The IIF staining pattern that shows a Perinuclear or nuclear staining pattern is typically associated with which autoantibody?

The perinuclear or nuclear staining pattern observed in immunofluorescence (IIF) assays is typically associated with p-ANCA (perinuclear anti-neutrophil cytoplasmic antibodies). This staining pattern occurs due to the binding of the p-ANCA antibodies to antigens located in the perinuclear region of neutrophils, which leads to the characteristic perinuclear fluorescence under a fluorescence microscope.

p-ANCA is commonly associated with certain autoimmune conditions, particularly those affecting small blood vessels, such as vasculitis. It is important to note that while other antibodies can present with various staining patterns, the distinct perinuclear pattern is a defining characteristic of p-ANCA.

In contrast, c-ANCA (cytoplasmic anti-neutrophil cytoplasmic antibodies) is associated with a different staining pattern that shows a diffuse cytoplasmic fluorescence. Anti-Smith and Anti-RNP antibodies are primarily linked with systemic lupus erythematosus (SLE) and certain other autoimmune disorders, showing different patterns in immunofluorescence studies. Anti-Smith antibodies, for instance, are often associated with a nuclear homogeneous pattern while Anti-RNP can show a speckled pattern. Understanding