Immune deposits in cutaneous lesions of Wegener's granulomatosis: predictor of an active disease.

A retrospective analysis was conducted of eight cases of Wegener's granulomatosis (WG), who presented with cutaneous lesions. The clinical, immunopathologic and histopathologic features of the cutaneous lesions were reviewed. Antineutrophil cytoplasmic antibody (ANCA) status of the patients was established. When possible, a comparison of immunofluorescence findings of skin biopsies was made with those of renal biopsies taken at the same time. In all except one, systemic and cutaneous disease developed concurrently. On histopathology, leukocytoclastic vasculitis was noted in five patients and features of lupus erythematosus and pyoderma gangrenosum in one case each. Four patients showed immunoglobulin deposits in subepidermal blood vessel walls, while one patient showed granular immune deposits at dermo-epidermal junction only. Immunoglobulin G was the most common immunoreactant detected. C-ANCA/proteinase 3 (PR3)-ANCA was positive in six patients, P-ANCA/myeloperoxidase (MPO)-ANCA in one patient, while one patient did not show ANCA positivity on indirect immunofluorescence. All four renal biopsies showed pauci-immune glomerulonephritis, irrespective of the presence (n=3) or absence (n=1) of immune deposits in the skin biopsy. Skin manifestations are encountered in nearly half of the patients with WG, thus it is important to be familiar with cutaneous histopathologic as well as immunofluorescence findings in WG patients.

Introduction

Skin involvement is not unusual in Wegener's granulomatosis (WG) and occasionally may be a premonitory sign of the disease.[1] Accurate interpretation of skin biopsies taken from the lesions is essential for diagnosis and management of these patients since histologic diagnosis may correlate with the activity and course of WG.[23]

The present retrospective study was undertaken to focus attention on clinical, immunofluorescence and histopathologic findings in skin lesions of patients with WG, which have not been reported from India so far. Very few studies[1-3] have highlighted the presence of immunoglobulin deposits in skin lesions of WG. Thus, these observations can open interesting avenues for future studies to understand the immunopathogenesis of WG.

Case Report

A subgroup of eight patients of WG who underwent skin biopsies was generated from the database from August 2008 to August 2009. All patients fulfilled both the classification criteria of the American College of Rheumatology (ACR) and the Chapel-Hill Consensus definition for WG and presented with cutaneous lesions. The age at onset ranged from 9 to 52 years; three patients developed disease below 20 years. Male and female ratio was 1:1.

Clinically, skin lesions included palpable purpura in five cases, and erythema, necrotizing ulcer and macule in one case each. Lesions were present on lower extremities in all the patients. A detailed clinical description of cutaneous lesions as well as results of laboratory investigations is presented in Table 1. In all except one, systemic and cutaneous disease developed concurrently, while in one patient (Patient no. 5), it developed 2 years after the diagnosis of systemic disease. In all patients, skin biopsies were taken from newly developing skin lesions.

Table 1

Clinical, histopathologic and immunofluorescence findings of skin biopsies in patients with Wegener's granulomatosis

Histopathologic features of cutaneous lesions showed leukocytoclastic vasculitis (LCV) in five patients. Fibrinoid necrosis of blood vessel walls was a finding specific for LCV. Medium-sized dermal vessels were invaded by polymorphonuclear leukocytes with resultant destruction of vessel walls and leukocytes producing nuclear dust. Swollen endothelial cells and extravasated red blood cells were invariably present in all cases. Vesicle was noted in one case. The epidermis was unremarkable in all cases. Granulomas were not seen in any biopsy. Patient no. 5 showed mild perivascular and periadenexal lymphomononuclear inflammatory infiltrate with no evidence of vasculitis and was reported as showing “nonspecific changes.” Patient no. 2 showed features consistent with lupus erythematosus (LE) with flattening and focal squamatization of the basal layer of epidermis. Biopsy from thigh ulcer in patient no. 6 was reported as pyoderma gangrenosum with evidence of vasculitis and showed mixed inflammatory infiltrate in the reticular dermis with a central lymphoplasmacytic rich area and peripheral neutrophilic infiltrate.

