Positive C-ANCA and cavitary lung lesion: recurrence of Wegener granulomatosis or aspergillosis?

Abstract: A case of a cavitary lung lesion in the right middle lobe of a 34-year-old woman who presented with hemoptysis is presented. The patient had a 2-year history of Wegener granulomatosis that had been treated with cyclophosphamide and corticosteroids. Although the patient gradually achieved remission of her disease, she developed new pulmonary symptoms and a cavitary lesion in her right lung. Further workup revealed elevated C- and P-ANCA titers. Following partial resection of her right lung, she was found to have an aspergilloma and no evidence of active Wegener granulomatosis. Pulmonary aspergillosis was felt to be the cause of both the hemoptysis and the cavitary lesion. We postulate that C-ANCA and P-ANCA were falsely positive in this case. Although rare, false positive C-ANCA and P-ANCA have been reported in pulmonary fungal infections.

Key Words: Wegener granulomatosis, C-ANCA, false-positive, pulmonary aspergillosis

Case Report

A 34-year-old woman with a 2-year history of Wegener granulomatosis presented to our institution with a recent episode of hemoptysis. She denied chest pain, acute shortness of breath, fever, weight loss, or night sweats. The patient was a lifelong nonsmoker. The initial manifestations of Wegener granulomatosis 2 years before the current presentation included cough, dyspnea, hemoptysis, and pulmonary infiltrates. Cytoplasmic antineutrophil cytoplasmic antibody (C-ANCA) was positive, perinuclear antineutrophil cytoplasmic antibody (P-ANCA) was negative, and open lung biopsy showed capillaritis. There was no upper airway or renal involvement. The patient was treated with prednisone and cyclophosphamide which resulted in remission of the vasculitis, and she was subsequently maintained on cyclophosphamide. During follow-up, C-ANCA was persistently negative and she reported improvement in her symptoms. She did not experience recurrence of hemoptysis until the current presentation. Eleven months before the current admission the patient developed a subcutaneous abscess of the left thigh that required surgical drainage and IV antibiotics. A chest x-ray at that time was unremarkable. Consequently, cyclophosphamide therapy was held. Seven months before presentation, the patient reported increased cough and dyspnea. A computed tomography (CT) scan of the chest showed a new cavitary lesion in the right middle lobe and repeat C-ANCA and P-ANCA were positive. The patient was started on 30 mg of prednisone daily, and her symptoms improved. Nevertheless, a repeat chest CT scan four months before presentation showed progression of the right middle lobe cavitary lesion. Cyclophosphamide therapy was restarted for presumed relapse of Wegener granulomatosis. On current presentation, another chest CT was obtained that again showed progression of the right middle lobe lesion with extension to the right upper lobe (Fig. 1). The patient continued to have hemoptysis after admission to the hospital. Physical examination at admission revealed a temperature of 97.8[degrees]F, blood pressure of 183/85 mm Hg, heart rate of 102 beats per minute, and respiratory rate of 20 breaths per minute. Cardiac, abdominal, skin, and neurologic examinations were all unremarkable. Chest auscultation revealed diffuse expiratory wheezing, mostly over the right hemithorax. Laboratory findings included white blood cell count of 7.4 x [10.sup.3]/L, hemoglobin of 10.9 g/dL, sodium of 137 mmol/L, potassium of 3.6 mmol/L, bicarbonate of 26 mmol/L, and creatinine of 0.9 mg/dL, P-ANCA titer of > 1:640, C-ANCA titer of > 1:640, antiproteinase 3(PR3) antibody of 3.33 (normal range: 0-20), and antimyeloperoxidase (MPO) antibody of 1.40 (normal range: 0-20). Urinalysis was normal. Serum IgG was elevated. Serum galactomannan assay was not done.

Bronchoscopic examination of the airways showed active bleeding from the right middle lobe bronchus. Cytologic examination of bronchoalveolar lavage (BAL) fluid did not identify any pathogenic organisms and BAL cultures were negative. The patient underwent thoracotomy with resection of the right upper and middle lobes.

