PReS-FINAL-2359: Renal involvement in hypocomplementemic urticarial vasculitis syndrome (huvs): report of 3 paediatric cases

Abstract

Objective: HUVS has been described only in 8 children, with a rapid progressive glomerulonephritis in 4 and end stage renal disease in 4. We describe the histopathological picture and renal involvement in 3 children with HUVS. Method(s): 3 children (4-9 yrs of age at onset) diagnosed with HUVS (2 major criteria, chronic urticarial skin lesions, hypocomplementemia, and >=2 minor criteria), who developed persistent microhaematuria 1-3 years after diagnosis (isolated in Case 1, associated with mild proteinuria in case 2, with nephrotic syndrome in Case 3), underwent renal biopsy. Result(s): Laboratory: Anti-C1q precipitin were positive and C3-C4 low in all cases; serum autoantibodies were negative in Cases 1 and 2, while Case 3 became positive for anti-dsDNA, with no sufficient criteria to diagnose SLE. Renal biopsy. LM: isolated mesangial GN was found in Case 1, associated with focal necrotizing small-vessel vasculitis in Case 2, while GN with intense mesangial, endo- and extra-capillary proliferation in Case 3. IF: Cases 1 and 2 shared a full-house feature; Case 3 showed intense C1q and C3 positivity, with IgA +/- and negative IgG, IgM and fibrinogen. Treatment: Case1 was initially treated with PDN, after a second biopsy MMF and dapsone were added; Case 2 was treated withoral PDN and CPM for 3 months, then AZT; in Case 3, i.v.MPDN pulses, oral PDN, dapsone and i.v. CPM pulses were administered. Conclusion(s): This report shows a significant and severe renal involvement in paediatric HUVS; renal biopsy should be considered also when only isolated microhaematuria is present. Prompt treatment is mandatory in order to avoid progression to end-stage renal disease.