TRAPS

It’s been a long time since my last blog post, so I have decided to catch up by writing about two cases I saw in my transplant clinic. However, they have the same disease, a brother and sister who inherited the same autosomal dominant disease called tumor necrosis factor (TNF) receptor-1 associated periodic syndrome (TRAPS, formerly known as familial Hibernian fever). The genetic defect in TRAPS resides in the gene that encodes the 55 kDa receptor for tumor necrosis factor, TNFR1. These mutations lead to loss of normal function rather than gain of function as you may think, and thus the pathogenesis of TRAPS is an enigma. A recent PNAS publication shed some light on the pathogenesis of the disease. They showed that mutant TNFR1 accumulates intracellularly in peripheral blood mononuclear cells of TRAPS patients and in multiple cell types from two independent lines of knock-in mice harboring TRAPS-associated TNFR1 mutations. Mutant TNFR1 did not function as a surface receptor for TNF but rather enhanced activation of MAPKs and secretion of proinflammatory cytokines. These patients will present with recurrent fevers over months or years, in the absence of associated viral or bacterial infections. They also may have focal or sometimes migratory myalgias, conjunctivitis, periorbital edema, abdominal pain, monoarticular arthritis, and rash.

You might be wondering how they ended up in my transplant clinic. The answer is secondary (AA) amyloidosis primarily involving the kidney. However it only occurs in a minority of patients (approximately 15 percent in the United States).

Managing patients with TRAPS consists mainly of Etanercept, a fusion protein consisting of two copies of the 75kDa TNF receptor (TNFR2) bound to the Fc portion of human IgG. Etanercept can be highly effective in many patients with TRAPS, though not all respond and the response is sometimes partial.

Finally, the major question remains, do those patients need to be on Etanercept after transplantation, considering that they are already immunosuppressed with our maintenance regimen? Well, it’s not clear in the literature…. In our cases, the brother was maintained on Etanercept and he didn’t have any flare of the disease with stable kidney function and no recurrence of amyloidosis. The sister however, was not on Etanercept and she had recurrence of AA amyloidosis in the transplanted kidney. My approach will be to keep those patients on Etanercept and have low threshold to reduce maintenance immunosuppression.

Deciphering the pathologists secret code!

I will share with you some of the tips I learned from my pathologist friend Ibrahim Batal.

When evaluating an allograft kidney biopsy for acute changes, you should:

First, scan at low power magnification, look for arteries, check for necrosis or infiltration:

*Fibrinoid necrosis (seen as the red pink color, Figure 1, star) will automatically indicate Banff type 3 T cell mediated rejection TCMR or severe rejection. Compare the Fibrinoid necrosis of this arteriole to the normal arterial tissue seen in Figure 1 marked by the arrow. To review Banff classification review Nate's prior post.

*Infiltrates seen inside the intima of the arteries (Figure 2, star) are lymphocytes and macrophages, which indicate Banff type 2 TCMR. See how the nuclei of those infiltrates look similar to the nuclei of the infiltrates in the interstitium (Figure 2, arrow) but they look different from the tubular epithelial nuclei that are perfectly rounded (Figure 2, circle).

Second, look at the interstitial infiltrates.

*Normally, the tubules should be packed and back-to-back, if infiltrates exist (Figure 3, blue small cells in the circle), we should be looking at the severity of the tubulitis in the most affected tubule. As you all know the more actively functional proximal tubule has a large strong eosinophilic cytoplasm (Figure 3, star) that differentiate it from the less active small cytoplasm of the distal tubules (Figure 3, arrow).

To differentiate between the tubular infiltrates and the tubular epithelium itself, compare those cells to the interstitial infiltrates, they should look similar. In addition the leukocytes in the tubules appears darker, sometimes with a hallow surrounding.

Now back to the most affected tubule (Figure 4, circle).

*If the infiltrating leukocytes are more than 10 in the absence of arteriolar infiltrate or necrosis, the TCMR is considered Banff 1B.

*If the infiltrates are between 5 and 10, the TCMR is considered Banff 1A,

*If the infiltrates are 4 or less, the TCMR is considered borderline cellular rejection.

*So imagine the sampling error in this classification.

