Anti-neutrophil cytoplasmic antibodies (ANCA) and infection

Bartonella Endocarditis and Pauci-Immune Glomerulonephritis: A Case Report and Review of the Literature

Among culture-negative endocarditis in the United States, Bartonella species are the most common cause, with Bartonella henselae and Bartonella quintana comprising the majority of cases. Kidney manifestations, particularly glomerulonephritis, are common sequelae of infectious endocarditis, with nearly half of all Bartonella patients demonstrating renal involvement. Although a pauci-immune pattern is a frequent finding in infectious endocarditis-associated glomerulonephritis, it is rarely reported in Bartonella endocarditis. Anti-neutrophil cytoplasmic antibody (ANCA) positivity can be seen with many pathogens causing endocarditis and has been previously reported with Bartonella species. In addition, ANCA-associated vasculitis can also present with renal and cardiac involvement, including noninfectious valvular vegetations and pauci-immune glomerulonephritis. Given the overlap in their clinical presentation, it is difficult to differentiate between Bartonella endocarditis and ANCA-associated vasculitis but imperative to do so to guide management decisions. We present a case of ANCA-positive Bartonella endocarditis with associated pauci-immune glomerulonephritis that was successfully treated with medical management alone.

Central venous catheter infection-related glomerulonephritis under long-term parenteral nutrition: a report of two cases

Background

Advances in long-term parenteral nutrition via indwelling central venous catheter have improved the quality of life and mortality in patients with life-threatening gastrointestinal diseases complicated with severely impaired absorption. However, infection to central venous catheter is still a common and critical complication for such patients. We encountered two patients under long-term parenteral nutrition who developed glomerulonephritis associated with central venous catheter infection. Persistent bacterial infection in indwelling medical devices placed in the blood-stream such as a ventricular-atrial shunt is known to cause glomerulonephritis, a condition termed shunt nephritis. We reported the clinical manifestations, treatment and their pathological findings in the two patients with glomerulonephritis associated with central venous catheter infection.

Case presentation

Both patients suffered from megacystis microcolon intestinal hypoperistalsis syndrome, a form of pseudo-Hirschsprung’s disease. They had been receiving home parenteral nutrition via central venous catheter because of severe malabsorption. They presented proteinuria, hematuria, hypocomplementemia and positive PR3-antineutrophilic cytoplasmic antibody accompanied by Staphylococcus epidermidis infection in the central venous catheter. Their renal biopsy revealed membranoproliferative glomerulonephritis with positive C3 deposition. One of them recovered completely following the removal of catheter and administration of antibiotics, while another did not respond to the treatments. We then treated her with methylprednisolone pulse therapy followed by prednisolone. She responded well, and achieved complete remission.

Conclusion

As central venous catheter infection-related glomerulonephritis has a similar etiology to shunt nephritis, removal of the catheter and administration of antibiotics is fundamental to the treatment. If a patient is resistant to such conventional therapy, additional steroid and/or immunosuppressive agent could be considered. Although the number of patients with classical shunt nephritis is decreasing since the ventricular-peritoneal shunt has become became the major procedure for hydrocephalus, central venous catheter infection-related glomerulonephritis may increase in the future due to a marked increase in the number of patients receiving long-term parenteral nutrition. Routine urinalysis should be considered in such patients for early detection of central venous catheter infection-related glomerulonephritis.

Rapidly progressive glomerulonephritis associated with PR3-ANCA positive subacute bacterial endocarditis

Patients with bacterial endocarditis often have renal complications. This report presents the case of an elderly man with rapidly progressive glomerulonephritis (RPGN) associated with subacute bacterial endocarditis (SBE) due to Enterococcus faecalis infection. The patient was positive for anti-proteinase 3-antineutrophil cytoplasmic antibody (PR3-ANCA) and rheumatoid factor (RF) with hypocomplementemia. Treatment for SBE with antibiotics and the surgical replacement of the affected valves resulted in an improvement of RPGN, the disappearance of PR3-ANCA and RF, and the normalization of hypocomplementemia. This rare case suggests the importance of recognizing the cause of positive PR3-ANCA, because SBE could be an occult cause of RPGN mimicking ANCA-associated vasculitis.

