Follicular Helper T Cells in Systemic Lupus Erythematosus: Why Should They Be Considered as Interesting Therapeutic Targets?

Decreased Jumonji Domain-Containing 3 at the Promoter Downregulates Hematopoietic Progenitor Kinase 1 Expression and Cytoactivity of T Follicular Helper Cells from Systemic Lupus Erythematosus Patients

T follicular helper (Tfh) cells are overactivated in systemic lupus erythematosus (SLE) patients and contribute to excessive immunity. Hematopoietic progenitor kinase 1 (HPK1), as an inhibitor of T cells, is underexpressed in SLE Tfh cells and consequently induces autoimmunity. However, the reason for downregulation of HPK1 in SLE Tfh cells remains elusive. By combining chromatin immunoprecipitation with quantitative polymerase chain reaction assays, it was found that histone H3 lysine 27 trimethylation (H3K27me3) at the HPK1 promoter in SLE Tfh cells elevated greatly. We also confirmed jumonji domain-containing 3 (JMJD3) binding at the HPK1 promoter in SLE Tfh cells reduced profoundly. Knocking down JMJD3 in normal Tfh cells with siRNA alleviated enrichments of JMJD3, H3K4me3, and mixed-lineage leukemia (MLL) 1 at the HPK1 promoter and increased H3K27me3 number in the region. HPK1 expression was lowered, while Tfh cell proliferation activity, IL-21 and IFNγ secretions in the supernatants of Tfh cells, and IgG1 and IgG3 concentrations in the supernatants of Tfh-B cell cocultures all upregulated markedly. In contrast, elevating JMJD3 amount in SLE Tfh cells by JMJD3-overexpressed plasmid showed opposite effects. The abundances of H3K4me3 and MLL1 at the HPK1 promoter in SLE Tfh cells were greatly attenuated. Our results suggest that deficient JMJD3 binding at the promoter dampens HPK1 expression in SLE Tfh cells, thus making Tfh cells overactive, and ultimately results in onset of SLE.

Liposomes Bearing Non-Bilayer Phospholipid Arrangements Induce Specific IgG Anti-Lipid Antibodies by Activating NK1.1+, CD4+ T Cells in Mice

Liposomes are artificial models of cellular membranes that are used as delivery systems for genes, drugs and protein antigens. We have previously used them to study the antigenic properties of their phospholipids. Here, we used them to induce the production of IgG anti-non-bilayer phospholipid arrangements (NPAs) antibodies in mice; these antibodies cause cell lysis and trigger a lupus-like disease in mice. We studied the mechanisms that lead to the production of these antibodies, and provide evidence that NK1.1⁺, CD4⁺ T cells respond to NPA-bearing liposomes and deliver the help required for specific B cell activation and antibody class-switching to IgG. We found increased numbers of IL-4-producing NK1.1⁺, CD4⁺ T cells in the secondary lymphoid organs of mice administered with NPAs, and these cells also expressed CD40L, which is required for B cell activation. Additionally, we isolated and purified NK1.1⁺, CD4⁺ T cells from spleens and determined that they over-expressed 40 genes, which are key players in inflammatory processes and B cell stimulation and have TRAF6 and UNC39B1 as key nodes in their network. These results show that liposomes are membrane models that can be used to analyze the immunogenicity of lipids.

Therapeutic Modulation of T Follicular Helper Cells by Low-Dose IL-2 Treatment

T follicular helper (Tfh) cells are a subset of specialized CD4⁺ T cell residing in B cell follicles and confer essential support for germinal center responses, which lead to the generation of long-lived humoral immunity. A great deal of evidence from the past 15 years indicate that excessive differentiation and dysregulated function of Tfh cells often promote autoimmunity by inducing autoantibody production. Interleukin-2 was identified as a major suppressor to inhibit Tfh differentiation. Therefore, IL-2 treatment was applied in suppressing Tfh function in mouse models and more recently in a clinical trial of patients with systemic lupus erythematosus. Here we describe a protocol for low-dose IL-2 treatment in a murine immunization model and on the assessment of the suppression of Tfh response using flow cytometry.

