Pulmonary capillaritis. The association with progressive irreversible airflow limitation and hyperinflation

Diffuse Alveolar Hemorrhage in Primary Versus Secondary Antiphospholipid Syndrome

BACKGROUND

Diffuse alveolar hemorrhage (DAH) occurs in patients with both primary and secondary antiphospholipid antibody syndrome (APS). We sought to determine the differences in clinical presentation, management, and outcomes of DAH in these patients.

METHODS

We performed a medical records review study and reviewed 30 patients with DAH in the setting of primary and secondary antiphospholipid syndrome seen at our institution between January 1, 1997, and December 31, 2018. We analyzed their demographics, clinical presentation, laboratory values, imaging studies, lung pathology results, management, and outcomes.

RESULTS

The patients in the secondary APS cohort were younger (median age, 48.5 vs 58 years) and comprised more females (75% vs 17%) compared with those with primary APS (p < 0.05). Two thirds of patients in the secondary APS group were anemic compared with less than one fourth in the primary APS group (p = 0.005). At the time of the first episode of DAH, the patients in the secondary APS required invasive and noninvasive ventilation, antibiotics, and combination immunosuppressive therapy (includes a combination of glucocorticoids with immunosuppressants or intravenous immunoglobulins or plasma exchange) more often compared with those with primary APS. There was only one in-hospital death (3% in-hospital mortality). One-year and 5-year mortality rates were 20% and 27%, respectively, with no significant difference between the primary and secondary APS groups.

CONCLUSIONS

Diffuse alveolar hemorrhage in the setting of APS, especially secondary APS, can be severe. However, in-hospital mortality is uncommon with current management strategies.

Pulmonary Low Attenuation Areas on CT in ANCA-associated Vasculitis: A quantitative and semi-quantitative analysis correlated with pulmonary function testing for obstructive airway disease

Objective:

A subset of ANCA-associated vasculitis (AAV) patients are known to manifest obstructive airway disease. Using low attenuation areas (LAA) in the lung on HRCT as an imaging marker for obstructive airway disease, we analyze HRCT studies in AAV patients compared to a matched non-AAV group using visual semi-quantitative and automated quantitative analysis for presence and severity of LAA. Furthermore, HRCT and pulmonary function testing are compared to assess agreement between tests for airway obstruction.

Materials and Methods:

100 randomly selected AAV patients with HRCT were compared to 100 best-fit matched control subjects. HRCT cases were visually assessed for LAA, along with additional pulmonary patterns. Automated quantitative software analyzed images for texture features and volume of attenuation values of −950 HU or less (e-950). Evidence of obstructive airway disease established by pulmonary function testing, when available, was compared to HRCT analysis for LAA. Additional clinical information, diagnostic testing and mortality data were also compared.

Results:

Both study groups were comprised of 57 females and 43 males with 35 smokers averaging 10.7 pk/yrs, with average age for the AAV and control groups being 59.4 yrs and 61.9 yrs, respectively. Visually, 46 AAV patients demonstrated LAA on HRCT compared to 25 control patients (p=0.0017) with the difference in LAA presence entirely within the non-smoking subgroup (25 to 3, respectively, p=<0.0001). Quantitatively, greater than 5% e-950 demonstrated similar significant differences between AAV (36/100) and controls (19/100) (p=0.0065), predominantly in non-smokers (p=0.006). Obstruction on PFTs was significantly increased in AAV (p=0.002) with moderate agreement of obstructive disease with visual LAA on CT (Kappa 0.509). Of the obstructive disease metrics, visual LAA on CT correlated best with mortality (p=0.0085).

