Steroid withdrawal protocols in Renal Transplantation

Corticosteroid use as a component of immunosuppression protocol is widespread, even though their mechanisms of action are imprecise. The burden of metabolic side effects of steroids and the impact on quality of life in kidney allograft recipients has led to attempts in minimizing steroid exposure. The concept of steroid withdrawal in patients requiring immunosuppression remains ill-defi ned without formally tested strategies balancing adverse events against good kidney allograft and patient outcomes. This review is aimed at assessing steroid withdrawal at 3 transplant centre strategies in the UK, Australia and Saudi Arabia in the light of current literature. Antibody mediated rejection, donor specifi c antibodies or surveillance biopsies are areas of unmet needs today that require urgent attention in this era of aggressive anti-lymphocyte or anticytokine induction. Use of newer induction agents such as Campath® and Simulect® are used effectively to achieve corticosteroid minimization. Since the evidence of long term patient or graft outcome reports of these corticosteroid minimization strategies is unclear, it is worth revisiting corticosteroid minimization strategies to establish evidence based practice. Review Article Steroid withdrawal protocols in Renal Transplantation Anindya Banerjee1,2, Bridson M Julie2, Ajay Sharma2,3 and Ahmed Halawa2,4* 1Wirral University NHS Trust and the Countess of Chester Hospital, UK 2Faculty of Health and Science, Institute of Learning and Teaching, University of Liverpool, UK 3Royal Liverpool University Hospital, Liverpool, UK 4Sheffi eld Teaching Hospitals, Sheffi eld, UK Received: 12 December, 2017 Accepted: 20 April, 2018 Published: 24 April, 2018 *Corresponding author: Ahmed Halawa, Consultant, Transplant Surgeon, Sheffi eld Teaching Hospitals, Senior Lecturer (Hon), University of Liverpool University of Sheffi eld, United Kingdom, Tel: 00447787542128; Fax: 00441142714606 E-mail:


Introduction
Organ transplantation requires immunosuppression (IS) to prevent rejection, induce immunologic acceptance and reduce immune mediated damage to transplanted organs (allograft). Treatment of rejection episodes is subdivided into cellular rejection when IVMP is used for 3 days followed by oral prednisolone. For acute vascular rejection, the step wise approach includes: IVMP, anti-thymocyte globulin (ATG), plasmapheresis and oral prednisolone.
Another centre in Australia in New South Wales [2] (NSW) however, minimizes exposure to corticosteroids by reducing the dose of prednisone to 5 mg within a few months following the transplant operation. Risk stratifi cation is followed similarly with low risk categorised as fi rst transplant with favourable recipient-donor matching; in such patients maintenance with TAC/MMF is preferred with tacrolimus levels aimed at 10-15 in fi rst 4 weeks. All patients undergoing transplants have antibody to interleukin 2 (IL-2) at induction along with IVMP.
A patient is high risk if 1st graft is lost early, in presence of high panel reactive antibody >50% (peak/current) or with B-cell +ve cross match. Although in 2009 the aim was to reduce steroid dose to 10mg by 3 months post-transplant, currently steroid Both also seem to be using IL-2 blocker antibody induction for low risk patients, whilst the RLBUHT is using Campath (antilymphocyte antibody) for anything other than low risk.
For the rationale for each of these approaches, around steroid avoidance or minimization, to be understood, the history of IS, the 3-signal model, actions of corticosteroids and their side effects or cost-benefi ts will need to be understood.

