M R J Green | PubMed Health

PubMed2005

Natural killer cell activity in families of patients with systemic lupus erythematosus: demonstration of a killing defect in patients.

Natural killer (NK) cell cytotoxic activity and cell frequency, expressed as a percentage of total lymphocytes, have been determined in peripheral blood mononuclear cells from first-degree relatives of patients with systemic lupus erythematosus (SLE), the patients themselves, a group of rheumatoid arthritis (RA) patients and controls. Low levels of killing activity relative to controls were found in some members of all groups with the extent of depression falling into two ranges. Moderate reductions were seen in female (3/31, 10%) and male (4/14, 29%) relatives of SLE patients, female (12/60, 20%) and male (3/4, 75%) SLE patients and female RA patients (6/17, 35%). A more profound depression of killing activity was confined to other female SLE patients (15/60, 25%). There were strong correlations in all groups between killing activity and percentage of NK cells, but analysis of the ratio of these parameters and studies with purified preparations of NK cells suggest that the reduced activity in SLE frequently involves a defect in the killing capacity of the individual cells in addition to the reduced levels of NK cells. Azathioprine (AZA), which was used in treatment of 12 SLE patients, was invariably associated with low values of killing activity. It appears to substantially reduce the percentage of NK and B cells in an action unconnected with the NK cell abnormalities associated with SLE. The finding of low killing activity in relatives and a correlation between their activity and that of their patients support the view that NK cell deficiency is a genetic determinant of SLE. NK cells in SLE may produce insufficient levels of cytokines required for the regulation of IgG production.

Adolescent↗

PubMed2004

Monocyte derived dendritic cell responses in common variable immunodeficiency.

The phenotype and function of monocyte derived dendritic cells (MdDC) were investigated in 25 patients with common variable immunodeficiency (CVID) to test for abnormalities that might help explain the failure of antibody production. Using MHC class II DR and CD86 as markers of maturation, DCs from the majority of CVID patients were normal. However 5 patients, the majority of whom had affected family members who had previously been shown to have a susceptibility genetic locus in the MHC region, expressed abnormally low levels of DR on repeated testing, in some cases associated with a reduced capacity to support antigen stimulated T cell proliferation; nevertheless costimulatory molecules for production of IL-13, IL-10 and IFN-gamma from T cells were intact. In contrast to DCs from healthy donors, DCs from many CVID patients had high spontaneous production of IL-8 and lipopolysaccharide stimulation often caused a reduction in DR expression. Expression of other cytokines (IL-1a, IL-6 and IL-12), either before or after LPS stimulation, was normal. The data suggests there is a fundamental defect in the maturation of MdDCs in a subset of CVID patients that may compromise antigen presentation and subsequent antibody production.

Adult↗