Accelerated apoptosis in SLE neutrophils cultured with anti-dsDNA antibody isolated from SLE patient serum: a pilot study.

Increased numbers of apoptotic neutrophils are found in SLE, related to disease activity and levels of anti-dsDNA antibody. The mechanism of increased apoptosis is not clear, but anti-dsDNA antibody has been shown to induce apoptosis in neutrophils from normal subjects and in certain cell lines. In this study, polyclonal anti-dsDNA antibody was isolated from the serum of a patient with active SLE, and was shown to substantially accelerate apoptosis in neutrophils from SLE patients as compared with neutrophils from healthy control or rheumatoid arthritis subjects.

The CD14+ CD16+ monocyte subset in rheumatoid arthritis and systemic lupus erythematosus.

Most human peripheral blood monocytes strongly express surface CD14, but not CD16 (CD14+ +/CD 16-). A smaller group of monocytes express lower levels of CD14 and also express CD16 (CD14+/CD16+). This subgroup has different functional characteristics and is expanded in a number of disease states. We aimed to determine the percentage of circulating CD14+ /CD16+ monocytes in rheumatoid arthritis and systemic lupus erythematosus (SLE) and relate this to disease measures. Peripheral blood was sampled from 31 SLE patients, 19 rheumatoid arthritis patients, and 19 healthy controls. The percentage of CD14+/CD16+ monocytes was determined by immunofluorescence labelling and dual colour flow cytometry. The percentage of CD14+/CD16+ monocytes was significantly lower in rheumatoid arthritis (median 4.90%) than in normal subjects (median 7.30%, P = 0.014), and in rheumatoid arthritis than in SLE patients (median 9.40%, P = 0.009). The percentage of CD14+/CD16+ monocytes in SLE was not significantly different from that in healthy subjects. This lower percentage of CD14+/CD16+ monocytes in rheumatoid arthritis may be important in the pathogenesis of this disease.

Immune reactions to Bacteroides fragilis populations with three different types of capsule in a model of infection.

The survival and growth of populations of the obligately anaerobic pathogenic bacterium Bacteroides fragilis enriched for large capsules (LCs), small capsules (SCs) or an electron-dense layer (EDL; non-capsulate by light microscopy) were examined in a mouse model of infection over a minimum period of 20 d. Chambers which allowed the influx of leukocytes, but not the efflux of bacteria, were implanted in the mouse peritoneal cavity. The LC and EDL populations consistently attained viable cell densities of the order of 10(8)-10(9) c.f.u. ml-1 within 24 h, whereas the SC population did not. However, after 3 d, all three bacterial populations maintained total viable numbers of 10(8)-10(9) c.f.u. ml-1 within the chambers. LC expression was selected against within 24 h in the model, the populations becoming non-capsulate by light microscopy, whereas in the SC population expression of the SC was retained by approximately 90% of the population. The EDL population remained non-capsulate by light microscopy throughout. Lymphocytes infiltrated the chambers to an equal extent for all three B. fragilis populations and at approximately 1000 times higher concentration than chambers which contained only quarter-strength Ringer's solution. The presence of neutrophils within the chambers did not cause a decrease in the total viable bacterial count. Each population elicited antibodies specific for outer-membrane proteins and polysaccharide, as detected by immunoblotting, which cross-reacted with the other populations. Differences were observed in the immunogenicity of the outer-membrane proteins within the three populations. Neutrophils were initially the predominant cell type in the chambers, but as the total leukocyte count increased with incubation time, neutrophils were outnumbered by other leukocytes.(ABSTRACT TRUNCATED AT 250 WORDS)