Now will shift to the acute antibody mediated rejection where the tissue injury is mainly manifested in the microcirculation mainly peritubular capillaries and or glomerular capillaries in its typical form.

*First, We look at the peritubular capilarities, you have to “imagine” a capillary (Figure 5, circled) between the different surrounding tubules (Figure 5 stars). The “imaginary capillary” is infiltrated by neutrophils (appreciate the multilobular appearance of the nuclei) and macrophages (Figure 5 arrows).

*Second, Because those pathologic manifestations are not sensitive, we always stain for C4d either by immunofluorescence or immunoperoxidase according to the institutions preference, Immunoperoxidase being less sensitive but easier to perform. C4d should be evaluated in the peritubular capillaries (Figure 6, arrow).

*In contrast to antibody-mediated rejection, when neutrophils are mainly concentrated within the tubular lumen rather than peritubular capillaries (Figure 7, star), then bacterial urinary infection should be high on our differential.

Conclusion: It is always good to have a pathologist as a friend. However, this review should be helpful in trying to interpret renal pathology.

The bad habit of ACEI!!!!

Coming to the transplant clinic from 2 years of CKD clinic, prescribing ACEI/ARBs was a habit, a good one I guess. Does this hold truth in the transplant world, well... I am not sure anymore after I read this meta analysis in Transplantation last year. The reason simply is that kidney recipients are biologically different from CKD patients. Most of our kidney transplant patients are on calcineurin inhibitors (CNI) which induce afferent arteriolar vasoconstriction. Thus, the advantage of calcium channel blockers (CCB) over ACEI in this population is that it may promote vasodilation of afferent arterioles which may counteract CNI’s effect.

In this meta analysis of 60 trials, enrolling 3802 recipients:

· 29 trials (2262 patients) compared calcium channel blockers (CCB) with placebo or no treatment

· 10 trials (445 patients) compared angiotensin-converting enzyme inhibitors (ACEi) with placebo or no treatment

· 7 studies (405 patients) compared CCB with ACEi

CCB compared with placebo or no treatment (plus additional agents in either arm as required) reduced graft loss (risk ratio [RR] 0.75, 95% confidence intervals [CI] 0.57–0.99) and improved glomerular filtration rate (GFR; mean difference [MD] 4.5 mL/min, 95% CI 2.2–6.7).

Data on ACEi versus placebo or no treatment were inconclusive for GFR (MD -8.1 mL/min, 95% CI -18.6–2.4) and inconsistent for graft loss, precluding meta-analysis.

In direct comparison with CCB, ACEi decreased GFR (MD 11.5 mL/min, 95% CI 7.2–15.8), proteinuria (MD 0.28 g/day, 95% CI 0.10–0.47), hemoglobin (MD 11.5 g/L, 95% CI 7.2–15.8), and increased hyperkalemia (RR 3.7, 95% CI 1.9–7.7). Graft loss data were inconclusive (RR 7.4, 95% CI 0.4–140).

So according to this study there is no advantage of ACEI/ARBs over CCB, with more side effects from angiotensin inhibitors. Obviously, a good randomized trial is needed to resolve this issue.

These data suggest that CCB may be preferred as first-line agents for hypertensive kidney transplant recipients and the KDIGO guidelines consider ACEI/ARB as first line therapy for HTN in renal transplant patients only if their proteinuria is > 1gm/day. A good practice would be to hold them in acute illness as those patients are very sensitive to dehydration due to afferent arterioles vasoconstriction by CNI.

Does CMV glomerulopathy exist?

I asked this question during my clinical renal fellowship at Brigham, where I had the chance to take care of a 39 yo female with a history of ESRD secondary to MPGN s/p DCD kidney transplant 8 months ago from CMV positive donor, she was CMV negative. She developed CMV disease, was treated with IV Ganciclovir with significant improvement, was switched to Valcyte 900 BID than switched to 450 BID. She was taken off her Valcyte by an outside nephrologist for decreased WBC. Her viral load increased and she was started again on Valcyte. She presented with low grade fever, neutopenia and and an elevated creatinine to 1.8 mg/dl from a baseline of 1,2 mg/dl. Her CMV viral load increased and it was obvious that we are dealing with resistant CMV disease. Interestingly, her kidney biopsy showed CMV inclusions in the epithelial and endothelial cells with no interstitial nephritis.

