抗心磷脂抗体检测及其影响因素的研究

目的：研究血清样品稀释度、温度、离子强度以及样品检测间隔时间对血清抗心磷脂抗体（ＡＣＡ）检测结果的影响。方法：采用酶联免疫吸附测定法（ＥＬＩＳＡ）检测ＡＣＡ。结果：血清样品最佳稀释度为１：５０;３７℃时光吸收值比２２℃和２５℃的光吸收值显著下降;１５ｍｏｌ／Ｌ ＮａＣｌ可明显抑制ＡＣＡ与抗原结合（Ｐ〈０．０１）,抑制率平均为４５．４％,包被１４ｄ以上的检测结果明显高于１ｄ和７ｄ的测定结果（Ｐ〈０．     

Complement classical pathway components are all important in clearance of apoptotic and secondary necrotic cells

Inherited deficiencies in components of the classical complement pathway are strong disease susceptibility factors for the development of systemic lupus erythematosus (SLE) and there is a hierarchy among deficiency states, the strongest association being with C1q deficiency. We investigated the relative importance of the different complement pathways regarding clearance of apoptotic cells. Phagocytosis of labelled apoptotic Jurkat cells by monocyte‐derived macrophages in the presence of sera from individuals with complement deficiencies was studied, as well as C3 deposition on apoptotic cells using flow cytometry. Sera from individuals deficient in C1q, C4, C2 or C3 all showed decreased phagocytosis. Mannose binding lectin (MBL) and the alternative pathway did not influence phagocytosis. Notably, the components of the complement classical pathway, including C1q, were equally important in clearance of apoptotic cells. This indicates that deposition of C3 fragments is of major significance; we therefore studied C3 deposition on apoptotic cells. Experiments with MBL‐deficient serum depleted of C1q or factor D confirmed the predominance of the classical pathway. At low dilution, sera deficient of C1q, C4 or C2 supported C3 fragment deposition demonstrating alternative pathway activation. In conclusion, we have found that complement‐mediated opsonization and phagocytosis of apoptotic cells, particularly those undergoing secondary necrosis, are dependent mainly upon an intact classical pathway. The alternative pathway is less important, but may play a role in some conditions. C1q was not more important than other classical pathway components, suggesting a role in additional pathogenetic processes in SLE other than clearance of apoptotic cells.     

BAFF: a local and systemic target in autoimmune diseases

BAFF (B lymphocyte activating factor of the tumour necrosis factor family) is a vital homeostatic cytokine for B cells that helps regulate both innate and adaptive immune responses. Increased serum levels of BAFF are found in a number of different autoimmune diseases, and BAFF is found in inflammatory sites in which there is lymphoid neogenesis. BAFF antagonism has been used in several autoimmune disease models, resulting in B cell depletion, decreased activation of T cells and dendritic cells (DC) and a reduction in the overall inflammatory burden. BAFF, through its interaction with BAFF‐R, is required for survival of late transitional, marginal zone and mature naive B cells, all of which are depleted by BAFF blockade. Through their interactions with TACI (transmembrane activator and calcium modulator and cyclophilin ligand interactor) and BCMA (B cell maturation protein), BAFF and its homologue APRIL (a proliferation‐inducing ligand), support the survival of at least some subsets of plasma cells; blockade of both cytokines results in a decrease in serum levels of immunoglobulin (Ig)G. In contrast, neither BAFF nor APRIL is required for the survival or reactivation of memory B cells or B1 cells. BAFF also helps DC maturation and interleukin (IL)‐6 release and is required for proper formation of a follicular dendritic cell (FDC) network within germinal centres, although not for B cell affinity maturation. The clinical efficacy of BAFF blockade in animal models of autoimmunity may be caused both by the decline in the number of inflammatory cells and by the inhibition of DC maturation within target organs. Blockade of BAFF and its homologue APRIL are being explored for human use; several Phase I and II clinical trials of BAFF inhibitors for autoimmunity have been completed and Phase III trials are in progress.     