Evolution of IS
Over the decades, pharmacologic therapy originally using corticosteroids, 6-mercaptopurine and total body irradiation in the 1950s changed to azathioprine and corticosteroids in the 1960s leading to the fi rst successful outcomes in unrelated kidney transplantation. In the 80s Cyclosporine reduced rejection rates greatly while OKT3 was able to reverse steroid resistant rejection. In the 90s Tac replaced cyclosporine in most transplant centres. MMF replaced azathioprine. Sirolimus was introduced as an alternative to azathioprine or MMF. In the 2000s belatacept was approved as a co-stimulation blocker [3][4][5][6]. The rationale for using different types of IS comes from the 3 signal model in fi gure 2 [8] that is widely recognized as the steps in rejection in allo-immune responses.
As corticosteroids act in multiple areas rather than being a more specifi c IS agent, there has been debate around the risks versus benefi ts of steroids.   An antigen on the surface of dendritic cells that triggers T cells with cognate T-cell receptors constitutes signal 1, which is transduced through the CD3 complex. Dendritic cells provide co-stimulation (signal 2), which is delivered when CD80 and CD86 on the surface of dendritic cells engage CD28 on T cells. Signals 1 and 2 activate 3 signal-transduction pathways: (1) the calcium-calcineurin pathway, (2) the RAS-mitogen-activated protein kinase pathway, and (3) the nuclear factor-kappaB pathway. These pathways activate transcription factors that trigger the expression of many new molecules, including interleukin-2, CD154, and CD25. Interleukin-2 and other cytokines activate the target of rapamycin pathway to provide signal 3, the trigger for cell proliferation. CDK = cyclin-dependent kinase; IKK = I[kappa] B kinase; mAb = monoclonal antibody; MAP = mitogen-activated protein; MHC = major histocompatibility complex; MPA = mycophenolic acid; mRNA = messenger RNA; mTOR = mammalian target of rapamycin.Antigenexperienced T cells home to and infi ltrate the graft and engage the parenchyma to create typical rejection lesions such as tubulitis and, in more advanced rejection, endothelial arteritis. If the rejection does not destroy the graft, adaptation occurs and is stabilized by IS drugs [7]. DOI: http://dx.doi.org/10.17352/acn.000029 of using corticosteroids therefore mean inhibition of cytokine production like interleukins 1, 2, 3, 4, 6, tumor necrosis factoralpha and gamma-interferon. It also decreases activation and proliferation of lymphocytes and macrophages, prevents macrophage antigen presentation and phagocytic activity, inhibits dendritic cells, suppresses infl ammatory leukotrienes and prostaglandins and alters cell traffi cking by decreasing ability of leukocytes to adhere to vascular endothelium.

Side effects of steroids [9]
Side effects specifi c to corticosteroids are related to multiple effects of these drugs. Hypertension is related to fl uid retention in 15% of cases, diabetogenesis is related to increased insulin resistance or altered carbohydrate metabolism in 10% of cases, dyslipidaemia is related to very low density lipoprotein synthesis or down regulation of low density lipoprotein receptors, cataracts and glaucoma occur in 22% from water accumulation or free radical damage whilst osteoporosis occurs from increased bone resorption or reduced bone formation in 2% annually. Growth retardation in children and cardiovascular morbidity are also common side effects.

Cost benefi t of steroids [10]
Corticosteroids although inexpensive are associated with debilitating side effects. Treatment of these steroid-related side effects adds to the cost of transplants such as cataracts and avascular necrosis of the hip requiring hip surgeries. Steroid side effects are projected to cost over 10 years for a 50-patient cohort about $265,900 or $5300/transplant patient.
Hypertension and post-transplant diabetes (PTDM) trigger the highest costs. Steroid side effects also increase noncompliance leading to increased incidence of AR episodes, chronic rejection or graft loss.
There is, therefore, a hidden cost of steroid-related side effects with patients stating the IS drug they would most like not to take is prednisone. Table 1 outlines steroid minimizing strategies [11]:

Steroid minimisation strategies
The different strategies utilised to minimise steroid exposure is usually devised locally by each transplant centre.
As a general rule there are 3 strategies available: 1. Lower doses administered earlier after transplantation 2. Complete withdrawal, which can either be performed a) early after transplantation (approximately three to six months post-surgery) or b) at a later time (after one year)

