Lymphocyte subset proportions in Guillain-Barré syndrome patients treated with plasmapheresis

Current Therapies in Kidney Transplant Rejection

Despite significant advancements in immunosuppressive therapies, kidney transplant rejection continues to pose a substantial challenge, impacting the long-term survival of grafts. This article provides an overview of the diagnosis, current therapies, and management strategies for acute T-cell-mediated rejection (TCMR) and antibody-mediated rejection (ABMR). TCMR is diagnosed through histological examination of kidney biopsy samples, which reveal the infiltration of mononuclear cells into the allograft tissue. Corticosteroids serve as the primary treatment for TCMR, while severe or steroid-resistant cases may require T-cell-depleting agents, like Thymoglobulin. ABMR occurs due to the binding of antibodies to graft endothelial cells. The most common treatment for ABMR is plasmapheresis, although its efficacy is still a subject of debate. Other current therapies, such as intravenous immunoglobulins, anti-CD20 antibodies, complement inhibitors, and proteasome inhibitors, are also utilized to varying degrees, but their efficacy remains questionable. Management decisions for ABMR depend on the timing of the rejection episode and the presence of chronic changes. In managing both TCMR and ABMR, it is crucial to optimize immunosuppression and address adherence. However, further research is needed to explore newer therapeutics and evaluate their efficacy.

Optic neuritis with potential for poor outcome

The Optic Neuritis Treatment Trial previously reported that corticosteroids accelerated visual recovery in optic neuritis (ON) without improving outcome. This finding related largely to multiple sclerosis (MS), and subsequently neurologists tended to await spontaneous recovery in ON. Since then, non-MS cases of ON have been identified with antibodies to aquaporin-4 (AQP4) or myelin oligodendrocyte glycoprotein (MOG). These disorders can closely mimic multiple sclerosis-associated or idiopathic demyelinating optic neuritis (MS/IDON) initially but risk a worse visual outcome. Scrutinising the clinical features and neuroimaging often enables differentiation between MS/IDON and other causes of ON. Early treatment with high-dose corticosteroids is an important determinant of visual outcome in non-MS/IDON. Prompt use of plasma exchange may also save sight. In this review, we contrast the presentations of myelin oligodendrocyte glycoprotein associated optic neuritis (MOG-ON) and aquaporin 4 associated optic neuritis (AQP4-ON) with MS/IDON and provide an approach to acute management while awaiting results of antibody testing.

Therapeutic apheresis in kidney transplantation: An updated review

Therapeutic apheresis is a cornerstone of therapy for several conditions in transplantation medicine and is available in different technical variants. In the setting of kidney transplantation, immunological barriers such as ABO blood group incompatibility and preformed donor-specific antibodies can complicate the outcome of deceased- or living- donor transplantation. Postoperatively, additional problems such as antibody-mediated rejection and a recurrence of primary focal segmental glomerulosclerosis can limit therapeutic success and decrease graft survival. Therapeutic apheresis techniques find application in these issues by separating and selectively removing exchanging or modifying pathogenic material from the patient by an extracorporeal aphaeresis system. The purpose of this review is to describe the available techniques of therapeutic aphaeresis with their specific advantages and disadvantages and examine the evidence supporting the application of therapeutic aphaeresis as an adjunctive therapeutic option to immunosuppressive agents in protocols before and after kidney transplantation.

Differences in the Reponses to Apheresis Therapy of Patients With 3 Histopathologically Classified Immunopathological Patterns of Multiple Sclerosis

Importance

Plasma exchange and immunoadsorption are second-line apheresis therapies for patients experiencing multiple sclerosis relapses. Early active multiple sclerosis lesions can be classified into different histopathological patterns of demyelination. Pattern 1 and 2 lesions show T-cell- and macrophage-associated demyelination, and pattern 2 is selectively associated with immunoglobulin and complement deposits, suggesting a humoral immune response. Pattern 3 lesions show signs of oligodendrocyte degeneration. Thus it is possible that pathogenic heterogeneity might predict therapy response.

Objective

To evaluate the apheresis response in relation to histopathologically defined immunopathological patterns of multiple sclerosis.

Design, Setting and Participants

This single-center cohort study recruited 69 patients nationwide between 2005 and 2016. All included patients had a diagnosis of early active inflammatory demyelination consistent with multiple sclerosis; were classified into patterns 1, 2, or 3 based on brain biopsy analysis; and underwent apheresis treatments. Patients who had concomitant severe disease, neuromyelitis optica, or acute disseminated encephalomyelitis were excluded.

Main Outcomes and Measures

The primary therapy outcome was a functionally relevant improvement of the relapse-related neurological deficit. Radiological and Expanded Disability Status Scale changes were secondary outcome parameters.

