title: Immunoglobulin A multiple myeloma presenting with Henoch-Schönlein purpura associated with reduced sialylation of IgA1.
abstract: Henoch-Schönlein purpura is characterized by immunoglobulin A1 (IgA1) depositions in blood vessels of the skin or in glomeruli, resulting from altered hinge region O-glycosylation. Henoch-Schönlein purpura is seldom reported as a complication of IgA1 myeloma, even when the circulating IgA concentration is very high. We report two patients with IgA1 myeloma presenting with Henoch-Schönlein purpura. The O-glycosylation of these patients' IgA1 was studied. Both patients showed increased binding to peanut agglutinin lectin, suggesting a low degree of sialylation of the hinge region of IgA1 that was confirmed by mass spectrometry. IgA multiple myeloma, secreting IgA1 molecules with decreased sialylation, presenting with a Henoch-Schönlein purpura-like syndrome was diagnosed.
authors.affiliation: Department of General Internal Medicine, Leiden University Medical Center, Leiden, The Netherlands. AvdHelm@lumc.nl
authors.forename: Annette H M
authors.initials: AH
authors.lastname: Van Der Helm-Van Mil
authors.forename: Alice C
authors.initials: AC
authors.lastname: Smith
authors.forename: Shideh
authors.initials: S
authors.lastname: Pouria
authors.forename: Edward
authors.initials: E
authors.lastname: Tarelli
authors.forename: Nigel J
authors.initials: NJ
authors.lastname: Brunskill
authors.forename: Heroen C J
authors.initials: HC
authors.lastname: Eikenboom
mesh_terms: D006031:Glycosylation; D006801:Humans; D011695:IgA Vasculitis / Q000097:blood / Q000209:etiology*; D007070:Immunoglobulin A / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009101:Multiple Myeloma / Q000097:blood / Q000150:complications*
chemical_list: D007070:Immunoglobulin A