Tissue transglutaminase autoantibodies in patients with non-Hodgkin's lymphoma - Case reports

Background: Tissue transglutaminase (tTG) has recently been identified as t he autoantigen recognized by endomysial antibodies in celiac disease (CD) p atients and this has permitted the use of an ELISA test to detect the prese nce in the serum of autoantibodies specific for the diagnosis of CD. Aim: W e report two cases of anti-tTG positivity in patients with non-Hodgkin's ly mphoma (NHL)without evidence of CD. Case Reports: Both patients were males aged 67 and 69 years respectively; both were hospitalized for fever and per ipheral adenopathy. Lymph node histology showed an immunoblastic high-grade T-cell NHL at the IVth the stage of disease in both cases. They were inclu ded in a multicenter study on the association between CD and NHL. Serologic al screening for CD showed the presence of serum anti-tTG antibodies, with values within the range of those recorded in untreated CD patients in our l aboratory; however, both patients had negative anti-endomysial antibodies a nd in both cases intestinal histology showed normal mucosa with villi and c rypts of normal height and depth (villi/ crypts ratio greater than or equal to 2.5, within the range of normal subjects for our laboratory), and no in crease in intraepithelial lymphocytes. The HLA phenotype was obtained givin g the following antigens: Case 1:A 3, A 24(9), B 22, B 35, BW 6, DR 1, DR 1 1 (5), DQ 3, DR 52. Case 2: A 2, A 3, B 51 (5), B 8, BW 4, BW 6, DR B1*02, DR B1*03, DR B3*01. Both subjects were also positive for serum anti-smooth muscle antibodies and one for antinuclear antibodies. Conclusions: (1) Seru m anti-tTG positivity can be found in subjects with NHL without CD and the real frequency of these 'false positives' must be investigated both in subj ects with lymphoproliferative disorders and in patients with autoimmune dis eases. (2) In patients with NHL, without CD, anti-tTG positivity may be una ssociated with EmA positivity and the biological significance of this findi ng must be clarified. Copyright (C) 2000 S. Karger AG, Basel.