<\/span><\/h3>\nDIF is useful in the diagnosis of cutaneous vasculitis and some other types of inflammatory<\/span> Skin illness:<\/p>\n\n- Small pot (hypersensitivity<\/span>) vasculitis <\/li>\n
- Henoch - Sch\u00f6nlein purple<\/span><\/li>\n
- Lichen planus<\/li>\n
- Cutaneous porphyria delays<\/li>\n
- Some adverse skin reactions to drugs.\n<\/li>\n
- \nPhotosensitivity<\/span> rashes<\/li>\n<\/ul>\n
\n
\n
\n
\n<\/div><\/div><\/div><\/div>\n
<\/span>Site of biopsy<\/span>
\n<\/span><\/h2>\nThe optimal site to take a skin biopsy depends on the suspected disease.<\/p>\n
\n- \nAutoimmune bullous diseases<\/strong>: takes on a normal appearance perilesional<\/span> skin within 1 cm of a bulla<\/span>. Since false negative results can arise from samples from the lower extremities, avoid these sites if possible.<\/li>\n
- \nConnective tissue diseases<\/strong>: the biopsy should be taken from a injury<\/span> (often in areas exposed to the sun), ideally over 6 months old but still active. An additional sample is often taken in a place protected from the sun.<\/li>\n
- \nVasculitis<\/strong>: For best results, take a puncture biopsy<\/span> or a deepshaving biopsy<\/span> from an injury that is less than 24 hours old.<\/li>\n<\/ul>\n
Another routine hematoxylin-eosin (H&E) biopsy is usually taken. histology<\/span>. Note that the optimal biopsy site and required time differ for these examples.<\/p>\n\n- \nAutoimmune bullous diseases<\/strong>: remove an integer vesicle<\/span> or biopsy of the edge of a blister.<\/li>\n
- \nVasculitis<\/strong>- Select a purple lesion less than 72 hours long.<\/li>\n<\/ul>\n
<\/span>Transport and storage of the biopsy sample.<\/span><\/h2>\nSamples for DIF should not be placed in formalin, as this alters the proteins and significantly decreases the precision of the results. Transport the sample to the laboratory as soon as possible. Options for transporting the sample include:<\/p>\n
\n- Placed in a saline<\/span>soaked gauze<\/li>\n
- In saline solution solution<\/span>\n<\/li>\n
- In special media (eg, Michel or Zeus)<\/li>\n
- Frozen in liquid nitrogen (sample should not be allowed to thaw).<\/li>\n<\/ul>\n
Each laboratory has its own protocols. Samples in saline solution can produce higher<\/span> sensitivity over other media if processed within 24-48 hours.<\/p>\n<\/span>What happens to the sample in the laboratory?<\/span><\/h2>\nDIF can be carried out on an automated machine or manually. The process involves first making frozen sections and then carrying out immunofluorescence.<\/p>\n
<\/span>Preparing frozen sections <\/span><\/h3>\n\n- A needle biopsy is transported to the laboratory on gauze soaked in saline.<\/li>\n
- The sample is placed in a gel<\/span>.<\/li>\n
- Liquid nitrogen is used to freeze the sample and the gel.<\/li>\n
- The frozen sample is contained within the frozen gel.<\/li>\n
- The sample can be stored in liquid nitrogen for about a week.<\/li>\n
- Slices 4\u20136 microns thick are cut.<\/li>\n<\/ol>\n\n
<\/span>Preparing frozen sections<\/span><\/h5>\n<\/section>\n\n\n
\n
\n<\/div>\n
Put biopsy on gauze soaked in saline solution<\/p>\n
\n
\n<\/div>\n
Gel sample<\/p>\n
\n
\n<\/div>\n
Liquid nitrogen storage<\/p>\n
\n
\n<\/div>\n
Frozen specimen<\/p>\n
\n
\n<\/div>\n
Sample in liquid nitrogen<\/p>\n
\n
\n<\/div>\n
Cut thin slices of skin<\/p>\n<\/p><\/div>\n<\/section>\n
<\/div>\n
<\/span>Carrying out direct immunofluorescence.<\/span><\/h3>\n\n- Five or six slides are made; each one for a different reagent<\/span>. A slide will be used for normal H&E staining.<\/li>\n
- A special pen is used to draw a perimeter to keep reagents<\/span> inside the slides.<\/li>\n
- The slides are washed.<\/li>\n
- The reagents are composed.<\/li>\n
- The reagents (antibody-fluorophore are conjugated with IgG, IgM, IgA, complement<\/span> C3 protein, and when required fibrinogen<\/span>) are dropped onto the slides and the slides are left for a time in the dark.<\/li>\n
- The slides are washed again in solution.<\/li>\n
- Glass covers are placed over the slides.<\/li>\n<\/ol>\n\n
<\/span>Carrying out direct immunofluorescence.<\/span><\/h5>\n<\/section>\n\n\n
\n
\n<\/div>\n
Five slides are made.<\/p>\n
\n
\n<\/div>\n
A special pen is used.<\/p>\n
\n
\n<\/div>\n
Slides washed in solution<\/p>\n
\n
\n<\/div>\n
Preparing reagents<\/p>\n
\n
\n<\/div>\n
Reagents<\/p>\n
\n
\n<\/div>\n
Reagent dropped on slides<\/p>\n
\n
\n<\/div>\n
Wash in solution<\/p>\n
\n
\n<\/div>\n
Prepare for the coverslip<\/p>\n
\n
\n<\/div>\n
Glass cover<\/p>\n<\/p><\/div>\n<\/section>\n