Examination of the surgical resection specimen revealed a large, 8 cm cavity within one lobe that was encircled by a thick fibrous wall and filled with necrotic debris. The remaining lung parenchyma was remarkable for the presence of focal small heterogeneous pale areas that were separate from the cavity. Histologic sections revealed a necrotic cavity with numerous fungal colonies that contained septate hyphae and acute angle branches characteristic of Aspergillus (Fig. 2). Although there was no apparent evidence for invasion of the wall of the cavity by the fungal organisms, fungal elements were found in uninflamed pulmonary parenchyma and in satellite abscesses removed from the cavity. The histology showed no evidence of active Wegener granulomatosis.

Discussion

Wegener granulomatosis (WG) is a systemic vasculitis that mainly involves the upper airways, lungs, and kidneys. Corticosteroids and cyclophosphamide are the mainstays of treatment (1); however, these drugs increase the patient's susceptibility to potentially life-threatening infections. The appearance of new pulmonary lesions or progression of old lesions present a diagnostic challenge for clinicians as it is difficult to distinguish between treatment failure and the development of opportunistic pulmonary infections. The diagnosis of infection or recurrence of vasculitis usually requires invasive procedures such as bronchoscopy and biopsy. In this report, we describe a patient with pulmonary aspergillosis with a history of Wegener granulomatosis. The ANCA test was positive for cytoplasmic staining (C-ANCA) and perinuclear staining (P-ANCA) that we believe was falsely positive as a result of the fungal infection.

[FIGURE 1 OMITTED]

Antibodies directed at neutrophil cytoplasmic antigens were described and linked to WG and microscopic polyangiitis in the 1980s, and currently they play an important role in the classification and diagnosis of vasculitides. (2) In general, C-ANCA is associated with WG and P-ANCA is linked to microscopic polyarteritis and Churg-Strauss syndrome. (3) Although approximately 90% of patients with active and generalized WG are C-ANCA positive, up to 40% of the patients may be C-ANCA negative in the absence of renal involvement. The relevant antigens for C-ANCA and P-ANCA are PR3 and MPO, respectively. (4) There are two techniques available for the detection of ANCA. Indirect immunofluorescence uses ethanol-fixed neutrophils to reveal characteristic patterns of staining, namely cytoplasmic (C-ANCA) or perinuclear (P-ANCA). These patterns demonstrate distribution of fixed antigenic materials and are not antigen specific. Enzyme-linked immunosorbant assay (ELISA) is used to detect antibodies with target specificities for PR3 and MPO. (4)

[FIGURE 2 OMITTED]

The diagnostic value of ANCA in systemic vasculitis was evaluated in a multicentric study. Results from 169 newly diagnosed patients with systemic vasculitis were compared with 184 disease controls and 740 healthy controls. The sensitivity in WG was 64% for C-ANCA and 66% for anti-PR3. The specificity in WG related to disease controls was C-ANCA: 95% and anti-PR3: 91%. (3) In another study. Block-mans et al found that for 57 C-ANCA positive patients, only 23 had WG. The positive predictive value (PPV) in this study was only 40%. However, PPV of anti-PR3 antibodies for WG was 85%. The low PPV of C-ANCA compared with anti-PR3 antibodies for WG was caused by a high percentage of anti-PR 3 antibody negative, C-ANCA positive determinations in patients with diagnoses other than WG. There was a positive correlation between these falsely elevated C-ANCA titers and the level of hypergammaglobulinema. The authors suggested that hypergammaglobulinemia could be responsible for the elevated C-ANCA values in anti-PR3 negative patients. (5) The indirect immunofluorescence technique that is being used to determine C-ANCA titer is prone to false positives due to antibodies targeted to similarly distributed epitopes in the cytoplasm. For example, the anticytokeratin antibodies have been shown to produce false-positive C-ANCA in immunofluorescence assays. (6)

