An introduction to immunology and immunopathology

In basic terms, the immune system has two lines of defense: innate immunity and adaptive immunity. Innate immunity is the first immunological, non-specific (antigen-independent) mechanism for fighting against an intruding pathogen. It is a rapid immune response, occurring within minutes or hours after aggression, that has no immunologic memory. Adaptive immunity, on the other hand, is antigen-dependent and antigen-specific; it has the capacity for memory, which enables the host to mount a more rapid and efficient immune response upon subsequent exposure to the antigen. There is a great deal of synergy between the adaptive immune system and its innate counterpart, and defects in either system can provoke illness or disease, such as autoimmune diseases, immunodeficiency disorders and hypersensitivity reactions. This article provides a practical overview of innate and adaptive immunity, and describes how these host defense mechanisms are involved in both health and illness

A multicenter study of skin toxicity management in patients with left-sided, RAS/BRAF wild-type metastatic colorectal cancer treated with first-line anti-EGFR-based doublet regimen: is there room for improvement?

Background Skin toxicity in patients affected by metastatic colorectal cancer (mCRC) treated with epidermal growth factor receptor (EGFR) inhibitors is well known. However, ad hoc ESMO guidelines have only recently been published. Aim and methods To describe the management (pre-emptive or reactive) of anti-EGFR-related cutaneous adverse events (AEs), in a real-life clinical context, in a selected population of patients with left-sided, metastatic RAS/BRAF wild-type mCRC treated with doublet chemotherapy plus anti-EGFR monoclonal antibody (i.e., panitumumab or cetuximab) as first-line regimen at 22 Institutions. The measured clinical outcomes were treatment-related adverse events, objective response rate (ORR), progression-free survival (PFS), and overall survival (OS). Results Of 515 patients included in the analysis, 173 (33.6%) received a pre-emptive and 342 (66.4%) a reactive treatment. The median follow-up period for the overall population was 30.0 months. A significantly lower incidence of any grade acneiform rash was found in the pre-emptive compared to the reactive cohort both in the overall population (78.6% vs 94.4%, p < 0.001) and in patients treated with panitumumab (76.1% vs 93.7%, p < 0.001) or cetuximab (83.3% vs 95.4%, p = 0.004), respectively. A lower incidence of any grade (41.6% vs 50.9%, p = 0.047) but a higher incidence of G3-G4 (9.2% vs 4.7%, p = 0.042) paronychia/nail disorders were found in the pre-emptive compared to the reactive cohort. Nevertheless, a lower rate of patients within the reactive compared to the pre-emptive cohort was referred to dermatological counseling (21.4% vs 15.3%, respectively, p = 0.001). A higher rate of anti-EGFR therapy modification was needed in the pre-emptive compared to the reactive cohort (35.9% vs 41.6%, respectively, p < 0.001). The pre-emptive approach did not reduce the efficacy of antineoplastic therapy compared to the reactive in terms of ORR (69.2% vs 72.8%), median PFS (12.3 vs 13.0 months), and median OS (28.8 vs 33.5 months). Conclusion Although recommended by international guidelines, the pre-emptive approach of anti-EGFR-related skin toxicity in mCRC patients still appears less adopted in daily clinical practice, compared to the reactive one. A wider reception and application of this indication is desirable to improve patients' quality of life without compromising the continuity and efficacy of antineoplastic therapy