Inhibition of allogeneic lymphocyte E-rosettes induced by sera from newly diagnosed type I diabetics.

Sera from 64 juvenile onset insulin-dependent diabetics (Type I diabetics) and 30 normal subjects were tested for their ability to inhibit sheep red blood cell rosette formation (E-rosette) by normal allogeneic lymphocytes. Inhibition of E-rosette formation by greater than 20% was found with 16 (66%) sera from newly diagnosed patients, 3 (16%) sera from patients with duration of disease between 2 and 12 months and with 4 (18%) sera from diabetics with duration of disease between 1 and 7 years. On the other hand, only 2 (6%) control sera showed inhibitory effect. No relationship between E-rosette inhibition and islet-cell antibodies presence, anti-lymphocyte antibodies occurrence, anti-HLA activity, blood glucose levels, respectively, was found. Investigation of the properties of this inhibitory factor suggests that it is different from other substances that reportedly inhibit E-rosette formation.