Clinical impact of altered immunoglobulin levels in Henoch-Schonlein purpura

The aim of the present study was the identification of immunological features, present at the time of diagnosis, that would predict the severity of Henoch-Schonlein purpura and its outcome. A cohort study was carried out in a tertiary pediatric hospital of 69 children with Henoch-Schonlein purpura, in whom serum complement components C3, C4 and IgA, IgM, IgG were repeatedly determined. During the acute phase of the disease in 54/69 patients (78.3%) immunological imbalances were observed. In 24/54 cases (44.4%) certain complications involving the kidneys and the gastrointestinal tract were noted as opposed to in 3/15 children (20%) without immunologic abnormalities. In 50/69 children (72.5%), elevated serum IgA was detected and 16 of them (32%) developed renal involvement while only 1/19 children (5.3%) with normal IgA concentration had renal involvement. Considering separately the group of 9/69 children (13%) with increased IgM and those with normal IgM levels (53/69; 76.8%), irrespective of IgA and IgG concentration, we found a comparable percentage of children who had both renal and intestinal involvement without, however, developing severe complications, which were exclusively seen in patients with increased IgA (5/7 children) and reduced IgM levels. Serum C3 fraction was elevated in 26 children (37.7%) and in 73% of cases it was associated with increased serum IgA values. Renal involvement was seen in 32% of children with increased IgA values. Most importantly, elevated IgA concentration along with reduced IgM levels was associated with higher prevalence of severe complications.