New onset of lupus nephritis in two patients with SLE shortly after initiation of treatment with belimumab

In this report, apart from our two patients, we discuss the relevant literature consisting of a handful of studies and case reports. The studies analyze patients with renal involvement treated with belimumab and are inconclusive. There are only a few case reports in which belimumab along with other agents had a potential benefit, although not straightforward. There is only one case report with striking similarities to the two patients with SLE we report herein. It could be claimed that belimumab was unable to prevent the appearance of lupus nephritis during a potentially serious disease exacerbation. Certainly, a causative association between belimumab treatment and the de novo appearance of lupus nephritis cannot be claimed because of our report. However, a potential association between belimumab treatment and the development of such a serious manifestation cannot be entirely excluded. In support of the latter hypothesis is the quick resolution/significant reduction of proteinuria shortly after belimumab discontinuation and before other treatment measures had any reasonable effect. Studies evaluating the potential usefulness of belimumab in patients with lupus nephritis are currently ongoing; until then, one should keep in mind unanswered questions as far as renal safety is concerned.