1. Lupus band test

2. Direct imunofluorescence of systemic LE with granular deposits of IgM at dermoepidermal junction. The lupus band test is considered positive when one or more immunoreactasnt ( IgG,IgM, IgA , C3) is found at dermoepidermal junction.When 3 or more of immunoreactants are present at dermoepidermal junction in non lesional region, the diagnosis specificity for systemic LE is very high.

3. Direct imunofluorescence of systemic LE with granular deposits of IgG at dermoepidermal junction

4. Uses of lupus band test
1.It is of diagnostic specificity for differentiating LE from other clinically similar cutaneous diseases e.g. polymorphic light eruption, benign lymphocytic infiltrate of Jessner, lymphocytoma cutis…etc
2. For differentiating systemic LE from discoid LE. Both involved & non involved skin in systemic LE show positive lupus band test but in discoid LE , only involved skin is positive
3. Systemic LE without cutaneous lesion shows positive lupus band skin in the uninvolved skin.
4. Lupus band test is positive in systemic LE but not in other antinuclear – antibody positive diseases e.g. drug induced LE, scleroderma, dermatomyositis & connective tissue disease

6. Direct immunofluorscence to bullous pemphigoid with a band of IgG with dark center & brighter , sharply demarcated margins while LE band is wider & homogenous. In addition, bullous pemphigoid has a circulating antibodies against epithelial basement membrane & a negative ANA

7. Direct immunoflourescence of dermatitis herpeitiformis with granular deposits of IgA at dermo-epdermal junction with suprapapillary accentuation

8. Direct immunofluorecence of porphyria: the flourescence is much less in the band than that found in the blood vessels. The reverse is seen in LE. In addition complement is rarely found in the band

9. False positive lupus band test
1. Bullous pemphigoid
2. Porphyria
3. Dermatitis herpitiformis
4. Rosacea: The band is weaker in intensity & more focal & interrupted pattern is seen.
5. Autoflourescence of dermal collagen & elastic fibers forming a fibrillar pseudo-band.
6. 2O% of healthy adults have a positive lupus band test in son exposed non lesional skin regions. Positive immunofluorescence in non sun exposed areas is rare in normal healthy iondividuals