Reduced expression of hematopoietic progenitor kinase 1 in T follicular helper cells causes autoimmunity of systemic lupus erythematosus

BACKGROUD

T follicular helper (Tfh) cells have been discovered to be the main CD4⁺ T cells assisting B cells to produce antibody. They are over activated in patients with systemic lupus erythematosus (SLE) and consequently lead to excessive immunity. Hematopoietic progenitor kinase 1 (HPK1) negatively regulates T cell-mediated immune responses and TCR signal. This study aimed to investigate the roles of HPK1 in SLE Tfh cells.

METHODS

HPK1 mRNA and protein levels in Tfh cells were measured by real-time quantitative PCR and western blot analysis, respectively. The production of IL-21, B cell-activating factor (BAFF), interferon γ (IFNγ), IL-17A, IgM, IgG1, IgG2, and IgG3 were analyzed using enzyme linked immunosorbent assay. Tfh cells proliferation was evaluated with 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay.

RESULTS

HPK1 mRNA and protein levels were significantly reduced in SLE Tfh cells, and negatively correlated with SLE disease activity index (SLEDAI) and Systemic Lupus International Collaborating Clinics/American College of Rheumatology (SLICC/ACR) Damage Index for SLE (SDI). Knocking down HPK1 with siRNA in normal Tfh cells greatly elevated Tfh cells proliferation and secretions of IL-21, BAFF, IFNγ, IgG1, IgG2, and IgG3. There were no marked alterations in IL-17A and IgM productions. The opposite effects were observed in SLE Tfh cells transfected with HPK1 overexpressing plasmid: Tfh cells proliferation and productions of IL-21, BAFF, IFNγ, IgG1, IgG2, and IgG3 were all alleviated. And there were no significant changes in IL-17A and IgM levels.

CONCLUSION

Our results suggest for the first time that inhibited expression of HPK1 in SLE Tfh cells leading to Tfh cells overactivation and B cells overstimulation, subsequently, the onset and progression of SLE.

High BTLA Expression Likely Contributes to Contraction of the Regulatory T Cell Subset in Lupus Disease

B and T lymphocyte attenuator (BTLA) is a co-inhibitory receptor that is expressed by lymphoid cells and regulates the immune response. Consistent with an inhibitory role for BTLA, the disease is exacerbated in BTLA-deficient lupus mice. We recently demonstrated that the BTLA pathway is altered in CD4⁺ T cells from lupus patients. In the present work, we aimed at delineating the expression pattern of BTLA on CD4⁺ T cell subsets suspected to play a key role in lupus pathogenesis, such as circulating follicular helper T cells (cT_FH) and regulatory T cells (Tregs). We did not detect significant ex vivo variations of BTLA expression on total CD4⁺ T cells (naive and memory), cT_FH or T_FH subsets between lupus patients and healthy controls. However, we interestingly observed that BTLA expression is significantly increased on activated Tregs, but not resting Tregs, from lupus patients, especially those displaying an active disease. Moreover, it correlates with the diminution of the Tregs frequency observed in these patients. We also showed that both BTLA mRNA and protein expression remain low after TCR stimulation of activated Tregs sorted from healthy donors and evidenced a similar dynamic of BTLA and HVEM expression profile by human Tregs and effector CD4⁺ T cells upon T cell activation than the one previously described in mice. Finally, we observed that the HVEM/BTLA ratio is significantly lower in Tregs from lupus patients compared to healthy controls, whereas ex vivo effector CD4⁺ T cells express higher BTLA levels. Our data suggest that an altered expression of BTLA and HVEM could be involved in an impaired regulation of autoreactive T cells in lupus. These results provide a better understanding of the BTLA involvement in lupus pathogenesis and confirm that BTLA should be considered as an interesting target for the development of new therapeutic strategies.