Very low dose maintenance therapy
Tapering glucocorticoids to 0.05 to 0.1 mg/kg per day of prednisone or less by one year or sooner is in widespread use. In the absence of AR, for example, the East Coast NSW Transplant Service generally reduce glucocorticoids to a maintenance dose of 5 mg per day by 6 months following kidney transplantation.
Decreased rejection and avoidance of chronic allograft nephropathy (CAN) can be a benefi cial result, compared with early steroid withdrawal/avoidance.
The one prospective, well-designed study that compared very early steroid cessation to low-dose, long-term steroid therapy in kidney recipients receiving modern maintenance immunosuppression was in 386 patients [12]. Following rabbit ATG in (68 percent) or IL-2 receptor antibody (32 percent) as induction and maintenance with TAC, MMF and 7-days of corticosteroids, these patients were blindly randomized to either steroid withdrawal or steroid continuation at 5 mg daily by six months after transplant.
At fi ve years, there was no signifi cant difference in the primary composite endpoint (death, allograft loss, or moderate/ severe rejection) or in any of the individual components.
The very early withdrawal group was associated with signifi cant increases in the incidence of CAN (10% vs 4%) as well as biopsy-proven AR (18% vs 11%). Given that the rate of moderate/severe rejection was similar in the two groups, these fi ndings suggest that very early withdrawal increased the risk of mild rejection. Any rejection can then potentially prime the kidney for future damage.
In terms of corticosteroid-associated side effects, there were no signifi cant differences in blood pressure, new-onset diabetes after transplant (NODAT), serum cholesterol, or lowdensity lipoprotein (LDL) levels, and rates of bone fracture or cataracts.
Whilst the authors concluded very early withdrawal is safe and provides similar fi ve-year renal allograft outcomes, this strategy resulted in double the rate of CAN compared with continuance of corticosteroid therapy. Continued maintenance therapy is probably then preferable to very early withdrawal.
The ECRS protocol follows this principle. In the current era of further information around mechanisms of CAN, the strategy of using 5mg of steroids long term would seem sensible. As any strategy requires a risk benefi t assessment, toxicities around 5mg of steroids long-term needs an analysis. There is some literature evidence that toxicity associated with chronic low-dose corticosteroids is probably overestimated.
Bone resorption resulting in bone loss is seen only with doses achieving circulation levels above physiological range13.
Prednisone 5 mg can achieve blood levels of cortisol that are in the range of physiological levels whilst >5 mg prednisone can cause circulating cortisol levels higher than physiological levels resulting in side effects [13]. Low glucocorticoid concentrations appear to stimulate osteoblast differentiation as against the inhibitory effect associated with bone loss seen with high concentrations.
Additionally, low-dose corticosteroids had no signifi cant effect on hypertension and infection while low-dose steroid maintenance therapy of ≤2.5 mg/day resulted in stable blood pressure, lipid levels and basal metabolic panel over 3 years [14].
The risk of AR is markedly increased with the withdrawal of corticosteroids within weeks to months after transplantation

Withdrawal within several weeks to months after transplantation
There is a signifi cantly increased risk of AR and possible decreased long-term allograft survival if withdrawal is performed less than three to six months after surgery [16,17].
This adverse effect of early withdrawal upon allograft survival emerges only after extended follow-up [16].
Although less than 2 year graft survival is not compromised, a multicenter Canadian trial [18] evaluating 523 stable transplant recipients randomly assigned at day 90 following renal transplant to placebo or alternate-day prednisone found adverse outcomes at 5 years with 73 and 85 percent allograft survival respectively, without any effect on patient survival. In another uncontrolled trial in 30 African-Americans, excellent short-term results from steroid withdrawal within 3 months of transplantation failed to translate to better long-term allograft survival 4 years later [19].
A meta-analysis of seven randomized, prospective trials of complete avoidance of steroids or withdrawal of steroids within a 6-month period after transplantation showed an increased risk of AR. At 2 years' follow-up, steroid withdrawal had not affected patient or graft survival, despite demonstrated increase in AR [20].Only using anti-lymphocyte induction agents or in low immunological risk patients was complete steroid withdrawal successful and was dependent upon the choice of maintenance IS [21,22].

Withdrawal years after transplantation
Confl icting results would suggest the need for caution in such a withdrawal regimen. If patients are carefully chosen for steroid withdrawal for example low-risk profi le or defi nite benefi t identifi able on withdrawal, this would identify only 1% or less of patients who are on a small dose of steroids at 12 months, in whom the risk would be small but clear [11].
A meta-analysis of 20 glucocorticoid withdrawal studies from 2000 showed a higher relative risk of graft failure of 1.34 and an increased risk of AR (14%) [23]. these were worse results when compared to cyclosporine withdrawal.
A large, prospective, nonrandomized European study on 1110 cadaveric kidney recipients who underwent slow glucocorticoid withdrawal after at least six months post-transplantation over 7 years reported glucocorticoid withdrawal being benefi cial for graft survival (92% vs 75%), patient survival (89% vs 84%), The modifi cation of diet in renal disease glomerular fi ltration rate (MDRD GFR) was stable through 7 years, over 80% of recipients remained prednisone-free long-term.
Recipients had signifi cantly lower rates of cataracts (P <

