Objective. Disease activity in systemic lupus erythematosus (SLE) is usually assessed with complex disease activity scores comprising a variety of different parameters. In order to determine whether SLE disease activity correlates with abnormal B lymphocyte activity, B cell subsets were analyzed, and their relationship to clinical and humoral measures of disease activity was assessed.Methods. The distribution of B cell subsets was determined by fluorescence-activated cell sorting analysis and assessed in relation to the autoantibody profile, disease activity measured by the SLE Disease Activity Index (SLEDAI) and the European Consensus Lupus Activity Measure scores, disease duration, and therapy.Results. The number and frequency of CD27 high plasma cells were significantly correlated with the SLE disease activity indices and with the titer of antidouble-stranded DNA (anti-dsDNA) autoantibodies. Circulating B cell subsets were not influenced by age or sex, but appeared to relate to the duration of disease and the therapeutic regimen, with the number and frequency of CD27 high plasma cells increasing and those of CD27؊ naive B cells decreasing over time. Patients were divided into those with a SLEDAI score of 0-8 (low disease activity) and those with SLEDAI score >8 (high disease activity). Patients with high disease activity had an increased frequency of both CD19؉ B cells and CD27 high plasma cells. By using a nonparametric data sieving algorithm, we observed that these B cell abnormalities provided predictive values for nonactive and active disease of 78.0% and 78.9%, respectively. The predictive value of the B cell abnormalities (78.9%) was greater than that of the humoral/clinical data pattern (71.4%), including anti-dsDNA antibody levels, circulating immune complexes, increased erythrocyte sedimentation rate, mucocutaneous involvement, and acute renal involvement.Conclusion. Flow cytometric monitoring of B cell subsets in the peripheral blood provides new insights into abnormalities of B cell function in SLE and may also be a diagnostically valuable option for monitoring the activity of this autoimmune disease.

Objective. Double-stranded DNA (dsDNA) is a well-known target of autoantibodies in systemic lupus erythematosus (SLE). The majority of these autoanti-bodies are of the IgG isotype and show affinity matura-tion, both of which are known hallmarks of T cell help. T cell responses to autoantigens, including DNA, have been reported only incidentally in SLE patients. Nevertheless , in murine SLE, naked DNA and complexed DNA (nucleosomes) are known to be recognized by T cells. This study aimed to characterize the antinucleo-some response and its clinical impact on human SLE. Methods. Nucleosomes were prepared from chicken erythrocytes. Sera from SLE and control patients were investigated by enzyme-linked immunosor-bent assay (ELISA) for nucleosome-specific antibody responses. Peripheral blood mononuclear cells (PBMC) from SLE and control patients were analyzed by a kinetic T cell proliferation assay. PBMC were subsequently analyzed for nucleosome-specific T cell proliferation. Results. Of 136 SLE patients, 56% were seropos-itive for antinucleosome antibodies. In contrast, only 3% of 309 control patients (with rheumatoid arthritis, mixed connective tissue disease, undifferentiated connective tissue disease, Lyme borreliosis, scleroderma, Sjögren's syndrome, ulcerative colitis, hepatitis B virus infection, or human immunodeficiency virus infection) were seropositive. Thus, the antinucleosome ELISA had a sensitivity of 56%, a specificity of 97%, and a diagnostic confidence of 90% when applied to SLE. It was therefore superior to an anti-DNA ELISA that demonstrated a 69% diagnostic confidence in the same population. Antinucleosome reactivity in SLE patients correlated significantly with disease activity (P < 0.0001), nephritis (P < 0.002), and psychosis (P < 0.02). When proliferation assays were applied, 14 of 26 SLE patients (54%) were positive for nucleosome-specific T cells that proliferated in response to their cognate antigen. A suppressed response was elicited in 3 SLE patients (12%); in these patients, the PBMC response to nucleo-somes was lower than the proliferation of PBMC in the presence of culture medium only. PBMC from the remaining 9 SLE patients (35%) were nonresponsive to nucleosomes in either way. Responding, nonresponding, and suppressed populations differed from each other significantly (P < 0.0001). None of the PBMC from 7 healthy donors and 10 control patients could be stimulated with nucleosomal antigens. Conclusion. We present evidence that nucleo-somes are major autoantigens in human SLE and that antinucleosomal antibodies are highly specific for the disease. The antinucleosome ELISA has been shown to be superior to the anti-dsDNA ELISA and may thus be a significantly better tool for diagnosing SLE. Nucleosome-specific T cells in SLE patients may help B cells class switch to IgG and undergo affinity matura-tion.

