Kenjiro Tsuruoka1, Shigeo Wakabayashi2, Hirofumi Morihara3, Ninso Matsunaga1, Yasuhito Fujisaka1, Isao Goto1, Akihisa Imagawa1, Michio Asahi4. 1. Division of Internal Medicine (I), Faculty of Medicine, Osaka Medical College, 2-7, Daigaku-machi, Takatsuki, Osaka 569-8686, Japan. 2. Department of Pharmacology, Faculty of Medicine, Osaka Medical College, 2-7, Daigaku-machi, Takatsuki, Osaka 569-8686, Japan. Electronic address: pha047@osaka-med.ac.jp. 3. Department of Pharmacology, Faculty of Medicine, Osaka Medical College, 2-7, Daigaku-machi, Takatsuki, Osaka 569-8686, Japan. 4. Department of Pharmacology, Faculty of Medicine, Osaka Medical College, 2-7, Daigaku-machi, Takatsuki, Osaka 569-8686, Japan. Electronic address: masahi@osaka-med.ac.jp.
Abstract
BACKGROUND: Although immune checkpoint inhibitors (ICIs) have made an immense breakthrough in cancer therapeutics, they can exert unique, immune-related adverse events. Among them, myocarditis is less frequent, but it is serious and often follows a lethal course. METHODS: To examine the changes in cardiac autoimmunity after ICI administration, we developed a mouse experimental autoimmune myocarditis (EAM) model via intraperitoneal administration of murine α-cardiac myosin heavy chain (MyHC-α) fragment. Thereafter, the mouse anti-PD-1 antibody (mPD1ab) was administered at two time points, subsequent to and concurrent with MyHC-α fragment administration. RESULTS: Severe EAM developed in 3 weeks; wide inflammatory lesions were observed in the cardiac sections. Furthermore, inflammatory/fibrotic genes, such as interleukin 1β, interleukin 6, and collagen 1, were upregulated, although the cardiac function was not significantly affected. The subsequent administration of mPD1ab at 2 weeks post administration of the first MyHC-α fragment exacerbated EAM, whereas the administration of mPD1ab concurrent with MyHC-α fragment administration did not exacerbate EAM. The subsequent administration of mPD1ab significantly increased the infiltration of cluster of differentiation (CD)4- and F4/80-positive cells, whereas the concurrent administration of mPD1ab significantly decreased the infiltration of CD4-positive cells, indicating that the concurrent and subsequent administration of mPD1ab had opposite effects on immune/inflammatory cell infiltration. CONCLUSIONS: These data suggest that the appearance of ICI-induced autoimmune myocarditis might be related to autoimmune system activity before ICI administration. Although ICIs do not adversely affect patients with normal immune systems, we propose that ICI administration should be avoided in patients with autoimmune disorders.
BACKGROUND: Although immune checkpoint inhibitors (ICIs) have made an immense breakthrough in cancer therapeutics, they can exert unique, immune-related adverse events. Among them, myocarditis is less frequent, but it is serious and often follows a lethal course. METHODS: To examine the changes in cardiac autoimmunity after ICI administration, we developed a mouse experimental autoimmune myocarditis (EAM) model via intraperitoneal administration of murine α-cardiac myosin heavy chain (MyHC-α) fragment. Thereafter, the mouse anti-PD-1 antibody (mPD1ab) was administered at two time points, subsequent to and concurrent with MyHC-α fragment administration. RESULTS: Severe EAM developed in 3 weeks; wide inflammatory lesions were observed in the cardiac sections. Furthermore, inflammatory/fibrotic genes, such as interleukin 1β, interleukin 6, and collagen 1, were upregulated, although the cardiac function was not significantly affected. The subsequent administration of mPD1ab at 2 weeks post administration of the first MyHC-α fragment exacerbated EAM, whereas the administration of mPD1ab concurrent with MyHC-α fragment administration did not exacerbate EAM. The subsequent administration of mPD1ab significantly increased the infiltration of cluster of differentiation (CD)4- and F4/80-positive cells, whereas the concurrent administration of mPD1ab significantly decreased the infiltration of CD4-positive cells, indicating that the concurrent and subsequent administration of mPD1ab had opposite effects on immune/inflammatory cell infiltration. CONCLUSIONS: These data suggest that the appearance of ICI-induced autoimmune myocarditis might be related to autoimmune system activity before ICI administration. Although ICIs do not adversely affect patients with normal immune systems, we propose that ICI administration should be avoided in patients with autoimmune disorders.