Immune-related adverse events

Immune-related adverse events (irAEs) are the inflammatory, autoimmune-like toxicities of immune checkpoint inhibitors. Because checkpoint blockade releases a systemic brake on T-cell tolerance, an irAE can involve nearly any organ system — skin, gut, liver, lung, endocrine glands, heart, nerves, joints, blood, eyes, and the kidney, where the characteristic lesion is acute interstitial nephritis.

Each card is anchored on the society chapters this atlas holds for that organ — ASCO, ESMO, EULAR and SITC, though no organ has all of them, and each page names its own. The supporting sentence is stored verbatim beside every dose, threshold and rate. Where a guideline states nothing, the card says so instead of filling the gap. Where sources genuinely disagree, every position is shown side by side, each labeled with what kind of source it is — a single center’s protocol and a society guideline do not carry the same weight, and a grading vocabulary is neither.

Browse by organ

• Kidney3 entriesAcute tubulointerstitial nephritis dominates; glomerular lesions and electrolyte disturbances are increasingly reported.ICI-associated acute tubulointerstitial nephritisICI-associated kidney allograft rejectionICI-associated glomerular diseaseOpen
• Gastrointestinal1 entryThe commonest serious ICI toxicity and the one most skewed to CTLA-4 blockade. Diarrhea and colitis are not the same event and do not occur at the same rate — the gap between them is what decides whether steroids are indicated at all.ICI-associated diarrhea and colitisOpen
• Liver1 entryUsually asymptomatic transaminase elevation found on pre-cycle bloods, most often in the first 6-12 weeks. Steroid-responsive, and the alternative causes of liver injury have to be excluded first.ICI-associated hepatitisOpen
• Lung1 entryPneumonitis, whose symptoms and imaging are non-specific enough that the work-up is largely one of exclusion — infection, tumor progression, embolism, cardiac causes — and which can be radiographically visible while the patient is asymptomatic.ICI-associated pneumonitisOpen
• Endocrine5 entriesHormone deficiency, not inflammation to be suppressed: thyroid dysfunction, hypophysitis, primary adrenal insufficiency and insulin-dependent diabetes, each with its own replacement.ICI-associated hypothyroidismICI-associated hyperthyroidismICI-associated hypophysitisICI-associated primary adrenal insufficiencyICI-associated insulin-dependent diabetesOpen
• Skin2 entriesThe commonest and usually the earliest irAEs — mostly inflammatory eruptions, pruritus and vitiligo, rarely a reason to stop the drug. Blisters, mucosal involvement or bullous formation are the finding that changes the pathway.ICI-associated inflammatory and bullous dermatoses, pruritus and vitiligoSevere cutaneous adverse reactions (SJS/TEN, DRESS, AGEP)Open
• Heart1 entryUncommon, and the most lethal irAE by reported share: half of the myocarditis reports in the WHO pharmacovigilance database ended in death. Onset is early, and an asymptomatic troponin rise is a presentation rather than an incidental result.ICI-associated myocarditisOpen
• Nervous system5 entriesNeurological irAEs are mostly non-specific grade 1-2 events, and high-grade ones run below 1% — but the phenotypes that do reach this atlas are among the most lethal in it. Myasthenia gravis carries roughly 20% fatality in the pharmacovigilance record, arrives earliest of the neurological events, and travels with myocarditis and myositis.ICI-associated myasthenia gravisICI-associated encephalitisICI-associated Guillain-Barré syndromeICI-associated aseptic meningitisICI-associated peripheral neuropathy (non-Guillain-Barré)Open
• Blood3 entriesRare — under 1% across a 745-patient registry — and high-grade in most REPORTED cases: 25 of 35 (71%) reached grade 4. That 35-patient cohort was assembled from grade-2-or-worse cases, so its denominator excludes grade 1 by construction and the share is not the severity rate of hematologic irAEs in general. The three commonest presentations are neutropenia, autoimmune hemolytic anemia and immune thrombocytopenia, each managed as its hematological standard of care with a steroid backbone.ICI-associated immune thrombocytopeniaICI-associated autoimmune hemolytic anemiaICI-associated neutropeniaOpen
• Eye1 entryUncommon but sight-threatening, and the one organ SITC manages almost entirely by referral: an ophthalmologist grades and directs treatment, and systemic or topical steroids for the eye are started under that guidance. Uveitis and dry eyes are the commonest; untreated, they can end in vision loss.ICI-associated uveitisOpen
• Rheumatologic4 entriesMostly arthralgia and myalgia, which are common and rarely dangerous. The exception carried here is myositis — around 1% on anti-PD-(L)1, and the member of the myositis/myocarditis/myasthenia triad most likely to present first.ICI-associated myositisICI-associated inflammatory arthritisICI-associated polymyalgia rheumatica (± giant-cell arteritis)ICI-associated sicca syndrome and dry mouthOpen

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