012
Test #
Laminin Beta 4 (p200) antibodies (IIF)
CPT Code(s) #
88346, 88350
If Profile, Includes Tests:
Disease Name:
p-200 pemphigoid
Type of Study:
p-200 pemphigoid
Methodology:
Indirect Immunofluorescence
Substrate:
Recombinant lamβ4-expressing HEK293 cells
Reference Range:
Negative: < 1:10
Positive: ≥ 1:10
Units:
Titer
Schedule:
Assay performed once every week.
Specimen Requirements:
Collect 2-5 ml of blood in a red top Vacutainer or serum separator (SST) tube, allow blood to clot, and centrifuge. Label tube appropriately.
Sample Stability:
Room temperature = stable during shipment for up to 1 week
2ºC to 8ºC = 2 weeks
-25ºC to -15ºC = good for one freeze/thaw cycle
Clinical Relevance:
P-200 pemphigoid is a rare sub-epidermal blistering disease first described by Zillikens in 1996. This novel disease is defined by tissue-bound immunoglobulins and/or complement C3 along the basement membrane zone (BMZ) and serum autoantibodies targeting a 200- kDa protein localized within the lower lamina lucida of the BMZ. Laminin γ1 has been described as the 200 kDa target antigen recognized by 70% to 90% of patients. Failure of anti-laminin γ1 IgG to show pathogenic effects in vitro and in vivo point to the presence of another autoantigen in anti-p200 pemphigoid. Recently, laminin β4 (LAMB 4) has been identified as additional target antigen of anti-p200 pemphigoid. Clinically, p-200 pemphigoid may mimic bullous pemphigoid (BP) or other bullous autoimmune diseases. The clinical presentation can be like BP (approx. in 66% patients), linear IgA bullous dermatosis, epidermolysis bullosa acquisita (EBA), dermatitis herpetiformis and mucous membrane pemphigoid. Patients present with tense blisters, erosions and urticarial plaques, scars and/ or milia can be present. The extremities (hands and feet) are most frequently involved followed by the trunk, and palmoplantar and cephalic involvement. Psoriasis is the most common coexisting dermatosis and it may precede anti-p200 pemphigoid.