PTPN22 polymorphisms,but not R620W,were associated with the genetic susceptibility of systemic lupus erythematosus and rheumatoid arthritis in a Chinese Han population

ObjectivesThe present study aimed to detect a possible association between PTPN22 gene polymorphisms and rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) in a Chinese Han population.Methods7 PTPN22 SNPs were genotyped in 358 patients with RA and 713 patients with SLE, as well as 564 RA controls and 672 SLE controls by Restriction Fragment Length Polymorphism (RFLP). Association analyses were conducted on the whole data set. Significant relationships were also examined between clinical features and SNPs for both RA and SLE.ResultsRs2476601 was lack of polymorphism with a ⩽0.1% frequency in both SLE and RA patients and healthy controls in our study. The two SNPs rs1217414 and rs3811021 of PTPN22 shown strong association with both SLE (rs1217414T: p_adj = 6.07e−004, OR = 0.57; rs3811021C: p_adj = 4.68e−005, OR = 0.65) and RA (rs1217414T: p_adj = 2.01e−008, OR = 0.26; rs3811021C: p_adj = 0.028, OR = 0.70). And the rs3765598 revealed a strong risk factor for SLE (p = 9.38e−009, p_adj = 6.57e−008, OR = 1.93), but not for RA (p = 0.48, OR = 1.12). Moreover, protective haplotype ACTTC in RA (p = 7.73e−016, p_adj = 5.51−015, OR[95%CI] = 0.02[0.002–0.10]) and SLE (p = 8.29e−018, p_adj = 5.80e−017, OR[95%CI] = 0.11[0.06–0.21]) were observed. In addition, the distribution of risk haplotypes ACGTC and GCTTT in RA (ACGTC: p = 0.0006, p_adj = 0.004, OR[95%CI] = 1.85[1.29–2.63]; GCTTT: p = 2.62e−005, p_adj = 1.85e−004, OR[95%CI] = 2.40[1.57–3.65]) and SLE (ACGTC: p = 0.0006, p_adj = 0.004, OR[95%CI] = 1.85[1.29–2.63]; ACGTC: p = 7.74e−011, p_adj = 6.81e−010, OR[95%CI] = 2.21[1.12–3.34]; GCTTT: p = 2.40[1.57–3.65], p_adj = 2.26e−006, OR[95%CI] = 2.64[1.79–3.87]) were significant different from that in controls. Furthermore, significant association was observed between the PTPN22 rs3765598 and antinuclear antibodies 1 (ANA1) in SLE.ConclusionsOur data provide strong evidence that the rs1217414 and rs3811021 in PTPN22 gene might be common protective factors contributed to SLE and RA susceptibility in the Chinese Han population. While, the rs3765598 might increase the genetic susceptibility of SLE, but not RA.     

Anti-ribosomal antibodies from lupus patients bind DNA

Antibodies specific for ribosomal P proteins (anti-P) are a hallmark of systemic lupus as anti-DNA antibodies are. It has been reported that anti-P antibodies are more frequently detected in anti-dsDNA positive sera. The aim of the present study was to verify the binding ability of anti-P antibodies towards polynucleotides and nucleosomes. We purified anti-P antibodies from 8 SLE patients' sera and we analysed them by ELISA on plates coated with DNA or nucleosomes. We performed also inhibition experiments in order to verify the specificity of the binding. All the purified anti-P antibodies bound DNA, but some anti-DNA binding activity remained among the non-anti-P antibodies in the flow through. Only half of the purified antibodies bound to nucleosomes, and anti-nucleosomal activity was demonstrated also in non anti-P antibody fraction. The inhibition experiments performed on two anti-P antibodies pointed out that only the homologous antigen inhibited the binding to either P peptide or DNA coated onto the solid phase. These results show that sera in which the two specificities coexist contain antibodies endowed with a double binding ability for DNA and the P peptide.     

The many faces of Mac-1 in autoimmune disease

Mac-1 (CD11b/CD18) is a β2 integrin classically regarded as a pro-inflammatory molecule because of its ability to promote phagocyte cytotoxic functions and enhance the function of several effector molecules such as FcγR, uPAR, and CD14. Nevertheless, recent reports have revealed that Mac-1 also plays significant immunoregulatory roles, and genetic variants in ITGAM, the gene that encodes CD11b, confer risk for the autoimmune disease systemic lupus erythematosus (SLE). This has renewed interest in the physiological roles of this integrin and raised new questions on how its seemingly opposing biological functions may be regulated. Here, we provide an overview of the CD18 integrins and how their activation may be regulated as this may shed light on how the opposing roles of Mac-1 may be elicited. We then discuss studies that exemplify Mac-1's pro-inflammatory versus regulatory roles particularly in the context of IgG immune complex-mediated inflammation. This includes a detailed examination of molecular mechanisms that could explain the risk-conferring effect of rs1143679, a single nucleotide non-synonymous Mac-1 polymorphism associated with SLE.