What is double-stranded DNA (dsDNA)?

From the Guidelines

Double-stranded DNA (dsDNA) is a complex molecule consisting of two complementary strands of nucleotides that wind around each other in a double helix structure, with each strand made up of a sugar-phosphate backbone and four types of nitrogenous bases: adenine (A), thymine (T), guanine (G), and cytosine (C) 1. The structure of dsDNA is crucial for its function, with the complementary base pairing between the two strands allowing for the storage and transmission of genetic information. The base pairing is specific, with adenine pairing with thymine and guanine pairing with cytosine, through hydrogen bonds that create the rungs of the ladder-like structure. This structure is essential for DNA replication, as each strand serves as a template for creating a new complementary strand during cell division.

Some key points to consider when discussing dsDNA include:

• The double-stranded structure provides stability and protection for the genetic information encoded in the sequence of bases 1
• The genetic information encoded in dsDNA directs protein synthesis and ultimately determines the characteristics and functions of all living organisms 1
• Anti-dsDNA autoantibodies can be observed in healthy individuals, as well as in other autoimmune syndromes, bacterial, viral, and parasitic infections, and cancer 1
• The term anti-dsDNA encompasses a great diversity of antibodies with different antigenic specificities, targeting multiple and different DNA structures 1

It is also important to note that the conception of anti-dsDNA as a uniform group of antibodies that work as a highly specific SLE biomarker targeting a unique form of dsDNA with great sensitivity is incorrect 1. Instead, anti-dsDNA refers to a heterogeneous set of antibodies with mature affinity and a whole spectrum of unique specificities for the different DNA structures present in chromatin.

The use of anti-dsDNA autoantibodies in the diagnosis and follow-up of systemic lupus erythematosus (SLE) is a complex issue, with different assays and methods available for detection 1. The reference method for anti-dsDNA detection is considered the Farr assay, but this assay is not used in clinical practice due to its limitations 1. Instead, a double-screening strategy using a last-generation SPA in the first place and, subsequently, the CLIFT as the confirmation test is recommended 1.

In terms of the clinical relevance of anti-dsDNA, it is essential to consider the different types of anti-dsDNA and their predictive value for well-defined dsDNA structures 1. This would facilitate defining the different SLE phenotypes and their corresponding pathophysiological situations.

Overall, dsDNA is a complex molecule that plays a crucial role in the storage and transmission of genetic information, and its structure and function are essential for understanding its role in living organisms. The use of anti-dsDNA autoantibodies in the diagnosis and follow-up of SLE is a complex issue that requires careful consideration of the different assays and methods available, as well as the clinical relevance of the different types of anti-dsDNA.

From the Research

Definition of Double-Stranded DNA (dsDNA)

• Double-stranded DNA (dsDNA) refers to the structure of DNA where two strands of nucleotides are paired together in a double helix formation 2, 3, 4, 5, 6.
• The double helix structure is composed of two complementary strands of DNA that are held together by hydrogen bonds between the nucleotide bases 3.
• dsDNA is a crucial component of cells and plays a central role in the storage and transmission of genetic information 2, 6.

Characteristics of dsDNA

• dsDNA is characterized by its double-stranded structure, which provides stability and protection to the genetic material 3.
• The double-stranded structure of DNA also allows for the replication and transcription of genetic information 4.
• dsDNA can be found in various forms, including linear and circular molecules, and can be packaged into chromosomes or found in extrachromosomal elements such as plasmids 5, 6.

Role of dsDNA in Systemic Lupus Erythematosus (SLE)

• Anti-dsDNA antibodies are a hallmark of SLE and are used as a diagnostic criterion for the disease 2, 5, 6.
• The presence of anti-dsDNA antibodies is associated with disease activity and can be used to monitor disease flares 2, 5.
• Studies have shown that a surge in anti-dsDNA titer can predict a severe lupus flare within six months 5.