Complement Terminal Pathway Activation and Intrarenal Immune Response in C3 Glomerulopathy

BACKGROUND

C3 glomerulopathy is a rare disease resulting from an overactivation of the complement alternative pathway. Although there is also evidence of terminal pathway activation, its occurrence and consequences on the disease have been poorly studied.

METHODS

We retrospectively studied a cohort of 42 patients diagnosed with C3 glomerulopathy. We performed centralized extensive characterization of histological parameters. Kidney C5b-9 staining was performed as a marker of terminal pathway activation, intra-renal immune response was characterised through transcriptomic analysis.

RESULTS

Eighty-eight percent of biopsies showed C5b-9 deposits in glomeruli. Biopsies were grouped according to the amount of C5b-9 deposits (no or low n=15/42, 36%, intermediate n=15/42, 36%, and high n=12/42, 28%). Patients with high C5b-9 deposits significantly differed from the 2 other groups patients and were characterized by a significant higher histological chronicity score (p=0.005) and lower outcome-free survival (p=0.001). In multivariable analysis, higher glomerular C5b-9 remained associated with poor kidney prognosis after adjustment. One third of the 847 studied immune genes were upregulated in C3 glomerulopathy biopsies compared to controls. Unsupervised clustering on differentially expressed genes identified a group of kidney biopsies enriched in high glomerular C5b-9 with high immune and fibroblastic signature and showed high chronicity scores on histological examination.

CONCLUSIONS

In a cohort of patients with C3 glomerulopathy, intra-renal terminal pathway activation was associated with specific histological phenotype and disease prognosis.

MRI for characterization of benign hepatocellular tumors on hepatobiliary phase: the added value of in-phase imaging and lesion-to-liver visual signal intensity ratio

OBJECTIVES

To evaluate the lesion-to-liver visual signal intensity ratio (SIR) before and at the hepatobiliary phase MRI (HBP-MRI) after gadobenate dimeglumine (Gd-BOPTA) injection, using several T1-weighted images (T1-WI), for the characterization of benign hepatocellular lesions.

METHODS

Patients with histologically proven focal nodular hyperplasia (FNH) and hepatocellular adenoma (HCA), who underwent Gd-BOPTA-enhanced HBP-MRI from 2009 to 2017, were retrospectively identified. The lesion-to-liver SIR was visually assessed by two radiologists on HBP (post-HBP analysis) and compared with that of unenhanced sequences (pre/post-HBP analysis) on T1-WI in-phase (T1-IP), out-of-phase (T1-OP), and fat suppression (T1-FS). Lesions were classified as hyper-, iso-, or hypointense on post-HBP, and as decreasing, stable, or increasing SIR on pre/post-HBP analyses. The performance of the different T1-WI sequences for the diagnostic of FNH was evaluated on post-HBP analysis.

RESULTS

Twenty-nine FNHs and 33 HCAs were analyzed. On post-HBP analysis, FNHs appeared hyper-/isointense in 89.7% of all T1-WI. HCAs appeared hypointense in 93.9%, 63.6%, and 69.7% of T1-IP, T1-OP, and T1-FS, respectively. FNHs exhibited an increasing SIR in 55.2-58.6%, a stable SIR in 44.8-58.6%, and a decreasing SIR in 0%, whereas HCAs exhibited a decreasing SIR in 66.7-93.9%, a stable SIR in 6.1-33.3%, and an increasing SIR in 0% (p < 0.0001). The specificity of T1-IP was significantly higher than that of T1-OP (p = 0.015) and T1-FS (p = 0.042).

CONCLUSION

T1-IP is the most reliable sequence due to misleading tumor/liver signal ratio in the case of fatty liver when using T1-FS or T1-OP. The pre/post-HBP lesion-to-liver SIR is accurate to classify benign hepatocellular lesions and contributes to avoid biopsy.

KEY POINTS

•The T1-weighted images in-phase should be systematically included in the HBP-MRI protocol, as it is the most reliable sequence especially in the case of fatty liver. •The comparison between lesion-to-liver signal intensity ratios on unenhanced and at the hepatobiliary phase sequences is useful to classify benign hepatocellular lesions in three categories without misclassification: FNH (increasing signal intensity ratio), HCA (decreasing signal intensity ration), and indeterminate lesions (stable signal intensity ratio).

Disease severity of proliferative lupus nephritis in Maghrebians

Objective To study the influence of Maghrebian ethnicity on lupus nephritis. Methods We retrospectively reviewed the files of a cohort of 194 patients with proliferative lupus nephritis followed in seven lupus centres belonging to three groups: Europeans living in Belgium/France (E; n = 111); Maghrebians living in Europe, in casu Belgium/France (ME; n = 43); and Maghrebians living in Morocco (MM; n = 40). Baseline presentation was compared between these three groups but complete long-term outcome data were available only for E and ME patients. Results At presentation, the clinical and pathological characteristics of lupus nephritis did not differ between E, ME and MM patients. Renal relapses were more common in ME patients (54%) than in E patients (29%) ( P < 0.01). Time to renal flare and to end-stage renal disease was shorter in ME patients compared to E patients ( P < 0.0001 and P < 0.05, respectively). While proteinuria measured at month 12 accurately predicted a serum creatinine value of less than 1 mg/dl at 7 years in E patients, this was not the case in the ME group, in whom serum creatinine at month 12 performed better. Conclusion Despite a similar disease profile at onset, the prognosis of lupus nephritis is more severe in Maghrebians living in Europe compared to native Europeans, with a higher relapse rate.

[Giant cell aortitis complicated by AA amyloidosis diagnosed with imaging techniques: Report of a case]

INTRODUCTION

AA amyloidosis is a common but severe complication of many chronic inflammatory processes of infectious, autoimmune, or neoplastic origin. It frequently leads to renal damage, often presenting as a nephrotic syndrome. Giant cell arteritis is a common inflammatory arteritis in elderly people, but rarely complicated by AA amyloidosis.

CASE REPORT

We report an 87-year-old female who presented with a nephrotic syndrome and a chronic inflammation, in whom the kidney biopsy showed secondary amyloidosis. Etiological investigations concluded an amyloidosis related to giant cell pan-aortitis, whereas there were no typical clinical signs for this diagnosis. Outcome was rapidly unfavourable despite the treatment.

CONCLUSION

In case of chronic inflammation of unknown origin in elderly patients, aortitis complicating a giant cell arteritis should be looked for with imaging techniques, as clinical diagnosis of this presentation is difficult, whereas delayed diagnosis exposes to severe or fatal issues.

FDG PET/CT allowing detection and follow-up of tumor cell transplantation

After detection of small cell lung cancer in a 67-year-old patient who had donated a kidney 7 months earlier, the graft recipient underwent FDG-PET/CT to determine the presence/absence of tumor cell transmission. It showed abnormal increased uptake of the renal graft, associated with hypermetabolic lymph nodes and hepatic, pulmonary and bone lesions. Emergency graft resection was performed 5 days after PET/CT, permitting immunosuppressive therapy withdrawal. Pathologic examination of the kidney showed parenchymal infiltration by tumor cells compatible with small cell lung cancer. Thereafter, pathologists proved that the recipient's and donor's tumor cells matched using microsatellite markers. FDG-PET/CT was performed in the follow-up and showed progression in the donor despite chemotherapy and radiotherapy. He died a few months later. However, FDG-PET/CT showed a complete metabolic response after only 3 courses of chemotherapy in the recipient.