Conclusion:

Visual LAA and automated quantitative analysis for e-950 on HRCT demonstrate statistically significant increases in AAV patients compared to age, gender and smoking matched controls, with differences primarily seen in the non-smoking subset. AAV revealed statistically significant greater obstructive pulmonary disease on PFTs (Sarcoidosis Vasc Diffuse Lung Dis 2020; 37 (4): e2020016)

Diffuse alveolar haemorrhage associated with subsequent development of ANCA positivity and emphysema in three young adults

BACKGROUND

Diffuse alveolar haemorrhage (DAH) is characterized by the diffuse accumulation of red blood cells within the alveoli, presence of ground glass opacities and/or consolidation on computed tomography (CT). Aside from identifiable non-immune causes, DAH is classically subdivided into idiopathic (idiopathic pulmonary haemosiderosis, IPH) and autoimmune DAH. Here we describe three cases presenting with recurrent pulmonary haemorrhage, initially classified as IPH, who, several years after first presentation, develop anti myeloperoxidase antibodies (MPO) positivity, emphysema on CT and, in one case, renal involvement.

CASE PRESENTATION

Patient 1 was diagnosed with IPH aged 14. Her disease remained poorly controlled despite immunosuppression, although ANCA remained negative over the years. Nineteen years from initial presentation, she developed MPO-ANCA positive antibodies and mild renal impairment. She was treated with Rituximab with good response. From first presentation, the chest CT was consistently characterized by diffuse ground-glass opacities and interlobular septal thickening. Ten years later, cystic opacities consistent with emphysema, with a striking peribronchovascular distribution, developed. Patient 2 was diagnosed with IPH aged 32. He was treated with corticosteroids and methotrexate, with fluctuating response. At 11 years from initial presentation, MPO-ANCA positivity was identified, and emphysema with a peribronchovascular distribution was observed on CT, with subsequent significant increase in extent. Patient 3 was diagnosed with IPH at the age of seven, and had recurrent episodes of haemoptysis of varying degree of severity, treated with intermittent courses of corticosteroids until age 11, when he was intubated due to severe DAH. Eight years after the diagnosis emphysematous changes were noted on CT and MPO-ANCA positivity developed for the first time 11 years after initial diagnosis.

CONCLUSIONS

We believe these three cases highlight: 1) the possibility of development of ANCA positivity several years down the line from first DAH presentation 2) the possibility that DAH may lead to cystic/emphysematous changes with peribronchovascular distribution on CT. Moreover, the need for ongoing immunosuppressive treatment and the development of emphysema, emphasize a possible role played by autoimmune phenomena, even when DAH is initially diagnosed as "idiopathic". Further studies are required to better understand the relationship between DAH, ANCA positivity and development of emphysema.

Clinical Insights into Diffuse Alveolar Hemorrhage in Antiphospholipid Syndrome

PURPOSE OF REVIEW

Diffuse alveolar hemorrhage (DAH) is a rare but devastating manifestation of antiphospholipid syndrome (APS) patients with or without other systemic autoimmune diseases. Data regarding diagnosis and treatment are limited to case series. We review diagnostic and therapeutic strategies employed in APS patients with DAH and discuss our experience in managing these complex patients.

RECENT FINDINGS

Pulmonary capillaritis likely contributes to the pathogenesis, however is only observed in half of the biopsies. Corticosteroids induce remission in the majority of patients, however almost half recur and require a steroid-sparing immunosuppressive to maintain remission. Cyclophosphamide- or rituximab-based regimens achieve the highest remission rates (50%); other strategies include intravenous immunoglobulin, plasmapheresis, mycophenolate mofetil, and/or azathioprine. Given the rarity of DAH in APS, treatment is guided by interdisciplinary experience. Why certain patients achieve full remission with corticosteroids while others require immunosuppressive agents is unknown; future research should focus on the pathophysiology and optimal management.

Beneficial Effect of Gabexate Mesilate on Microscopic Polyangiitis With Renal Dysfunction and Pulmonary Hemorrhage

Corticosteroids and cyclophosphamide are the mainstay of the treatment of microscopic polyangiitis involving pulmonary hemorrhage or rapidly progressive glomerulonephritis. However, patients with advanced age are unable to tolerate this combined therapy, because of a relatively high incidence of side effects including infection, hemorrhagic cystitis, and bone marrow suppression. The authors encountered an 80-year-old patient with pulmonary hemorrhage and renal dysfunction ascribed to microscopic polyangiitis and achieved successful treatment by employing gabexate mesilate in addition to corticosteroids. The present case suggests that gabexate mesilate may be a therapeutic option for microscopic polyangiitis with progressive renal failure and pulmonary hemorrhage.