The Potential of Harnessing IL-2-Mediated Immunosuppression to Prevent Pathogenic B Cell Responses

Immunosuppressive drugs can partially control Antibody (Ab)-dependent pathology. However, these therapeutic regimens must be maintained for the patient's lifetime, which is often associated with severe side effects. As research advances, our understanding of the cellular and molecular mechanisms underlying the development and maintenance of auto-reactive B cell responses has significantly advanced. As a result, novel immunotherapies aimed to restore immune tolerance and prevent disease progression in autoimmune patients are underway. In this regard, encouraging results from clinical and preclinical studies demonstrate that subcutaneous administration of low-doses of recombinant Interleukin-2 (r-IL2) has potent immunosuppressive effects in patients with autoimmune pathologies. Although the exact mechanism by which IL-2 induces immunosuppression remains unclear, the clinical benefits of the current IL-2-based immunotherapies are attributed to its effect on bolstering T regulatory (Treg) cells, which are known to suppress overactive immune responses. In addition to Tregs, however, rIL-2 also directly prevent the T follicular helper cells (Tfh), T helper 17 cells (Th17), and Double Negative (DN) T cell responses, which play critical roles in the development of autoimmune disorders and have the ability to help pathogenic B cells. Here we discuss the broader effects of rIL-2 immunotherapy and the potential of combining rIL-2 with other cytokine-based therapies to more efficiently target Tfh cells, Th17, and DN T cells and subsequently inhibit auto-antibody (ab) production in autoimmune patients.

Alopecia areata in patients with systemic lupus erythematosus treated with belimumab: a plausible association

Belimumab, an anti-B-lymphocyte stimulator monoclonal antibody, was recently approved for the treatment of systemic lupus erythematosus. Alopecia areata is characterized by an acute immune-mediated hair loss. Herein, we report on three adult systemic lupus erythematosus patients who developed alopecia areata in association with belimumab treatment. Alopecia areata was resolved in all three patients and belimumab was discontinued in two of them. Thus, in the current report, we explore the plausible link between alopecia areata and belimumab.

Mechanisms of action of low-dose IL-2 restoration therapies in SLE

Interleukin-2 (IL-2) shortage is a hallmark of Systemic Lupus Erythematosus (SLE). Importantly, clinical and preclinical studies demonstrate the potential clinical benefits of IL-2-based restoration therapies for the treatment of SLE. Here we discuss the immunological consequences of IL-2 deficiency in SLE patients and the mechanisms underlying the therapeutic effects of low-dose IL-2 regimens.

The expansion of circulating IL-6 and IL-17-secreting follicular helper T cells is associated with neurological disabilities in neuromyelitis optica spectrum disorders

Due to their function in assisting B cells, T_FH cells may be involved in the production of pathogenic IgG in neuromyelitis optica spectrum disorder (NMOSD). In the present study, the proportion of IL-6⁺ and IL-17⁺ T_FH cell subsets was higher in NMOSD patients than healthy individuals. The frequency of both T_FH cell subsets were directly associated with disease activity. By contrast, NMOSD patients with a higher proportion of IL-10⁺ T_FH cell subsets showed a lower neurological disabilities score. In summary, all findings suggest that expansion of peripheral IL-6⁺ and IL-17⁺ T_FH cells may be involved in the severity of NMOSD.

Decreased expression of circulating Aire and increased Tfh/Tfr cells in myasthenia gravis patients

Myasthenia gravis (MG) is a rare prototypical autoimmune disorder caused by antibodies (Ab) against postsynaptic membrane proteins. Most reports have investigated the role of autoimmune regulator gene (Aire) in thymic tissue in machianism of MG initiation. So far, the expression of Aire in human peripheral blood cells (we call it circulating Aire expression in the following passage) has not been reported. Herein, we explore the expression of Aire in peripharal blood, circulating T-follicular helper (cTfh) and T-follicular regulatory (cTfr) cells in MG patients. In our research, we found that the acetylcholine receptor (AChR) Ab level is higher in generalized MG (GMG) than that in ocular MG (OMG). Compared with the control group (CG), lower expression of Aire was found in MG patients, especially in GMG. The ratio of Tfh/Tfr was higher in GMG patients, and then in the OMG patients, and lowest in CG. All these differences above were statistically significant. Negative relation was discovered between expression of Aire in circulating blood and ratio of Tfh/Tfr, so did it exist between Aire expression and the severity of MG. Meanwhile, positive relation was discovered between ratio of Tfh/Tfr and the severity of MG. However, no significant relation was manifested in our study between the subset age of MG and Aire level. Overall, these findings imply circulating Aire might play a role in the imbalance of cTfh and cTfr cells and participate in the pathogenesis of MG.

