Serum angiotensin-converting enzyme and lysozyme in granulomatous diseases of unknown cause

Screening of serum samples from Wegener's granulomatosis patients using antibody microarrays

Wegener's Granulomatosis (WG) is an idiopathic granulomatosis autoimmune vasculitis that primarily affects small vessels and is associated with glomerulonephritis and pulmonary granulomatous vasculitis. Anti-neutrophil cytoplasmic auto-antibodies (cANCA) against proteinase-3 are used to identify WG, but ANCA titers are not present in some patients with the localized disease. The objective of this study was to develop an antibody array to help identify protein expression patterns in serum from patients with WG as compared to normals. The arrays were tested for limits of detection, background, and cross reactivity using standard proteins. The arrays were hybridized with either normal patient serum (n = 30) or with serum samples from a population of WG patients (n = 26) that were age and sex matched. Data analysis and curve fitting of the standard dilution series calculated r(2) values and determined a sensitivity of <50 pg/mL for the majority of proteins. A total of 24 proteins were assessed. Several statistically significant increases (p<0.05) were seen in the expression of: angiotensin converting enzyme-I, IFN-γ, IL-8, s-ICAM-1 and s-VCAM in WG patients as compared to controls. Utilizing the antibody microarray technology has led to the identification of potential biomarkers of vascular injury in the serum of WG patients.

The usefulness of angiotensin converting enzyme in the differential diagnosis of Crohn's disease and intestinal tuberculosis

BACKGROUND

Since the pathologic findings of Crohn's disease (CD) and intestinal tuberculosis (IT) overlap to a large degree, the development of other biomarkers will be of great help for making the differential diagnosis of these 2 diseases. The aim of the present study is to examine the clinical efficacy of using the tissue angiotensin converting enzyme (ACE) assay in making the differential diagnosis between CD and IT.

METHODS

Tissue specimens were obtained from 36 patients who were diagnosed with CD or IT by the colonoscopic biopsy, as well as by the clinical findings. The expression of tissue ACE was detected by immunohistochemical staining. The optimal cut-off value of the immunoreactive scoring (IRS) system we used to differentiate CD from IT was determined by analysis of the ROC curve and AUROC.

RESULTS

Granuloma was present in 15 of 19 patients with CD (78.9%) and in 15 of 17 patients with IT (88.2%). ACE was present in the cytoplasm of the epithelioid cells in the granulomas from 13 of 15 patients with CD and in 14 of 15 patients with IT. The IRS scores of ACE were greater in the patients with CD than that of the patients with IT (8.07 +/- 4.38 vs. 4.13 +/- 2.47, respectively, p = 0.006). In differentiating CD from IT, the AUROC curve for the IRS of ACE was 0.767 with a sensitivity of 66.7%, a specificity of 93.3% and the cut-off point was 7.5.

CONCLUSIONS

The results of our study suggest that the assessment of the tissue ACE expression can be helpful for making the differential diagnosis between CD and IT.

Idiopathic granulomatous orbital inflammation

PURPOSE

Granulomatous orbital inflammation may occur as an isolated condition of unknown origin. These idiopathic granulomatous lesions are believed to belong to the orbital pseudotumor group by some authors, whereas others consider them sarcoidosis limited to the orbit. The aim of this study is to define the clinicotherapeutic aspects of these lesions.

METHODS

The records of all patients with diagnosis of orbital pseudotumor and orbital sarcoidosis from the Orbital Center Amsterdam in the period between 1976 and 1994 were reviewed to define those with idiopathic granulomatous orbital inflammation. The authors studied the clinicotherapeutic aspects and histopathology of idiopathic granulomatous orbital inflammation by analysis of their own series and the literature.

RESULTS

Their study group encompassed seven patients with idiopathic granulomatous orbital inflammation. The mean follow-up was 9.5 years (range, 3.5-16.0 years). All had unilateral orbital presentation, with localization in the lacrimal gland in three patients. The lesions clinically presented with signs of mass effect or inflammation or both and were treated successfully with surgery, systemic corticosteroids, a combination of surgery and systemic corticosteroids, or systemic corticosteroids followed by irradiation. Histopathologic analysis showed a spectrum of granulomatous inflammation, admixed with nongranulomatous inflammation and fibrosis. There have been 30 similar cases described in the literature with comparable clinicotherapeutic characteristics.

