in the treatment of various autoimmune/autoinflammatory disorders. The randomized, double-blind placebo-controlled study of topical administration of the active forms of simvastatin and atorvastatin has been designed to evaluate their efficacy in patients with vitiligo. The study was registered in clinicaltrials.gov (registration number NCT03247400, date of registration: 11th August 2017). A total of 24 patients with the active form of non-segmental vitiligo were enrolled in the study. The change of absolute area of skin lesions, body surface area and vitiligo area scoring index were evaluated throughout the 12 week application of ointments containing simvastatin and atorvastatin. Measurements were performed with planimetry and processed using digital software. Use of active forms of simvastatin and atorvastatin did not result in a significant repigmentation of the skin lesions throughout the study period. Within the limbs treated with topical simvastatin, inhibition of disease progression was significantly more frequent than in the case of placebo (p = 0.004), while the difference was not statistically significant for atorvastatin (p = 0.082). Further studies of topical simvastatin in vitiligo patients should be considered.

CD28 null CD4 T-cell expansions in autoimmune disease suggest a link with cytomegalovirus infection

Immunosenescence is thought to contribute to the increase of autoimmune diseases in older people. Immunosenescence is often associated with the presence of an expanded population of CD4 T cells lacking expression of CD28 (CD28 ^null). These highly cytotoxic CD4 T cells were isolated from disease-affected tissues in patients with rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis, or other chronic inflammatory diseases and their numbers appeared to be linked to disease severity. However, we recently demonstrated that the common herpes virus, cytomegalovirus (CMV), not ageing, is the major driver of this subset of cytotoxic T cells. In this review, we discuss how CMV might potentiate and exacerbate autoimmune disease through the expansion of CD28 ^null CD4 T cells.

TNFα in the regulation of Treg and Th17 cells in rheumatoid arthritis and other autoimmune inflammatory diseases

TNFα is a principal pro-inflammatory cytokine vital for immunity to infections. However, its excessive production is involved in chronic inflammation and disease pathology in autoimmune diseases. Evidence for its pathogenic role is validated by the fact that its neutralisation by therapeutic agents in vivo is beneficial in ameliorating disease and controlling symptoms. Paradoxically, however, treatment with TNFα inhibitors can either have no clinical effects, or even exacerbate disease in some patients. The explanation for such contradictory outcomes may lay in how and which downstream signalling pathways are activated and drive disease. TNFα causes its effects by binding to either or both of two membrane-bound receptors, TNFR1 and TNFR2. Engagement of the receptors can induce cell death or cell proliferation. T cells both produce and respond to TNFα and depending on whether the cytokine is membrane-bound or soluble and the level of expression of its two receptors, the biological outcome can be distinct. In addition, polymorphisms in genes encoding TNFα and T cell signalling proteins can significantly impact the outcome of TNFα receptor engagement. Early studies revealed that effector T cells in patients with rheumatoid arthritis (RA) are hyporesponsive due to chronic exposure to TNFα. However, recent evidence indicates that the relationship between TNFα and T cell responses is complex and, at times, can be paradoxical. In addition, there is controversy as to the specific effects of TNFα on different T cell subsets. This review will summarise knowledge on how TNFα modulates T cell responses and the effect of engaging either of its two receptors. Furthermore, we discuss how such interactions can dictate the outcome of treatment with TNFα inhibitors.

T cells and cytokines in atherogenesis

Recent findings suggest that inflammation plays a key role in atherosclerosis from the earliest stage of lesion initiation, to the ultimate complication of thrombosis. In patients who died because of acute coronary syndromes (ACS), coronary atherosclerotic plaques are characterized by the presence of macrophages, and to a lesser extent T-lymphocytes, at the immediate site of either plaque rupture or superficial erosion. The rupture-related inflammatory cells are activated, indicating ongoing inflammation. ACS patients are also characterized by activated circulating lymphocytes, monocytes and neutrophils, and by increased concentrations of proinflammatory cytokines and of the highly sensitive acute phase reactant C-reactive protein. Interestingly, an unusual subset of T cells, CD4+CD28null T cells, involved in vascular complication of rheumatoid arthritis because of their functional profile predisposing for vascular injury, are expanded in the peripheral blood and infiltrate the coronary lesions of ACS patients. The presence of activated T lymphocytes implies antigenic stimulation, but the nature of such antigen(s) remains to be investigated. Several autoantigens expressed in the atherosclerotic plaque, including oxidized LDL and heat shock proteins, and infectious agents are able to elicit an immune response. The inflammatory component is not localized to the ‘culprit’ plaque, but it is diffused to the entire coronary vascular bed, and involves also the myocardium.

