Scleroderma, which literally means hard skin, is a disorder of the immune system. It comes in two varieties - morphea (restricted to the skin) and progressive systemic sclerosis (which involves internal organs also>. The underlying mechanism of scleroderma is autoimmunity. This implies that the immune system, for reasons as yet unknown, turns against an individual's own tissues. In general, the immune attack appears to start with a type of white blood cells called lymphocytes (see magnified view of lymphocytes at left). Both types of lymphocytes, T-lymphocytes and B-lymphocytes, participate.
The B-lymphocytes produce antibodies, proteins that are coded to attack specific substances; normally a specific type of antibody is generated against each type of infectious agent (i.e. viruses, bacteria etc.) that the body encounters. In scleroderma and other autoimmune disorders, antibodies are frequently produced against an individual's own tissues. This can be demonstrated by a laboratory test called the ANA (anti-nuclear antibody) test. To see how this test works, let us first examine the parts of an average human cell (see left), basically the nucleus and the cytoplasm. In the ANA test, the serum from an individual with anti-nuclear antibodies will, when poured onto human cells grown in a test tube, attach to the nuclei of the test cells. When stained with a special dye and viewed under a fluorescent microscope the nuclei of the test cells attacked by the antibodies are seen to light up. The test cells are shown on the right before and after serum is added.
The T-lymphocytes are closer to the scene of the activity. The role of the T-lymphocytes is rather complex but, in brief, they form part of the chronic inflammation that destroys the normal tissues (normal skin is shown on the left, with the epidermis forming the upper one-third, the dermis the middle one-third, and fat the lower one-third). The T-lymphocytes spread through the dermis and underlying fat (see right), and in the case of progressive systemic sclerosis, they also spread through the internal organs. In their wake, scar tissue replaces the normal tissues.
Note: The material provided in this web page is educational in nature and not medical advice. It is meant neither for self-diagnosis nor as a treatment recommendation. If you are concerned about any condition you think you may have, CONSULT YOUR DOCTOR.