I reviewed the literature for CMV glomerulopathy at that point.

Dr. Rubin from MGH described the first cases in 5 our of 14 renal allograft recipients during clinically manifest viremic CMV infection, with little or no tubulointerstitial changes.
The characteristics of this glomerulopathy are:

• Endothelial cell hypertrophy or necrosis
• Narrowing or obliteration of capillary lumens
• Fibrillar deposits in glomerular capillaries
• Mild segmental hypercelbularity
• Mononuclear cell infiltration without tubular changes
• IF revealed deposition of IgG, IgM, and C3 along the glomerular basement membrane and within the mesangium
• One specimen, anti-CMV antibody staining was observed within glomerular capillaries
• No viral inclusions were found on EM.

Others reported different types of lesions like cryoglobulinemic necrotizing GN or immunotactoid glomerulopathy. The association in those cases were made based on temporal relationship between the appearance of CMV antigenemia and the lesion.

The existence of this CMV-associated glomerulopathy described by Dr. Rubin has been questioned, however, by Herrara et al. Kidney Int 1986, who studied four different groups of immunocompromised patients with CMV infection, including seven with renal allograft dysfunction. In all seven patients, biopsy specimens demonstrated glomerular pathology similar to the changes described by Dr. Rubins’s group at MGH. Nevertheless, IF failed to show anti-CMV antibody deposition. In addition, no viral particles were detected on EM.

The authors suggested that the glomerular changes represented a form of acute transplant gbomerulopathy resulting from antiendothelial antibody injury or a protracted, early, or unresolved form of acute vascular rejection. Furthermore, Harmon et al. showed that this glomerulopathy occurred in only seven of 56 renal allograft recipients with a clinical diagnosis of CMV disease. Three of the seven patients with this lesion were not even viremic. Anderson et al., using immunohistochemistry and in situ hybridization on 15 biopsy specimens from viremic renal allograft recipients with glomerulopathy, found no evidence of CMV antigens or DNA.

Our case is different because there are viral inclusions in the epithelial but also in the endothelial cells with some swelling noticed by our famous pathologist. There was no associated glomerular inflammation and C4d staining was negative. The lesion was called CMV glomerulitis but it is obviously different from the CMV glomerulopathy described by Dr. Rubin in his NEJM paper. Patient was treated with Cidofovir. Her creatinine improved to baseline and her lesions improved on a subsequent follow up kidney biopsy. Since than, many reports described the same lesions associated with CMV infection, including a report in AJKD. The CMV glomerulitis similar to our case progressed to collapsing FSGS. The lack of proteinuria before transplantation supported the contention that the collapsing glomerulopathy arose de novo rather than being recurrent.

I think we have enough evidence that CMV glomerulitis exist. The bottom line remains how to prevent the disease, prevent resistance and be aware of the deleterious effects of underdosing like in this case.

Compensation for living organ donation! status quo no more but...

I talked earlier this year about “Compensation for living donation”. The comments I got show how controversial this subject is. I was happy to see that ATC this year opened the debate on this crucial matter because keeping the status quo means more people dying on dialysis. I will try to summarize the discussion and you can refer to the ATC website for more details.

Dr. Ghahramani reported on the Iranian system. Although, it’s obviously not the ideal system, there are some lessons to learn from it:

1. The system eliminated the waiting list so more lives were saved.
   
2. He claims that potential donors were evaluated thoroughly by nephrologists and the transplant team for clearance.
3. Patients paid 3/4 of the amount of the compensation that is set by the transplant community. This amount is revised every year depending on inflation. The government paid 1/4. Charity organizations took over in cases of patients of low socioeconomic status.
4. The donor was offered free follow up medical care by the government.
   

From the data shown, LRD was minimal in this system, most likely because relatives lost the incentives to donate. DCD kidneys were also minimal because “buying a kidney” would limit the time on dialysis. A recent change to the system was made and every ESRD patient had to stay on the deceased transplant list for at least 6 months before looking for a living donor. It seems that LRD and DCD transplants increased after the implementation of this new policy probably because relatives now had an incentive to donate so they can limit the time on dialysis for their loved ones. Dr. Padilla talked about the failed system for organ compensation in the Philippines. She felt this was mainly due to the government's failure to regulate the system.