The story of CD4+ CD28- T cells revisited: solved or still ongoing?

CD4⁺CD28⁻ T cells are a unique type of proinflammatory T cells characterised by blockade of costimulatory CD28 receptor expression at the transcriptional level, which is still reversible by IL-12. In healthy individuals older than 65 years, these cells may accumulate to up to 50% of total CD4⁺ T lymphocytes as in many immune-mediated diseases, immunodeficiency, and specific infectious diseases. Here we focus on CD4⁺CD28⁻ T cells in chronic immune-mediated diseases, summarizing various phenotypic and functional characteristics, which vary depending on the underlying disease, disease activity, and concurrent treatment. CD4⁺CD28⁻ T cells present as effector/memory cells with increased replicative history and oligoclonality but reduced apoptosis. As an alternative costimulatory signal instead of CD28, not only natural killer cell receptors and Toll-like receptors, but also CD47, CTLA-4, OX40, and 4-1BB have to be considered. The proinflammatory and cytotoxic capacities of these cells indicate an involvement in progression and maintenance of chronic immune-mediated disease. So far it has been shown that treatment with TNF-α blockers, abatacept, statins, and polyclonal antilymphocyte globulins (ATG) mediates reduction of the CD4⁺CD28⁻ T cell level. The clinical relevance of targeting CD4⁺CD28⁻ T cells as a therapeutic option has not been examined so far.

Apoptotic effects of antilymphocyte globulins on human pro-inflammatory CD4+CD28- T-cells

Background

Pro-inflammatory, cytotoxic CD4⁺CD28⁻ T-cells with known defects in apoptosis have been investigated as markers of premature immuno-senescence in various immune-mediated diseases. In this study we evaluated the influence of polyclonal antilymphocyte globulins (ATG-Fresenius, ATG-F) on CD4⁺CD28⁻ T-cells in vivo and in vitro.

Principal Findings

Surface and intracellular three colour fluorescence activated cell sorting analyses of peripheral blood mononuclear cells from 16 consecutive transplant recipients and short-term cell lines were performed. In vivo, peripheral levels of CD3⁺CD4⁺CD28⁻ T-cells decreased from 3.7±7.1% before to 0±0% six hours after ATG-F application (P = 0.043) in 5 ATG-F treated but not in 11 control patients (2.9±2.9% vs. 3.9±3.0%). In vitro, ATG-F induced apoptosis even in CD4⁺CD28⁻ T-cells, which was 4.3-times higher than in CD4⁺CD28⁺ T-cells. ATG-F evoked apoptosis was partially reversed by the broad-spectrum caspase inhibitor benzyloxycarbonyl (Cbz)-Val-Ala-Asp(OMe)-fluoromethylketone (zVAD-fmk) and prednisolon-21-hydrogensuccinate. ATG-F triggered CD25 expression and production of pro-inflammatory cytokines, and induced down-regulation of the type 1 chemokine receptors CXCR-3, CCR-5, CX3CR-1 and the central memory adhesion molecule CD62L predominately in CD4⁺CD28⁻ T-cells.

Conclusion

In summary, in vivo depletion of peripheral CD3⁺CD4⁺CD28⁻ T-cells by ATG-F in transplant recipients was paralleled in vitro by ATG-F induced apoptosis. CD25 expression and chemokine receptor down-regulation in CD4⁺CD28⁻ T-cells only partly explain the underlying mechanism.

Baseline numbers of circulating CD28-negative T cells may predict clinical response to abatacept in patients with rheumatoid arthritis

OBJECTIVE

To evaluate the number of circulating CD28-negative (CD28-) T cells as a predictor of clinical response to abatacept in patients with rheumatoid arthritis (RA).

METHODS

Peripheral blood CD28- T cell subsets were evaluated by flow cytometry at baseline in 32 patients with RA treated with abatacept. Receiver-operator curves were applied to examine the predictive value of T cell populations and to choose the cutoff for the best performance of the test. Remission was defined using the Disease Activity Score 28 based on C-reactive protein.

