RESUMEN
Introduction This case report represents, to our knowledge, the first suspected case of Light Chain Deposition Disease (LCDD) relapse associated with mRNA COVID-19 vaccination. It must be made clear that timing is the only link between the vaccination and the relapse of LCDD, and since millions of individuals received these vaccines, an event like this may be due to chance. At the same time, this case report may be an entry point into further explorations of the pathogenesis of LCDD, given the mechanism of action of the vaccine and the pathophysiology of the disease, as it is currently understood. Case presentation The 75-year-old female patient of Greek ethnicity was admitted into our clinic for the investigation of worsening renal function that was detected on routine lab examinations two weeks after she received the second dose of the moderna COVID vaccine (mRNA-1273). Rapidly progressive glomerulonephritis and anemia were the most notable findings upon admission. She had a history of Light Chain Deposition Disease (LCDD) which had remained stable under management for four years. Serum protein electrophoresis was performed and showed monoclonal kappa zones, while bone marrow biopsy revealed 5% plasma cell infiltration. All the above, along with other investigations, established the diagnosis of LCDD recurrence. She was started on chemotherapy, which improved her immunological profile but not her renal function. The patient has remained on hemodialysis since. Conclusions The association between mRNA vaccinations and LCDD relapse may be ground for investigations into the pathophysiology of MGRS, given the patient’s previous long-term remission. In this context, we want to stress once again the importance of following standardized routine mandates on COVID vaccination, especially in immunocompromised patients. This case report is not intended to directly inform changes in clinical practice.