Dr. Danovitch certainly made excellent comments on how "Commercial living donation displaces non-commercial living unrelated donation and comes at the expense of living related donation". This was obvious in the Iranian and the Israeli experience, although one may think that enrollment of the ESRD patients on the deceased list before they are allowed to look for a living donor could potentially give incentives to friends and family to donate. I think the most important comment he made is about how “the rest of the world might follow suit if the U.S. allowed incentivized organ donation”. Those parts of the world may not have the regulation ability as the US government, causing what Dr. Danovitch called "blowback" in a global competition of incentives. On the other hand, Dr. Danovitch talked about the disincentives for people to donate. He showed data that more people of high socioeconomic status are donating as LURD. I can’t believe that people of low socioeconomic status have less good intentions than rich people but simply they couldn't afford to do this act of love to friends or beloved ones because of the disincentives I talked about in the previous blog.

Dr. Matas offered an interesting potential model in the US including “national criteria for selecting donors under an incentivized plan. The organ procurement organization could set up screening interviews, including medical and psychological evaluation and panel reviews involving the surgeons, other transplant physicians, transplant coordinators, social workers and patient advocates. If accepted, a computer algorithm would determine the allocation of the kidney to a center with an appropriately matched candidate at the top of a wait list”.

An interesting comment during this session came from Dr. David Sachs who saw that both Dr. Danovitch and Dr. Matas were talking about the same thing and he felt that eliminating disincentives or compensating donation could be the same thing and we should be working together to eliminate the waiting list rather that fighting.

Those disincentives could be eliminated by indirect compensation. I think it’s about time to start discussing this issue with an open mind and no prejudice, knowing that most people including myself have controversial feelings and need more enlightenment from other people.

I would appreciate your comments and voting.

Does CAPRIT trial need a TREAT!!!!!

This morning at ATC, the results of a very interesting trial were presented. I would like to share them with you so we can look at them more carefully once the paper is published. The CAPRIT trial is the first randomized trial in kidney transplant recipients to evaluate the impact of complete normalization of anemia on the progression of the allograft function. Another anemia study!!!

It is a European multicentral trial of 126 patients who received kidney transplants more than 12 months before enrollment with CrCL between 20 and 50 and Hg level less than 11.5 mg/dL. Patients were randomized to either high Hg level group A with target Hg of 13-15 or to the low Hg level group B with Hg goal of 10.5-11.5 and were treated accordingly with ESA to achieve goal. Patients’ characteristics were similar, mainly the age at inclusion, age at transplant and mean GFR (34 and 33). Number of patients on ACEI/ARBs was similar in the two groups, both at the start of the study and at 2 years (the end of the study). Patients with Rapamune were excluded and all patients were on CNI and MMF with or without prednisone. 89% of the patients in group A were treated with EPO v.s 61 % in the lower Hg group with obviously higher dose in the higher Hg group.

There was a significantly higher mean GFR in the high Hg level group compared to low Hg level group and an increase rate of graft survival at 2 years with no difference in adverse events including cardiovascular events, stroke or thrombosis events. How to look at this data few months after the TREAT trial results were reported?

Although we are looking at different population of patients in the two trials but I find it difficult to believe this data in view of all the evidence that higher Hg is harmful, and we probably should wait for larger trial before we change our practice.

Monitoring the immune function: a shot in the dark!!

Almost every transplant clinic I have, one of my patients will ask about reducing his or her immunosuppression. This happened again this week. Needless to say that this is one of the most frustrating area in transplantation where we lack reliable assays to assess immune function. It is like treating BP without having BP cuff waiting for syncope or stroke to adjust medications. We still rely on measuring IS drug levels, which impact individual’s immune systems differently, and we evaluate graft functions that are usually late markers for events. Numerous assays been suggested but none predict the immune function accurately.

