Immunofluorescence in Nonneoplastic Medical Lung Disease
Immunofluorescence in Nonneoplastic Medical Lung Disease
Fresh open lung biopsy material from 57 patients was incubated with fluoresceinated complement and immunoglobulin antisera. An indirect immunofluorescent assay using neonatal lung as substrate was conducted as well. Direct immunofluorescent patterns could be categorized into interalveolar septal capillary deposition, large vessel wall localization, alveolar basement membrane localization, or a pauci-immune immunofluorescence pattern. With respect to the septal capillary pattern, endothelial cell decoration was seen with scleroderma, mixed connective tissue disease, anti-Ro-associated lupus erythematosus, dermatomyositis, humoral allograft rejection, and patients with isolated pulmonary fibrosis in whom autoantibodies were established, including antiphospholipid antibodies. A similar pattern of endothelial cell staining was seen in these cases via the indirect assay. Granular mural septal capillary deposition was seen in the aforesaid settings along with rheumatoid factor-positive rheumatoid arthritis, type II cryofibrinogenemia, and mixed cryoglobulinemia and, in some cases, light microscopically corresponded to a neutrophilic capillaritis. Isolated vascular IgA corresponded with rheumatoid arthritis corresponding to IgA-specific antiendothelial cell antibodies, celiac disease-associated pulmonary hemorrhage, Schönlein-Henoch purpura and with IgA antiphospholipid antibodies. Alveolar wall deposition was seen with anti-glomerular basement membrane disease.
Immunofluorescent testing is an important diagnostic adjunct in the assessment of immunologically mediated diseases of the skin and kidney. The 2 main methods of immunofluorescent testing are direct and indirect immunofluorescence. Direct immunofluorescence (DIF) involves the overlay of fluorescein-conjugated antibodies directed against immunoglobulins (IgG, IgM, and IgA) and complement fractions onto frozen sections of patient tissue. Indirect immunofluorescence (IIF), by definition uses a linking antibody; in its common use, IIF refers to patient serum in concert with fluorescein-conjugated human anti-IgG applied to a mucosal substrate, such as guinea pig, monkey esophagus, or rat bladder.
The use of either a DIF or an IIF assay has received little attention as a diagnostic aid in lung disorders. There are, however, many conditions affecting lung for which an initial inciting trigger leading to pulmonary injury has an immune-based cause. Often the septal microvasculature is the target, either directly through anti-endothelial cell antibodies or indirectly via circulating immune complexes. The morphologic spectrum stemming from a septal capillary injury phenomenon is varied. It encompasses pauci-inflammatory hemorrhage best exemplified by anti-glomerular basement membrane antibody disease and idiopathic pulmonary hemosiderosis6 to one comprising a neutrophil-rich septal capillaritis characteristic of anti-Ro-associated lupus pneumonitis, dermatomyositis, mixed cryoglobulinemia, microscopic polyarteritis nodosa, Wegener granulomatosis, and Schönlein-Henoch purpura. Because the aforesaid conditions are all pathogenetically different, one could surmise that the immunofluorescent profile might narrow etiologically the basis of the microvascular injury syndrome. Furthermore, there are fibrosing disorders of the lung in which the immunofluorescent profile might predict an association with certain connective tissue disease syndromes. The spectrum of published works describing DIF results on lung biopsy material is limited. In fact, there are no recent publications addressing the usefulness of DIF. We used direct and indirect methods to explore the usefulness of DIF as a diagnostic adjunct in the evaluation of patients with interstitial lung disease.
Fresh open lung biopsy material from 57 patients was incubated with fluoresceinated complement and immunoglobulin antisera. An indirect immunofluorescent assay using neonatal lung as substrate was conducted as well. Direct immunofluorescent patterns could be categorized into interalveolar septal capillary deposition, large vessel wall localization, alveolar basement membrane localization, or a pauci-immune immunofluorescence pattern. With respect to the septal capillary pattern, endothelial cell decoration was seen with scleroderma, mixed connective tissue disease, anti-Ro-associated lupus erythematosus, dermatomyositis, humoral allograft rejection, and patients with isolated pulmonary fibrosis in whom autoantibodies were established, including antiphospholipid antibodies. A similar pattern of endothelial cell staining was seen in these cases via the indirect assay. Granular mural septal capillary deposition was seen in the aforesaid settings along with rheumatoid factor-positive rheumatoid arthritis, type II cryofibrinogenemia, and mixed cryoglobulinemia and, in some cases, light microscopically corresponded to a neutrophilic capillaritis. Isolated vascular IgA corresponded with rheumatoid arthritis corresponding to IgA-specific antiendothelial cell antibodies, celiac disease-associated pulmonary hemorrhage, Schönlein-Henoch purpura and with IgA antiphospholipid antibodies. Alveolar wall deposition was seen with anti-glomerular basement membrane disease.
Immunofluorescent testing is an important diagnostic adjunct in the assessment of immunologically mediated diseases of the skin and kidney. The 2 main methods of immunofluorescent testing are direct and indirect immunofluorescence. Direct immunofluorescence (DIF) involves the overlay of fluorescein-conjugated antibodies directed against immunoglobulins (IgG, IgM, and IgA) and complement fractions onto frozen sections of patient tissue. Indirect immunofluorescence (IIF), by definition uses a linking antibody; in its common use, IIF refers to patient serum in concert with fluorescein-conjugated human anti-IgG applied to a mucosal substrate, such as guinea pig, monkey esophagus, or rat bladder.
The use of either a DIF or an IIF assay has received little attention as a diagnostic aid in lung disorders. There are, however, many conditions affecting lung for which an initial inciting trigger leading to pulmonary injury has an immune-based cause. Often the septal microvasculature is the target, either directly through anti-endothelial cell antibodies or indirectly via circulating immune complexes. The morphologic spectrum stemming from a septal capillary injury phenomenon is varied. It encompasses pauci-inflammatory hemorrhage best exemplified by anti-glomerular basement membrane antibody disease and idiopathic pulmonary hemosiderosis6 to one comprising a neutrophil-rich septal capillaritis characteristic of anti-Ro-associated lupus pneumonitis, dermatomyositis, mixed cryoglobulinemia, microscopic polyarteritis nodosa, Wegener granulomatosis, and Schönlein-Henoch purpura. Because the aforesaid conditions are all pathogenetically different, one could surmise that the immunofluorescent profile might narrow etiologically the basis of the microvascular injury syndrome. Furthermore, there are fibrosing disorders of the lung in which the immunofluorescent profile might predict an association with certain connective tissue disease syndromes. The spectrum of published works describing DIF results on lung biopsy material is limited. In fact, there are no recent publications addressing the usefulness of DIF. We used direct and indirect methods to explore the usefulness of DIF as a diagnostic adjunct in the evaluation of patients with interstitial lung disease.