Disturbances of B cell homeostasis may be critical in TA. Circulating plasmablasts could be a useful biomarker of disease activity and a tool for selecting appropriate candidates for BCDT. B cells and plasmablasts/plasma cells may therefore represent novel targets for effective therapies for TA.

ObjectiveRheumatoid arthritis (RA) accompanies infiltration and activation of monocytes in inflamed joints. We investigated dominant alterations of RA monocytes in bone marrow (BM), blood and inflamed joints.MethodsCD14+ cells from BM and peripheral blood (PB) of patients with RA and osteoarthritis (OA) were profiled with GeneChip microarrays. Detailed functional analysis was performed with reference transcriptomes of BM precursors, monocyte blood subsets, monocyte activation and mobilisation. Cytometric profiling determined monocyte subsets of CD14++CD16−, CD14++CD16+ and CD14+CD16+ cells in BM, PB and synovial fluid (SF) and ELISAs quantified the release of activation markers into SF and serum.ResultsInvestigation of genes differentially expressed between RA and OA monocytes with reference transcriptomes revealed gene patterns of early myeloid precursors in RA-BM and late myeloid precursors along with reduced terminal differentiation to CD14+CD16+monocytes in RA-PB. Patterns associated with tumor necrosis factor/lipopolysaccharide (TNF/LPS) stimulation were weak and more pronounced in RA-PB than RA-BM. Cytometric phenotyping of cells in BM, blood and SF disclosed differences related to monocyte subsets and confirmed the reduced frequency of terminally differentiated CD14+CD16+monocytes in RA-PB. Monocyte activation in SF was characterised by the predominance of CD14++CD16++CD163+HLA-DR+ cells and elevated concentrations of sCD14, sCD163 and S100P.ConclusionPatterns of less mature and less differentiated RA-BM and RA-PB monocytes suggest increased turnover with accelerated monocytopoiesis, BM egress and migration into inflamed joints. Predominant activation in the joint indicates the action of local and primary stimuli, which may also promote adaptive immune triggering through monocytes, potentially leading to new diagnostic and therapeutic strategies.

Objectives: The aim of this study was to noninvasively evaluate changes in renal stiffness, diffusion, and oxygenation in patients with chronic, advanced stage immunoglobulin A nephropathy (IgAN) by multiparametric magnetic resonance imaging using tomoelastography, diffusion-weighted imaging (DWI), and blood oxygen level-dependent (BOLD) imaging. Materials and Methods: In this prospective study, 32 subjects (16 patients with biopsy-proven IgAN and 16 age-and sex-matched healthy controls) underwent multifrequency magnetic resonance elastography with tomoelastography postprocessing at 4 frequencies from 40 to 70 Hz to generate shear wave speed (meter per second) maps reflecting tissue stiffness. In addition, DWI and BOLD imaging were performed to determine the apparent diffusion coefficient in square millimeter per second and T2* relaxation time in milliseconds, respectively. Regions including the entire renal parenchyma of both kidneys were analyzed. Areas under the receiver operating characteristic (AUCs) curve were calculated to test diagnostic performance. Clinical parameters such as estimated glomerular filtration rate and protein-tocreatinine ratio were determined and correlated with imaging findings. Results: Success rates of tomoelastography, DWI, and BOLD imaging regarding both kidneys were 100%, 91%, and 87%, respectively. Shear wave speed was decreased in IgAN (−21%, P < 0.0001), accompanied by lower apparent diffusion coefficient values (−12%, P = 0.004). BOLD imaging was not sensitive to IgAN (P = 0.12). Tomoelastography detected IgAN with higher diagnostic accuracy than DWI (area under the curve = 0.9 vs 0.8) and positively correlated with estimated glomerular filtration rate (r = 0.66, P = 0.006). Conclusions: Chronic, advanced stage IgAN is associated with renal softening and restricted water diffusion. Tomoelastography is superior to DWI and BOLD imaging in detecting IgAN.