What is dsDNA?
“DsDNA” is an abbreviation for double-stranded deoxyribonucleic acid. It is a type of DNA with two strands connected to each other by nucleotides. This type of DNA forms the helical structure of the DNA found in human cells [1].
The nucleotides in the dsDNA are complementary [1]. It means they are linked according to a sequence. Adenine (A) is connected to thymine (T) only and guanine (G) to cytosine (C). Strands connected like this are named complementary strands.
The rule for the connection between the strands is crucial for any operation on the dsDNA. It is also vital for the replication process. It allows an exact genome replication based on one of the complementary strands [1].
In animals, dsDNA functions as a genetic information data bank. It is found in nearly all cells and is responsible for transmitting the genome during cell division [1].
What is anti-dsDNA?
The term anti-dsDNA refers to antibodies that target dsDNA. These antibodies are autoantibodies, as they are produced by the organism against itself. The antibodies damage the tissues of the body [2], eventually leading to organ damage and, over time, dysfunction [3]. For instance, they can damage the kidneys or the nervous system [3].
The antibodies are produced in autoimmune diseases, such as systemic lupus erythematosus (SLE) [4]. However, they can also be found in some oncological patients [5].
Interestingly, people who have cancer and produce these antibodies in higher amounts can have a better outcome than those with lower production. It indicates that these antibodies may play an important role in suppressing the tumor [5].
For the detection of anti-dsDNA antibodies, the most commonly used enzyme-linked immunosorbent assay (ELISA) is used in laboratories [6].
What is considered a high level of anti-dsDNA?
The values can vary slightly from laboratory to laboratory. The normal value of anti-dsDNA is 30 UI/ml [7].
Based on SLE patients, medium values can be considered up to around 80 UI/ml [8]. Above that, the values can be regarded as high, while levels above 200 UI/ml can be seen as very high [9].
What causes high levels of anti-dsDNA?
High levels of anti-double-stranded DNA (anti-dsDNA) antibodies are often associated with chronic autoimmune diseases like systemic lupus erythematosus (SLE) [10, 11].
Additionally, the antibodies can be higher in rheumatological disease, during some infections, and in malignancies. Around one-third of all patients without lupus and high anti-dsDNA have a rheumatological disorder, while only twelve and seven percent have an infection or malignancy, respectively [10].
External factors can trigger the production of anti-dsDNA [12]. Among them are drugs like chlorpromazine or procainamide[13], viral infections [14], and bacterial [15].
Also, some research indicates an intrinsic factor. During the training (the somatic hypermutation) in the lymph nodes, some of the B-lymphocytes can turn into autoreactive cells, producing anti-dsDNA antibodies [16].