Use Of Cyclophosphamide Research Articles

Refurbishment of NK cell effector functions through their receptors by depleting the activity of nTreg cells in Dalton's Lymphoma-induced tumor microenvironment: an in vitro and in vivo study.

Natural killer (NK) cells play a crucial role in the anti-tumor transaction through cytolytic activity with the help of proportionate expression of their activating receptors (ARs) and inhibitory receptors (IRs). The proliferation, differentiation, and effector's functions of NK cells were affected and regulated by CD4+CD25+ regulatory T (Treg) cells through the NKG2D receptor expressed on NK cells. It has not yet been established whether Treg cells also affects the expression and functions of other receptors of NK cell. Moreover, the effect of cyclophosphamide (CYP) treatment on the expression and functions of AR and IR receptors of NK cells regulated by Treg cells during cancer progression is not clearly understood. Therefore, we have used the metronomic dose of CYP and anti-CD25 and anti-TGF-β to inhibit the effects of Treg cells in DL-induced tumor microenvironment and analyze the expression of ARs and IRs on NK cells and the FoxP3 level on Treg cells. It was observed that treatment of CYP and blocking antibodies not only affects the functions of tumor-associated NK cells (TANK cells) by modulating the expression of ARs and IRs in DL-induced tumor microenvironment, but also downregulates the functions of Treg cells. The findings of our study supported and suggested that the use of CYP in combination with other therapeutic approaches will effectively reduce tumor growth directly and/or indirectly by modulating the NK cell-mediated immune response of the host.

Uroprotective mechanisms of natural products against cyclophosphamide-induced urinary bladder toxicity: A comprehensive review.

One of the widely used anticancer drugs for the treatment of various neoplasms is cyclophosphamide (CYP). The inactive prodrug CYP is metabolized by cytochrome P450 enzyme into active metabolites, phosphoramide mustard and acrolein. The accumulation of acrolein metabolite inside the urothelium results in hemorrhagic cystitis (HC) which is a urotoxic adverse effect associated with the use of CYP. To counteract the occurrence of HC induced by CYP, Mesna is usually used, with allergic reactions reported in some cases. Therefore, several natural products have drawn much attention as alternative safe therapies to reduce the urotoxicity produced from the use of CYP. This review will focus on certain uroprotective mechanisms related to some medicinal plants that are used to ameliorate the CYP-induced urotoxicity in experimental models. The mechanisms involving oxidative stress, inflammation, immune system, apoptosis, DNA fragmentation, uroplakins, purinergic signaling and muscarinic receptors, and CytoP450 metabolism are discussed.

Mechanisms of Graft-versus-Host Disease Prevention by Post-transplantation Cyclophosphamide: An Evolving Understanding.

Post-transplantation cyclophosphamide (PTCy) has been highly successful at preventing severe acute and chronic graft-versus-host disease (GVHD) after allogeneic hematopoietic cell transplantation (HCT). The clinical application of this approach was based on extensive studies in major histocompatibility complex (MHC)-matched murine skin allografting models, in which cyclophosphamide was believed to act via three main mechanisms: (1) selective elimination of alloreactive T cells; (2) intrathymic clonal deletion of alloreactive T-cell precursors; and (3) induction of suppressor T cells. In these models, cyclophosphamide was only effective in very specific contexts, requiring particular cell dose, cell source, PTCy dose, and recipient age. Achievement of transient mixed chimerism also was required. Furthermore, these studies showed differences in the impact of cyclophosphamide on transplanted cells (tumor) versus tissue (skin grafts), including the ability of cyclophosphamide to prevent rejection of the former but not the latter after MHC-mismatched transplants. Yet, clinically PTCy has demonstrated efficacy in MHC-matched or partially-MHC-mismatched HCT across a wide array of patients and HCT platforms. Importantly, clinically significant acute GVHD occurs frequently after PTCy, inconsistent with alloreactive T-cell elimination, whereas PTCy is most active against severe acute GVHD and chronic GVHD. These differences between murine skin allografting and clinical HCT suggest that the above-mentioned mechanisms may not be responsible for GVHD prevention by PTCy. Indeed, recent work by our group in murine HCT has shown that PTCy does not eliminate alloreactive T cells nor is the thymus necessary for PTCy's efficacy. Instead, other mechanisms appear to be playing important roles, including: (1) reduction of alloreactive CD4+ effector T-cell proliferation; (2) induced functional impairment of surviving alloreactive CD4+ and CD8+ effector T cells; and (3) preferential recovery of CD4+ regulatory T cells. Herein, we review the history of cyclophosphamide's use in preventing murine skin allograft rejection and our evolving new understanding of the mechanisms underlying its efficacy in preventing GVHD after HCT. Efforts are ongoing to more fully refine and elaborate this proposed new working model. The completion of this effort will provide critical insight relevant for the rational design of novel approaches to improve outcomes for PTCy-treated patients and for the induction of tolerance in other clinical contexts.