RESULTS

The overall predictive values of the CD8+CD28- and CD4+CD28- cells for remission after 6 months of abatacept therapy were 0.802 (SE 0.078) and 0.743 (SE 0.089), respectively. Cutoff values of < 87 CD8+CD28- cells/μl and < 28 CD4+CD28- cells/μl had 80.0% sensitivity and 81.8% specificity (Fisher test: p = 0.001), and 60.0% sensitivity and 77.3% specificity (p = 0.043), respectively, for prediction of remission at 6 months. Patients having low baseline numbers of CD8+CD28- T cells had a more than 4-fold higher probability of achieving remission within 6 months than patients with higher levels of these cells.

CONCLUSION

A simple laboratory measure, the baseline number of circulating CD28- T cells, predicted remission after 6 months of abatacept treatment in patients with RA.

The CD4+CD28null and the regulatory CD4+CD25High T-cell phenotypes in patients with ulcerative colitis during active and quiescent disease, and following colectomy

The CD4+CD25High T-cell phenotype has an essential immunoregulatory role, while the CD4+CD28null T-cell reflects immune pathology. We investigated the profiles of the CD4+CD25High and the CD4+CD28null T-cell phenotypes in patients with ulcerative colitis (UC) during active and quiescent phases as well as following colectomy. Fifty-nine UC patients, 34 active (UCa) and 25 quiescent (UCq) together with 19 healthy controls (HC) were included. Ten of 34 UCa patients underwent colectomy due to unremitting UC (UCo). Immunohistochemical phenotypic of the peripheral blood lymphocytes bearing CD4, CD25 or CD28 was done for analyzes by a multiparameter fluorescence activated cell sorting technique. The expression of the CD4+CD25High phenotype was higher in UCq (P<0.01) or UCo (P<0.01) group vs UCa group. Further, the expression of the CD4+CD28null phenotype in UCa or UCo group was higher than in the HC group (P<0.05). However, the expression of the CD4+CD28null phenotype up to 12 months after colectomy was not significantly different from the levels in the same patients during acute phase. Our impression is that a high CD4+CD25High T-cell reflects alleviation of inflammation, while the expression of the CD4+CD28null T-cell phenotype is an etiologic feature in UC patients, and is maintained after removing the affected colon.

A case of progressive multifocal leukoencephalopathy in a patient treated with infliximab

We describe a 72-year-old white man with erosive rheumatoid arthritis in whom subacute neurologic and psychiatric symptoms developed after 3 years of treatment with infliximab, prednisone, and methotrexate. White matter demyelination was seen on magnetic resonance imaging of the brain, and progressive multifocal leukoencephalopathy (PML) was ultimately confirmed by brain biopsy. The patient was treated with supportive therapy and discontinuation of disease-modifying antirheumatic drugs, resulting in stabilization of the disease process. The patient survived, but neurologic and cognitive deficits persisted. The distribution and pathology of this patient's disease are unique from almost all reported incidents of oral methotrexate-associated leukoencephalopathy. The pathogenesis of disease may be linked to a T cell-mediated process that is potentially impacted by infliximab. This case provides the first reported evidence that PML can be seen in association with infliximab therapy.

Clonal expansions in selected TCR BV families of rheumatoid arthritis patients are reduced by treatment with the TNFα inhibitors etanercept and infliximab

Clonal expansions of autoreactive CD4+ T cells are frequently present in patients with rheumatoid arthritis (RA) and are stable over long periods of time. This study was undertaken to investigate the influence of anti-TNFα treatment on such clonal expansions in the peripheral CD4+ T-cell compartment. TNFα inhibiting therapies significantly reduced the total number of expanded clonotypes. This effect was mainly observed in clonal expansions in the BV6 family, while in clonal expansions of the BV14 family no such effect was seen. No change in the percentage of CD4+ CD28 null T cells was observed. Serum concentrations of the pro-homeostatic cytokine IL-7 were found to increase in patients responding TNFα-inhibiting therapy. These data argue for a normalization of adaptive immune mechanisms under TNFα inhibiting therapies, which may be secondary to the control of inflammation but contribute to the efficacy of cytokine blockade therapy.