CONCLUSIONS

Based on this study and the literature, it appears that idiopathic granulomatous orbital inflammation is more related to orbital pseudotumor than to orbital sarcoidosis.

The role of platelets in essential hypertension

Recent research is helping us understand the complex interactions that occur between platelets and their environment. The several intracellular events that occur during platelet activation are being identified as ar their effects on other platelets, the endothelium and coagulation factors. Heightened platelet activation is seen early in essential hypertension and probably plays an important role in the initiation and progression of atherosclerosis and the disorders associated with it. This review identifies some of the changes in platelet structure and function in essential hypertension and their role in the pathogenesis of hypertensive vascular disease.

ANCA and associated diseases: immunodiagnostic and pathogenetic aspects

The past decade has seen an explosion of data on the new group of autoantibodies known collectively as ANCA (anti-neutrophil cytoplasmic antibodies). ANCA are specific for granule proteins of granulocytes and monocytes and induce distinct fluorescence patterns, e.g. the cytoplasmic (classic) cANCA and the perinuclear pANCA. cANCA is induced by antibodies directed against Proteinase 3 (PR3; PR3-ANCA) in about 90% of all ANCA-positive sera, and pANCA is induced by antibodies against myeloperoxidase (MPO; MPO-ANCA) in about 40%. A further staining pattern, which does not have a clear cut association with a distinct granule protein, is sometimes seen in chronic inflammatory bowel diseases. PR3-ANCA are serological markers for Wegener's granulomatosis (WG) and MPO-ANCA are associated with certain subtypes of primary vasculitides. Evidence exists that both the autoantigen and ANCA participate in the pathogenesis of at least the group of 'ANCA-associated vasculitides'.

Calcium and vitamin D metabolism in granulomatous diseases

Overproduction of the active metabolite of vitamin D 1,25-dihydroxyvitamin D (1,25(OH)2D) has been described in sarcoidosis and other granulomatous diseases. High circulating concentrations of 1,25(OH)2D lead to increased intestinal absorption of calcium, possibly to enhanced bone resorption, and may result in hypercalcaemia and/or hypercalciuria. Data obtained in vivo and in vitro demonstrated that the unregulated production of 1,25(OH)2D lies within the granulomatous tissue and is controlled by glucocorticoids. This abnormal production of 1,25(OH)2D seems to be a general phenomenon of granulomatous processes, which is not exceptional in sarcoidosis, but appears seldom in tuberculosis. These abnormalities, however, are not pathognomonic of granulomatous processes, since they have been described in other diseases such as lymphomas.

Subretinal neovascularisation and snow banking in a case of sarcoidosis: case report

A 49-year-old Japanese man presented with chronic granulomatous uveitis in his left eye. Later he developed macular subretinal neovascularisation. The chest x-ray showed bilateral hilar lymphadenopathy. Bronchoscopy and gallium-67 scanning were positive, PPD skin test negative, and serum angiotensin converting enzyme (ACE) levels increased. Ophthalmoscopy and fluorescein angiography of the left eye showed perivasculitis, retinochoroidal exudates, snow banking, and vitreous opacity. On these findings, the diagnosis of sarcoidosis was made. Treatment was based on topical corticosteroids, mydriatics, beta blockers, and oral carbonic anhydrase inhibitors. After 15 months the visual acuity decreased in the left eye, and a neovascular membrane was observed in the macula. Fluorescein angiography confirmed subretinal neovascularisation. Almost two years later the patient still has the neovascular membrane in his left eye.

