Simple Measurement of IgA Predicts Immunity and Mortality in Ataxia-Telangiectasia

Patients with ataxia-telangiectasia (A-T) sufer from progressive cerebellar ataxia, immunodefciency, respiratory failure, and cancer susceptibility. From a clinical point of view, A-T patients with IgA defciency show more symptoms and may have a poorer prognosis. In this study, we analyzed mortality and immunity data of 659 A-T patients with regard to IgA defciency collected from the European Society for Immunodefciencies (ESID) registry and from 66 patients with classical A-T who attended at the Frankfurt Goethe University between 2012 and 2018. We studied peripheral B- and T-cell subsets and T-cell repertoire of the Frankfurt cohort and survival rates of all A-T patients in the ESID registry. Patients with A-T have signifcant alterations in their lymphocyte phenotypes. All subsets (CD3, CD4, CD8, CD19, CD4/CD45RA, and CD8/ CD45RA) were signifcantly diminished compared to standard values. Patients with IgA defciency (n=35) had signifcantly lower lymphocyte counts compared to A-T patients without IgA defciency (n=31) due to a further decrease of naïve CD4 T-cells, central memory CD4 cells, and regulatory T-cells. Although both patient groups showed afected TCR-ß repertoires compared to controls, no diferences could be detected between patients with and without IgA defciency. Overall survival of patients with IgA defciency was signifcantly diminished. For the frst time, our data show that patients with IgA defciency have signifcantly lower lymphocyte counts and subsets, which are accompanied with reduced survival, compared to A-T patients without IgA defciency. IgA, a simple surrogate marker, is indicating the poorest prognosis for classical A-T patients. Both non-interventional clinical trials were registered at clinicaltrials.gov 2012 (Susceptibility to infections in ataxia-telangiectasia; NCT02345135) and 2017 (Susceptibility to Infections, tumor risk and liver disease in patients with ataxia-telangiectasia; NCT03357978)