The "multi-hit theory/4-hit theory" pathogenesis hypothesis is widely accepted and IgA nephropathy (IgAN) is understood to be a disease originating from Hit 1, galactose deficient IgA1 (GdIgA1). The chronic repetitive activation of the complement pathway (alternative and lectin pathways) and the subsequent inflammation results in progressive glomerular damage that spills over into increased intraglomerular pressure and other hemodynamic changes, increased urinary protein, glomerulosclerosis, and tubulointerstitial fibrosis. The basic pathophysiology of this disease is the progression of a mixture of such acute and chronic pathologies. Currently, a number of new drugs has emerged as promising agents, such as complement regulators, endothelin receptor antagonists, and SGLT2 inhibitors, which are associated with each pathological step after glomerular deposition of GdIgA1/immune complexes. On the other hand, the molecular mechanisms of GdIgA1 production are gradually being elucidated, and the development of several novel therapeutic agents targeting the responsible B cells and their international clinical trials are progressing. These agents that inhibit or control the production of the Hit1, GdIgA1, are highly expected as essential therapies for this disease. The large body of clinical and basic research findings to date strongly suggest that nephritogenic GdIgA1 is a polymeric IgA1 of mucosal origin. In addition, the B cells involved in its nephritogenic GdIgA1 production are mainly differentiated mature B cells such as plasma cells, which may migrate to the bone marrow as well as the mucosa. The innate immune system in the mucosa, especially Toll-like receptors (TLRs), is thought to be involved in their production. Among TLRs, TLT9 and TLR7, which recognize bacterial and viral unmethylated DNA and RNA, have been reported to be involved. The mucosal activation of these TLRs is associated with the production of APRIL (A Proliferation Inducing Ligand) and BAFF (B cell activating factor), which are TNF superfamily cytokines involved in B cell maturation, survival, and IgA class switching, and may also be involved in the production of nephritogenic GdIgA1. It is still inconclusive whether APRIL or BAFF is more closely involved in the production of nephritogenic GdIgA1. Phenotypes in transgenic animal models suggest BAFF involvement, however, a genome wide association study (GWAS) analysis of human IgAN has identified APRIL, not BAFF, as a candidate gene. Based on the above background, several international clinical trials are underway for drugs such as TLR regulators (hydroxychloroquine), anti-APRIL drugs, anti-BAFF drugs, APRIL/BAFF receptor (TACI) binding inhibitors, and cytoreductive drugs (proteasome inhibitors, anti-CD38 antibodies) to inhibit nephritogenic GdIgA1 production in responsible B cells. This session will provide an overview of the responsible B cells, their GdIgA1 production mechanism, and ongoing drugs.
Post-infectious glomerulonephritis (PIGN), an uncommon variety of glomerulonephritis (GN), is characterized by emergence of nephritic syndrome within a few weeks following an infectious event. PIGN typically presents as a mild condition and tends to resolve by the time of diagnosis for GN. Aggregatibacter actinomycetemcomitans belongs to the HACEK group of bacteria, which constitutes less than 3% of bacteria responsible for community-acquired infective endocarditis. We present a case of 29-year-old man suspected of lymphoma with B-symptoms along with severe splenomegaly and nephromegaly. Shortly after, he developed an episode of nephritic syndrome accompanied by acute kidney injury (AKI) and high titers of cytoplasmic ANCA (c-ANCA)-positivity. Kidney biopsy revealed PIGN with tubulointerstitial nephritis. Despite treatment with antibiotics and corticosteroid, he visited the emergency room due to worsening dyspnea and multi-organ failure. An echocardiogram showed a bicuspid aortic valve with vegetation unseen on previous echocardiogram. He underwent aortic valve replacement immediately without adverse events. Four months after valve replacement, his renal function and cardiac performance have remained stable. We report a case of PIGN with AKI and high titers of c-ANCA appearing later as an infective endocarditis due to Aggregatibacter actinomycetemcomitans. With careful clinical observation and appropriate and timely management, satisfactory outcomes for patient health are possible.
When Berger et al. first reported IgA nephropathy in 1968, the prognosis was generally thought to be benign. However, as more case data were accumulated, it became evident that not all patients with IgA nephropathy necessarily had a good prognosis. IgA nephropathy has a significant morbidity, culminating in end-stage kidney disease (ESKD) in about 40% of patients without treatment within 20 years of the diagnosis. Although almost 20% of patients remain stable in their renal function, 30%-40% of patients develop ESKD from its onset. The important factors of renal outcome in patients with IgA nephropathy is the severity of histopathological findings, heavy proteinuria, long duration of proteinuria, haematuria and hypertension.
Aim: To study COVID-19 vaccination status in kidney transplant recipients (KTRs), reasons for incomplete vaccination and the clinical impact of vaccination on patient outcomes.
Methods: A single-centre retrospective analysis of KTR (n = 543) conducted between 1970 and December 2022. Data included baseline demographics, number of vaccinations, reason for incomplete vaccination and patient outcomes following COVID-19 infection. A completed course of COVID-19 vaccination was defined as four or more vaccine doses.
Exclusion criteria: those deceased prior December 2019, managed by another health service, failed graft, or deceased secondary to non-COVID cause.
Results: 273 of 543 patients met inclusion criteria. Mean age was 58.1 ± 12.2 years, 66% were male. 58.2% of patients were fully vaccinated, 22.7% received three doses, 7.7% received two doses, 0.7% received one dose, 0.7% received zero doses, and 10% incomplete records. The most common reasons for incomplete vaccination were COVID-19 infection, concern for side effects, and patient unawareness of booster recommendations. Vaccination uptake was greater in Australian born patients compared with those born overseas, odds ratio 0.40 (95% CI 0.23-0.69). KTR with incomplete vaccination had poorer outcomes, higher rate of AKI, long COVID, and increased hospitalization.
Conclusion: The majority of KTR were fully vaccinated. KTR with incomplete vaccination status had poorer outcomes with COVID-19 infection and other issues. Patient education is a major area for improvement targeting patients born overseas and better information regarding side effects. Potential interventions need to address improved communication, cultural relevancy, and language.