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