Abstract Introduction Immune checkpoint inhibitors (ICIs) have revolutionized cancer therapy by enhancing T-cell-mediated immune responses against tumor cells. However, this immune activation also predisposes to autoimmune toxicities known as immune-related adverse events (irAEs), which can affect nearly every organ system. Among these, immune checkpoint inhibitor-induced pneumonitis (ICI-pneumonitis) are sometimes serious and can be fatal. It is defined as noninfectious inflammation of the lung parenchyma resulting from immune activation following ICI exposure. overall incidence is estimated to be about 5%. Differentiating ICI-pneumonitis from aspiration or infectious pneumonia is crucial in oncology patients, who often have risk factors for both. ICI-pneumonitis most commonly presents radiologically as organizing pneumonia pattern followed by nonspecific interstitial pneumonitis. It is primarily a diagnosis of exclusion.Management relies on prompt initiation of corticosteroids—prednisone or methylprednisolone at 1-2 mg/kg/day—followed by a gradual taper over 4-6 weeks. Despite the growing clinical relevance of irAEs such as pneumonitis, few systematic studies have evaluated how host factors, body mass index (BMI), race, sex and age. This study addresses these gaps with retrospective analysis of 244 patients who developed irAEs after ICI therapy. Methods and Results Among 244 patients, 58% were female; 84% White, 13% Hispanic, 2% African American, and 1% Asian; 23% were 65 years, 38% aged 65-79, and 39% ≥80. Pneumonitis occurred in 33 (13.5%) patients. Univariate analysis revealed a statistically significant association between BMI and pneumonitis (χ² = 9.54, p = 0.02), though this was not retained on multivariable logistic regression after adjusting for confounders. No significant associations were identified with age, sex, or race. Conclusions In the univariate analysis of predictors for ICI-pneumonitis, BMI emerged as the only significant variable (p = 0.02). Patients with a normal BMI (18.5-24.9 kg/m²) accounted for 64% of pneumonitis cases compared to 39% in the non-pneumonitis group, suggesting a potential link between lower body mass and increased susceptibility to pulmonary immune toxicity. A borderline association was noted with sex (p = 0.055), with pneumonitis occurring more frequently in males (58%) than females (42%). No significant differences were observed across racial groups (p = 0.61) or age categories (p = 0.36). While the majority of pneumonitis cases were seen with pembrolizumab(85%), followed by nivolumab (9%) and combination ipilimumab + nivolumab therapy (6%), these associations did not reach statistical significance. Overall, these findings suggest that patients with normal BMI and male sex may be more prone to developing ICI-pneumonitis, however more studies are needed for further analysis This abstract is funded by: none
Qaiser et al. (Fri,) studied this question.