Long-term Outcomes of Rituximab Therapy in Ocular Granulomatosis with Polyangiitis: Impact on Localized and Nonlocalized Disease

To evaluate the long-term outcomes of rituximab (RTX) treatment in patients with ocular granulomatosis with polyangiitis (GPA) with localized or generalized disease. Retrospective cohort. Thirty-seven patients with ocular GPA receiving RTX in a multidisciplinary vasculitis clinic between 2004 and 2013. A total of 100 patients who received a course of RTX were identified, and notes were reviewed. Baseline demographic details, clinical characteristics (including organ involvement), drugs used, and outcome measures were recorded. The percentage in remission (inactive disease with prednisolone ≤7.5 mg with or without maintenance treatment) at 6 months, time to remission, percentage relapsing, side effects, B-cell count, antineutrophil cytoplasm antibody titers, induction, and maintenance regimens. The median follow-up time after the first RTX course was 36.5 months. Twenty patients had scleritis, and 17 patients had orbital disease; 86% achieved remission at 6 months. The percentage in remission versus partial remission was not statistically significant between patients with scleritis and patients with orbital disease (85% vs. 15% with scleritis and 82% vs. 18% with orbital disease; P = 1.00). The percentage relapsing was not statistically significant (P = 0.33) between scleritis (60%) and orbital disease (41%). Localized disease (ocular ± ear-nose-throat/lung) was observed in 57%, and generalized disease (ocular plus other organs) was observed in 43%, the former having a median duration of disease of 40 months. There was no statistically significant difference (P = 0.37) in the percentage in remission between localized and generalized ocular disease. Relapses occurred in 51%, with localized disease being a significant risk factor for relapse. Fifty percent of patients with generalized disease versus none with localized disease received cyclophosphamide (CYP) as part of the induction regimen. Patients who received CYP during induction had significantly (P = 0.027) lower ratios of baseline 12-month proteinase 3 titers than patients who did not have CYP. Infections were observed in 16% of patients, with 8% requiring hospital admission. Our long-term data suggest that RTX is effective for inducing disease remission in localized and generalized ocular GPA. Localized disease is a significant risk factor for relapse, which may be related to less use of CYP in the induction regimen.

What does the future hold for clinical studies in vasculitis?

The era prior to 1990 was a time of careful observation of disease presentation, course, outcomes and meticulous pathology studies. These mainly single-centre studies introduced new life-saving therapies for drugs still used effectively today. In the 1970-1980s, cyclophosphamide (CyP) added to glucocorticosteroids (GCS) was shown to be life-saving. The trade-off was often severe adverse events. Some forms of vasculitis were found not as ominous as thought initially. Some could be treated with safer drugs [e.g. methotrexate (MTX)]. However, whether mild or severe, patients were not cured. From 1990 to the present large collaborative networks have provided studies were not possible heretofore. Randomized controlled trials captured and manipulated vast amounts of data, banked biological specimens and shared these resources and intellectual capital, moving the field forward at an extraordinary pace. We now know that even for severe forms of granulomatosis and polyangiitis [granulomatosis with polyangiitis (GPA), Wegener's granulomatosus (WG)], microscopic polyangiitis (MPA) and Churg-Strauss syndrome (CSS), we do not need to use CyP for extended periods. We have learned recently that rituximab is as effective as CyP for severe WG and MPA. We should never again see the permanent toxicities born from years of chronic CyP use. However, short courses of CyP remain useful and can be life-saving. Step-down therapy from CyP is now a standard of care, perhaps to be replaced by rituximab in the future. If one accepts the premise that there are few cures at present for idiopathic large- and small-vessel vasculitis, we will serve our patients well if we can determine the most effective initial therapy that leads to a maintenance strategy for remission with least risk. Ultimately, we wish to identify causes of vasculitis so they can be used as a wedge to secure cures. Unmet needs and strategies are as follows: (1) to increase the numbers of vasculitis-trained physicians; (2) to define risk-benefit formulae for chronic maintenance therapy versus discontinuation of treatment after remission; (3) to define risk- and cost-benefit formulae for laboratory monitoring; (4) large-scale studies with longer follow-up that explore inhibition of interleukin-5 in CSS; (5) to explore the value of anti-interferon-γ for GCA, Takayasu's and other granulomatous vasculitides; and (6) identification of aetiological factors: cures will probably be linked to knowledge of the antigen driving the disease, plus vulnerabilities of the patient that prepare them to develop an illness phenotype. Improved outcomes using anti-inflammatory/immunosuppressive agents do not rule out infection as a driver for autoimmunity. Techniques that can facilitate pathogen discovery have never been more sophisticated.

