Specificity of dermal mucin in the diagnosis of lupus erythematosus: comparison with other dermatitides and normal skin

Colloidal iron staining used for amniotic fluid in lung sections of stillborn infants in histopathology

In forensic pathology, intrauterine amniotic fluid aspiration must be examined in lung sections of a stillborn fetus in late pregnancy. Alcian blue staining and immunohistochemistry are routinely performed using anti-cytokeratin antibody to detect the components. Colloidal iron staining is another method for acidic mucus polysaccharides. Retrospectively, we examined 15 forensic cases of stillborn and neonatal deaths with autopsies conducted at our department. Colloidal iron staining caused positive features of amniotic mucin in 14 cases, but Alcian blue staining could not be confirmed clearly in 8 cases because of weak color development. For detection of amniotic mucin, colloidal iron staining showed a richer color with contrast than other methods. Moreover, mucin masses were observed in two live-born infants, and in all stillborn infants, one of which was clinically diagnosed as having meconium aspiration syndrome. Non-specific reaction to iron ions such as hemosiderin-phagocytic macrophages might occur in the lung sections. However, colloidal iron staining should be the alternative routine for lung tissue from stillborn infants.

Histopathologic Overlap Between Bullous Lupus Erythematosus and Linear IgA Bullous Dermatosis: A Comparative Study

ABSTRACT

Bullous lupus erythematosus (BLE) and linear IgA disease (LAD) are rare autoimmune subepidermal blistering diseases, with overlapping features despite different pathogenetic mechanisms. Diagnosis is based on immunofluorescence and serology. This retrospective study was undertaken to compare the histopathologic features of BLE and LAD (11 cases each). The mean age was 36 years in both groups, and female preponderance was noted in BLE. Clinically, all cases presented as tense, itchy blisters distributed over the trunk, face, and extremities. Subepidermal neutrophil-rich blisters were seen in 60% BLE and 54.54% LAD cases. Eosinophils in the blisters were noted in 4 cases (36.4%) of linear IgA bullous dermatosis, but not in any of the BLE cases. The adjacent epidermal changes noted include spongiosis (33%; 40%), papillary microabscesses (22%; 20%), and basal tagging by neutrophils (77%; 70%). Superficial perivascular inflammation was seen in all cases while deep perivascular inflammation was observed in 54% BLE and 36% LAD cases. Lymphocytes were the predominant infiltrate. Increased dermal mucin was seen in 60% BLE and 45% LAD cases. None of the histopathologic features showed a statistically significant difference between the 2 groups. Hence, histopathology alone is of limited value in distinguishing the 2 groups. Diagnosis rests on immunofluorescence and serologic findings, which should be used even in cases that seem to be classic LAD or patients without history of systemic lupus erythematosus.

Intestinal Submucosal Mucinosis in a Patient With Systemic Lupus Erythematosus: A Case Report

Systemic lupus erythematosus (SLE) is an autoimmune disease with various clinical presentations. Mucin deposition is a characteristic finding in skin lesions, but it is rare in other organs. We present a case with erythematous patches from the terminal ileum to the anus in an SLE patient. Diffuse colitis was diagnosed clinically. However, in addition to inflammatory cell infiltration, there was abundant mucinous material deposition in the submucosa. The mucinous material was positive for Alcian blue staining (pH 2.5) and was sensitive to hyaluronidase digestion. These findings are similar to those of cutaneous mucinosis in SLE patients. This is thought to be the first case of gastrointestinal tract mucinosis in SLE reported in the literature.

Cutaneous manifestations of lupus erythematosus: A practical clinicopathologic review for pathologists

Accurate diagnosis of connective tissue diseases is often challenging and relies on careful correlation between clinical and histopathologic features, direct immunofluorescence studies, and laboratory workup. Lupus erythematosus (LE) is a prototype of connective tissue disease with a variety of cutaneous and systemic manifestations. Microscopically, cutaneous LE is classically characterized by an interface dermatitis, although other histopathologic patterns also exist depending on the clinical presentation, location, and chronicity of the skin lesions. In this article, we review the clinical, serologic, histopathologic, and direct immunofluorescence findings in LE-specific and LE-nonspecific skin lesions, with an emphasis on lesser known variants, newly described features, and helpful ancillary studies. This review will guide general pathologists and dermatopathologists in accurately diagnosing and subclassifying cutaneous LE.

Fas ligand promotes an inducible TLR-dependent model of cutaneous lupus-like inflammation

Toll-like receptors TLR7 and TLR9 are both implicated in the activation of autoreactive B cells and other cell types associated with systemic lupus erythematosus (SLE) pathogenesis. However, Tlr9-/- autoimmune-prone strains paradoxically develop more severe disease. We have now leveraged the negative regulatory role of TLR9 to develop an inducible rapid-onset murine model of systemic autoimmunity that depends on T cell detection of a membrane-bound OVA fusion protein expressed by MHC class II+ cells, expression of TLR7, expression of the type I IFN receptor, and loss of expression of TLR9. These mice are distinguished by a high frequency of OVA-specific Tbet+, IFN-γ+, and FasL-expressing Th1 cells as well as autoantibody-producing B cells. Unexpectedly, contrary to what occurs in most models of SLE, they also developed skin lesions that are very similar to those of human cutaneous lupus erythematosus (CLE) as far as clinical appearance, histological changes, and gene expression. FasL was a key effector mechanism in the skin, as the transfer of FasL-deficient DO11gld T cells completely failed to elicit overt skin lesions. FasL was also upregulated in human CLE biopsies. Overall, our model provides a relevant system for exploring the pathophysiology of CLE as well as the negative regulatory role of TLR9.