Results

The mean (SD) age of patients was 36.6 (13.3) years; 46 of the 69 participants (67%) were female. Overall, 16 patients (23%) exhibited pattern 1 lesions, 40 (58%) had pattern 2 lesions, and 13 (19%) had pattern 3 lesions. A functional therapy response was observed in 5 of the 16 patients with pattern 1 disease (31%) and 22 of the 40 patients with pattern 2 disease (55%), but none of the 13 patients with pattern 3 disease exhibited improvement (pattern 2 vs 3 P < .001). Radiological improvements were found in 4 (25%), 22 (56%), and 1 (11%) of patients with patterns 1, 2, and 3, respectively. The respective rates of response measured by changes in Expanded Disability Status Scale scores were 25%, 40%, and 0%. Brainstem involvement was a negative predictive factor for the functional therapy response (logarithmic odds ratio [logOR], -1.43; 95% CI, -3.21 to 0.17; P = .03), while immunoadsorption (as compared with plasma exchange) might be a positive predictive factor (logOR, 3.26; 95% CI, 0.75 to 8.13; P = .01).

Conclusions and Relevance

This cohort study provides evidence that the response to apheresis treatment is associated with immunopathological patterns. Patients with both patterns 1 and 2 improved clinically after apheresis treatment, but pattern 2 patients who showed signs of a humoral immune response benefited most. Apheresis appears unlikely to benefit patients with pattern 3 lesions.

The mechanisms of action of plasma exchange

The initial description of therapeutic plasma exchange (TPE) in an animal model was published almost 100 years ago. Since that time, this treatment has been applied to a wide variety of diseases but limited research has been published examining the mechanisms of action of TPE. The therapeutic effects of TPE could include the removal of pathological substances from the blood, such as monoclonal paraproteins and autoantibodies, as well as the replacement of deficient plasma components when plasma is used as a replacement fluid. Beyond these potential mechanisms, other possible mechanisms include possible alterations in lymphocyte proliferation and function that could sensitize these cells to immunosuppressant and chemotherapeutic agents and alterations in the immune system including changes in B and T cell numbers and activation, increased T suppressor function, and alteration in T-helper cell type 1/2 (Th1/Th2) ratio. Much remains unknown about the mechanisms of action of TPE, indicating a need for basic research into this therapy.

A decrease in the percentage of CD3+ cells is correlated with clinical improvement during plasmapheresis in patients with myasthenia gravis

Plasmapheresis not only removes circulating antibodies but also modulates cellular immunity, including lymphocyte subsets. To investigate the effect of double-filtration plasmapheresis (DFPP) on the ratio of lymphocyte subsets in patients with myasthenia gravis (MG), we examined the percentages of B-cells, T-cells, T helper (Th) cells, T suppressor (Ts) cells, natural killer (NK) cells, NKT cells, and Th/Ts ratio before and after a single DFPP session and after a course of DFPP. A total of 26 patients were recruited; their peripheral blood lymphocyte subsets were assayed using flow cytometry. After a single session of DFPP treatment, the percentages of T-cells (P = 0.0200), Th cells (P = 0.0178), and the Th/Ts ratio (P = 0.0309) decreased significantly, whereas the percentage of NK cells (P = 0.0007) increased significantly. More importantly, after one course of DFPP treatment, the reduced clinical quantitative MG (QMG) score was correlated with the decrease of the percentage of T-cells (r = 0.5005, P = 0.0092). Fourteen thymectomized MG patients had decreased percentages of T-cells (P = 0.0304) and Th cells (P = 0.0444), whereas they had increased NK cells (P = 0.0197) after a single DFPP session. Here, transiently decreased percentages of T-cells after the full DFPP course could enhance the effectiveness of plasmapheresis for MG patients.

Can plasma exchange therapy induce regulatory T lymphocytes in multiple sclerosis patients?

Plasma exchange is used increasingly as an individual therapeutic decision for treating of severe, steroid-resistant relapses of multiple sclerosis (MS). However, given that its mechanism of action in this CD4(+) T cell-mediated autoimmune disease remains unknown, it is not yet considered as a routine therapy for this prevalent neuroimmune disorder. In this regard, we hypothesized that plasma exchange, by depleting the body of inflammatory mediators that acts as providers of co-stimulatory signals for the adaptive immune system, provides the immune system with an exceptional break for de-novo recognition of autoantigens in a tolerogenic manner. This may lead to an increase in the frequency and function of myelin-specific regulatory T cells. For evaluating this we suggest some in vitro and in vivo studies to analyse the effects of varied dilutions of normal and MS plasmas on the induction of regulatory T cells or on the function of isolated and purified regulatory T cells. Clarifying the effects of therapeutic plasma exchange on regulatory T cells as the major controllers of autoimmune responses may provide us with strong evidence to use this procedure as a disease-modifying treatment in remission phase for reducing the rate and severity of future attacks, in addition to more trustworthy therapy in severe relapses of MS.