I recently revisited this subject in the context of transplantation tolerance: These assays can be antigen specific, meant to evaluate donor-specific T-cell responses against recipient antigens measuring proliferation of donor T cells in mixed leukocyte reaction (MLR), measuring lysis of recipient T cells in cytotoxic T lymphocyte (CTL) assay, or measuring production of interleukins either with enzyme-linked immunosorbent (ELISA) assay or with enzyme-linked immunospot (ELISPOT) assay. Transvivo delayed-type hypersensitivity (DTH) assay uses an immune-deficient mouse as an “in vivo milieu” for the interaction between donor T-cells and the recipient antigens that are both injected in its footpads, causing swelling, relative to the level of sensitivity that can be quantified with a caliper. These assays may also be non-antigen specific by measuring regulatory cells like CD4⁺CD25^high T-cells known as Treg, plasmacytoid dendritic cells that were reported to promote a Th2-type response that is more tolerogenic.

I think that the most popular test that became FDA approved in 2008 is the ImmuKnow assay that I personally order for my patients in certain conditions. It measures the T-cell response to a non-specific polyclonal stimulus by quantifying the intracellular ATP production as a marker of the level of the cell immune function. A simple blood draw will give clinicians a level of ATP that classifies the patient into one of three categories: Low Immune cell response if the level is less than 225 ng/ml, Moderate between 226 and 524 and strong above 525. The problem is when you want to decide on an individual basis, a patient with level above 525 could still be overimmunosuppressed and acting among the numbers will be very misleading. Low numbers seem to correlate better with overimmunosuppression and in the case of low risk patients who’s level is below 100, we are more comfortable to reduce immunosuppression with close follow up. What I find useful is the variation from the individual baseline and in one study they found that variation of more than 50% correlated better with events. Although this test became very popular across the country, it is obviously not the answer we’re looking for as transplant nephrologists and extensive research is needed in this area. Cylex may be used as an additional marker along with other indicators of immune function like drug level, BK viremia, CRP, WBC.

Please share your experience with us.

Technology wins again???

The interest in machine perfusion for preservation of kidney transplants has been revived. Were we serious when we decided to put the organ in ice??? A recent NEJM prospective, controlled trial randomizing 336 consecutive deceased donors to either machine prefusion or static cold storage preservation showed the advantage of technology!!!

The incidence of delayed graft function (DGF) was less in the machine perfusion group compared to cold storage (20.8% vs 26.5% respectively, P = 0.01) but if DGF developed, it was 3 days shorter with machine perfusion (10 days vs 13 days, P = 0.04). The most interesting result of this study was that the 1-year kidney graft survival rate was significantly greater in the machine perfusion group (94% vs 90%, P = 0.04). The superiority of the machine perfusion technology was shown regardless of deceased donor category. No differences were noted in patient survival, length of hospital stay, acute rejection, or calcineurin inhibitor toxicity between the 2 groups. Seriously, Ice????

Compensation for living organ donation! A taboo no more but....

Talking to Nate always stimulated new ideas and new challenges. Last time I met him, we played soccer in the park with the kids (that was also a challenge but fun and easy to win…). We also talked about an interesting hot ethical topic (It was hard and no winners…). Compensation for living organ donors! A taboo no more but nonetheless remains an ethical dilemma that needs public debate, engaging mainly specialists who care for end-stage kidney disease patients. I thought using Nate’s blog for such a debate will please him, so here we are…

My approach will be, what are the facts?

• We have an increasing demand for kidney transplantation that our deceased donor waiting list can’t match. And living donation is not increasing especially when being an organ donor can negatively affect the likelihood of obtaining life, disability and health insurance. This concern is frequently raised by many potential donors.
• Recipients of living donor kidney transplants do better than recipients of deceased donor transplants.
• More people are dying on dialysis waiting for a transplant.
• Kidney donation is safe (Ibrahim et al. NEJM 2009)… Trust me, I finally watched a hockey game last week after I saw a Canadian flag in our Lab.
• And for the government (no offense) and the health insurance payers, Matas et al found that a LURD transplant saved $94,579 (US dollars, 2002), and 3.5 quality-adjusted life years (QALYs) were gained.

So no doubt increasing living donation through creating incentives for donors will save lives and money. Also keep in mind that we pay blood donors, plasma and sperm donors, egg donors and surrogate mothers…

What are the ethical hurdles?

If we allow direct compensation between donors and recipients, we are turning the poor of our society into providers of body parts to wealthy people.
But what if the compensation is indirect through government agencies, providing donors, for example, with lifetime health insurance or tax deduction and maybe by treating them as the nation heroes which they deserve by the way.

I’ll be happy to hear your comments.