ABSTRACT
Dust-like particles, producing a specific fine-speckled, epidermo-subepidermal direct immunofluorescence staining pattern, have been associated mainly with subacute cutaneous lupus erythematosus (LE). Under experimental conditions the appearance of immunoglobulins along the basement membrane in ultraviolet (UV) light-induced lesions has been reported as a late phenomenon. In this study, photoprovocations with UVA and UVB light were carried out in 16 photosensitive patients with discoid (n = 13), subacute cutaneous (n = 2) or systemic LE (n = 1) and serial biopsies from UV-induced lesions were processed for direct immunofluorescence. A specific, fine-speckled epidermal staining was detected within 7 to 14 days after UV provocation in 7/16 of the patients; in the majority of those patients associated with anti-SSA antibodies adn discoid LE without systemic manifestations of their disease.
Subject(s)
Biomarkers/analysis , Lupus Erythematosus, Systemic/immunology , Skin Diseases/immunology , Skin/immunology , Skin/radiation effects , Adult , Aged , Antibodies, Antinuclear/analysis , Antibodies, Antinuclear/immunology , Antibodies, Antinuclear/radiation effects , Complement C1q/analysis , Complement C1q/immunology , Complement C1q/radiation effects , Complement C3/immunology , Complement C3/radiation effects , Dust/analysis , Female , Fluorescent Antibody Technique , Humans , Immunoglobulin G/analysis , Immunoglobulin G/immunology , Immunoglobulin G/radiation effects , Immunoglobulin M/analysis , Immunoglobulin M/immunology , Immunoglobulin M/radiation effects , Lupus Erythematosus, Cutaneous/complications , Lupus Erythematosus, Cutaneous/immunology , Lupus Erythematosus, Discoid/complications , Lupus Erythematosus, Discoid/immunology , Lupus Erythematosus, Systemic/complications , Male , Middle Aged , Photosensitivity Disorders/complications , Photosensitivity Disorders/immunology , Skin/chemistry , Skin Diseases/complications , Skin Diseases/etiology , Ultraviolet Rays/adverse effectsABSTRACT
The structural transformations of C1q-protein induced by the UV-light at doses 151 and 2265 J/m2 has been determined by means of acid-basic titration, IR- ans UV-spectrophotometry. These transformations are stipulated by unfolding of its molecules without change of the secondary structure types ratio and accompanies by exposition on aromatic amino acid residues as well as glutamine and asparagine acids, lysine, hydroxylysine and cysteine on the globule surface. The correlation between structural photomodifications and processes of functional activation of C1q has been established.
Subject(s)
Complement C1q/radiation effects , Ultraviolet Rays , Amino Acids/analysis , Asparagine/analysis , Complement C1q/metabolism , Complement C1q/physiology , Cysteine/analysis , Glutamine/analysis , Humans , Hydroxylysine/analysis , Lysine/analysis , Models, Immunological , Spectrophotometry, Infrared , Spectrophotometry, UltravioletABSTRACT
IgG can be denatured in vitro by reactive oxygen species (ROS). Native IgG activates the complement cascade through C1q. Using a modified ELISA, C1q binding activity of rheumatoid IgG has been compared to IgG denatured by neutrophil-derived ROS. The C1q binding activity of rheumatoid synovial fluid IgG is greater than the corresponding serum IgG (P < 0.01). Denaturation of IgG by activated polymorphs or the Fenton reaction decreased its C1q binding activity (P < 0.01). In vitro exposure of IgG to OH. and ROO. increased its interaction with C1q (P < 0.01). Hypochlorous acid had no effect. ROS-induced alteration to IgG-C1q binding activity may promote the inflammatory response in rheumatoid arthritis.