Plasma exchange and intravenous immunoglobulins: mechanism of action in immune-mediated neuropathies

Immune-mediated neuropathies are a heterogeneous group of peripheral nerve disorders, which are classified by time course, clinical pattern, affected nerves and pathological features. Plasma exchange (PE) and intravenous immunoglobulins (IVIg) are mainstays in the treatment of immune-mediated neuropathies. Of all treatments currently used, IVIg has probably the widest application range in immune-mediated neuropathies and efficacy has been well documented in several randomized controlled trials for Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy (CIDP). Beneficial effects of IVIg have also been proven for multifocal motor neuropathy (MMN). Likewise, PE is an established treatment for GBS and CIDP, whereas it is considered to be ineffective in MMN. Different mechanisms of action are sought to be responsible for the immunemodulatory effect of PE and IVIg in autoimmune disorders. Some of those might be important for immune-mediated neuropathies, while others are probably negligible. The aim of this review is to summarize the recent advances in elucidating disease-specific mechanisms of actions of PE and IVIg in the treatment of immune-mediated neuropathies.

Circulating subsets and CD4(+)CD25(+) regulatory T cell function in chronic inflammatory demyelinating polyradiculoneuropathy

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an inflammatory disease of the peripheral nervous system that is probably autoimmune in origin. Different components of the adaptive and innate immunity may be responsible for the aberrant response towards nerve antigens. To investigate this, we examined lymphocyte subsets and regulatory T cell (Treg) function in the blood of CIDP patients, healthy controls (HC) and subjects with non-immune mediated neuropathies (other neuropathies, ON). We used flow cytometry to determine the frequency of monocytes, B cells, natural killer (NK) and NK-T cells, total and activated CD4(+) and CD8(+) T cells, effector memory and central memory CD4(+) and CD8(+) T cells, and CD4(+)CD25(high)Foxp3(+) Tregs. Treg function was studied after polyclonal stimulation and antigen specific stimulation with myelin protein peptides in CIDP and HC. There was an increased frequency of monocytes (p = 0.02) and decreased frequency of NK cells (p = 0.02) in CIDP compared with HC but not ON. There were no significant differences in other populations. Treg function was impaired in CIDP compared to HC (p = 0.02), whilst T cell proliferation to myelin protein peptides before and after depletion of Tregs was not different between patients and controls. This study shows increased circulating monocytes and reduced NK cells in CIDP. Although Treg frequency was not altered, we confirm that Tregs display a defect of suppressive function. Myelin protein peptides were not the target of the altered peripheral regulation of the immune response. The mechanisms of peripheral immune tolerance in CIDP and their relevance to the pathogenesis deserve further exploration.

Reduced circulating CD4+CD25+ cell populations in Guillain–Barré syndrome

Guillain-Barré syndrome (GBS) is a monophasic inflammatory disease considered to be due to autoimmunity. In order to test the hypothesis that the disease is associated with a perturbation of the circulating lymphoid cell population, we tested the mononuclear cells from the venous blood of 21 patients with Guillain-Barré syndrome (GBS) and 20 healthy controls by flow cytometry. The proportions and numbers of B and T lymphocytes, and CD4, CD8, double negative and gammadelta T cell subsets and numbers of monocytes were not significantly different in the patients compared with the controls. However, the number and proportion of CD4+CD25+ cells were reduced in acute GBS (mean number 61.7 cells/microl, 95% CI 42.9-80.4 and mean percentage 4.6%, 95% CI 3.8-5.4) compared with controls (mean number 99.8 cells/microl, 95% CI 74.7-124.9, p=0.02, and mean percentage 6.0%, 95% CI 4.9-7.1%, p=0.037). In addition, in GBS patients, the number and proportion of CD4+ T cells expressing CD25+ and HLA-DP, DQ, DR (mean number 11.9 cells/microl, 95% CI 7.6-16.1 and mean percentage 0.8%, 95% CI 0.5-1.1%) was lower than in healthy controls (23.5 cells/microl, 95% CI 16.4-30.6, p=0.01, and mean percentage 1.4%, 95% CI 1.1-1.8%, p=0.005. Since CD4+CD25+ cells include cells with special immunoregulatory functions, further investigation of this phenomenon and its relation to possible loss of regulatory T cell function in GBS is warranted.