Association of vascular endothelial growth factor and renal thrombotic microangiopathy-like lesions in patients with Castleman's disease

A Case of Castleman's Disease during the Long-Term Course of Membranous Nephropathy

Concomitant with nephrotic syndrome and multicentric castleman's disease (MCD) has only been described in a limited number of small studies and case reports. Among those, none confirmed the renal pathology prior to the onset of MCD, and none of the cases had a history of nephrotic syndrome. A 76 year-old Japanese man visited a nephrologist because of incident nephrotic syndrome. He had previously experienced three episodes of nephrotic syndrome, the last one 13 years ago, and had been diagnosed with membranous nephropathy by renal biopsy. Apart from these previous episodes, he also suffered from systemic lymphadenopathy, anemia, elevated C-reactive protein, polyclonal hypergammopathy, and elevated interleukin (IL)-6. An inguinal lymph node biopsy revealed CD138-positive plasma cells in the interfollicular region. Based on these findings, MCD was diagnosed. Renal biopsy indicated primary membranous nephropathy with spike lesions and bubbling in the basement membranes and deposition of immunoglobulin (Ig) G, IgA, IgM, and phospholipase A2 receptor along the glomerular basement membrane. Corticosteroid monotherapy successfully reduced the edema, proteinuria, and IL-6, but hypoalbuminemia was not sufficiently improved due to castleman's disease and remission of the nephrotic syndrome was not achieved. Later, tocilizumab was administered for remission induction in another facility. To the best of our knowledge, this represents the first report of Castleman's disease with previously diagnosed membranous nephropathy. This case does not provide a causal mechanism for the pathophysiology, but it may be worth suggesting possible involvement of MCD as a trigger for recurrence of membranous nephropathy.

Distinguishing immune activation and inflammatory signatures of multisystem inflammatory syndrome in children (MIS-C) versus hemophagocytic lymphohistiocytosis (HLH)

BACKGROUND

Multisystem inflammatory syndrome in children (MIS-C) is a potentially life-threatening sequela of severe acute respiratory syndrome coronavirus 2 infection characterized by hyperinflammation and multiorgan dysfunction. Although hyperinflammation is a prominent manifestation of MIS-C, there is limited understanding of how the inflammatory state of MIS-C differs from that of well-characterized hyperinflammatory syndromes such as hemophagocytic lymphohistiocytosis (HLH).

OBJECTIVES

We sought to compare the qualitative and quantitative inflammatory profile differences between patients with MIS-C, coronavirus disease 2019, and HLH.

METHODS

Clinical data abstraction from patient charts, T-cell immunophenotyping, and multiplex cytokine and chemokine profiling were performed for patients with MIS-C, patients with coronavirus disease 2019, and patients with HLH.

RESULTS

We found that both patients with MIS-C and patients with HLH showed robust T-cell activation, markers of senescence, and exhaustion along with elevated TH1 and proinflammatory cytokines such as IFN-γ, C-X-C motif chemokine ligand 9, and C-X-C motif chemokine ligand 10. In comparison, the amplitude of T-cell activation and the levels of cytokines/chemokines were higher in patients with HLH when compared with patients with MIS-C. Distinguishing inflammatory features of MIS-C included elevation in TH2 inflammatory cytokines such as IL-4 and IL-13 and cytokine mediators of angiogenesis, vascular injury, and tissue repair such as vascular endothelial growth factor A and platelet-derived growth factor. Immune activation and hypercytokinemia in MIS-C resolved at follow-up. In addition, when these immune parameters were correlated with clinical parameters, CD8+ T-cell activation correlated with cardiac dysfunction parameters such as B-type natriuretic peptide and troponin and inversely correlated with platelet count.

CONCLUSIONS

Overall, this study characterizes unique and overlapping immunologic features that help to define the hyperinflammation associated with MIS-C versus HLH.

Membranous nephropathy associated with multicentric Castleman's disease that was successfully treated with tocilizumab: a case report and review of the literature

Background

Multicentric Castleman’s disease is a life-threatening disorder involving a systemic inflammatory response and multiple organ failure caused by the overproduction of interleukin-6. Although renal complications of Castleman’s disease include AA amyloidosis, thrombotic microangiopathy, and membranoproliferative glomerulonephritis, membranous nephropathy is relatively rare. We experienced a case of secondary membranous nephropathy associated with Castleman’s disease.

