Dysfunction of CD27+IgD+ B cells correlates with aggravated systemic lupus erythematosus.

OBJECTIVE: The apoptotic signaling pathway is obviously disordered in systemic lupus erythematosus (SLE). Natural IgM (nIgM) is important in clearing apoptotic cells and preventing them from triggering deleterious autoimmunity. B-1 and innate-like B (ILBs) cells are the main nIgM producers. Human CD27+IgD+ B cells (un-switched memory B cells) are considered ILBs. However, their functional properties in SLE remain undefined. METHODS: Peripheral blood sample of 50 SLE patients and 50 healthy controls were collected, and twelve SLE patients were assessed in a follow-up study. The amount of CD27+IgD+ B cell in each population was analyzed by flow cytometry. The IgM and IL-10 levels of CD27+IgD+ B cell were assessed by ELISPOT and qRT-PCR, respectively. SPSS 17.0 (SPSS, USA) was employed for data analysis. P < 0.05 indicated statistical significance. RESULT: The amounts of CD27+IgD+ B cell were significantly decreased in SLE patients than healthy control (P < 0.01). CD27+IgD+ B cell amounts were positively correlated with WBC (r = 0.337, P = 0.017), platelet count (r = 0.396, P = 0.004), and serum C3 levels (r = 0.415, P = 0.003) and negatively correlated with serum creatinine levels (r = - 0.285, P = 0.045), SLEDAI(r = - 0.724, P = 0.000), and anti-dsDNA(r = - 0.477, P = 0.000). The IgM and IL-10 levels of CD27+IgD+ B in active SLE were decreased than healthy control (P < 0.001). Moreover, CD27+IgD+ B cells are increased in SLE cases after treatment than before treatment (P < 0.001). CONCLUSION: The amounts of CD27+IgD+ B cell were significantly decreased in SLE patients compared with the healthy population, and CD27+IgD+ B cell was verified to be correlated with clinical and immunological features in SLE patients. CD27+IgD+ B cells had impaired function associated with IgM and IL-10 production in active SLE. Moreover, the amounts of CD27+IgD+ B cells were recovered to the normal level in SLE cases with treatment-related disease remission. Key Points • CD27+IgD+ B cell amounts are significantly decreased in SLE patients than healthy control. • CD27+IgD+ B cells are functionally impaired in producing natural antibody-like IgM and IL-10 in SLE patients. • CD27+IgD+ B cell amounts are correlated with clinical and immunological features in SLE.

[Prevalence and significance of antibodies to citrullinated human fibrinogen ß67-77 peptide in rheumatoid arthritis].

OBJECTIVE: To detect the antibodies against human fibrinogen (FIB) ß67-77 peptide and citrullinated human FIB ß67-77 peptide in rheumatoid arthritis (RA) and examine their diagnostic values in RA. METHODS: The antibodies against FIB ß67-77 peptide and citrullinated FIB ß67-77 peptide were detected by enzyme-linked immunosorbent assay (ELISA) in 227 RA patients, 188 other connective tissue disease and 100 healthy controls. And their clinical applications were analyzed in the diagnosis of RA. RESULTS: (1) The prevalence and titer of IgG, IgA and IgM isotypes of anti-citrullinated FIB ß67-77 peptide antibodies in RA were significantly higher than those with other rheumatic diseases and healthy individuals. However, the prevalence of anti-FIB ß67-77 peptide antibodies in RA patients was similar to those with other rheumatic diseases and healthy individuals (P > 0.05). (2) The diagnostic sensitivity of IgG, IgA and IgM of anti-FIB ß67-77 peptide antibodies for RA were 50.7%, 48.5% and 55.1% and the specificity 94.8%, 92.7% and 92.4% respectively. The sensitivity of combined detection of 3 subtypes was up to 87.7% and the specificity 78.5%. (3) No significant correlations existed between anti-citrullinated FIB ß67-77 peptide antibodies, RF, anti-CCP antibody, AKA and APF respectively. Moreover, the seropositive rates of IgG, IgM and IgA of anti-citrullinated FIB ß67-77 peptide were 52.9%, 39.2% and 54.9% in IgM-RF negative patients Versus 48.5%, 53.1% and 37.5% in anti-CCP antibody, AKA and APF negative patients respectively. CONCLUSION: IgG, IgM and IgA antibodies to citrullinated FIB ß67-77 peptide are sensitive and specific in the diagnosis of RA. And the test of anti-citrullinated FIB ß67-77 peptide antibodies is especially useful in diagnosing RA with other negative autoantibodies.