Skewed distribution of proinflammatory CD4+CD28null T cells in rheumatoid arthritis

Expanded populations of CD4+ T cells lacking the co-stimulatory molecule CD28 (CD4+CD28null T cells) have been reported in several inflammatory disorders. In rheumatoid arthritis, increased frequencies of CD4+CD28null T cells in peripheral blood have previously been associated with extra-articular manifestations and human cytomegalovirus (HCMV) infection, but their presence in and contribution to joint manifestations is not clear. In the present article we investigated the distribution of CD4+CD28null T cells in the synovial membrane, synovial fluid and peripheral blood of RA patients, and analysed the association with erosive disease and anti-citrullinated protein antibodies. CD4+CD28null T cells were infrequent in the synovial membrane and synovial fluid, despite significant frequencies in the circulation. Strikingly, the dominant TCR-Vbeta subsets of CD4+CD28null T cells in peripheral blood were often absent in synovial fluid. CD4+CD28null T cells in blood and synovial fluid showed specificity for HCMV antigens, and their presence was clearly associated with HCMV seropositivity but not with anti-citrullinated protein antibodies in the serum or synovial fluid, nor with erosive disease. Together these data imply a primary role for CD4+CD28null T cells in manifestations elsewhere than in the joints of patients with HCMV-seropositive rheumatoid arthritis.

Modulation of CD4 + CD28 null T Lymphocytes by Tumor Necrosis Factor-α Blockade in Patients With Unstable Angina

BACKGROUND

Tumor necrosis factor-alpha (TNF-alpha) is a proinflammatory cytokine that favors the expansion of CD4(+)CD28null T cells, an aggressive and unusual proinflammatory lymphocyte subset frequently observed in patients with unstable angina (UA). The purpose of the present ex vivo study was to evaluate whether inflammation in patients with UA may be modulated by selective blockade of TNF-alpha.

METHODS AND RESULTS

Peripheral blood samples were collected from 17 patients with UA (Braunwald's class IIIB). CD4(+)CD28null T cells were assessed by flow cytometry and expressed as a percentage of all CD4+ T cells after 24 hours of incubation of whole blood with and without increasing doses (0.1, 1, 10, and 100 microg/mL) of infliximab, an anti-TNF-alpha monoclonal antibody. In addition, CD28 expression was assessed and expressed as mean fluorescence intensity (geometric mean of the CD28 fluorescence value on all CD4+ T cells). CD4(+)CD28null T-cell percentage decreased from a median of 6.2% (range, 1.2% to 23.9%) to 4.9% (range, 1.1% to 21.9%), 4.5% (range, 1.1% to 21.6%), and 4.1% (range, 0.4% to 21.4%) after incubation with 1, 10, and 100 microg/mL of infliximab (P for trend=0.043). Analysis of CD28 mean fluorescence intensity showed that the expression of CD28 on cell surface significantly increased after incubation with increasing doses of infliximab (P for trend=0.03).

CONCLUSIONS

The findings of this ex vivo study show that CD4(+)CD28null T-cell expansion in patients with UA may be reduced by selective TNF-alpha blockade. Further studies are warranted to evaluate the clinical benefit of CD4(+)CD28null T-cell modulation.

[Cardiovascular manifestations in rheumatoid arthritis]

Rheumatoid arthritis (RA) is a chronic inflammatory disease, characterized by a polyarticular joint inflammation which eventually leads to joint destruction and general disability. Besides these polyarticular manifestations, several systemic immune phenomena have been described. An increased mortality in RA patients is evident and is mainly caused by an increased cardiovascular risk. The correlation between disease activity and mortality highlighted the important role of the systemic inflammatory reaction in induction and progression of vascular damaging processes. Endothelial dysfunction and vascular inflammation are important, mechanisms in atherosclerosis and induced by conventional risk factors and systemic inflammation. It has been shown that the deleterious influence of conventional risk factors is aggravated by inflammatory mediators, mainly by pro-inflammatory cytokines. In addition, certain inflammatory mediators exert damaging effects to blood vessels. Especially CRP, merely considered as a risk indicating parameter in the past, has attracted remarkable attention. Also certain RA specific immune phenomena are of considerable proatherosclerotic potential. At least in part, they could be responsible for the excess mortality in RA patients. The newer TNFalpha blocking agents interfere with different mechanisms responsible for induction and perpetuation of atherosclerotic processes. Time will show whether they make a remarkable impact on the cardiovascular mortality in RA patients.

Co-stimulatory blockade as therapy for rheumatoid arthritis

There is substantial evidence that rheumatoid arthritis is an autoimmune disease in which T cells are aberrantly activated. Existing therapies, including anti-tumor necrosis factor therapies, are successful for many patients, but the goal of lasting remission still frequently proves elusive. One novel therapeutic strategy is the blockade of T-cell co-stimulation to modulate T-cell activation. The first co-stimulation blocker to reach clinical trials is abatacept (CTLA4Ig). Initial abatacept trials have shown promise and further phase III trials are underway.