Direct immunofluorescence (DIF) findings of skin biopsy were available in seven patients. Four patients showed immunoglobulin deposits in subepidermal blood vessel walls [Figures 1 and 2]. Two of these patients showed deposits at dermo-epidermal junction (DEJ) in addition to the immune deposits at blood vessel walls, one showed granular positivity and the other showed linear positivity. Patient no. 2 who showed histopathologic features of LE on skin biopsy, demonstrated granular immune deposits at DEJ [Figure 3] consistent with lupus band test (LBT). IgG was the most common immunoreactant detected, being present in four cases, followed by IgM in three cases and IgA in two cases. IgA immunofluorescence pattern was indistinguishable from IgA staining pattern seen in patients with Henoch-Schonlein purpura. Complement C3 deposits were detected in the blood vessel walls of three patients. Immunoglobulin deposits in blood vessel walls were detected in skin lesions histopathologically showing LCV (three cases) and nonspecific changes (one case). Biopsy showing pyoderma gangrenosum from the ulcerated lesion did not reveal any immune deposits. Two patients showing LCV histologically had negative findings on DIF.

Figure 1

DIF photomicrograph of LCV (patient no. 1) showing granular (++++) deposits of IgG in the walls of blood vessels in the upper dermis (×100)

Figure 2

DIF photomicrograph of LCV (patient no. 1) showing granular (++++) deposits of IgG in the walls of blood vessels in the upper dermis (×400)

Figure 3

DIF photomicrograph of lupus erythematosus (patient no. 2) showing granular (+++) deposits of IgG at the DEJ (×200). Arrow shows lupus band at DEJ

In four out of eight patients, renal biopsies were carried out at the same time as the skin biopsies. All renal biopsies showed pauci-immune crescentic glomerulonephritis [Table 2]. Electron microscopy was performed in one renal biopsy (patient no. 3) and showed pauci-immune crescentic glomerulonephritis. In three of these four patients, immune deposits were found in the skin biopsy, while a pauci-immune pattern was found in both the kidney and skin biopsy of one patient.

Table 2

Immunopathological findings in skin and renal biopsies with clinical features according to ACR criteria

In patient no. 1 due to the presence of urinary symptoms like dysuria, nocturia and pyuria, a prostatic biopsy was also taken. Prostatic biopsy was taken 1 week prior to the appearance of skin lesions and showed necrotizing granulomatous inflammation. Stain for acid-fast bacillus (AFB) was negative and Periodic acid-Schiff (PAS) stain did not reveal any organisms. Based on these findings, a possibility of prostatic involvement by WG was also considered in this case, which is a rare presentation. Antineutrophil cytoplasmic antibody (ANCA) test results [indirect immunofluorescence (IIF) and enzyme-linked immunosorbent assay (ELISA)] were positive in all patients except one. C-ANCA/proteinase 3 (PR3) ANCA was present in six patients, while P-ANCA/myeloperoxidase (MPO)-ANCA was present only in one patient. ANCA on IIF was negative in patient no. 5 at all points in time whenever it was performed through the course of his illness. Antinuclear antibodies were negative in all the patients.

Discussion

Prevalence of skin lesions in WG has been reported to be between 35% and 50% and may occur at any time in the course of disease.[2] Four studies from India have described cutaneous manifestations in 32–39% of patients with WG, but none have described immunofluorescence as well as histopathologic findings in skin lesions.[4-7] To our knowledge and based on our data search, this is the first study from India that shows the presence of immune deposits in skin biopsies of WG. These studies and our results challenge the current notion that WG is a genuine pauci-immune vasculitis. We have shown that immune deposits may be present in skin lesions, even when they are absent in renal lesions. However, we cannot exclude unequivocally that “nonspecific trapping” in skin subepidermal blood vessels can occur as a result of vessel wall damage. Moreover, the immunoglobulin that probably causes trapping, i.e. IgM, was detected in minority of our biopsies, whereas damaged blood vessels were present in most of them.

