Desmoglein Antibodies in a case of Resistant Pemphigus - From Peter Bourke

Hi Glenn,

We have a 39yo Indigenous female patient with pemphigus (for >10 years) which was resistant to routine immunosuppression and so we tried rituximab.

Circulating CD19 B cells are undetectable still, now >4 months after rituximab but there is no significant improvement in the lesions 

(perhaps complicated by Staph & Strep colonisation).

It is a bit of an academic after thought but I am wondering if it is worth seeking titres of anti-desmoglein autoantibodies (1& 3?)?  I suppose it is possible that she still has circulating autoantibodies and we should probably treat with rituximab again (when CD19 B cells recover) to ensure at least 6 months of CD20+ B cell ablation before giving up on this therapy.  

I am seeking the thoughts of the group and whether anyone offers anti-desmoglein autoantibody testing.

Regards,

Peter.

Dr Peter Bourke PhD FRACP| Clinical Immunologist and Allergist
Division of Medicine | Department of Health
Royal Darwin Hospital, Rocklands Drive, Tiwi, NT 0810 | PO Box 41326, Casuarina, NT 0811
t... (08) 8922 8888 | f... (08) 8922 8463
e... peter.bourke@nt.gov.au | www.nt.gov.au/health

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For articles on Diagnosis and Management of Autoimmune Blistering Skin Diseases, go to Groups Readings Site and look under Pemphigus-Pemphigoid 

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Illustrative Case Report:

A 77-year old woman was referred to clinic for evaluation of an erythematous, partially denuded eruption over her face and trunk of 15 months duration. The eruption began with an enlarging area of redness confined to her left cheek and spread despite treatment with antibiotics, topical and intralesional corticosteroids. She had no constitutional symptoms throughout the course of her illness. Laboratory evaluations, including skin cultures, were negative. Three consecutive skin biopsies were interpreted as psoriasiform dermatitis. At presentation, she had well-demarcated erythematous and partially denuded plaques in a seborrheic distribution over her face, chest and back. Several 2-4mm flaccid vesicles were present within the facial plaques. Laboratory evaluation, including chemistry panel, complete blood cell count, erythrocyte sedimentation rate, RPR and urinalysis were all within normal limits. Serum antinuclear antibody was present at a titer of 1:40 (speckled pattern).
A punch biopsy of involved facial skin revealed acantholysis within the granular layer forming a subcorneal cleft, and a sparse perivascular lympho-plasmacytic infiltrate in the papillary dermis.
Direct immunofluorescence studies revealed IgG within the intercellular spaces of the epidermis and C3 confined to those granular layer keratinocytes forming the floor of the cleft. Indirect immunofluorescence for pemphigus antibody was present at a titer of 1:40.