Granulomatosis with polyangiitis and associated pulmonary emphysema: Breathtaking vasculitis

Pulmonary emphysema occasionally occurs in the absence of smoking or noxious exposures. Other than through a known association with alpha-1 antitryspin deficiency, to our knowledge, no reports implicate granulomatosis with polyangiitis (GPA) in causing airflow obstruction with small airway involvement and severe air trapping. To extend available experience, we report a 51-year-old male with biopsy-proven cytoplasmic-antineutrophilic cytoplasmic antibody proteinase 3 (ANCA PR3)-positive GPA who developed centrilobular emphysema and airflow obstruction during a phase of active vasculitis. He was a lifelong non-smoker and had a normal alpha-1 antitrypsin level and a PI*MM phenotype. Treatment with corticosteroids and cyclophosphamide caused clinical remission of his vasculitis which was associated with improvement in his respiratory symptoms. However, to date, structural changes of emphysema have persisted for over 9 years of follow-up. Clinicians should remain vigilant to the possibility of emphysema in patients with pulmonary vasculitis.

Diffuse pulmonary hemorrhage: clues to the diagnosis

Diffuse pulmonary hemorrhage (DPH) refers to an uncommon but significant condition of bleeding into the alveolar space. Anemia and hemoptysis are important clinical features, but they may be absent. Although the radiographic and computed tomography findings are often varied and nonspecific, the imaging manifestations of pulmonary hemorrhage and the associated findings in the thorax often provide important diagnostic information that may lead to a specific diagnosis. DPH significantly influences patient management and has important prognostic implications. This review article explores the imaging findings in DPH and its differential diagnosis, highlighting important clues to this diagnosis and to its underlying etiology. DPH is an uncommon condition characterized by bleeding into the alveolar space that, when recognized on imaging, provides important diagnostic and prognostic information.

Alveolar Hemorrhage

Diffuse alveolar hemorrhage (DAH) is a clinical syndrome characterized by generalized intra-alveolar bleeding originating from the pulmonary microcirculation. The finding of DAH carries an extended differential diagnosis and may be associated with a number of histopathologic patterns. The prompt recognition and diagnosis of DAH is of critical importance to the practicing clinician as accurate diagnosis and prompt initiation of therapy may dramatically improve patient outcomes. This chapter reviews the diagnosis and management of diffuse alveolar hemorrhage.

Increased incidence of autoimmune markers in patients with combined pulmonary fibrosis and emphysema

Background

Combined pulmonary fibrosis and emphysema (CPFE) is an umbrella term encompassing upper lobe emphysema and lower lobe pulmonary fibrosis with pathogenesis elusive. The aim of our study was to investigate the incidence of autoimmune markers in patients with CPFE.

Methods

In this multicenter study we retrospectively evaluated records from patients with CPFE (n=40) and IPF (n=60) without emphysema. Baseline demographic characteristics, high-resolution computed tomography (HRCT), spirometry, histopathological, treatment, serum immunologic and survival data were investigated. B cell presence was estimated with CD20 immunostaining in representative lung biopsy samples from CPFE patients and control subjects.

Results

A statistically significant increased number of CPFE patients with elevated serum ANA with or without positive p-ANCA titers compared to patients with IPF without emphysema was observed. Patients with CPFE and positive autoimmune markers exhibited improved survival compared to patients with a negative autoimmune profile. A massive infiltration of clusters of CD20+ B cells forming lymphoid follicles within the fibrotic lung in CPFE patients with positive serum immunologic profile compared to patients with negative profile, was noted and positively correlated with improved survival.

Conclusions

A significant proportion of patients with CPFE may present with underlying auto-immune disorders that may reside insidiously and be associated with favorable prognosis. Early identification of these patients using a panel of auto-antibodies may lead to more targeted and effective therapeutic applications.

