Clinical significance of immunoglobulin deposition in leukocytoclastic vasculitis: a 5-year retrospective study of 88 patients at cleveland clinic.

OBJECTIVE

To study the diagnostic utility and clinical associations of immunoglobulin deposition, determined by direct immunofluorescence (DIF) in cutaneous leukocytoclastic vasculitis (LCV).

METHODS

We performed a retrospective study of all biopsy-proven LCV cases seen at Cleveland Clinic between 2007 and 2012. All LCV cases in which DIF was performed were included.

RESULTS

Of the 218 LCV cases, 106 cases had DIF performed and data from 88 cases were available: median (SD) age 53.3 (19.4), 52% male, 64.1% white, duration of rash 5.5 (20.8) months; follow-up 14 (19.7) months. DIF results showed any immunoglobulin and/or complement and/or fibrinogen in 70.5%, immunoglobulin A (IgA) in 36.4%, immunoglobulin M (IgM) in 21.6%, immunoglobulin G (IgG) in 11.4%. Patients with IgA deposition by DIF, compared with those without IgA, were younger, 44 (19) versus 56 (17) (P = 0.006), more likely to be white (P = 0.025) and had more organs affected by vasculitis (P = 0.002), higher incidence of gastrointestinal tract involvement (P = 0.0001) and renal disease (P = 0.006). No differences between rates of infection or malignancy were seen between DIF IgA, IgM, or IgG-positive versus negative patients.

CONCLUSIONS

In patients with cutaneous LCV, IgA is the most common immunoglobulin found by DIF. IgA deposition, but not IgM or IgG, is predictive of associated renal and gastrointestinal organ involvement by vasculitis. No association between the type of immunoglobulin and preexisting infection or malignancy was found. DIF results add information that is clinically relevant to the diagnosis and management of LCV.