Isolated v-lesion in kidney transplant recipients: Characteristics, association with DSA, and histological follow-up.

Isolated v-lesion (IvL) represents a rare and challenging situation in renal allograft biopsies because it is unknown whether IvL truly represents rejection, antibody- or T cell-mediated, or not. This multicentric retrospective study describes the clinicopathological features of IvL with an emphasis on the donor-specific antibody (DSA) status, histological follow-up, and graft survival. Inclusion criteria were the presence of v-lesion with minimal interstitial (i ≤ 1) and microvascular inflammation (g + ptc≤1). C4d-positive biopsies were excluded. We retrospectively found 33 IvL biopsies in 33 patients, mainly performed in the early posttransplantation period (median time 27 days) and clinically indicated in 66.7%. A minority of recipients (5/33, 15.2%) had DSA at the time of biopsy. IvL was treated by anti-rejection therapy in 21 cases (63.6%), whereas 12 (36.4%) were untreated. Seventy percent of untreated patients and 66% of treated patients showed favorable histological evolution on subsequent biopsy. Kidney graft survival in IvL was significantly higher than in a matched cohort of antibody-mediated rejection with arteritis. In conclusion, IvL is not primarily antibody-mediated and may show a favorable evolution. The heterogeneity of IvL pathophysiology on early biopsies should prompt DSA testing as well as close clinical and histological follow-up in all patients with IvL.

Thrombotic Microangiopathy After Long-Lasting Treatment by Gemcitabine: Description, Evolution and Treatment of a Rare Case.

Thrombotic microangiopathy (TMA) is an uncommon but severe complication that may occur in cancer patients under gemcitabine chemotherapy. Gemcitabine-induced thrombotic microangiopathy (G-TMA) can clinically and biologically present as atypical hemolytic uremic syndrome, with activation of the complement pathway asking the question of the use of eculizumab. We describe here the case of a patient suffering from metastatic cholangiocarcinoma treated by gemcitabine for 4 years leading to the remission of the underlying neoplasia. Despite an impressive response to therapy, she developed thrombopenia, regenerative anemia, and acute kidney injury leading to the suspicion then diagnosis based on the renal biopsy of a very late G-TMA. Spontaneous evolution after treatment interruption was favorable without dialysis requirement. However, in this case where gemcitabine is the only chemotherapy remaining for a mortal underlying condition, we discussed the re-initiation of gemcitabine under eculizumab treatment. This atypical case of TMA illustrates the importance of recognizing, even belatedly, this rare but serious complication of chemotherapy. It asks the question of rechallenging discontinued chemotherapy notably under eculizumab cover, in this population with a high risk of cancer progression.