Immune Complex Diseases

A distinct collection of diseases characterised by predominant immune complexes causing and entertaining the disease process can be delineated. Desoxyribonucleic acid, DNA, is the predominant antigen in complexes found in systemic lupus erythematosus, and IgG itself is found in rheumatoid arthritis. The seropositive forms of ankylosing spondylitis and Wegeners granulomatosis fall in the same category without however displaying distinct antigen specificity. Infectious diseases, with which the host fails to remove the infectious antigen tend to become chronic immune complex diseases: Mycoplasma pneumoniae, Hepatitis, Dengue fever, Toxoplasma belong to these forms. Coxcsackie B3 virus encodes a protease which cleaves dystrophin and disrupts dystrophin-glycoprotein complex inducing heredetary-disease like symptoms. The impact of H5N1 bird flu influenza virus on the host is unknown but is subject of animal research (www.uptodate.com). Some renal diseases, i.e. IgA nephropathy, of HLA antigens with renal transplants hit the glomeruli; immunohematological diseases (immune hemolytic anemia, immune thrombocytopenia) and iatrogenic diseases (gold nephropathy, acute serum sickness with antilymphocyte globulin used to treat acute organ rejection in transplanted patients) are strongly dependent on circulating immune complexes. Common denominator of all these diseases: systemic or local damage due to immune complexes; distictive features: the predominance of organ deposition/damage which differs and gives the entities their names. In biopsies of patients with vasculitis deposits of immunoglobulins and complement components are often found. The nature of the antigen remains unknown in most cases, although associations between infections and vasculitis are not rare. In skin biopsies with vasculitis due to mixed essential cryoglobulinemia, hepatitis C virus has been identified.

Thus, both types of immune complexes exist: those which activate complement to cause damage and those who are damped thanks to complement activation, if both events do not occur jointly.

Major sites of human body where local immune complex disease might burst out due to on site deposition of circulating immune complexes or due to local formation of such complexes containing a local tissue-specific antigen, that became an autoantigen.

print version: pdf (72KB)