Discussion
We encountered a case of TAFRO syndrome that developed immediately
following the first COVID-19 mRNA vaccination. To the best of our
knowledge, this is the first reported case of TAFRO syndrome following a
COVID-19 mRNA vaccination. Various side effects of the COVID-19
vaccination have been reported worldwide. Braun et al . reported a
case of cerebral venous thrombosis and thrombotic thrombocytopenia
syndrome [2]. Lim et al . reported myocarditis after mRNA
COVID-19 vaccination [3]. Cases of kidney injury, such as IgA
nephropathy [4], minimal change disease [5-7], and IgG4-related
disease [8], following mRNA vaccination have accumulated in current
research.
Ubara et al . reported the renal histology of TAFRO syndrome as
glomerular endotheliopathy that is representative of endothelial cell
swelling, mesangiolysis, mesangial loosening (loss of mesangial matrix
staining), and GBM double contour and thickening. Electron microscopy
shows loss of mesangial architecture and endothelial space as well as
loss of endothelial cell fenestrations [6]. In the present case,
these findings, except for endothelial cell fenestrations, were
detected, confirming the diagnosis of TAFRO syndrome.
Previous reports have suggested that vaccination may trigger an
autoimmune response due to antigenic mimicry, as well as activation of
quiescent auto-reactive T and B cells [10]. These reports suggest
that the COVID-19 mRNA vaccine stimulates the immune system and causes
autoimmune reactions.
TAFRO syndrome is a systemic inflammatory disorder and a subtype of
HHV-8 negative MCD [11]. Although the etiology has not been
revealed, it has been demonstrated that hypercytokinemia related to IL-6
and stimulation of VEGF contributes to the pathophysiological mechanisms
of TAFRO syndrome [12,13]. It is suggested that the abnormal
autoimmune response induced by COVID-19 mRNA vaccination caused the
overproduction of cytokines, such as IL-6 and VEGF, in the present case.
The pathophysiology of TAFRO syndrome has not yet been clarified;
however, it often presents with progressive clinical symptoms and can be
fatal. We should be considered as one of the rare side reactions of the
COVID-19 vaccine and should be diagnosed earlier. Further studies are
needed to reveal the mechanisms of the immune response in developing
severe side effects following COVID-19 mRNA vaccination.
Conclusion Universal
vaccination against COVID-19 is important for lowering the risk of
spreading COVID-19 infection. Several complications, such as renal,
hematological, and heart diseases, have been reported; however, its
pathogenesis is unclear. The
possibility of various complications after COVID-19 vaccination,
including TAFRO syndrome, should be considered.