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

Abstract

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.

Modulatory Effects of CD14+CD16++ Monocytes on CD14++CD16− Monocytes: A Possible Explanation of Monocyte Alterations in Systemic Lupus Erythematosus

“…Similar proportions of monocyte subsets in both SLE patients and healthy controls have been previously reported (4,5,26). In contrast, one study demonstrated that patients with inactive SLE without immunosuppressive therapy had increased numbers and percentages of CD14ϩCD16ϩ monocytes as compared with patients with active SLE and healthy controls.…”

The dynamics of macrophage lineage populations in inflammatory and autoimmune diseases

“…However, the relevance of these changes to the increased numbers of macrophages in RA synovium discussed above remains to be established. Peripheral blood monocyte subsets have recently been identified (43)(44)(45) and, for reasons that are unclear, conflicting observations of their ratios have been reported in RA patients, with different studies showing an increased or reduced proportion of the CD14 low CD16ϩ subset (46,47). The potential significance of these subsets is detailed below.…”

“…In humans, 2 main monocyte populations have been delineated, namely, the major CD14ϩCD16Ϫ and the minor CD14 low CD16ϩ subsets (43). As mentioned above, there have been conflicting findings regarding the ratio of these subpopulations in the blood of RA patients (46,47). The CD14ϩCD16Ϫ subpopulation is considered to be the less mature, while the more mature CD14 low CD16ϩ monocytes have been called "inflammatory" monocytes (44,134), in part because their level may be elevated in blood in inflammatory conditions, such as RA (135), and in part because they produce TNF in response to LPS (44,134).…”

Immunization of Stage IV Melanoma Patients with Melan-A/MART-1 and gp100 Peptides plus IFN-α Results in the Activation of Specific CD8+ T Cells and Monocyte/Dendritic Cell Precursors

“…Of note, CD14 + CD16 + monocytes expressing low or high levels of CD14 seem to develop into dendritic cells or macrophages, respectively (16). In addition, several studies reported an increased number of circulating CD14 + CD16 + in the course of infections, inflammation, and malignant diseases (17)(18)(19)(20). Another subpopulation of circulating monocytes expresses the CD2 marker and these cells have been described as dendritic cells (21,22).…”