Clinically, no single skin change is pathognomonic of WG. More typical lesions consist of palpable purpura, papules, ulcerations, vesicles, subcutaneous nodules, necrotizing ulcerations, papulonecrotic lesions and petechiae.[1] The cutaneous histopathologic features of WG cover a wide spectrum of findings including LCV, palisading granulomas, granulomatous vasculitis and lymphomatoid granulomatosis.[13] Pyoderma-like ulcers or necrotizing ulcerations resembling pyoderma gangrenosum are rare manifestations.[8] None of the skin biopsy changes could be considered diagnostic of WG. LCV was by far the most common histopathologic pattern in our series and occurred in patients with active multi-organ disease. A marked excess of joint and musculoskeletal symptoms and renal disease is seen in WG patients with LCV.[3] Similar findings were already reported by Hu et al.,[9] Barksdale et al. suggested that patients with LCV had more rapidly progressive and widespread WG than patients with granulomatous skin lesions or those without skin lesions.[3] None of the patients with granulomatous skin lesion in their study showed renal or pulmonary manifestation of WG and their disease progressed at a slower rate than that of patients with LCV. Therefore, cutaneous lesions may, to a certain extent, distinguish different subgroups of WG patients: patients with an extensive vasculitic diathesis at one end of the spectrum and patients with superficial granulomatous lesions at the other. Thus, cutaneous lesions characteristic of WG may correlate with the activity, distribution and course of the disease.

Only a few case reports and small-sized studies have described the presence or absence of immune deposits in skin biopsies of patients with WG.[1-3] Daoud et al. showed IgM as the most common immunoreactant deposited in and around dermal vessels in 79% of 14 skin biopsies showing LCV, followed by C3, while 4 patients had completely negative DIF findings.[1] Hu et al. have shown immunofluorescence results in 4 of 19 skin lesions showing LCV and only one biopsy showed the presence of IgM in the dermal blood vessels.[9] In a series by Brons et al., 4 of 11 skin biopsies taken at initial presentation and 4 of 21 biopsies taken at the onset of relapse of WG showed IgG and/or IgA containing immune deposits in the subepidermal blood vessels.[2]

In patient no. 2, histopathology as well as DIF of the skin biopsy suggested LE. Because of nephrotic range proteinuria and active urinary sediment, a renal biopsy was also performed at the same time. On light microscopy, renal biopsy showed crescentic golmerulonephritis. Immunofluorescence gave negative results, which tended to rule out renal LE. The patient also had lower respiratory tract involvement in the form of hemoptysis and pulmonary nodules on chest X-ray. The absence of systemic lupus erythematosus (SLE) symptoms and classic SLE serologic data argued against SLE clinically. It has been already shown that skin biopsies of patients with WG may demonstrate findings consistent with LE.[10] Although pathologic findings in these two diseases can overlap, the clinical categories can be distinct.

WG requires both clinical and pathologic features for diagnosis that can be complicated by the fact that not all patients demonstrate the classical triad of upper and lower respiratory tract disease with renal involvement. Furthermore, biopsy specimens from the lung and upper respiratory tract do not often show the classical pathologic triad of granulomatous inflammation, necrosis and vasculitis.[11] Also, all the major histopathologic features of WG found in the lung and upper respiratory tract (parenchymal necrosis, granulomatous inflammation and LCV) are also found in cutaneous lesions. So, in combination with findings from biopsy at other sites and/or clinical information, cutaneous findings could assist in diagnosis or in monitoring activity of disease.

The results shown here suggest that a substantial number of patients with WG show immunoglobulin deposits in skin lesions. The immune complexes from the skin can be eluted and further analyzed to detect the antigenic component triggering the disease. Skin manifestations are encountered in nearly half of the patients and also the skin is more readily accessible for biopsies than the other sites. Thus, it is important to be familiar with cutaneous histopathologic as well as immunofluorescence findings in WG patients.