Topic 12 Diseases

Disease Key immune cells Major molecular / immune mechanisms Simple symptoms Classic / established therapies
Psoriasis Dendritic cells, Th17/Th1 cells, keratinocytes, neutrophils IL-23/IL-17 axis → keratinocyte hyperproliferation; TNF signaling Well-demarcated scaly erythematous plaques (skin) Topical steroids, phototherapy, methotrexate/cyclosporine; biologics (anti-TNF, anti-IL-17, anti-IL-23)
Multiple Sclerosis (MS) Autoreactive CD4 (Th1/Th17), CD8 T cells, B cells, microglia, macrophages Autoimmune demyelination in CNS; blood–brain barrier breach; complement & cytotoxicity Relapses of focal neuro deficits, sensory/motor impairment, visual problems High-dose corticosteroids (relapses), disease-modifying therapies: interferon-β, S1P modulators, anti-CD20 (rituximab/ocrelizumab), natalizumab
Crohn’s Disease Innate immune cells, Th1/Th17, B cells, macrophages Barrier dysfunction, dysregulated mucosal immunity (NOD2, IL-12/23, TNF); chronic transmural inflammation Abdominal pain, diarrhea, weight loss, fistulas Aminosalicylates (limited), corticosteroids (induction), immunomodulators (azathioprine), anti-TNF, anti-IL-12/23
HIV → AIDS CD4⁺ T cells (primary target), macrophages, dendritic cells Lentiviral infection → progressive CD4 depletion, immune deficiency, opportunistic infections Lymphadenopathy → opportunistic infections, weight loss, chronic fever Combination antiretroviral therapy (ART); opportunistic infection prophylaxis
SLE (systemic lupus erythematosus) B cells, plasmablasts, Tfh, plasmacytoid DCs, complement Autoantibodies (anti-dsDNA), immune complexes → complement activation; type I IFN signature Malar rash, arthritis, nephritis, cytopenias, photosensitivity Hydroxychloroquine, corticosteroids, immunosuppressants (azathioprine, mycophenolate), biologics (belimumab), supportive care
Aicardi–Goutières Syndrome (AGS) Microglia, innate immune sensors, plasmacytoid DCs Genetic defects in nucleic acid metabolism → chronic type I interferonopathy (sensing of self-nucleic acids) Early onset encephalopathy, intracranial calcifications, developmental delay Supportive; immunomodulation (JAK inhibitors) and symptomatic care (experimental)
COPA syndrome T cells, B cells, innate immune cells Defect in ER-Golgi transport → autoimmune/autoinflammatory phenotype often with elevated type I IFN Interstitial lung disease, arthritis, autoimmunity Immunosuppression (steroids, calcineurin inhibitors), targeted approaches (JAK inhibitors); lung transplant in severe ILD
Alzheimer’s disease (microglia-related aspects) Microglia, complement components, astrocytes Microglial activation, complement-mediated synapse pruning, TREM2 pathway; chronic neuroinflammation Progressive memory loss, cognitive decline Symptomatic drugs (AChE inhibitors, memantine); anti-amyloid / anti-tau immunotherapies (experimental); symptomatic/supportive care
Autism Spectrum Disorder (ASD) — microglia associations Microglia (proposed role), peripheral immune cells (associations) Associations of neuroimmune dysregulation in some cases (microglial activation/inflammation) — heterogeneous and incompletely understood Social-communication deficits, restricted/repetitive behaviors Behavioral therapies (ABA), developmental interventions; no standard immunotherapy (research ongoing)
Sepsis Innate immune cells (neutrophils, macrophages), endothelial cells, lymphocytes Dysregulated host response to infection → excessive cytokines, coagulopathy, immune paralysis/sequential hypo-inflammation Fever/hypothermia, tachycardia, hypotension, organ dysfunction Early antibiotics, source control, fluid resuscitation, vasopressors, organ support; adjunctive immunomodulation selective in trials
COVID-19 (severe) Epithelial cells, innate immune cells, T cells, neutrophils Viral infection with possible hyperinflammation (cytokine storm), coagulopathy, impaired antiviral immunity Fever, cough, dyspnea → hypoxemia, ARDS in severe cases Antivirals (where approved), dexamethasone for severe disease, supportive care, monoclonal antibodies (prophylaxis/early disease), vaccines (preventive)
Rheumatic Fever Cross-reactive T/B cells, antibodies Molecular mimicry after Group A strep → immune cross-reaction against heart/striatum → carditis Fever, migratory polyarthritis, carditis, chorea (Sydenham) Eradicate streptococcal infection (penicillin), anti-inflammatory therapy (aspirin, steroids), long-term prophylaxis
Rheumatoid Arthritis (RA) Synovial macrophages, fibroblast-like synoviocytes, Th17, B cells (autoantibodies RF/ACPA) Autoantibody-associated chronic synovitis; TNF, IL-6, IL-1 pathways; joint erosion mediated by osteoclasts Symmetric peripheral polyarthritis, morning stiffness, joint erosions NSAIDs, glucocorticoids (bridging), DMARDs (methotrexate), biologics (anti-TNF, anti-IL-6, anti-CD20)
Rheumatic Heart Disease (RHD) Result of post-streptococcal immune injury (T/B cells) Chronic valvular damage from immune cross-reactivity after rheumatic fever Valvular regurgitation/stenosis, heart failure, arrhythmias Secondary prophylaxis (penicillin), medical management of heart failure; valve repair/replacement surgery
Guillain–Barré syndrome (GBS) Peripheral nerve-targeting antibodies, complement, macrophages Autoimmune peripheral demyelination (often post-infection); anti-ganglioside antibodies in subtypes → complement & macrophage-mediated injury Rapidly progressive ascending weakness, areflexia, possible respiratory failure IV immunoglobulin (IVIG) or plasmapheresis, supportive respiratory care, rehab
Cancer (immune aspects) Cytotoxic CD8 T cells, NK cells, tumor-associated macrophages, Tregs, MDSCs Immune evasion (PD-L1, CTLA-4, antigen loss), chronic inflammation, immunosuppressive tumor microenvironment Variable by tumor type — mass effect, organ-specific symptoms, constitutional symptoms Surgery, chemo, radiotherapy; immunotherapies: checkpoint inhibitors (anti-PD-1/PD-L1, anti-CTLA-4), CAR-T, cytokine therapies, targeted small molecules