Streptococcal viridans subacute bacterial endocarditis associated with antineutrophil cytoplasmic autoantibodies (ANCA)

We report an illustrative case of a 60-year-old man with Streptococcus viridans subacute bacterial endocarditis (SBE) and positive antineutrophil cytoplasmic autoantibodies (c-ANCA). C-ANCA positivity has been associated with a variety of rheumatic and infectious disease areas, but has been rarely associated with SBE. The patient had mitral valve prolapse with mitral regurgitation, and S viridans SBE developed after a dental procedure. Laboratory abnormalities included anemia, elevated erythrocyte sedimentation rate, positive rheumatoid factor, positive anticardiolipin antibody, positive lupus anticoagulant, and highly elevated c-ANCA level. We believe this is only the ninth reported case of S viridans SBE with a positive c-ANCA, and the third with mitral valve prolapse and vegetations.

Antineutrophil cytoplasmic autoantibody in the absence of Wegener's granulomatosis or microscopic polyangiitis: implications for the surgical pathologist

Antineutrophil cytoplasmic antibodies (ANCA) are useful serologic markers for the diagnosis and management of patients with Wegener's granulomatosis (WG) and microscopic polyangiitis (MPA). However, problems in diagnosis and classification may occur when patients with other disorders develop ANCA. A 7-year review (1993-1999) disclosed 247 patients whose sera tested positively for ANCA by an indirect immunofluorescence method: 166 patients for cytoplasmic-ANCA (C-ANCA) and 81 patients for perinuclear-ANCA (P-ANCA) Twenty-seven patients had active pulmonary disease and underwent open-lung biopsy or transbronchial biopsy. Eight patients (30%) had a disease other than WG or MPA, and their clinical, pathological, and serological findings were reviewed. The patients, all women, ranged in age from 28 to 77 years (median, 37 y). Dyspnea (n = 6), cough (n = 6), chest pain (n = 2), and/or hemoptysis (n = 2) were present. The duration of symptoms lasted from 3 weeks to 6 years (median, 6 mo). ANCA titers were C-ANCA (n = 4; range, 1:40-1280) or P-ANCA (n = 4; range, 1:40-640). The lung biopsies disclosed nonspecific interstitial pneumonia (n = 4), bronchiolitis obliterans organizing pneumonia (n = 1), diffuse alveolar damage (n = 1), organizing diffuse alveolar hemorrhage without capillaritis (n = 1), and necrotic granuloma (n = 1). No cases showed characteristic histology for WG or MPA. The final diagnoses were various connective tissue disorders (n = 5), chronic hypersensitivity pneumonia (n = 1), postinfectious bronchitis/bronchiectasis (n = 1), and ulcerative colitis-related lung disease (n = 1). Surgical pathologists should be aware that significantly elevated ANCA titers may be associated with diverse forms of pulmonary disease. ANCA positivity alone, in the absence of appropriate clinical or pathologic findings, should not be used to substantiate a diagnosis of WG or MPA.

Anticytokeratins are a potential source of false-positive indirect immunofluorescence assays for C-ANCA

Antibodies to neutrophil cytoplasmic antigens (ANCA) targeted toward granule enzymes have been recognized as a valuable diagnostic tool in the detection of Wegener's granulomatosis and systemic vasculitides. However, the most commonly used method of detection, the indirect immunofluorescence assay, is prone to false-positive results due to antibodies of different pathological significance either targeted to, or cross-reacting with, similarly distributed epitopes. Using double immunofluorescence, the present study demonstrates that anticytokeratin antibodies are able to produce false-positive C-ANCA immunofluorescence assays. In addition, a case of natural appearance of cytokeratin-reactive antibodies causing a false-positive "pseudo-ANCA" staining pattern in a patient presenting with sepsis is reported. Since the expression of cytokeratins is almost exclusively confined to epithelial cells, the most plausible explanation for both phenomena is a crossreaction of anticytokeratin antibodies with granule associated epitopes. Due to the natural appearance of anticytokeratin antibodies in association with a variety of other pathologic entities, it is of crucial importance for the diagnostic significance of the C-ANCA immunofluorescence assay to exclude anticytokeratin caused false-positive results. It is shown that supplementary indirect immunofluorescence tests performed on cultured human epithelial cells readily distinguish anticytokeratin caused "pseudo-ANCA" from true C-ANCA.

Membranous lupus nephritis with antineutrophil cytoplasmic antibody-associated segmental necrotizing and crescentic glomerulonephritis

Focal segmental necrotizing and crescentic lupus nephritis accompanied by perinuclear antineutrophil cytoplasmic antibody (P-ANCA) seropositivity is an unusual occurrence. We report the first biopsy-documented cases of membranous lupus nephritis class V with associated "pauci-immune" segmental necrotizing glomerulonephritis and P-ANCA seropositivity. The absence of subendothelial electron-dense deposits favored a manifestation of superimposed ANCA-associated glomerulonephritis rather than class III lupus nephritis. The pathogenetic implications of this association are explored.