Version June 2024
| Disorder | Complement profile | Examples |
| Immune complex syndromes | Decreased CH50, C4, C3, and other components of classical pathway.* Immune complexes are often present in substantial quantities and activate the classical pathway. Tissue damage is partly mediated by complement. | SLE, anti-cardiolipin syndrome, Sjogren's disease, MCTD, vasculitis, mixed cryoglobulinemia, serum sickness, some glomerulonephritides including post-streptococcal nephritis. |
| Autoantibody (IgG/IgM) binds to a plasma or membrane protein | Classical pathway activation profile similar to immune complex syndromes but serum levels usually normal (synthesis matches modest increase in catabolism). Complement activation is noted by the presence of C1q, C4, C3, and C5-9 at sites where the autoantibody is bound. IgM and IgG activate the classical pathway. Complement participates in local tissue damage at sites of antibody binding. | Neurologic: Anti-nerve sheath, some demyelinating syndromes, myasthenia gravis. Endocrinologic: Thyroiditis, adrenalitis, insulitis. Dermatologic: Bullous skin diseases, urticarial vasculitis. Renal: Anti-GBM disease (Goodpasture's syndrome), forms of glomerulonephritis. Hematologic: Autoimmune hemolytic anemia, immune thrombocytopenic purpura. |
| Altered self (tissue injury and debris deposition) | Normal serum levels. Deposition in tissue detected by immunofluorescence: Multiple pathways may be activated depending upon the nature of the debris. | Acne, Alzheimer disease, ARDS, asthma, atheroma, inflammatory bowel disease, multiple sclerosis, myositis, preeclampsia, porphyrias, psoriasis, sarcoidosis, SSPE, vitiligo, AMD, hemolytic uremic syndrome. |
| Foreign materials | Alternative pathway activation with elevated C3a and C5a. | Dialysis membrane, heart-lung bypass, some contrast dye reactions, foreign bodies. |
| Ischemia reperfusion injury | Both classical and alternative pathway activation deposits at sites of ischemia. | Myocardial infarction, stroke, ischemic muscle, traumatic injury. |
SLE: systemic lupus erythematosus; MCTD: mixed connective tissue disease; IgG: immunoglobulin G; IgM: immunoglobulin M; GBM: glomerular basement membrane; ARDS: acute respiratory distress syndrome; SSPE: subacute sclerosing panencephalitis; AMD: age-related macular degeneration.
* C4 may be low and C3 in normal range with classical pathway activation in SLE, mixed cryoglobulinemia, and membranoproliferative glomerulonephritis (MPGN) types I and II. The explanation for this is the formation of the C3 convertase is inefficient in plasma, such as on soluble immune complexes.آیا می خواهید مدیلیب را به صفحه اصلی خود اضافه کنید؟
