There is a failure to make reactive oxygen intermediates and to raise the pH in the phagocytic vacuole, which facilitates microbicidal action.

Proteases are enzymes that break the peptide bond that joins amino acids together in proteins. It is essential for the life-cycle of HIV and is responsible for processing the viral proteins of HIV following transcription and translation.

The spontaneous creation of alternative pathway C3 convertase on the red cell is normally eliminated through membrane bound DAF.

Mutations occur in the Bruton's tyrosine kinase (Btk) gene.

Stem cells are unable to differentiate to mature T-cells in the absence of the thymic microenvironment.

Within 24 h of stimulation by lymphocyte polyclonal activators, high concentrations of binding sites for this lectin appear on the surface of the cell.

Immunoglobulin-secreting cells produce an excess of light chain over heavy chain. Fragments of this excess light chain form the amyloid deposits found in 10–20% of patients with multiple myeloma.

Immunological surveillance refers to the recognition of altered cells with a neoplastic potential, which may then be eliminated to prevent the emergence of the tumor.

SLE is a disease involving antibodies to non-organ specific antigens such as DNA and induces immune complexes, which deposit in the vascular bed causing kidney, skin, joint and cerebral lesions.

They give a speckled nuclear fluorescence pattern.

The non-nucleoside reverse transcriptase inhibitors bind to an allosteric binding site next to the active site of reverse transcriptase.

Graves' disease is a fairly frequent organ-specific disease and is often found in association with pernicious anemia.

Individuals with HLA-DR2 are more at risk of developing multiple sclerosis than those with other HLA-DR specificities. Thus a higher frequency of HLA-DR2 is found in MS patients versus the normal population.

The higher concordance rate for genetically identical monozygotic compared to the genetically non-identical dizygotic twins brought up in the same environment clearly favours a strong genetic element.

Parietal cell antibodies detected by immunofluorescence on stomach sections are important markers of inflammatory atrophic gastritis and the subsequent pernicious anemia which can develop. Antibodies to intrinsic factors are even stronger confirmation.