Case presentation

The patient was a 43-year-old Japanese man who had shown a high zinc sulfate value in turbidity test, polyclonal hypergammaglobulinemia, anemia, and proteinuria. A physical examination revealed diffuse lymphadenopathy, an enlarged spleen and papulae of the body trunk. A skin biopsy of a papule on the patient’s back showed plasma cells in the perivascular area and he was diagnosed with multicentric Castleman’s disease, plasma cell variant. Kidney biopsy showed the appearance of bubbling in the glomerular basement membranes in Periodic acid methenamine silver stain and electron microscopy revealed electron dense deposits within and outside the glomerular basement membranes. Since immunofluorescence study showed predominant granular deposition of IgG1 and IgG2, he was diagnosed with secondary membranous nephropathy associated with Castleman’s disease. He was initially treated with prednisolone alone, however his biochemical abnormalities did not improve. After intravenous tocilizumab (700 mg every 2 weeks) was started, his C-reactive protein elevation, anemia, and polyclonal gammopathy improved. Furthermore, his urinary protein level declined from 1.58 g/gCr to 0.13 g/gCr. The prednisolone dose was gradually tapered, then discontinued. He has been stable without a recurrence of proteinuria for more than 6 months.

Conclusions

Tocilizumab might be a treatment option for secondary membranous nephropathy associated with Castleman’s disease.

Five biopsies, one diagnosis: challenges in idiopathic multicentric Castleman disease

A previously healthy 29-year-old man initially presented to the hospital with pleuritic chest pain and shortness of breath. Over the next 2 months he developed ongoing fevers and night sweats with recurrent exudative pleural effusions and ascites. He had an extensive infectious and autoimmune workup that was unremarkable. He had an initial lymph node biopsy that showed reactive changes only. He had an acute kidney injury and his renal biopsy revealed thrombotic microangiopathy. His liver biopsy showed non-specific inflammatory changes. His bone marrow biopsy showed megakaryocyte hyperplasia and fibrosis, which raised suspicion for the thrombocytopenia, ascites, reticulin fibrosis, renal dysfunction and organomegaly syndrome subtype of multicentric Castleman disease. This prompted a repeat lymph node biopsy, showing changes consistent with mixed type Castleman disease that fit with his clinical picture. He was initiated on steroids and siltuximab with significant clinical improvement.

Podocyte Involvement in Renal Thrombotic Microangiopathy: A Clinicopathological Study

BACKGROUND

The current study aimed to evaluate the associations between podocyte injury and clinicopathological features in renal thrombotic microangiopathy (TMA) based on a Chinese cohort, which might be underscored in this disease.

METHODS

The clinical, laboratory, and renal histopathological data of patients with renal biopsy-proven TMA from 2000 to 2015 in our institute were collected. Foot process effacement (FPE) was quantified by foot process width (FPW) by electron microscopy. Podocytes in the renal specimens were also detected by stainings for podocyte-specific markers, including Wilms tumor 1 (WT-1), synaptopodin, and podocalyxin. The associations between FPW and clinico-histopathological data were further analyzed. A composite end-point was defined by all-cause death or end-stage renal disease to address the predictive value of FPW.

RESULTS

Sixty-three patients with renal biopsy-proven TMA were enrolled. The FPW of renal TMA patients was 1,090 ± 637 nm (range, 572-4,748 nm), which was significantly higher than the normal range in our center (p = 0.005). By immunohistochemistry and immunofluorescence assays, we found decreased expressions of synaptopodin, podocalyxin, and WT-1 and continued stainings of WT-1 in some podocytes without detectable synaptopodin stainings in the areas of sclerotic tufts and cellular crescents. The FPW value was correlated with the serum albumin concentration (rs = -0.281, p = 0.026), proteinuria amount (rs = 0.255, p = 0.047), serum creatinine levels (rs = 0.339, p = 0.007), and eGFR (rs = -0.335, p = 0.007). According to ROC curve analysis, the optimal cutoff level of FPW for predicting the composite end-point was 869 nm. In patients with FPW ≥ 869 nm, FPW levels were further correlated with the severity of mesangiolysis (rs = 0.351, p = 0.033) and glomerulosclerosis (rs = 0.369, p = 0.025) in pathological evaluations. Patients without clinical remission also had higher FPW than those with remission (1,240 ± 793 vs. 925 ± 344 nm, p = 0.013). The multivariate Cox hazard model showed that FPW ≥ 869 nm was an independent risk factor for the composite end-point (hazard ratio: 3.64, 95% CI: 1.37-9.66, p = 0.009).

CONCLUSION

The podocyte injury was prevalent and the FPW levels were closely associated with clinicopathological features, especially prognosis, in renal TMA patients.

Mimickers of pulmonary lymphoma

There are multiple entities that involve the lung that have radiographic, clinical, and morphologic overlaps with pulmonary lymphoma. In this review, we will discuss these entities in detail and provide relevant updates.