Glucocorticoid-free regimens or very early withdrawal < 7 days
Glucocorticoid avoidance protocols tend to choose low-risk individuals and utilize aggressive induction therapy [11].
In the 1980s a multi-centre European study of 232 cadaveric renal transplants demonstrated a one-year allograft survival rate of 77 percent with cyclosporine only, as compared with 63 percent in the azathioprine and prednisone control group [25]. Since the 1990s a transplant group in Denmark has also successfully adopted a glucocorticoid-free IS strategy (including its avoidance in treating rejection) in combination with induction therapy utilizing rabbit ATG [26,27]. In a report summarizing their more recent experience, maintenance IS consisted of cyclosporine and MMF in 100 consecutive patients [27]. Acute rejections (AR), which were treated with anti- Data from low risk living donor patients that are not ethnically diverse or are predominantly non-sensitised cannot be extrapolated without inherent risks to other cohorts [31].
For example in the deceased donor subgroup in the data from this group (a higher risk group), the 1 year AR was 16% versus 11% in living donors.
IS agents like sirolimus, TAC, IL-2 inhibitors and Campath/ ATG may impact on steroid free IS [11]. Signifi cantly lower incidence of PTDM is observed in steroid withdrawal groups (4% vs 21%) whilst at 3 years -AR, patient and allograft survival and CAN/subclinical rejection or kidney function were similar whether steroids were withdrawn on day 2 or continued -with IS using basiliximab for induction and calcineurin inhibitor plus MMF or sirolimus for maintenance therapy [32].
Similarly reports of AR free graft survival at one and three years of 94 and 92% respectively, and patients and allograft survival at three years of 95 and 93% respectively have been reported in 349 patients administered a glucocorticoid-free regimen consisting of ATG, either MMF or sirolimus, and a calcineurin inhibitor [33].
Unfortunately, long-term experience beyond 5 years with glucocorticoid-free IS is limited [12]. In a prospective, welldesigned study comparing very early steroid cessation to low-dose, long-term steroid therapy in kidney recipients receiving modern maintenance immunosuppression already mentioned earlier, 386 patients were randomly assigned to corticosteroid withdrawal at one week post-transplant or continuance of corticosteroids. Induction therapy with either rabbit ATG (68%) or IL-2 receptor antibody (32%) was given.
Maintenance therapy consisted of Tac, MMF, and seven days of corticosteroids followed by blinded randomization to either withdrawal or continuation tapered to 5mg by 6 months after transplant.
Although the authors concluded that very early withdrawal is safe and provides similar fi ve-year renal allograft outcomes, yet this strategy resulted in double the rate of CAN, compared with continuance of corticosteroid therapy (10% vs 4%) or biopsy-proven AR (18% vs 11%). Given that the rate of moderate/severe rejection was similar in the two groups, these fi ndings suggest that very early withdrawal increased the risk of mild rejection [11]. also the follow-up was for 5 years only.

Maintenance in recipients following AR with rapidly decreased prednisolone within < 7 days
In 26 months of follow-up following AR treatment with a steroid taper (with or without antibody) or maintenance prednisone (5 mg/d) or a steroid-free protocol, there was no signifi cant difference between groups in graft survival or renal function. However the risk for a 2nd AR was related to whether or not steroids had been added to the maintenance protocol.
Those most unlikely to have a 2 nd AR -ie those recipients with very minimal-to-mild AR -the rate signifi cantly increased if the recipient had returned to steroid-free immunosuppression [37].

