Arising from: Bargman J (2007) Why are rheumatologists treating lupus nephritis? Nat Clin Pract Nephrol 3: 296–297 doi:10.1038/ncpneph0489

I would like to applaud Dr. Bargman for her Viewpoint on the treatment of lupus nephritis. As she notes, nephrologists should have an essential role in this setting, because “Nephrologists are aware from their management of diseases such as postinfectious glomerulonephritis that severely inflamed glomeruli or tubules can take many weeks or months to heal. It is not rare for a patient to remain on dialysis for several months before signs of renal improvement become apparent and dialysis can be withdrawn.” I would suggest that, by now, everyone should know that this phenomenon is not rare in lupus nephritis. It is almost a quarter of a century since my group demonstrated that many patients with lupus nephritis were able to successfully discontinue dialysis after many months of not receiving immunosuppressants (see Supplementary Figure 1).1 Hopefully everyone knows by now that even extrarenal lupus often becomes quiescent on dialysis (see Supplementary Figure 1), which allows withdrawal of immunosuppression, with excellent long-term survival (see Supplementary Figure 2). Yet many studies reporting poor survival rates on dialysis have continued immunosuppression in the absence of extrarenal disease activity, because the persistent renal failure was considered to be a sign of active disease.2 It is impossible to know how many patients have been lost to the complications of immunosuppression whose disease would have eventually become quiescent on dialysis.

Perhaps we feel that because modern immunosuppressive regimens have become more benign, the involvement of the nephrologist in the treatment of lupus nephritis is not as critical as it used to be. Recently, even the role of high-dose intravenous cyclophosphamide in maintenance therapy of diffuse proliferative disease has been challenged.3 Other immunosuppressants like azathioprine and mycophenolate mofetil may indeed be safer and more efficacious than cyclophosphamide.3 Yet reviews and guidelines often focus on the therapeutic end point of preventing a doubling of serum creatinine levels.4 Nephrologists understand, however, that the relationship between creatinine and glomerular filtration rate has always been a marriage of convenience.5 As Dr. Bargman notes, there are so many factors that affect serum creatinine levels other than glomerular filtration rate,6 that it is essential for people who have the experience to understand the imperfections of creatinine to be involved in the interpretation of such results. Only one of nineteen authors of the recently published European guidelines was a nephrologist, however.4 We should become more involved.