KL-6, a Human MUC1 Mucin, as a prognostic marker for diffuse alveolar hemorrhage syndrome

Background

Diffuse alveolar hemorrhage syndrome is a life threatening condition with diverse etiologies. Sensitive prognostic markers for diffuse alveolar hemorrhage have not been well investigated. Serum KL-6 is a biomarker for various interstitial lung disease associated with disease activity and prognosis. The purpose of the present study was to evaluate the clinical utility of serum KL-6 level as a prognostic marker for diffuse alveolar hemorrhage.

Methods

We retrospectively collected 41 consecutive patients clinically diagnosed as having diffuse alveolar hemorrhage who were admitted to the Intensive Care Unit of Hiroshima University Hospital between 2004 and 2011. Correlation between prognosis and age, sex, laboratory findings including serum KL-6, radiological findings, ventilatory modes or therapeutic regimens were evaluated.

Results

Baseline and peak serum KL-6 levels were significantly higher in non-survivors compared with survivors. An increase in KL-6 levels during the initial week was associated with a subsequent deterioration of the oxygenation index. Higher baseline KL-6 levels and higher peak KL-6 levels were strongly correlated with death. With a cut-off level of 700 U/mL for peak KL-6, the sensitivity, specificity and accuracy for non-survival were 75%, 85% and 78%, respectively. In the multivariate analysis, only the peak KL-6 level ≥700 U/ml was an independent poor prognostic factor for diffuse alveolar hemorrhage.

Conclusions

Peak serum KL-6 level ≥700 U/ml may become a clinically useful marker of poor prognosis for diffuse alveolar hemorrhage.

Respiratory system involvement in antineutrophil cytoplasmic-associated systemic vasculitides: clinical, pathological, radiological and therapeutic considerations

Wegener's granulomatosis (WG), microscopic polyangiitis (MPA) and Churg- Strauss syndrome (CSS) are small-vessel vasculitides that, because of their frequent association with antineutrophil cytoplasmic antibodies (ANCA), are usually referred to as ANCA-associated systemic vasculitides (AASV). The diagnosis of AASV is made on the basis of clinical findings, biopsy of an involved organ and the presence of ANCA in the serum. Lung disease is a very common and important clinical feature of AASV. In WG, almost all patients have either upper airway or lower respiratory tract disease. Solitary or multiple nodules, frequently cavitated, and masses are the most common findings on chest radiography. Asthma is a cardinal symptom of CSS, often preceded by allergic rhinitis. Pulmonary transient and patchy alveolar infiltrates are the most common radiographic findings. In MPA, diffuse alveolar haemorrhage as a result of alveolar capillaritis is the most frequent manifestation of respiratory involvement, and is clinically expressed as haemoptysis, respiratory distress and anaemia. However, diffuse alveolar haemorrhage may also be subclinical and should be suspected when a chest radiograph demonstrates new unexplained bilateral alveolar infiltrates in the context of falling haemoglobin levels. Normal and high-resolution CT have a higher sensitivity than chest radiography for demonstrating airway, parenchymal and pleural lesions. However, many of these radiological findings are nonspecific and, therefore, their interpretation must take into account all clinical, laboratory and pathological data. Therapy of AASV is commonly divided into two phases: an initial 'remission induction' phase, in which more intensive immunosuppressant therapy is used to control disease activity, and a 'maintenance' phase, which uses less intensive therapy, for maintaining disease remission while lowering the risk of adverse effects of immunosuppressant drugs. In patients with AASV refractory to standard therapy with corticosteroids and oral cyclophosphamide, new therapeutic options are now available. Recurrence of pulmonary symptoms suggesting a flare indicates the need for a careful search for an opportunistic lung infection or iatrogenic pulmonary complications. In conclusion, involvement of the respiratory system is a very common and important organ manifestation of AASV. Respiratory system involvement comprises a wide spectrum of clinical features and radiological findings, and because of its frequency and prognostic significance, a complete assessment of the respiratory system should be included in the work-up of all patients with AASV.