Angiotensin I converting enzyme activity in hypertension. Relationship to blood pressure, renin-sodium profiles, and antihypertensive therapy

The activity of the angiotensin I converting enzyme was measured in 55 patients with untreated essential hypertension, 11 patients with untreated renovascular hypertension, five patients with untreated primary aldosteronism, and 23 normotensive subjects. Converting enzyme activity was significantly higher (p less than 0.025 or less) in essential hypertension (28 +/- 1 units/ml) and renovascular hypertension (28.5 +/- 3 units/ml) when compared with the activity in the normotensive subjects (21 +/- 1.5 units/ml). Seventeen (31 percent) of the patients with essential hypertension and three (27 percent) patients with renovascular hypertension had an elevated converting enzyme activity above the mean +2 standard deviations value of the normotensive subjects (32.8 units/ml), ranging from 33 to 55.8 units/ml. Converting enzyme activity was similar in black and white patients and in male and female patients, but it tended to decrease with increasing age in both the hypertensive and the normotensive subjects. In the untreated patients with essential hypertension (n = 55), converting enzyme activity was inversely related to mean arterial pressure and age (r = -0.34, p less than 0.01) and positively related to plasma renin activity (r = 0.31, p less than 0.05). Converting enzyme activity was always decreased during captopril therapy, and it was not affected by beta blockers, but it was increased by diuretics. These findings indicate that converting enzyme activity is elevated in patients with essential and renovascular hypertension.

Serum angiotensin-converting enzyme and delayed hypersensitivity in pulmonary tuberculosis

In contrast to sarcoidosis, there was no difference between serum angiotensin-converting enzyme (ACE) levels in a group of 100 adult Indonesian patients with active pulmonary tuberculosis and in 108 matched healthy control subjects. There was a significant inverse correlation between the diameter of the cutaneous reaction to tuberculin and serum ACE levels. It is postulated that, as both delayed hypersensitivity and ACE synthesis within granulomas appear to be the result of T-cell induced secretory activities of macrophages, this inverse relationship results from competition for receptor sites for the relevant signal molecules on the macrophage surface.

Elevated serum angiotensin-converting enzyme (SACE) activity in acute pulmonary histoplasmosis

Serum angiotensin-converting enzyme (SACE) levels were measured in 44 subjects six weeks after acute pulmonary histoplasmosis. All patients were infected in a common-source outbreak of histoplasmosis which occurred on one day. All patients had both strictly defined clinical and serologic evidence of infection. The SACE activity was elevated at six weeks compared to normal controls, and seven of the 44 had levels more than 2 SD above the normal mean. SACE levels were also measured at three and 24 weeks after acute infection in a smaller number of the same subjects. Serial observations demonstrated that all subjects (including those with normal and elevated SACE at six weeks) had a rise and fall in SACE activity following symptomatic acute pulmonary histoplasmosis. Our findings suggest that elevated SACE does not reliably separate sarcoidosis from histoplasmosis, although elevations in histoplasmosis are much less common and may occur only briefly following acute pulmonary histoplasmosis. More important, it seems that SACE activity rises acutely in all patients with symptomatic acute histoplasmosis and then falls gradually toward baseline over several months, coinciding temporally with the granulomatous response.

Unusual clinical and histopathological findings in ocular sarcoidosis

A 37-year-old Caucasian woman presented with a blind left eye and granulomatous panuveitis in the right eye. There was a subretinal neovascular membrane with haemorrhage beneath the macula and widespread subretinal lesions that were interpreted as choroidal granulomas in the right eye. A chest x-ray that showed diffuse pulmonary fibrosis without hilar lymphadenopathy was the only contributory clinical finding. Systemic and subconjunctival steroids and photocoagulation to the right macula brought about temporary remission. The painful left eye was enucleated. Histopathological examination revealed diffuse, noncaseating granulomas in the iris and ciliary body, retina, choroid, optic nerve, sclera and scleral emissaria, and inferior oblique muscle. A preretinal membrane was studied by electron microscopy. It was composed of a collagenous matrix containing fibroblasts and fibrous astrocytes. Some vessels, surrounded by a multilaminar basement membrane, revealed many features of normal retinal vasculature. Others were lined by markedly attenuated endothelial cells with occasional "open' junctions and fenestrations.