Body: Our center had a case of a 20-year old female with severe bi-ventricular dysfunction, leading to an LVAD placement and heart transplantation. Strong GSTT1 Ab was detected pre-transplant using non-HLA antibody panel, alerting us and leading us to further study its significance. Glutathione S-transferases (GSTs) are an important class of enzymes that metabolize xenobiotics and protect cells from reactive oxygen species and environmental carcinogens. There are common polymorphisms with GSTs which can lead to complete deletion of the gene creating a null allele. We hypothesize that having a GSTT1 gene deletion can generate high titer non-HLA antibodies to GSTT1 in the recipient. When a donor organ is transplanted, the anti-GSTT1 antibodies can bind to functional GSTT1 and contribute to allo-rejection. We used rigorous genetic testing for the GSTT1 genotype with Real-Time PCR on a QuantStudio 6 using SYBR green as a reagent, along with extensive antibody screening using both HLA and non-HLA panels. The PCR reaction was designed to detect GSTT1 (257 bp PCR product) with Bcl2 (155 bp PCR product) used as an internal control and to exclude false negatives. DNA extracted from our heart transplant patient at initial evaluation was found to have a high Ct level of 37.1745, suggesting low or undetectable GSTT1 DNA, which indicates a GSTT1 null genotype. Pre transplant serum was tested for non-HLA antibodies and antibodies to GSTT1 were high at 10,206 MFI. One year post-transplant, there was an abnormal heart transplant biopsy with ABMR detected by MMDx heart (Figure 1), showing both intraluminal mononuclear cells as well as plasma cells, an atypical infiltrate. There was low level de novo DQ8 within the first year, which only rose two years later with accompanying DQ6. Following intensive and broad ABMR treatment to enhance immunosuppression including plasmapheresis, intravenous steroids and more, the GSTT1 Ab level decreased to 1311 MFI. Follow up biopsy and MMDx showed increased inflammation, yet no definite ABMR or TCMR with some parenchymal injury. Despite successful immunosuppression and ABMR therapies, the patient required re-transplantation after two years due to worsening CAV.
Conclusion: The data highlights the need for rigorous pretxp testing of non-HLA Ab to guide patient immunosuppression and induction protocols to improve graft survival and patient outcomes.
