Human Immunity and Blood

AB positive blood type is considered the universal recipient because it has both A and B antigens and no antibodies against A or B.

Rheumatoid factor does indicate a poor prognosis when found in RA patients, correlating with extra-articular (non-joint) complications of RA such as nodules, lung disease and vasculitis as well as with severely affected joints.

In RA, CD4 T cells produce cytokines including Tumour Necrosis Factor [TNF], which activates macrophages to produce tissue destroying enzymes and remodelling cytokines which deform the affected joints. Anti-TNF therapies provide potent therapies for many but not all patients with RA.

Intraepithelial lymphocytes are T cells of various types, not B cells. CD19 is a B cell marker.

Type III cryoglobulins are formed through mixed complexes of polyclonal antibodies with antigen, usually in the form of large complexes; there is a strong association with hepatitis C.

IL-8 is a chemokine which mediates in chemotaxis and in the activation of neutrophils.

Immature lymphocytes which are destined to become T-cells travel from the bone marrow to the thymus where they differentiate to immunocompetence and are educated to recognize peptides derived from foreign antigens presented by self MHC molecules. Thus in a thymectomized animal, this process cannot take place.

LFA-1 is a member of the integrin family, molecules concerned with leukocyte binding to endothelial cells and to extracellular matrix proteins. The VLA molecules are also members of the integrin superfamily.

The peptide in the MHC groove is derived from intracellular proteins, either endogenous or exogenously derived.

The cytosolic proteins are cleaved to small peptides in the proteasome complex before they are transported by the TAP-1/2 molecules into the endoplasmic reticulum.

Cortical epithelial cells may be relatively inefficient antigen processors and only deliver a weak signal which induces proliferation rather than deletion of immature thymocytes.

Neutrophils are chemotactically attracted to the site of inflammation by C5a and mast cell chemotactic factors such as leukotriene B4.

Von Willebrand's disease is a genetic disorder caused by missing or defective von Willebrand factor, a protein essential for blood clotting.

Factor IX is known as the Christmas factor, named after the first patient diagnosed with the deficiency.

Human blood has two parts, fluid and cellular. The fluid part is known as blood plasma, that makes 55% of total blood volume, and the rest are the cellular components. When a sample of blood is centrifuged, results show separation of blood into different layers, based on their density. Three layers are visible after centrifugation is complete. The bottom layer is red colored that is composed of Red Blood Cells (RBCs), above it there's a white band, made up of White Blood Cells (WBCs) and platelets. The third or the topmost layer is a straw colored liquid, that is made up of blood plasma. The cells present in the blood, are also known as formed elements.