Kalaaji, Amer N.

Patzelt et al. previously characterized dermal-binding autoantibodies using an indirect immunofluorescence (IIF) mosaic assay with cells transfected with p200-laminin β4, laminin-332 or collagen VII subunits among specimens showing a dermal pattern on IIF using salt-split skin (IIF-SSS) and IgG. This study expanded testing to include specimens with either a dermal or mixed pattern on IIF-SSS and demonstrated improved test sensitivity with modified testing methods.

AbstractBackgroundCertain autoimmune bullous dermatoses are mediated by autoantibodies of the IgG4 subclass. We determined the diagnostic impact of adding IgG4 to our conventional direct immunofluorescence (DIF) panel.MethodsFor all cases submitted to our referral laboratory for DIF over 1 month (n = 630), we performed IgG4 testing and collected consecutive biopsy specimens showing definite or indeterminate linear or cell‐surface deposition of IgG, IgG4, and/or C3. On retrospective blinded review, we classified the pattern and whether the findings were definite, indeterminate, or negative. When present, substantial background staining was recorded.ResultsSeventy DIF specimens met the inclusion criteria. Of 22 (31.4%) specimens equivocal for linear or cell‐surface deposition, 9 (40.9%) had definitive IgG4 findings, either linear (3 of 14 equivocal linear cases; 21.4%) or cell‐surface (6 of 8 equivocal cell‐surface cases; 75.0%). Background deposition was substantial in 14 cases (20.0%) for IgG but in none for C3 or IgG4.ConclusionIgG4 allowed the classification of over 40% of DIF cases that were otherwise equivocal by IgG and C3. IgG4 staining showed lower levels of non‐specific background staining than IgG or C3. IgG4 appears to contribute most value in cases with cell‐surface deposition or with equivocal linear IgG deposition and negative C3 results.

SummaryPneumocystis jiroveci pneumonia is an opportunistic infection associated with substantial rates of mortality in immunosuppressed patients. Prophylaxis recommendations are mostly targeted toward patients with non‐dermatologic diagnoses. This study was conducted to determine when dermatology patients treated with immunosuppressive medications should be offered P. jiroveci pneumonia prophylaxis. We searched the literature from January 1, 1993, to December 31, 2013, using terms relating to P. jiroveci pneumonia and dermatologic diagnoses to analyze the clinical characteristics of previously affected patients. Guidelines for P. jiroveci pneumonia prophylaxis from other medical fields were also analyzed. Of 17 dermatology patients reported to have contracted P. jiroveci pneumonia, eight (47.1%) died of the pneumonia. Risk factors included lack of prophylaxis, systemic corticosteroid therapy, lymphopenia, hypoalbuminemia, low serum CD4 counts, comorbid pulmonary or renal disease, malignancy, and prior organ transplantation. The present conclusions are limited by heterogeneity among the selected studies and limitations in their identification and selection. However, P. jiroveci pneumonia in dermatology patients is associated with a high mortality rate. Based on our analysis, we propose that prophylaxis be considered in dermatology patients in whom treatment with systemic corticosteroids at doses exceeding 20 mg/day or treatment with corticosteroid‐sparing immunosuppressive agents is anticipated for at least 4 weeks, and in patients with additional risk factors for P. jiroveci pneumonia.

BackgroundCutis laxa‐like features were observed in a subset of patients with scleromyxedema. Given this observation, clinical and histopathologic features of scleromyxedema were reviewed in correlation with elastic tissue staining.MethodsWe retrospectively reviewed clinical records and histopathologic features from patients with scleromyxedema seen at our institution from 1992 through 2013. We also evaluated available skin biopsies with an elastin stain and assessed whether dermal elastin fibers were diminished in density or were fragmented (or both).ResultsNineteen patients with scleromyxedema and 34 skin biopsies were identified. Alcian blue (mucin) stain was used to grade mucin deposition as weakly positive (24%), positive (44%) and markedly positive (32%). Eight patients (42%) had clinical findings of cutis laxa, which were often observed in conjunction with areas of papular eruption or induration. Elastic tissue fibers were normal in 9 of 34 skin specimens (26%), 18 of 34 specimens (53%) had diminished elastic fiber density and 7 of 34 (21%) had markedly decreased density. The elastic tissue was fragmented in 25 specimens (74%).ConclusionsA cutis laxa‐like clinical presentation and decreased elastic tissue density on skin biopsy were consistent findings. Dermatologists and dermatopathologists should be aware of these previously unreported clinical and histopathologic findings.