Immune and Autoimmune Disorders

Autoimmunity is not simply an immune system that is “too strong.” It reflects a breakdown in central and/or peripheral self-tolerance, allowing autoreactive T cells and B cells to recognize and injure host tissues. Genetic susceptibility, infections, environmental exposures, medications, and tissue injury may influence when disease appears, but the clinical pattern depends on the autoantigens and immune pathways involved. Some disorders are organ-specific; others are systemic. Systemic lupus erythematosus (SLE) may affect the skin, joints, blood cells, lungs, heart, nervous system, and kidneys. Rheumatoid arthritis (RA) primarily targets synovial tissue but can also cause extra-articular disease. The same patient may therefore present with fatigue and joint pain one month and organ-threatening renal or pulmonary findings later. That changing pattern creates a practical nursing question: is this a flare, an infection, or medication toxicity? Fever, fatigue, cytopenias, rash, and renal dysfunction can occur in more than one of these situations. The answer matters because increasing immunosuppression may help a flare but worsen an unrecognized infection. Hypersensitivity is a different immune problem. In type I hypersensitivity, an allergen cross-links IgE on mast...