<prompt> Which antibody is incriminated in causing Henoch Schonlein Purpura?IgAIgGIgMIgD  <response>: Ans. a IgARef: Harrison 18th edition, Chapter 326 The Presumptive pathogenic mechanism for Henoch- Schonlein purpura is immune-complex deposition. IgA is the antibody class most often seen in the immune complexes and has been demonstrated in the renal biopsies of these patients. A number of inciting antigens have been suggested including upper respiratory tract infections, various drugs, foods, insect bites, and immunizations. 