A Very Uncommon Cause of Acute Kidney Injury in Infancy

We report herein a unique case of immune disorder with severe kidney manifestations in a 4-month-old boy who initially presented with the triad of symptoms of hemolytic uremic syndrome, including anemia, thrombocytopenia, and anuric acute kidney injury, requiring peritoneal dialysis in a context of unusual severe recurrent infections. Surprisingly, kidney biopsy did not exhibit thrombotic microangiopathy but glomerular and tubulointerstitial nephritis with immune cell infiltration and circulating inflammatory cells (Figure 1a–d). Lymphocyte immunophenotyping revealed an important lymphopenia with unusual T lymphocytes exhibiting T-cell receptor γ3δ1+ (Figure 1e and f) that were shown to be transplacentally acquired maternal T cells (fluorescent in situ hybridization revealed 65% of XX cells). Identification of a hemizygous IL2RG variant confirmed the diagnosis of severe combined immune deficiency. Fluorescent in situ hybridization analyses further demonstrated that lymphocyte infiltration observed on the kidney biopsy was also from maternal origin (Figure 1g), confirming the exceptional diagnosis of maternal-fetal graft-versus-host disease caused by intrauterine maternal-fetal transfusion.