British Association of Dermatologists' Guidelines for the Management of Pemphigus Vulgaris 2017

K.E. Harman; D. Brown; L.S. Exton; R.W. Groves; P.J. Hampton; M.F. Mohd Mustapa; J.F. Setterfield; P.D. Yesudian

Disclosures

The British Journal of Dermatology. 2017;177(5):1170-1201. 

In This Article

Laboratory Diagnosis

Perilesional skin biopsies should be taken for histology and direct immunofluorescence (DIF). In patients with isolated oral disease, a histology specimen should be taken from perilesional mucosa and a DIF sample taken from an uninvolved area, ideally from the buccal mucosa.[18] Suprabasal acantholysis with blister formation is highly suggestive of PV, but the diagnosis should be confirmed by the characteristic deposition of IgG and/or complement on the cell surfaces of epithelial keratinocytes. Indirect immunofluorescence (IIF) is less sensitive than DIF[19–21] but may be helpful if a biopsy is difficult, for example in children and uncooperative adults.

Commercial enzyme-linked immunosorbent assays (ELISAs) are available for direct measurement of desmoglein 1 and desmoglein 3 antibodies in serum. They potentially offer advantages over IIF, such as increased sensitivity, but are not helpful in cases in which there are other antigens.[22–24] Therefore, IIF and ELISA should be considered complementary and DIF remains the gold-standard diagnostic investigation.[25] Five millilitres of blood is sufficient for both IIF and ELISA. Saliva is potentially a useful alternative to serum for ELISA; there is emerging evidence that desmoglein 3 IgG is detectable in saliva by ELISA with a similar sensitivity to serum (61% saliva vs. 74% serum).[26]

In patients with oral pemphigus, an intraoral biopsy is optimum, but IIF or DIF on a skin biopsy may suffice. One study showed that the sensitivity of DIF was 71% in oral biopsies compared with 61% in normal skin taken from 28 patients with oral PV.[27] Another study reported that the sensitivity of DIF was 89% in oral biopsies compared with 85% for IIF.[15] If there are no skin lesions and a sample for DIF is to be taken from the oral mucosa, the buccal mucosa can be exposed by everting the cheek, placing the thumb at the commissure and reflecting the corner of the mouth, applying external pressure on the cheek with the index finger to present the buccal mucosa.

The transport medium into which samples for DIF are placed varies, including saline, Michel's medium and snap freezing in liquid nitrogen.[28] Liquid nitrogen gives good preservation of immunoreactants but has practical disadvantages. However, it has been shown in one study using matched biopsy specimens that transportation in saline, for up to 48 h, gave superior results to liquid nitrogen, providing a more practical and cost-effective medium for getting samples to the lab.[29] Transportation in saline for up to 24 h was optimum[29] and Michel's medium is favoured for longer transportation times.[28]

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