Histopathological findings in the gastrointestinal tract of primate recipients of porcine renal xenografts following different immunosuppressive regimens

Cyclophosphamide (CYP) and methotrexate (MTX) have been used as immunosuppressants in induction or maintenance protocols in a large variety of xenotransplantation models. Combining the use of transgenic porcine organs expressing human decay-accelerating factor (hDAF) with immunosuppressive therapy that included the use of CYP or MTX, survival of primate recipients of life-supporting renal xenografts has been prolonged. However, both drugs can cause significant systemic toxicity and, in particular, gastrointestinal (GI) toxicity. To date only limited data have been reported on the histopathological features deriving from the use of such agents in non-human primates. Cyclophosphamide or MTX was used as part of the immunosuppressive regimen in 15 bilaterally nephrectomized non-human primate (Macaca fascicularis) recipients of a life-supporting hDAF porcine kidney. At post-mortem, a detailed analysis of the GI tract in animals receiving either CYP or MTX was performed. Paraffin-embedded sections of each portion of the GI tract were prepared and stained with hematoxylin and eosin (H&E). In some animals, additional investigations by immunohistochemistry (CD3, CD5, CD20, CD79 alpha cy, lambda, and kappa light chains) and by in situ hybridization for EBV encoded RNA (EBER) were undertaken. The xenografted animals from the CYP group had a mean survival of 31 days (range: 0 to 90 days); animals from the MTX group survived a median of 14 days (range: 0 to 39 days). GI complications were the most frequent cause of euthanasia after renal failure. In CYP-treated animals GI-tract lesions were primarily characterized by diffuse, severe lymphoplasmocytic mucosal inflammatory infiltrate. Variable degrees of villi atrophy and fusion, gut-associated lymphoid tissue (GALT) and goblet cell hyperplasia were also observed. In MTX-treated primates, findings were consistent with severe villi atrophy associated with mild-to-moderate disseminated lymphoplasmocytic infiltration. In conclusion, GI tract lesions are an early and consistent finding when CYP or MTX are used as induction agents in this model. The two compounds induce different types of GI tract damage, however, in agreement with their different mechanisms of action. Whilst CYP primarily determines inflammatory lesions, MTX leads to a degenerative type of damage. This study indicates that immunosuppressive drugs can cause severe GI tract damage in primate recipients of renal xenografts and may be responsible for life-threatening lesions.

A short course of high-dose cyclophosphamide induces long-term survival of intestinal allografts in mice.

Several transplant programs have recently added cyclophosphamide (CyP) to their immune suppression protocols in an attempt to reduce intestinal graft rejection rates. The present study was undertaken to confirm the benefits of this drug in a murine small bowel transplant model. A short course of monotherapy with CyP 20 mg/kg per dose resulted in a mean survival time (MST) of 17.5 +/- 3.6 days, compared with a MST of 7.5 +/- 0.7 days in the untreated controls (P < 0.01). Cyclosporin A (CsA) 30 mg/kg per day produced comparable survival rates when used as monotherapy (MST: 14.2 +/- 1.3 days) or in combination with CyP 20 mg/kg per dose (MST: 21.3 +/- 5.1 days). Treatment with high dose CyP (40 mg/kg per dose) completely prevented graft loss in 8 of 10 animals (MST: 72.5 +/- 5.3 days, P < 0.01). However, adding CsA abrogated the induction of long-term survival achieved by CyP alone (MST: 23 +/- 0.4 days). These data have important implications for the use of CyP in clinical transplantation.