Prolonged infections associated with antineutrophil cytoplasmic antibodies specific to proteinase 3 and myeloperoxidase: diagnostic and therapeutic challenge. Clin Rheumatol. 2010;29:893-904. [PMID: 20306213 DOI: 10.1007/s10067-010-1424-4]

Current modalities in the diagnosis of pulmonary vasculitis

INTRODUCTION

This review addresses the pulmonary manifestations of the vasculitides, with a focus on diagnostic modalities. Haemorrhagic presentations (usually associated with nephritis: the pulmonary-renal syndrome) are the most common vasculitic cause of early death.

AREAS COVERED

The diagnostic modalities in the pulmonary vasculitides are reviewed, with a focus on primary systemic vasculitis. A literature search of original research and review articles on pulmonary vasculitides was undertaken using the PubMed database.

EXPERT OPINION

Small-vessel anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis, especially granulomatosis with polyangiitis (Wegener's granulomatosis) are the most frequent causes of pulmonary vasculitis and typically present as nodules, alveolar infiltrates (haemorrhagic or not), cavities or tracheobronchial stenosis. Lung involvement is less common in large-vessel vasculitis when pulmonary vascular abnormalities can be seen. No single test is pathogonomonic and diagnosis requires integration of clinical, laboratory, imaging and histological findings. Treatment follows similar regimens to other vasculitic presentations, with glucocorticoids in conjunction with immunosuppressive agents, and management of intercurrent sepsis and the increased risk of cardiovascular and thromboembolic events. Prompt diagnosis and intensive treatment of pulmonary vasculitis is essential to improve early mortality and long-term outcomes.

Life-threatening ANCA-positive vasculitis associated with rickettsial infection

We present a 47-year-old Caucasian fire fighter who developed multisystem organ failure in the setting of a positive antineutrophil cytoplasmic autoantibody (myeloperoxidase) as well as confirmed Rocky Mountain spotted fever by skin biopsy PCR. This case provided a diagnostic challenge, a rare association of a Rickettsia infection and autoimmune vasculitis as well as a unique management approach.

Concomitant drug- and infection-induced antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis with multispecific ANCA

OBJECTIVE

To report the first case of concomitant drug- and infection-induced antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) in a patient treated with propylthiouracil (PTU) and suffering from tuberculosis.

PRESENTATION AND INTERVENTION

A 28-year-old woman with PTU-treated hyperthyroidism presented with fever, purpura, pulmonary cavitations and ANCA to myeloperoxidase, bactericidal/permeability-increasing protein (BPI), proteinase-3 and elastase. Skin histopathology confirmed vasculitis. However, sputum examination revealed Mycobacterium tuberculosis. Remission was achieved after PTU withdrawal and treatment with antituberculosis drugs.

CONCLUSION

Our case confirmed that BPI-ANCA are elevated in active tuberculosis. Multispecific ANCA were helpful for the diagnosis of concomitant PTU- and M. tuberculosis-induced AAV.

Complements do not lie

A 74-year-old patient presented with constitutional symptoms and was found to have acute kidney injury. He was known to have a prosthetic aortic valve. He was febrile with splenomegaly and vasculitic lesions on both hands. Nephritic screen revealed strongly positive cytoplasmic-antineutrophil cytoplasmic antibodies (c-ANCA). Differential diagnosis thus included a small vessel vasculitis or infective endocarditis. Transoesophageal echocardiography demonstrated no vegetations and serial blood cultures were negative. Immunosuppression for presumed granulomatosis with polyangiitis (Wegeners granulomatosis) was therefore instituted. The patient deteriorated, requiring multi-organ support. Renal biopsy showed a proliferative glomerulopathy and complements were low. Atypical screen for culture negative endocarditis revealed a strongly positive IgG-antibody titre against Bartonella henselae. Immunosuppression was discontinued and treatment for chronic Bartonellosis commenced. The patient made a remarkable recovery. His renal function quickly returned to normal, and ANCA titres and complements normalised. He was discharged home after completing a 6 week course of antibiotic therapy.

Autoantibodies in patients with chronic hepatitis C virus infection: pitfalls for the diagnosis of rheumatic diseases

Hepatitis C virus infection (HCV) is one of the best mimes in medicine. About 40-70% of patients suffering from this disorder develop at least one extra-hepatic disorder that can have a rheumatic nature (arthralgias, arthritis, vasculitis and sicca syndrome) and must be differentiated from the primitive rheumatic diseases. In addition, HCV infection can also alter the laboratory tests. Several alterations of first line laboratory tests can be usually found in both chronic HCV infection and chronic inflammatory rheumatic disorders. In the present review we analyze the interference of HCV in tests more specifically used in rheumatology: rheumatoid factor and other autoantibodies (ANA, anti-ENA, ANCA, anti-DNA, antiphospholipid, anti-CCP). In patients suffering from HCV infection, the diagnosis of connective tissue diseases (CTD) or rheumatoid arthritis (RA) should be made only when the detected symptoms or laboratory data are not inducible by HCV, otherwise only a diagnosis of "possible CTD" or "possible RA" should be considered.

