A 8-year-old male had non-blanching rashes over the shin and swelling of the knee joint with haematuria +++ and protein +. Microscopic analysis of his renal biopsy specimen is most likely to show –
Tubular necrosis
Visceral podocyte fusion
Mesangial deposits of IgA
Basement membrane thickening
This child has →

i) Rash             
ii) Arthritis (swelling of knee joint)                       
iii) Haematuria

All these suggest the diagnosis of Henoch Schonlein purpura
HSP is characterized by deposition of IgA in the mesangium.