Alveolar hemorrhage in anti-basement membrane antibody disease: a series of 28 cases

Anti-basement membrane antibody disease is a rare disorder characterized by the presence of autoantibodies binding to the alveolar and glomerular basement membranes, and mediating both alveolar hemorrhage and acute glomerulonephritis. We retrospectively analyzed 28 cases of anti-basement membrane antibody disease with alveolar hemorrhage proven by bronchoalveolar lavage. The median age of patients at diagnosis was 23 years; 68% were male, 89% were active smokers, and 36% were exposed to some other inhaled agent. At diagnosis, 46% had predominant pulmonary involvement with normal initial serum creatinine. Lung function tests disclosed a restrictive ventilatory defect in 28% (n = 11) and hypoxemia (moderate in 29% and severe in 29%, n = 21). Carbon monoxide transfer factor was elevated in only 25% (n = 12). Bronchoalveolar lavage was more sensitive than any other criterion for detecting alveolar hemorrhage. After onset of treatment, new hemoptysis or transient worsening of hypoxemia occurred in 29% but did not affect pulmonary outcome. In contrast, worsening of renal function occurred in 33% and adversely affected renal outcome. At last follow-up (median, 2.6 yr; n = 24), all patients were alive and a complete cure was achieved in 50%. Long-term dialysis or renal transplantation was required in 42%, and 8% had mild chronic renal insufficiency. Last chest X-ray was normal in all cases, and no patient had respiratory insufficiency. All patients with predominant pulmonary involvement at presentation maintained independent renal function. In summary, this cohort was characterized by frequent exposure to tobacco smoking and other inhaled agents, and a constantly favorable pulmonary outcome contrasting with frequent chronic renal failure. Renal outcome was excellent in the subgroup of patients with predominant pulmonary involvement.

Impairment of lung function, health status and functional capacity in patients with ANCA-associated vasculitis

OBJECTIVE

To determine the effects of lung involvement on respiratory function in patients with ANCA-associated vasculitis and the relation to impaired health status.

METHODS

Thirty patients with ANCA-associated vasculitis in remission (15 with lung involvement at diagnosis as determined by an abnormal chest X-ray) were examined. We measured lung function, skeletal muscle strength [quadriceps force (QF), respiratory muscle strength (Pi(max))], exercise capacity (VO(2) peak) using treadmill exercise tests, and health status using the Short Form 36 and St George's respiratory questionnaires.

RESULTS

Exercise capacity was reduced compared with predicted values (58.2%, range 23-123%) and 18 patients showed functional aerobic impairment. Respiratory muscle function was reduced (72.1% predicted, range 20-108%) and was not related to lung involvement or steroid usage. Transfer factor correlated significantly with exercise capacity, suggesting inadequate delivery of oxygen to muscles. Nine patients had reduced transfer factor (seven with lung involvement). Patients with lung involvement had impaired gas transfer compared with those without lung involvement (96.9 +/- 6 vs 113.3 +/- 4.7% predicted, P = 0.04). However, there were significant abnormalities in other lung function parameters not related to previous lung involvement (eight patients had reduced forced expiratory volume in 1 s, and five patients had reduced residual volume). Twelve patients (five with previous lung involvement) had obstructive airways disease. Physical health status was impaired to a greater degree than mental health status across the whole group and was not related to lung involvement or original disease severity, but correlated with transfer factor.

CONCLUSION

Patients with ANCA-associated disease may have significant lung function impairment irrespective of lung involvement at the time of diagnosis. Patients showed reduced respiratory muscle strength, health status and exercise capacity, which correlated with reduced transfer factor.

