Anti-nuclear antibodies Significance and limitations of test By Hatem H. Eleishi Consultant Rheumatologist

In this mini-lecture: What are ANAs How useful they are How unuseful they can be Conclusion

What are antinuclear antibodies? Antibodies to nuclear proteins What are nuclear proteins?

Nucleosomes Ro La Smith RNP Jo-1 Scl-70 dsDNA Nucleolar proteins Proteins that have been synthesized in the nucleus and thereafter where distributed to their respective sites in the cell

dsDNA dsDNA Nucleosomes Ro La Smith RNP Jo-1 Scl-70 Nucleolar Ro La Nucleolar proteins dsDNA Ro La Smith RNP Jo-1 Scl-70 Rim Speckled Homogenous

Importance of ANAs

One: Serologic hallmarks of patients with systemic autoimmune disease (ANA diseases).

Serologic hallmarks of patients with systemic autoimmune disease: • SLE – sensitivity, 99 percent • Scleroderma – 97 percent • Mixed connective tissue disease – 93 percent • Polymyositis/dermatomyositis – 61 percent • Rheumatoid arthritis – 52 percent • Rheumatoid vasculitis – 33 percent • Sjögren's syndrome – 90 percent • Drug-induced lupus –100 percent • Discoid lupus – 15 percent • Pauciarticular juvenile chronic arthritis – 71 percent

Two Can provide further diagnostic and prognostic data concerning patients who have minimal symptoms or who have clinical features of more than one autoimmune disease. Examples

A young female with: Polyarthralgias Fatigue Malar rash Positive ANA A lupus patient with: Anti-Ro antibodies

utility and reliability of systemic autoimmune diseases Limitations of utility and reliability of ANA in diagnosis of systemic autoimmune diseases Accurate interpretation of different nuclear patterns is confounded by the following difficulties: • The recognition of specific patterns is operator-dependent, and does not produce a permanent record. The fluorescence fades in one to two days, so that one cannot compare a result with other samples without photographing each test result. • Different serum dilutions can produce varying nuclear patterns. • One nuclear pattern may obscure and prevent the recognition of another pattern if several antibodies are present simultaneously. • Certain specificities are visible only on specific substrates. Anti-Ro antibodies and anticentromere antibodies, for example, are not detected with murine organs, but can be found with HEp2 cells. • Nuclear patterns are neither sensitive nor specific. As a result, no single pattern denotes a single disease and, conversely, several diseases may produce a particular ANA pattern.

One: Can also be found in association with: Many autoimmune disorders that are not defined by these antibodies In certain infections and other disorders In patients receiving certain drugs too. Autoimmune disorders that are not defined by these antibodies: Hashimoto's thyroiditis – 46 percent Graves' disease – 50 percent Autoimmune hepatitis – 71 percent Primary autoimmune cholangitis – 100 percent Primary pulmonary hypertension – 40 percent Chronic infectious diseases: Mononucleosis Subacute bacterial endocarditis Tuberculosis Other disorders: Some lymphoproliferative diseases. In up to 50 percent of patients taking certain drugs; however, most of these patients do not develop drug-induced lupus.

Two: Their presence does not mandate the presence of illness, since they can also be found in otherwise normal individuals. False positive ANAs (ie, ANAs in the absence of autoimmune disease or known antigenic stimuli) are more commonly seen in women and in elderly patients. They are invariably in low titer.

Three: Accurate interpretation of different nuclear patterns is confounded several difficulties as: • The recognition of specific patterns is operator-dependent, and does not produce a permanent record. The fluorescence fades in one to two days, so that one cannot compare a result with other samples without photographing each test result. • One nuclear pattern may obscure and prevent the recognition of another pattern if several antibodies are present simultaneously.

As a result, A positive ANA, although useful and important, yet should be interpreted with caution and within the appropriate clinical setting As a result, A good history compounded with a thorough clinical examination remain to be the mainstay of diagnosis

Thank you