Immunosuppressive therapy influences the accelerated age-dependent T-helper cell differentiation in systemic lupus erythematosus remission patients

Background

CD4⁺ T cells are of great importance in the pathogenesis of systemic lupus erythematosus (SLE), as an imbalance between CD4⁺ regulatory T cells (Tregs) and CD4⁺ responder T cells (Tresps) causes flares of active disease in SLE patients. In this study, we aimed to find the role of aberrant Treg/Tresp cell differentiation for maintaining Treg/Tresp cell balance and Treg functionality.

Methods

To determine differences in the differentiation of Tregs/Tresps we calculated the percentages of CD45RA⁺CD31⁺ recent thymic emigrant (RTE) Tregs/Tresps and CD45RA⁺CD31⁻ mature naive (MN) Tregs/Tresps, as well as CD45RA⁻CD31⁺ and CD45RA⁻CD31⁻ memory Tregs/Tresps (CD31⁺ and CD31⁻ memory Tregs/Tresps) within the total Treg/Tresp pool of 78 SLE remission patients compared with 94 healthy controls of different ages. The proliferation capacity of each Treg/Tresp subset was determined by staining the cells with anti-Ki67 monoclonal antibodies. Differences in the autologous or allogeneic Treg function between SLE remission patients and healthy controls were determined using suppression assays.

Results

With age, we found an increased differentiation of RTE Tregs via CD31⁺ memory Tregs and of RTE Tresps via MN Tresps into CD31⁻ memory Tregs/Tresp in healthy volunteers. This opposite differentiation of RTE Tregs and Tresps was associated with an age-dependent increase in the suppressive activity of both naive and memory Tregs. SLE patients showed similar age-dependent Treg cell differentiation. However, in these patients RTE Tresps differentiated increasingly via CD31⁺ memory Tresps, whereby CD31⁻ memory Tresps arose that were much more difficult to inhibit for Tregs than those that emerged through differentiation via MN Tresps. Consequently, the increase in the suppressive activity of Tregs with age could not be maintained in SLE patients. Testing the Tregs of healthy volunteers and SLE patients with autologous and nonautologous Tresps revealed that the significantly decreased Treg function in SLE patients was not exclusively attributed to an age-dependent diminished sensitivity of the Tresps for Treg suppression. The immunosuppressive therapy reduced the accelerated age-dependent Tresp cell proliferation to normal levels, but simultaneously inhibited Treg cell proliferation below normal levels.

Conclusions

Our data reveal that the currently used immunosuppressive therapy has a favorable effect on the differentiation and proliferation of Tresps but has a rather unfavorable effect on the proliferation of Tregs. Newer substances with more specific effects on the immune system would be desirable.

Electronic supplementary material

The online version of this article (10.1186/s13075-018-1778-6) contains supplementary material, which is available to authorized users.

Inhibition of glucose metabolism selectively targets autoreactive follicular helper T cells

Follicular helper T (T_FH) cells are expanded in systemic lupus erythematosus, where they are required to produce high affinity autoantibodies. Eliminating T_FH cells would, however compromise the production of protective antibodies against viral and bacterial pathogens. Here we show that inhibiting glucose metabolism results in a drastic reduction of the frequency and number of T_FH cells in lupus-prone mice. However, this inhibition has little effect on the production of T-cell-dependent antibodies following immunization with an exogenous antigen or on the frequency of virus-specific T_FH cells induced by infection with influenza. In contrast, glutaminolysis inhibition reduces both immunization-induced and autoimmune T_FH cells and humoral responses. Solute transporter gene signature suggests different glucose and amino acid fluxes between autoimmune T_FH cells and exogenous antigen-specific T_FH cells. Thus, blocking glucose metabolism may provide an effective therapeutic approach to treat systemic autoimmunity by eliminating autoreactive T_FH cells while preserving protective immunity against pathogens.

T cell functions depend on distinct metabolic fluxes. Here the authors show different metabolic requirements of humoral responses to self versus microbial antigens: while glucose is dispensable for antiviral Tfh and antibody responses, it is essential to mount these responses against autoantigens.