Imaging of macrophage-related lung diseases

Macrophage-related pulmonary diseases are a heterogeneous group of disorders characterized by macrophage accumulation, activation or dysfunction. These conditions include smoking-related interstitial lung diseases, metabolic disorders such as Niemann-Pick or Gaucher disease, and rare primary lung tumors. High-resolution computed tomography abnormalities include pulmonary ground-glass opacification secondary to infiltration by macrophages, centrilobular nodules or interlobular septal thickening reflecting peribronchiolar or septal macrophage accumulation, respectively, emphysema caused by macrophage dysfunction, and honeycombing following macrophage-related lung matrix remodeling.

The pulmonary physician in critical care * illustrative case 3: pulmonary vasculitis

The case history of a patient admitted to the ICU with severe hypoxic respiratory failure later diagnosed as Wegener's granulomatosis is presented. The diagnosis and management of patients with suspected pulmonary vasculitis is discussed.

Small-vessel diseases of the lung: CT-pathologic correlates

Diseases that primarily affect the small vessels of the lung are difficult to diagnose. Many conditions are characterized by involvement of small pulmonary vessels, and pathologically they can be conveniently divided into occluding and inflammatory types. The former, typified by chronic pulmonary thromboembolism and primary pulmonary hypertension, are relatively cryptic in terms of imaging. In contrast, inflammatory vasculitides, which often cause pulmonary hemorrhage and infarction, result in florid but nonspecific radiographic abnormalities. The spectrum of thin-section computed tomographic abnormalities encountered in the inflammatory vasculitides is wide: For example, in Wegener granulomatosis the pattern ranges from cavitating nodules to lobar consolidation to ground-glass opacity. This review highlights some of the less obvious imaging manifestations of occlusive and inflammatory diseases of the small pulmonary vessels.

Microscopic polyangiitis with alveolar hemorrhage. A study of 29 cases and review of the literature. Groupe d'Etudes et de Recherche sur les Maladies "Orphelines" Pulmonaires (GERM"O"P)

Microscopic polyangiitis (MPA) is a systemic small-vessel vasculitis primarily associated with necrotizing glomerulonephritis and pulmonary capillaritis. In this retrospective study of 29 patients with MPA and alveolar hemorrhage (AH), we characterized the pulmonary manifestations at presentation and assessed the short- and long-term outcome. AH was diagnosed when bronchoalveolar lavage was macroscopically bloody, or contained hemosiderin-laden macrophages, in the absence of lung infection or pulmonary edema. MPA was diagnosed when AH was associated with focal segmental necrotizing glomerulonephritis at kidney biopsy or pathologically proved small-vessel vasculitis. There were 17 women and 12 men, with a mean age of 55.8 +/- 16.7 years. The onset was rapidly progressive, but in 8 (28%) patients, symptoms preceded the diagnosis for more than 1 year. The most constant systemic findings associated with AH were glomerulonephritis in 28 (97%) patients; fever (62%); myalgia and arthralgia (52%); weight loss (45%); ear, nose, and throat symptoms (31%); and skin involvement (17%). Lung opacities were bilateral in 26 (90%) patients, most frequently involving the lower part of the lungs. Bronchoalveolar lavage, performed in 27 patients, was hemorrhagic in 25 (93%), and contained numerous siderophages in others. Most patients were severely anemic (mean hemoglobin, 8.1 +/- 1.8 g/dL). ANCA, present in 27 (93%) patients, gave a perinuclear (14), cytoplasmic (11), or mixed (1) pattern. Mean serum creatinine level was 407 +/- 415 mumol/L. Renal biopsy confirmed the presence of necrotizing glomerulonephritis in 27 patients. Patients were treated with corticosteroids (100%), cyclophosphamide (79%), plasmapheresis (24%), dialysis (28%), and mechanical ventilation (10%). The overall mortality rate was 31% (9 patients). Deaths were related to vasculitis (5 patients) or side effects of treatment (4). Deaths were more frequent in aged or mechanically ventilated patients. The 5-year survival rate was 68%. The recovery of respiratory function among survivors was clinically considered complete in 20 (69%) patients. However, 7 patients (24%) had persistent alterations on pulmonary function tests. Of the 11 patients who had relapses, 2 died from AH.

