Validation of the BIOCHIP test for the diagnosis of bullous pemphigoid, pemphigus vulgaris and pemphigus foliaceus.

BACKGROUND: The BIOCHIP is a novel multiplex indirect immunofluorescence technique used in the serological diagnosis of bullous pemphigoid and pemphigus. The BIOCHIP method combines the screening of autoantibodies and target antigen-specific substrates in a single miniature incubation field. OBJECTIVE: To evaluate the diagnostic accuracy of the new immunofluorescence BIOCHIP multiplex tool in pemphigus and bullous pemphigoid. METHODS: For the validation of the BIOCHIP, sera from patients with BP (n = 38), PF (n = 8) and pemphigus vulgaris (PV) (n = 23) were used. In addition, sera from disease control patients (n = 63) and healthy volunteers (n = 39) were used. The multiplex BIOCHIP and direct immunofluorescence (DIF) were performed for all BP, PF and PV patients. Additional indirect immunofluorescence (IIF) was performed on patients with BP, and ELISA was performed on patients with pemphigus. RESULTS: The BIOCHIP mosaic showed a sensitivity of 86.8% and specificity of 85% for BP180 or BP230 being positive in BP. It demonstrated a sensitivity of 75% and specificity of 97.7% for Dsg1 in PF. The BIOCHIP was found to have a sensitivity of 60.9% and specificity of 73.6% for Dsg3 in PV. CONCLUSION: The BIOCHIP mosaic-based immunofluorescence test is potentially a simple, time and effort saving test that can aid in the diagnosis and screening of BP, PV and PF. However, there is potential for interpretation bias and a learning curve that needs to be taken into consideration.

Inter-rater reliability of the BIOCHIP indirect immunofluorescence dermatology mosaic in bullous pemphigoid and pemphigus patients.

BACKGROUND: The BIOCHIP (Dermatology Mosaic 7; EUROIMMUN, Lubeck, Germany) is a novel multiplex indirect immunofluorescence (IIF) technique used in the serological diagnosis of bullous pemphigoid (BP) and pemphigus. OBJECTIVE: To validate the accuracy and inter-rater reliability (IRR) of the BIOCHIP in the diagnosis of BP, pemphigus foliaceus (PF) and pemphigus vulgaris (PV). METHODS: Sera from patients with BP (n = 38), PF (n = 8), PV (n = 23), control patients (n = 64) and healthy control volunteers (n = 39) were tested. Sera were collected and analysed during the course of the disease at 1-5 different time points. The BIOCHIP was performed for all patients, digital images were captured of each incubated field, and the images were shared with 10 dermatologists experienced in reading IF from around the world to report. There were 312 BIOCHIP slides consisting of 1872 photos in total. All patients were de-identified. Fleiss Kappa was used to estimate the IRR. RESULTS: Fleiss Kappa was computed for each category (Oesophagus, Oesophagus immunofluorescence pattern, Salt-Split Skin (SSS), SSS immunofluorescence location, BP180, BP230, Dsg 1 and Ds3). The inter-rater agreement between the 10 raters varied between fair and moderate for all categories. Those that demonstrated fair concordance included monkey oesophagus (k = 0.257, P < 0.0001), oesophagus pattern (k = 0.357, P < 0.0001), Dsg1 (k = 0.390, P < 0.0001) and BP230 (k = 0.281, P < 0.0001). Moderate agreement was demonstrated for SSS (k = 0.416, P < 0.0001), SSS immunofluorescence location (k = 0.505, P < 0.0001), Dsg3 (k = 0.437, P < 0.0001) and BP180 (k = 0.559, P < 0.0001). CONCLUSION: The BIOCHIP mosaic-based immunofluorescence test is a simple, time and effort saving test that can aid in the diagnosis and screening of BP, PV and PF. However, the level of agreement was relatively low. The authors found the most common causes to be variable levels of training, indicating the presence of a learning curve in the interpretation of the results and ambiguous staining patterns leading to incongruent results.

Clinical heterogeneity in recessive epidermolysis bullosa due to mutations in the keratin 14 gene, KRT14.

BACKGROUND: Epidermolysis bullosa simplex (EBS), the most common subtype of EB, is usually inherited as an autosomal dominant trait caused by mutations in either the keratin 5 (KRT5) or keratin 14 (KRT14) genes. Recessive EBS (R-EBS) is extremely rare. METHODS: We present the first Australian patient diagnosed with R-EBS, to our knowledge, and a comprehensive review of genotypes and phenotypes of R-EBS reported cases. RESULTS: The female proband, of Turkish descent with consanguineous parentage, was referred to us at the age of 8 years. Clinically, she had a severe phenotype including generalized blisters, mucosal involvement and EB naevi. Immunofluorescence mapping and electron microscopy were consistent with a diagnosis of EBS. Staining for Keratin 14 (K14) was negative. The basal layer, however, reacted with monoclonal antibodies to keratins 6 (K6) and 16 (K16). Mutation screening from genomic DNA showed that the proband was homozygous for the truncation mutation Y204X in exon 3 of KRT14, and both unaffected parents were heterozygous for a single KRT14 Y204X mutation. The phenotype of our patient is reported in more detail and with longer follow-up than those of others published in the literature. DISCUSSION: The proband's phenotype was severe as an infant but improved with age, suggesting that an alternative keratin is pairing with K5 in her skin to compensate for the loss of K14--a novel biological compensatory mechanism. It is interesting that K6 and K16 were expressed, as these are normally positive in hyperproliferative skin disorders.

Radar determination of the radius of venus.

The radius of Venus has been determined from radar-range data taken at the Jet Propulsion Laboratory's Goldstone facility. A simultaneous intergration of the equations of motion of the solar-system fit to this time-delay data gave a value of 6053.7 +/- 2.2 kilometers. A discussion of other Venusian radius determinations is made.