Serum complement

Das N, Srivastava N, Srivastava LM. 1988. Activation of serum complement by organochlorine insecticides, DDT and endosulfan. Curr Sci 57 524-526. 

Microbial toxins such as diphtheria toxin and activated serum complement components can produce large pores in cellular membranes and thereby provide macromolecules with direct access to the internal miheu. 

CH50 determinations can be used to analyze the total serum complement and are useful for monitoring immune complex diseases (Sullivan, 1989) activation of complement (Table 15.13) in the presence of autoantibodies is indicative of immune complex diseases and autoimmunity. The various components of the complement system (C3, C4) can also be measured to assess the integrity of the system. For instance, low serum concentrations of C3 and C4, with a concomitant decrease in CH50 may indicate activation of complement, while a low C4 alone is a sensitive indicator of reduced activation of the complement system. Since C3 is used as an alternate complement pathway, it usually measures high. Therefore, a low C3 with a normal C4 may indicate an alternate pathway of activation. 

Our data showing normal serum complement levels in cotton mill workers (normal and byssinotic) does not support a complement activation mechanism for the pathogenesis of byssinosis, but the data does not eliminate the possiblity of complement activation in the etiology of byssinosis (Table V). As complement activation is a local reaction, small amounts of complement fragments sufficient... 

This syndrome is characterized by proteinuria >3.5 g/day, hypoalbuminuria <3 g/dl, hyperlip-idaemia with an elevation of serum cholesterol, edema and oval fat bodies and fatty casts in the urinary sediment. A variety of disorders may produce nephrotic syndrome but, in the majority of cases, no cause is found. It is appropriate to define the selection of studies from the history and physical examination. Tests to order are antinuclear antibody, rheumatoid factor, cryoglobulins, serum complement, HBsAg VDRL serology (syphilis), protein electrophoresis of the serum and urine and HIV. If the cause is unclear a renal biopsy is done to define the glomerular lesion as treatment may on the underlying glomerular lesion. 

Measurement of serum immunoglobulins, serum complement, and specific antibodies to various natural and acquired antigens. 

DNA and serum complement (C3) levels. Application to diagnosis and classification of systemic lupus erythematosus. Am. J. Med. 74, 206-216 (1983). 

Mouse (B6C3F1) once (GO) 20 F (18% reduction in serum Complement 3) Lin and White 1993... 

White KL Jr, Lysy HH, McCay JA, et al. 1986. Modulation of serum complement levels following exposure to polychlorinated dibenzo-p-dioxins. Toxicol Appl Pharmacol 84 209-219. 

In experimental serum sickness, a fall in serum complement level occurs at the time immune complexes form and inflammatory lesions develop (D6). However, levels of complement do not always reflect activation or consumption by immune complexes. The rate of synthesis of complement proteins may be sufficient to replace the amount being consumed, and several of the complement components are so-called acute-phase reactants, i.e., their levels rise with inflammation. Thus, activation may occur despite normal or even elevated levels in the serum. Turnover studies provide more direct evidence of complement utilization but are technically cumbersome (K4). A simpler approach is the detection of split products of complement components, which provides direct evidence of complement activation, or the examination of effusions for evidence of complement depletion (H31, N7, P7). 

Runyon, B.A., Antillon, M.R., Montano, A.A. Effect of diuresis versus therapeutic paracentesis on ascitic fluid opsonic activity and serum complement. Gastroenterology 1989 97 158-162... 

A 59-year-old man, who had taken amiodarone 200 mg/day for 2 years, developed fever, pleuritic chest pain, dyspnea at rest, a non-productive cough, malaise, and joint pains (211). He had a verrucous endocarditis and a pleuropericardial effusion. He had raised titers of antinuclear antibodies (1 320) with anti-Ro specificity. Serum complement was normal and there were no circulating immune complexes, no cryoglobulins, and no anti-dsDNA, anti-La, anti-Ul ribonucleoprotein, anti-Sm, anti-Scl, 70, anti-Jo 1, antihistone, antiphosphohpid, anticentromere, anticardioli-pin, or anticytoplasmic antibodies. Within 7 days of withdrawal of amiodarone the signs and symptoms started to resolve, and he recovered fuUy with the addition of prednisolone. 

A 64-year-old man with no history of allergy had progressive fatigue, loss of appetite, and facial edema after 6 months of interferon alfa-2b treatment for chronic hepatitis C (319). Angioedema was diagnosed and it resolved after withdrawal of interferon alfa and a short course of prednisolone. Serum immunoglobuhn E and plasma bradykinin concentrations were raised, but the Cl esterase inhibitor and serum complement concentrations were normal. 

TABLE 47—5. Categorization of Renal Diseases Based on Serum Complement Levels... 

Low Serum Complement Level Normal Syrum Complement Level... 

In addition to heavy proteinuria, urinalysis often reveals lipiduria and oval fat bodies. Microhematuria is seen in fewer than 25% of patients, and gross hematuria and red cell casts are rare. In idiopathic membranous nephropathy, the serum complement concentrations are normal. Low levels of complement should alert one to search for secondary causes, such as lupus, hepatitis B infection, or an alterna-... 

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