Pulmonary vasculitis

Pulmonary vascular inflammation may be seen in a variety of primary lung diseases and in the setting of numerous systemic illnesses. This article reviews those entities in which pulmonary vasculitis represents a central feature of the pathologic process (Wegener's granulomatosis, Churg-Strauss syndrome, and pulmonary capillaritis). In addition, features of pulmonary involvement in other systemic vasculitides (Giant Cell Arteritis, Takayasu's Arteritis, and Behçet's disease) are described. Finally, general principles for the treatment of vasculitis are reviewed.

Obstructive pulmonary disease. The clinician's perspective

This article reviews the differential diagnosis of obstructive lung disease, including lesions that may mimic chronic obstructive pulmonary disease, as well as the tools on which the clinician relies for making a proper diagnosis. The clinician's view of the radiologist's role is briefly discussed, but the details of specific radiologic techniques are discussed elsewhere in this issue.

Pulmonary capillaritis and alveolar hemorrhage. Update on diagnosis and management

Pulmonary vascular inflammatory disorders may involve all components of the pulmonary vasculature, including capillaries. The principal histopathologic features of pulmonary capillaritis include capillary wall necrosis with infiltration by neutrophils, interstitial erythrocytes, and/or hemosiderin, and interalveolar septal capillary occlusion by fibrin thrombi. Immune complex deposition is variably present. Patients often present clinically with diffuse alveolar hemorrhage, which is characterized by dyspnea and hemoptysis; diffuse, bilateral, alveolar infiltrates on chest radiograph; and anemia. Pulmonary capillaritis has been reported with variable frequency and severity as a manifestation of Wegener's granulomatosis, microscopic polyarteritis, systemic lupus erythematosus, Goodpasture's syndrome, idiopathic pulmonary renal syndrome, Behçet's syndrome, Henoch-Schönlein purpura, IgA nephropathy, antiphospholipid syndrome, progressive systemic sclerosis, and diphenylhydantoin use. In addition to history, physical examination, and routine laboratory studies, certain ancillary laboratory tests, such as antineutrophil cytoplasmic antibodies, antinuclear antibodies, and antiglomerular basement membrane antibodies, may help diagnose an underlying disease. Diagnosis of pulmonary capillaritis can be made by fiberoptic bronchoscopy with transbronchial biopsy, but thoracoscopic biopsy is often employed. Since many disorders can result in pulmonary capillaritis with diffuse alveolar hemorrhage, it is crucial for clinicians and pathologists to work together when attempting to identify an underlying disease. Therapy depends on the disorder that gave rise to the pulmonary capillaritis and usually includes corticosteroids and cyclophosphamide or azathioprine. Since most diseases that result in pulmonary capillaritis are treated with immunosuppression, infection must be excluded aggressively.

Fibrosing vasculitis in Wegener's granulomatosis: ultrastructural and immunohistochemical analysis of the vascular lesions

This study of two cases of pulmonary Wegener's granulomatosis (WG) focuses on the ultrastructural aspects of the vascular wall injury and on the immunohistochemical characterization of the perivascular connective matrix. The iterative waves of endothelial cell necrosis and regeneration are demonstrated by the multilamellar appearance of the basal lamina. Neutrophils infiltrate the vessel wall and myofibroblasts are recruited to injured vessels. The perivascular connective matrix associates basement-membrane like and fibrillar material with fibrin deposits. The initiation of the fibrosing process was assessed by the visualization of matrix molecules involved in targeting (p-fibronectin), organizing (cellular fibronectin and tenascin) and stabilizing (lysyl-oxidase) the fibrogenic activity. These elementary lesions affect different levels of the vascular tree, and capillaritis is involved in the extension of the pathological process. Lysyl-oxidase labelling reveals the fibrosing front which is located on the border of dense fibrosis. The markers of fibrosing activity disappear in the areas of fibrosis following vasculitis and/or ischaemic necrosis and/or granulomatosis. Vasculitis plays a major role in both the genesis and progression of the fibrosis observed in the late stage of WG.