Mixed immunobullous disease: Is this linear IgA disease?

Abstract

We report five patients who demonstrated clinical, histological and direct immunofluorescence (IF) features typical of linear IgA disease (LAD), but who also displayed IgG anti-basement membrane zone (BMZ) antibodies on indirect IF. The presence of circulating IgG anti-BMZ antibodies is often said to exclude the diagnosis of LAD. Unable to confidently classify these patients, we reviewed their clinical progress for unifying features. This revealed an almost universal benefit from dapsone therapy. We therefore propose that when strong linear IgA deposition is observed at the BMZ, a first line trial of dapsone is indicated, irrespective of the presence of circulating IgG. The class of antibody fixed in vivo appears to influence the clinical picture more than the class of circulating antibody.

Linear Immunoglobulin A Bullous Dermatosis: Need for an Agreement on Diagnostic Criteria

“…For example, Sheridan et al [6] proposed that prominent linear IgA deposition at the BMZ, irrespective of the presence of circulating IgG, is consistent with a diagnosis of LABD, which justifies the introduction of dapsone as firstline treatment. The presence of acquired bullous disease and solely linear IgA at the BMZ in clinically uninvolved skin were the diagnostic criteria used by Lally et al [7] .…”

Dermatose por IgA e IgG linear: relato de caso com boa resposta terapêutica à dapsona e ao micofenolato mofetil

“…6,12 However, this medi ca tion pre sents impor tant adver se effects; among them, hema to lo gi cal alte ra tions, mainly methe mo glo bi ne mia and/or hemoly tic ane mia. Despite the known pre dis po si tion to drug into le ran ce of patients with G6PD defi ciency, even when this enzyme is nor mal the patient is not exempt from hemolysis risk.…”

“…In such cases, the main the ra peu tic alter na ti ves are glu co corti coids, aza thio pri ne, metho tre xa te, tetracy cli nes, eryth romy cin and cyclos po ri ne. 1,6,14 The MMF has been suc cess fully used with LAD patients. 2,15 It is an immuno sup pres si ve agent that inhi bits mono phos pha te dehy dro ge na se, the key enzy me in puri ne synthe sis.…”

“…5 Subsequent reports cor ro bo ra te the findings of this group. 3,[6][7][8] The pre sen ce of simul ta neous linear depo si tion of IgA and IgG was fun da men tal for the con cep tion of a new cli ni cal-patho lo gi cal entity, IgA and IgG linear der ma to sis (LAGD). 9,10 However, the mag ni tu de and cli ni cal rele van ce of this clas si fi ca tion remain con trover sial, as there seems to be no dif fe ren ces in the derma to lo gi cal pre sen ta tion and the ra peu tic spec trum of both disea ses.…”

“…The rea son for such simi la rity has been attri bu ted to the fact that IgA is an anti body with very hete ro ge neous tar get anti gens, against seve ral BM com po nents. A pos si ble mecha nism of inter mo le cu lar expan sion of epi to pes could be res pon si ble for the autoim mu nity exten sion of BP180 anti gen to the BP230 anti gen. 3,[5][6][7][8]11 In con trast, IgG seems to have a much more res tric ted res pon se. 3 In this study is pre sen ted a LAGD case com plica ted by mala ria, but with good res pon se to the treatment with dap so ne and myco phe no la te mofe til.…”