Experience elsewhere
In this setting, it may be useful to highlight a protocol [38] followed in the Middle East which would appear to be drawn on a combination of some of the data above.
Steroids are reduced to 5 mg in 8 weeks post-transplant following categorisation of patients on their risk assessment.
The general policy is to try and avoid steroid withdrawal all together except in very low immunological risk profi le.
This included 0/8 mismatch including DQ in human leucocyte antigen (HLA) mismatch. DR matching is not included in HLA matching as of yet.
The patients are categorised into 3 risk profi les. Intermediate and high risk patients receive ATG as induction therapy, the rest basiliximab. All patients receive 250 mg IVMP as induction with 80 mg orally from day 1 which is cut down gradually to 20 mg in one week, which is further reduced to 5 mg in 8 weeks' time.
Patients with identical sibling or with 0 mismatch have their steroids withdrawn afterwards.
Maintenance therapy includes prednisolone/Tac/MMF. This policy is based on awareness around de novo donor specifi c antibodies and risk of CAN -which is why steroid withdrawal or calcineurin minimisation is avoided. At King Faisal more than half of death censored graft loss is immunological in contrast to interstitial fi brosis and tubular atrophy -also known as CAN -previously believed to be related to calcineurin IS related.

Current unmet needs in corticosteroid withdrawal in kidney transplants
An AR episode is a major risk factor for long-term graft loss [27] if the severity of the rejection episode is enough to impair the recovery of the renal function to baseline levels [39]. AR is especially common within the fi rst 3-6 months after transplantation with risk factors such as race like African American predisposing to more AR episodes and a lower graft survival following an early AR episode [40].
Antibody mediated rejections and policies around withdrawal or recommencing steroids in such patients also remain largely unanswered. The possibility of de novo donor specifi c antibodies is a realistic concern when considering a steroid-free regimen [9].
The role of surveillance biopsies at predetermined time points independent of renal function or clinical status to assess graft injury [41] from subclinical antibody mediated rejection in sensitized high-risk patients [42] or subclinical BK virus nephropathy from over IS [43] or early CAN [44] is an area that may need consensus. Routine protocol biopsies may make individualization of steroid-free IS or withdrawal possible, especially in high-risk patients [44].
Trial outcomes from low-risk transplant populations cannot be generalized [45] as high-risk patients are different immunologically. The patients who initiate steroid use later, following early withdrawal, have graft survival rates that are worse than either those who maintain steroid use or those who continue on steroid avoidance after transplant [46]. It is probably also inaccurate to conclude that complete steroid avoidance is safer than steroid withdrawal as this seems to be only based on less frequent NODAT [47]. Rapid withdrawal of steroids seems in most studies un-associated with an increased rate of AR whilst steroid withdrawal at 3 months post-transplantation-using the same maintenance IS-is. It is possible that steroids lower cytokine production but upregulate cytokine receptor expression [9] -and when steroids are slowly withdrawn, cytokine release returns to normal in an environment of upregulated receptors.
Also steroids decrease the bioavailability of MMF by increasing hepatic UDP-glucuronyl transferase activity. Steroid tapering or withdrawal raises the MMF area-under-the-curve [9]; with more MMF exposure, less AR is possible. Similarly it is possible Tac exposure also increases after steroid withdrawal [9].
It is also important to balance steroid-free and calcineurin inhibitor-free approaches [9]. Steroid-free IS has the obvious advantages of eliminating steroid side effects. Better longterm kidney allograft function when calcineurin inhibitors are minimized or eliminated is also reported. Protocols that are both steroid and calcineurin inhibitor free have high risk but in this era of newer IS drugs hopefully long-term effective immunosuppression without side effects from such medications will one day be possible.

Conclusion
The potential benefi t of eliminating steroid-related side effects for transplant recipients is obvious. Yet concerns remain that steroid-free maintenance immunosuppression protocols may have some long-term detrimental effects. The ideal study would compare rapid steroid withdrawal to 5 mg/d with rapid tapering along with late withdrawal. As early transplant outcomes are good, the number of patients required to power such a study would be enormous.
Very early steroid withdrawal within a week may have a short-term effi cacy similar to that achieved with continuous steroid regimen but longer follow-up data along with donor specifi c antibody or outcomes from surveillance biopsies may be required. More studies are needed to test the actual benefi ts of early steroid withdrawal/avoidance especially in the long term and also in the high-risk patient. Surveillance biopsies may need to be incorporated routinely. Within the past decade, as a result of trials focusing on late steroid withdrawal or rapid withdrawal of prednisolone, recipients maintained on prednisone are taking far less prednisone than they would have been taking 10 years ago, and non-immunological side effects from steroid overexposure may well be of less importance today.