Hello Lupus_Help :lol:
Welcome to our family. Yes, this board is filled with people who are more than willing to provide information, give you answers, give you support and let you know that you are not alone.
Here is some information about the tests that you mentioned:
C3 and CH50 sediment tests are used for monitoring disease activity in Lupus. Normal C3 and C4 with abnormal C50 usually indicates a deficiency in other complex and alerts doctors that other testing may be necessary.
C3,C4 and C50 are all complements. Complement levels can be elevated or lowered in chronic inflamamtion as happens in Lupus (depending upon the activity of your disease). Doctors also use tests such as CRP or sedimentation rates to assess chronic inflammation.
Our immune system is composed of innate and acquired defenses. Antibodies and activated T-lymphocytes enhance our capacities for defense against many kinds of pathogens. The immune system is composed of a large number of defense molecules, including the complement system. The complement system is a major player in our innate immunity and is very involved in a large number of biological processes in our system, including the initiation and amplification of acquired immunity. Most of these biological activities are achieved by two mechanisms: first, by depositing opsonic fragments (especially of the components C3 and C4) on pathogens or other targets - and second, the initiation or induction of inflammatory responses following the release of small fragments from C3, such as C3a.
Three pathways of complement activation exist, namely the classical pathway, the alternative pathway and the lectin pathway. They merge at the level of C3, leading to the activation of a common sequence and the generation of the C5b-C9 membrane attack complex that can insert itself into membranes and cause cytolysis.
The lectin pathway of complement is activated following the recognition of specific carbohydrate patterns by molecules like mannan-binding lectin (MBL) and ficolins 1, 2 and 3. Once, binding of these molecules to target structures has occurred, the MBL-associated serum protease-2 (MASP-2) is activated and then cleaves its natural substrates C4 and C2, leading to the formation of C4b2a, a C3-convertase that cleaves C3 into C3b and C3a. C3b can attach itself in a covalent fashion to the activator and act as an opsonin.
The third pathway of complement, the alternative pathway, is based on the continuous low-grade hydrolysis of C3 leading to the formation of an enzyme complex composed of C3 and activated B that then catalyses the activation of small amounts of C3 and generation of C3b. On alternative pathway activators, this C3b is protected from inactivation by the plasma inhibitors factor I and H. The initially formed C3b then reacts with factors B, D and properdin to form a stable amplification C3 convertase, leading to efficient C3 activation and the generation of opsonic and inflammatory fragments
In Lupus, the immune system gets confused and the body starts to produce antibodies, (such as antinuclear antibodies [ANAs]), against its own cells. The formed antigen-antibody complexes then suppress the body's normal immunity and damages tissues. A significant feature in patients with SLE is their ability to produce antibodies against many different tissue components (such as red blood cells (RBCs), neutrophils, platelets, lymphocytes, and almost any organ or tissue in the body).
A compliment test (C3, C4, CH50, CH100) measures the amount of complementary proteins circulating in the blood. A sedimentation rate (ESR) or C-reactive protein (CRP) are used to measure inflammation levels.
Did this make sense to you or was I too clinical? Let me know if you need anything further!
Peace and Blessings
Look For The Good and Praise It!