Antimyeloperoxidase-antibody-positive rapidly progressive glomerulonephritis associated with Castleman's disease

Two cases of idiopathic multicentric Castleman disease with nephrotic syndrome treated with tocilizumab

We report two cases of idiopathic multicentric Castleman disease (iMCD) with nephrotic syndrome (NS) treated with tocilizumab. Case 1 was a 58-year-old man diagnosed with iMCD prior to the onset of NS. Renal biopsy revealed membranous nephropathy, which was considered to be secondary membranous nephropathy associated with iMCD. Case 2 was a 49-year-old woman diagnosed with iMCD prior to NS. Renal biopsy revealed renal amyloidosis positive for Congo red staining and amyloid A protein immunostaining. In both the cases, the proteinuria improved after the initiation of glucocorticoid and tocilizumab therapy. Tocilizumab may be a good therapeutic choice for iMCD with NS.

An autopsy case of TAFRO syndrome with membranoproliferative glomerulonephritis-like lesions

TAFRO syndrome (thrombocytopenia, anasarca, myelofibrosis, renal dysfunction, and organomegaly) is an atypical manifestation of multicentric Castleman's disease. Although overproduction of interleukin-6, vascular endothelial growth factor, and other cytokines may partially explain the pathophysiology of this rare syndrome, the precise mechanisms underlying the renal dysfunction associated with the condition remain unclear. Here, we describe a case of a 69-year-old male with TAFRO syndrome. He was treated with immunosuppressive agents and his renal function improved. Tapering of immunosuppressive agents resulted in a deterioration of renal function and an elevation of C-reactive protein. After 20 months of treatment, the patient died from tuberculous peritonitis and gastrointestinal bleeding. An autopsy revealed miliary tuberculosis, mediastinal lymphadenopathy, and gastric ulcers. Renal histopathology showed a membranoproliferative glomerulonephritis-like appearance. Almost all glomeruli showed lobular formations with mesangial proliferation and duplication of glomerular capillary walls on light microscopy. Immunofluorescence showed deposition of C1q and IgM along the glomerular capillary walls. Electron microscopy showed mesangial expansion and widening of the subendothelial space with a large number of electron-dense deposits. The glomerular lesions might be characteristic of TAFRO syndrome, and were regarded as the main cause of the patient's renal dysfunction.

The Clinical and Immunologic Features of Patients With Combined Anti-GBM Disease and Castleman Disease

Patients with both anti-glomerular basement membrane (anti-GBM) disease and Castleman disease have been rarely reported. In this study, we report 3 patients with this combination. They had immunologic features similar to patients with classic anti-GBM disease. Sera from the 3 patients recognized the noncollagenous (NC) domain of the α3 chain of type IV collagen (α3(IV)NC1) and its 2 major epitopes, EA and EB. All 4 immunogloblin G (IgG) subclasses against α3(IV)NC1 were detectable, with predominance of IgG1. In one patient with lymph node biopsy specimens available, sporadic plasma cells producing α3(IV)NC1-IgG were found, suggesting a causal relationship between the 2 diseases. One patient, who achieved remission with antibody clearance and normalization of serum creatinine and interleukin 6 concentrations after plasma exchange and 3 cycles of chemotherapy, experienced recurrence of anti-GBM antibodies and an increase in interleukin 6 concentration after chemotherapy discontinuation because of adverse effects, but both returned to normal after another cycle of chemotherapy. This clinical course and the pathologic findings support the hypothesis that the Castleman disease-associated tumor cells are the source of the anti-GBM autoantibodies.

A rare case of renal thrombotic microangiopathy associated with Castleman's disease

Background

Castleman’s disease (CD) is an uncommon, heterogeneous lympho-proliferative disorder leading to high circulating levels of interleukin-6 (IL-6) and vascular endothelial growth factor (VEGF). Renal involvement has been only described in a limited number of small studies. Herein, we report a rare case of renal thrombotic microangiopathy (TMA) associated with CD and investigate the podocyte expression of VEGF in the renal biopsy prior to initiation of treatment.

Case presentation

An 18-year-old male presented with fever, diarrhea, diffuse lymphadenopathy, ascites and acute kidney injury. Laboratory tests for hemolytic uremic syndrome and thrombotic thrombocytopenic purpura were negative. The kidney biopsy showed TMA. An excisional lymph node biopsy was consistent with CD, plasma cell variant. Immunofluorescence staining showed suppressed podocyte VEGF expression. Chemotherapy that inhibits production of inflammatory mediators including IL-6 and VEGF led to complete recovery of renal function.

Conclusions

Our case illustrates a rare renal histological feature of CD. IL-6 and VEGF are postulated to suppress glomerular VEGF expression, thereby causing renal TMA. Therapy directed against these inflammatory mediators may have important therapeutic implications.

Renal involvement in a large cohort of Chinese patients with Castleman disease

BACKGROUND

The association of kidney disease with Castleman disease (CD) is uncommon. To date, most studies have been based on single-case reports. Here, we describe renal involvement in CD in a large Chinese cohort.

METHODS

Seventy-six CD patients were identified in one clinical center. Clinical and pathological characteristics of patients with renal involvement were described, which were also compared with cases identified through a systematic literature review.

RESULTS

Nineteen patients (25%) exhibited renal involvement. Patients with multicentric clinical type (59 versus 0%) or plasma cell (PC)/mixed cellularity histological variant (61.5 versus 6%) were more likely to have renal involvement (P < 0.001). Proteinuria (with 7/19 reaching nephrotic range) and acute renal failure (12/19, 63%) were the main clinical presentations. Kidney biopsy revealed various glomerular diseases (10/11) and interstitial nephritis (1/11), while with 'thrombotic microangiopathy-like' lesions were the most common pathological characteristics (6/11, 55%). This contrasted significantly with the literature in which amyloidosis was the most reported. Renal outcomes responded well to chemotherapy. Nine (9/12, 75%) patients with acute renal failure recovered completely, one recovered partially. Overall, only three (3/19, 16%) patients progressed to end-stage kidney disease. Renal involvement did not influence survival rate (log-rank test, P = 0.73) in the follow-up.

CONCLUSIONS

CD with multicentric type and PC or mixed cellularity variant are often associated with renal complications. Thrombotic microangiopathy-like lesions are the most common pathological characteristics. Chemotherapy can reverse kidney damage in most cases.

IgA antineutrophil cytoplasmic antibodies in cutaneous vasculitis

BACKGROUND

Antineutrophil cytoplasmic antibodies (ANCA) of the IgA isotype have, for the most part, been detected in patients with Henoch-Schönlein purpura (HSP) or inflammatory bowel disease.

OBJECTIVES

We have evaluated the prevalence of IgA ANCA in a series of patients with different causes of cutaneous vasculitis.

METHODS

Forty consecutive patients with histologically proven leucocytoclastic vasculitis were included in the study: 18 had systemic vasculitis as well as cutaneous lesions, 10 of whom were diagnosed as having HSP, and 22 had only cutaneous vasculitis (with no identified cause in 10 cases). IgA ANCA were sought by indirect immunofluorescence using ethanol-fixed human neutrophil preparations as the substrate.

RESULTS

IgA ANCA were detected in six of 40 patients (15%) (one each with HSP, ulcerative colitis, Sjögren's syndrome, hypergammaglobulinaemia associated with Castelman's disease, erythema elevatum diutinum and bacterial endocarditis). Three of these patients also had IgG ANCA whose target antigen remained unidentified.

CONCLUSIONS

IgA ANCA are rarely observed in HSP (10%) and can be detected in a wide variety of other cutaneous vasculitides.