If an inflammation overwhelms the whole body, systemic inflammatory response syndrome (SIRS) is diagnosed. Sepsis, severe sepsis, and septic shock are progressively severe stages of SIRS. The criteria for SIRS require two or more conditions: alteration of body temperature (>38°C or 12.0 × 10(9)/L (or >10% immature forms). Sepsis is defined as SIRS + infection; severe sepsis is defined as sepsis + evidence of organ dysfunction. Patients with severe sepsis are considered to have defective adaptive immunity.

Sepsis begins when the innate immune system responds aggressively to the presence of bacteria. Toll-like receptors (TLR) cause the antigen presenting cell (APC) to produce proinflammatory cytokines. Biochemical markers associated with sepsis include tumor necrosis factor (TNF) and interleukins (ILs) IL-1 and IL-6, a proinflammatory cytokine. Other proteins produced in response infection and/or inflammation include procalcitonin and chemokine production. Another consequence of inflammation is that the liver is stimulated to produce C-reactive protein (C-RP) .

These cytokines produce systemic inflammation by activating circulating polymorphonuclear leukocytes (PMNs). APCs involve the adaptive immune system by presenting bacterial antigen to T-cell receptor using a Class II major histocompatibility complex (MHC) protein and co-stimulation of CD28.

مواضيع ذات صلة

Congenital Immunodeficiencies: Defects in Lymphocyte Maturation

Congenital Immunodeficiencies: Defects in Innate Immunity

Congenital (Primary) Immunodeficiencies

Neuroimmunology: Interactions Between the Immune and Nervous Systems

Disorders of Neutrophils

Cell Surface Receptors

Acute Inflammation

Diseases Caused by T Lymphocytes

Etiology, Examples, and Therapy of Immune Complex–Mediated Diseases

Examples and Treatment of Diseases Caused by Cell- or Tissue-Specific Antibodies

Mechanisms of Antibody-Mediated Tissue Injury and Disease

Hypersensitivity Disorders Caused by Immune Responses : Clinical Syndromes and Therapy