False positive C-ANCAs have been reported in different pulmonary and systemic disease processes including rheumatoid arthritis, sarcoidosis, polymyalgia rheumatica, Sjogren syndrome, lupus nephritis, cirrhosis, (5) subacute bacterial endocarditis, (7) inflammatory bowel disease, (5) cystic fibrosis with bronchiectasis, and lymphoma. (8) Elevated C-ANCA levels were also reported with various infections. Reported cases of C-ANCA positive infections are summarized in the Table. (2) Concomitantly positive P-ANCA and C-ANCA have also been observed in patients with falsely positive C-ANCA. These findings are consistent with our patient with pulmonary aspergillosis and a history of WG and positive C-ANCA, positive P-ANCA, negative anti-PR3 antibody, and negative anti-MPO antibody. Pathologic examination of lung tissue after resection did not show evidence of vasculitis or capillaritis that would have suggested recurrence of WG. Instead, fungal elements consistent with aspergillus were seen invading the lung parenchyma. Our patient was asymptomatic and had a persistently negative C-ANCA, stable chest x-ray, and normal renal function during follow-up, suggesting remission. As discussed above, the serologic findings and cavitary lung lesion can be explained by pulmonary aspergillosis. We believe this case presents an interesting manifestation of pulmonary aspergillosis in an immunocompromised patient with falsely elevated C-ANCA titers masquerading as recurrence of WG. (9-13)

The management of patients with a presentation similar to that of our patient requires a definitive diagnosis. Treatment of recurrent vasculitis requires immunosuppressive therapy that obviously could be detrimental in a patient with pulmonary aspergillosis. Invasive procedures are occasionally required to establish the nature of pulmonary lesions in these patients. The diagnostic yield of flexible bronchoscopy in non-HIV infected immunocompromised patients and pulmonary infiltrates is only about 56%. (14) Open lung biopsy may be necessary to make the definitive diagnosis. Detection of aspergillus circulating galactomannan by ELISA has been shown to have a sensitivity of 75 to 92% and a specificity of 95 to 100% to detect invasive aspergillosis in allogeneic hematopoietic stem cell transplant recipients. One study showed that the galactomannan ELISA is 55% sensitive and 92% specific for Aspergillus antigenemia in liver transplant recipients. The galatomannan ELISA assay could be potentially useful to differentiate between invasive aspergillosis and recurrent vasculitis. Further studies are necessary to determine the role of this assay in the evaluation of patients with vasculitis and new pulmonary lesions. This attractive diagnostic modality can potentially reduce the need for invasive procedures and their complications.

Conclusion

Pulmonary aspergillosis should be included in the differential diagnosis of patients on immunosuppressive therapy that present with new pulmonary lesions. Although C-ANCA has an important role in the diagnosis and classification of vasculitides, false positive C-ANCA does occur, as illustrated by our case. In a patient with a history of WG, the appearance of new pulmonary lesions suggests a recurrence of vasculitis, but clinicians should also have a high index of suspicion for possible pulmonary fungal infections. Positive C-ANCA with concurrently positive P-ANCA or negative anti-PR3 antibodies should alert the clinician to consider alternative diagnoses.

References

1. Langford CA, Hoffman GS. Rare diseases, III, Wegener's granulomatosis. Thorax 2000;54:629-637.

2. Davenport A. 'False positive' perinuclear and cytoplasmic anti-neutrophil cytoplasmic antibody results leading to misdiagnosis of Wegener's granulomatosis and/or microscopic polyarteritis. Clin Nephrol 1992;37:124-130.

3. Hagen EC, Daha MR, Hermans J. et al. Diagnostic value of standardized assays for anti-neutrophil cytoplasmic antibodies in idiopathic systemic vasculitis: EC/BCR Project for ANCA Assay Standardization. Kidney Int 1998;53:743-753.

