PMC10033602_01
Clinical features of this patient. (A, B) Erythema, blisters and bloody crusts on the knees and lower limbs (A) and on the hands (B). (C) Erythema and blisters on the buttocks and thighs. (D) Blisters on the face and bloody crusts around the eye. (E) Bloody crusts around the ear. (F) Sever mucosal lesions on the lips and in the oral cavity.
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An 80-year-old female presented with scattered erythema, blisters, erosions and bloody crusts with itch on the head, trunk and limbs ( Figures 1A-E ), accompanied with extensive oral mucosal lesions ( Figure 1F ).
The results of histopathological and immunofluorescence tests of this patient. (A) Histopathological features of biopsy from lesioned skin on the left forearm (HE staining, original magnification, x200). (B) Direct immunofluorescence (DIF) for IgG. (C) Indirect immunofluorescence with normal human skin (IIF) for IgG and IgA antibodies on Days 0 and 11. (D) IIF using 1 M NaCl-split normal human skin (ssIIF) for IgG and IgA antibodies on Days 0 and 11. (E) IIF using rat bladder tissue (Rat bladder IIF) for IgG antibodies on Days 0 and 11.
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Histopathology of biopsy from lesional skin on the left forearm showed subepidermal blister and infiltration of lymphocytes and eosinophils ( Figure 2A ). Direct immunofluorescence showed only linear basement membrane zone (BMZ) deposition of IgG ( Figure 2B ), but not of IgA, IgM and C3 (data not shown), without depositions to keratinocyte cell surfaces. By indirect immunofluorescence (IIF) using normal human skin, the patient serum taken at Day 0 showed IgG and IgA anti-BMZ antibodies, without antibodies to keratinocyte cell surfaces ( Figure 2C ), while the serum of Day 11 showed only IgG anti-BMZ antibodies ( Figure 2C ). IIF using 1M NaCl-split normal human skin (ssIIF), the patient serum of Day 0 showed IgG and IgA antibodies reactive with the epidermal side of the split skin ( Figure 2D ), while the serum of Day 11 showed strong IgG and weaker IgA reactivities to the epidermal side of the split skin ( Figure 2D ). IIF using rat bladder tissue showed IgG staining on transitional epithelia weakly for the serum of Day 0 and strongly for the serum of Day 11 ( Figure 2E ).
The results of immunoblotting tests and ELISAs of this patient. (A-C) Immunoblotting using normal human epidermal extract (A), recombinant proteins (RP) of laminin (LM) 332 (B) and RP of extracellular domain (ECD) of integrin (ITG) alpha6beta4 (C). IgG antibodies of bullous pemphigoid (BP) control serum were positive for BP230, BP180 and LAD-1, IgG antibodies of pemphigus vulgaris (PV) control serum were positive for desmoglein (Dsg) 1 and Dsg3, IgG antibodies of paraneoplastic pemphigus (PNP) control serum were positive for envoplakin and periplakin. IgG antibodies of anti-LM332-type mucous membrane pemphigoid (MMP) control serum were positive for three subunits of LM332. mAb, monoclonal antibody. The RPs of LM332 and ITGalpha6beta4 ECD were purchased from Biolamina (Sundbyberg, Sweden) and R&D systems (Minneapolis, MN, USA), respectively. (D) ELISAs using various RPs, including three commercially available ELSIA kits (MBL, Tokyo, Japan) and other in-house ELISAs for detection of IgG autoantibodies against corresponding autoantigens. (E) ELISAs using BP180 NC16a-domain and LM332 RPs for detection of IgA, IgM or IgE autoantibodies. (F) ELISAs using peptides of indicated autoantigens for detection of corresponding IgG and IgA autoantibodies. Dot lines indicate the cutoff values.
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BP180 and LAD-1, and IgA autoantibodies against envoplakin, periplakin and desmoglein (Dsg) 3, with relatively stronger IgA reactivities for the serum of Day 11( Figure 3A ). By immunoblotting of LM332 recombinant protein (RP), the serum of Day 11, but not of Day 0, showed IgA autoantibodies against LMbeta3 ( Figure 3B ). By immunoblotting of RP of extracellular domain (ECD) of ITGalpha6beta4, the sera of both Days 0 and 11 showed IgA autoantibodies against ITGalpha6 and ITGbeta4 ( Figure 3C ). BP180 NC16a-domain RP, IgA autoantibodies were positive at Days 0, 11 and 57 with decreasing levels with time, and IgM autoantibodies were positive at Days 0 and 11, but negative at Day 57, while IgE autoantibodies were continuously negative ( Figure 3E ). By ELISA of LM332 RP, IgA autoantibodies against LM332 was positive at Day 11, but negative at Days 0 and 57 ( Figure 3E ).