Biology of Disease

difficulties with diagnosis, so it must take full account of the range of
presentations. Diagnosis can be helped by demonstrating the presence of
ANAs in samples of plasma, using indirect immunofluorescence on cultured
Hep-2 cells. The commonest pattern seen is a diffuse staining throughout
the nucleus due to antibodies against chromatin. It is also possible to detect
different patterns of fluorescence which are indicative of antibodies to
different nuclear antigens and which can help in diagnosis or in assessing
prognosis (Table 5.10). Autoantibodies against extractable nuclear antigens
(ENA) can also be detected by RIA or ELISA (Chapter 4). Positive tests for
ANAs require further investigations, for example with tests for antidouble-
stranded dsDNA (dsDNA) antibodies. The presence in the blood of so-called
LE cells, which are neutrophils containing phagocytozed nuclei and resemble
large multinucleate cells, is also indicative of SLE. Other laboratory tests
used in the diagnosis of SLE include those listed in Table 5.11. Rheumatoid

AUTOIMMUNE DISORDERS

CZhhVg6]bZY!BVjgZZc9Vlhdc!8]g^hHb^i]:YLddY &&,

Figure 5.9 Schematic illustrating the area of

face typically covered with a ‘butterfly’ rash in

systemic lupus erythematosus.

Symmetrical arthritis involving any joint

Arthralgia (bone pain)

Erythematous rash; butterfly rash on face (Figure 5.9)

Mucosal ulcerations

Pleurisy

Pericarditis

Renal involvement

Fever

Nervous system involvement (psychosis, depression, convulsions, migraine)

Heart disease

Eye involvement (retinal vasculitis; corneal ulceration)

Gastrointestinal ulcers

Pancreatitis

Hepatitis

Sjogren’s disease (involving autoimmune destruction of lacrimal and salivary glands)

Hemolytic anemia

Table 5.9Clinical manifestations of SLE

Pattern of staining by indirect

immunofluorescence (IDID)

Target antigen Use

Homogeneous ANA chromatin screening but present in some normals

double

strandedDNA

specific for SLE

Speckled ANA (coarse) Sm* specific for SLE

Speckled ANA (coarse) U1-RNP found in SLE and mixed connective

tissue disease

*Antibodies to the Sm (Smith) antigen were first discovered in the serum of a patient with SLE called Stephanie Smith.
Antibodies to the Sm antigen bind to molecules in the nucleus called small nuclear riboproteins.

Table 5.10Antinuclear antibodies in SLE