4. Mandl LA, Solomon DH, Smith EL. et al. Using antineutrophil cytoplasmic antibody testing to diagnose vasculitis: can test-ordering guidelines improve diagnostic accuracy? Arch Intern Med 2002;162:1509-1514.

5. Blockmans D, Stevens E, Marien G, et al. Clinical spectrum associated with positive ANCA titers in 94 consecutive patients: is there a relation with PR-3 negative c-ANCA and hypergammaglobulinaemia. Ann Rheum Dis 1998:57:141-145.

6. Streicher J, Fabian B, Herkner K. et al. Anticytokeratins are a potential source of false-positive indirect immunofluorescence assays for C-ANCA. J Clin Lab Analysis 1998;12:54-59.

7. Choi HK, Lamprecht P, Niles JL, et al. Subacute bacterial endocarditis with positive cytoplasmic antineutrophil cytoplasmic antibodies and anti-proteinase 3 antibodies. Arthritis Rheum 2000;43:226-231.

8. Lee AS, Wiesner O, Gillespie DJ, et al. A 70-year-old man with pulmonary infiltrates and a positive antineutrophil cytoplasmic autoantibody test result. Chest 2005;127:1045-1050.

9. Galperin C, Shoenfeld Y, Gilburd B, et al. Anti-neutrophil cytoplasmic antibodies in patients with chromomycosis. Clin Exp Rheumatol 1996;14:479-483.

10. Byrd RP, Hourany J, Cooper C, Roy TM. False-positive antineutrophil cytoplasmic antibodies in a patient with cavitary pulmonary sporotrichosis. Am J Med 1998;104:101-103.

11. Kirchner J, Raab HP, Langer F, et al. Cavitating lung lesions in the course of ANCA-associated vasculitis: differential diagnostic aspects. Aktuelle Radiol 1998;8:114-118.

12. Milesi-Lecat AM, Aumaitre O, Deusebis T, et al. Semi-invasive diffuse pulmonary aspergillosis with antineutrophil cytoplasmic antibodies. 2 cases. Ann Med Interne (Paris) 1994;145:140-146.

13. Stappaerts I, Bogers J, Ebo D, et al. c-ANCA positivity in a Belgian patient with pulmonary paracoccidioidomycosis. Eur Respir J 1997:10:2419-2422.

14. Jain P, Sandur S, Meli Y, et al. Role of flexible bronchoscopy in immunocompromised patients with lung infiltrates. Chest 2004;125:712-722.

The goal of life is living in agreement with nature.
--Zeno

Bobbak Vahid, MD, Bernadette Wildemore, MD, Christopher Nguyen, MD, and Paul Marik, MD

From the Department of Pulmonary and Critical Care Medicine and the Department of Pathology, Thomas Jefferson University; Philadelphia, PA.

Reprint requests to Bobbak Vahid, MD, Thomas Jefferson University, 1015 Chestnut Street, Suite M-100, Philadelphia, PA 19107. Email: [e-mail]

Accepted February 15, 2006.

RELATED ARTICLE: Key Points

* Pulmonary aspergillosis should be included in the differential diagnosis of patients on immunosuppressive therapy that present with new pulmonary lesions.

* False-positive C-ANCA may be seen in immunosuppressed patients with pulmonary aspergillosis.

* Positive C-ANCA with concurrently positive P-ANCA or negative anti-PR3 antibodies should alert the clinicians to consider alternative diagnoses other than recurrent vasculitis.

* Although further studies are necessary, the galatomannan ELISA assay could be potentially useful to differentiate between invasive aspergillosis and recurrent vasculitis.

Table. Infections associated with positive C-ANCA

Bacterial infections      Bacterial pneumonias
                          Bacterial empyemas
Mycobacterial infections  Mycobacterium tuberculosis
                          Mycobacterium bovis
Fungal infections         Chromomycosis
                          Cavitary pulmonary sporotrichosis
                          Cavitating pulmonary aspergillosis
                          Semi-invasive pulmonary aspergillosis
                          Pulmonary paracoccidioidomycosis