Pathogenesis of antineutrophil cytoplasmic autoantibody vasculitis

PURPOSE OF REVIEW

Antineutrophil cytoplasmic autoantibodies (ANCAs) are associated with vasculitis. Current therapy involves administration of toxic therapy that is not optimally effective. This review will summarize evidence for the pathogenicity of ANCAs, which will suggest possible strategies for improving treatment.

RECENT FINDINGS

Pauci-immune small vessel vasculitis is associated with antibodies against myeloperoxidase (MPO-ANCA) and proteinase 3 (PR3-ANCA). One research group has reported a high frequency of autoantibodies against lysosomal-associated membrane protein 2 (LAMP-2) in patients with MPO-ANCA or PR3-ANCA. Epigenetic dysregulation appears to be the basis for increased MPO and PR3 neutrophil gene expression in ANCA disease. Release of neutrophil extracellular traps may be involved in initiating the ANCA autoimmune response and causing vessel injury. Generation of C5a by alternative pathway activation is involved in pathogenesis in mouse models. Intervention strategies in mice that target antigens, antibodies and inflammatory signaling pathways may translate into novel therapies. Animal models of LAMP-ANCA and PR3-ANCA disease have been proposed. Molecular mimicry and responses to complementary peptides may be initiating events for ANCAs. T cells, including regulatory T cells, have been implicated in the origin and modulation of the ANCAs, as well as in the induction of tissue injury.

SUMMARY

Our basic understanding of the origins and pathogenesis of ANCA disease is advancing. This deeper understanding already has spawned novel therapies that are being investigated in clinical trials. This brief review shows that there are more questions than answers, and new questions are emerging faster than existing questions are being answered.

Treatment of hepatitis C-mediated glomerular disease

Chronic kidney disease (CKD) is becoming a major public health issue worldwide, mainly due to the increasing prevalence of hypertension, diabetes and aging population. Chronic hepatitis C virus (HCV) infection commonly involves the kidneys, can be a cause of CKD, and significantly impacts morbidity and mortality in these patients. Prompt recognition and knowledge of how to best manage these patients are essential in order to have a successful renal outcome. Patients with HCV and kidney involvement can often be managed with a specific combination of antiviral drugs, immunosuppressants, plasmapheresis, and newer monoclonal antibodies. However, no large randomized controlled trials have been conducted in this patient population, optimal management of HCV-mediated kidney diseases is not well defined, and treatment itself can be associated with significant toxicity in patients with CKD. This article reviews the recent literature, discusses the limitations of current therapies, as well as toxicity associated with treatment, and suggests future areas for research.

A case of palpable purpura and nephropathy: Occam's Razor or Hickam's Dictum

Vasculitis causing palpable purpura, nephropathy, and hematologic abnormalities is a well-known entity. However, sometimes, vasculitis may not be the primary cause but is part of a systemic disease. Literature suggests that infections like HIV can induce nephropathy and antineutrophilic cytoplasmic antibody-positive vasculitis, which is different from the well-known entity of "antineutrophilic cytoplasmic antibody-associated vasculitis." We present a 46-year-old female patient with a history of intravenous drug abuse who reported with a rash, swelling, and palpable purpura of the lower extremities. Peripheral smear showed no evidence of disseminated intravascular coagulation or thrombotic thrombocytopenic purpura; metabolic profile showed acute kidney injury. She was found to be HIV- and hepatitis C-positive. Immunologic workup was positive for both MPO and PR3 antineutrophilic cytoplasmic antibodies and negative for cryoglobulins; complement levels were low. Skin biopsy showed leukocytoclastic vasculitis but kidney biopsy was negative for any immunologic involvement; it showed only glomerulosclerosis. Thus, it was thought that nephropathy and vasculitis, in this case, are two distinct pathologic processes, both induced by infection (HIV and/or hepatitis C). The patient responded to low-dose steroid therapy. She was later started on the definitive therapy, the highly active antiretroviral therapy regimen. This case illustrates the fact that low-dose steroids can still be a good alternative in acute situations in patients at risk from immunosuppression.

Unusual extracardiac manifestations of isolated native tricuspid valve endocarditis

Isolated native tricuspid valve endocarditis (TVE) in non-intravenous drug users is a very rare condition. We describe an unusual presentation of Enterococcus faecalis TVE associated with spondylodiscitis, positive cytoplasmic antineutrophil cytoplasmic antibodies and antiproteinase-3 antibodies vasculitic rash in an otherwise healthy patient with no history of intravenous drug use or underlying cardiac abnormalities. A high index of clinical suspicion is required in patients presenting with unusual features and pyrexia of unknown origin. Simple tests including serial blood cultures and echocardiography may help to establish the correct diagnosis and commence appropriate treatment.