Increased CCR7loPD-1hiCXCR5+CD4+ T Cells in Peripheral Blood Mononuclear Cells Are Correlated with Immune Activation in Patients with Chronic HBV Infection

T follicular helper cells (Tfh cells) affect essential immune pathogenesis in chronic hepatitis B virus (HBV) infection. The CCR7^loPD-1^hi Tfh subset has a partial Tfh effector phenotype and is associated with active Tfh differentiation, whereas the CCR7^hiPD-1^lo Tfh subset is a resting phenotype. We recruited 20 healthy volunteers and 77 patients with chronic HBV infection, including those in the immune tolerant (IT) phase (n=19), immune clearance (IC) phase (n=20), low replicative (LR) phase (n=18), and reactivation (RA) phase (n=20). The expression of CD4, CXCR5, PD-1, and CCR7 was detected in T cells from peripheral blood by flow cytometry. The frequency of the CCR7^loPD-1^hi T subset was significantly higher in the patients than in the healthy controls (14.92±4.87% vs 12.23±2.95%, p=0.018). The frequency of this Tfh subset in the IC group (18.42%±3.08) was increased compared with the IT group (11.94±2.87%, p=0.001) and LR group (13.65±4.93%, p=0.031) and was higher in the RA group than in the IT group (16.03±5.37% vs 11.94±2.87%, p=0.030). We observed a weak positive correlation between the CCR7^loPD-1^hi Tfh subset population and the alanine transaminase (ALT) level (r=0.370, p=0.001). The CCR7^loPD-1^h Tfh subset in the chronic HBV-infected patients was elevated to various degrees among the different immune phases. CCR7^loPD-1^hiCXCR5⁺CD4⁺ T cells are correlated with the immune status of chronic HBV infection patients and may be developed as a potential indicator for antiviral treatment.

Prophylactic and Therapeutic Effects of Interleukin-2 (IL-2)/Anti-IL-2 Complexes in Systemic Lupus Erythematosus-Like Chronic Graft-Versus-Host Disease

Murine chronic graft-versus-host-disease (cGvHD) induced by injection of parental lymphocytes into F1 hybrids results in a disease similar to systemic lupus erythematosus. Here, we have used DBA/2 T cell injection into (C57BL/6 × DBA/2)F1 (BDF1) mice as a model system to test the prophylactic and therapeutic effects of interleukin-2 (IL-2)/anti-IL-2 immune complexes on the course of cGvHD. Our findings demonstrate that pretreatment with Treg inducing JES6/IL-2 complexes render BDF1 mice largely resistant to induction of cGvHD, whereas pretreatment with CD8⁺ T cell/NK cell inducing S4B6/IL-2 complexes results in a more severe cGvHD. In contrast, treatment with JES6/IL-2 complexes 4 weeks after induction had no beneficial effect on disease symptoms. However, similar treatment with S4B6/IL-2 complexes led to a significant amelioration of the disease. This therapeutic effect seems to be mediated by donor CD8⁺ T cells. The fact that a much stronger cGvHD is induced in BDF1 mice depleted of donor CD8⁺ T cells strongly supports this conclusion. The contrasting effects of the two different IL-2 complexes are likely due to different mechanisms.

Plasmacytoid dendritic cells and RNA-containing immune complexes drive expansion of peripheral B cell subsets with an SLE-like phenotype

BACKGROUND

Hyperactive B cells and a continuous interferon (IFN)-α production by plasmacytoid dendritic cells (pDCs) play a key role in systemic lupus erythematosus (SLE). We asked whether the interaction between B cells and pDCs stimulated with RNA-containing immune complexes affects peripheral B cell subsets.

METHODS

B cells and pDCs were isolated from blood of healthy individuals and stimulated with immune complexes consisting of SLE-IgG and U1snRNP (RNA-IC). Expression of cell surface molecules as well as IL-6 and IL-10 production were determined by flow cytometry and immunoassays. Gene expression profiles were determined by a NanoString nCounter expression array.

RESULTS

We found a remarkable increase of double negative CD27-IgD- B cells, from 7% within fresh CD19+ B cells to 37% in the RNA-IC-stimulated co-cultures of B cells and pDCs, comparable to the frequency of double negative B cells in SLE patients. Gene expression analysis of the double negative CD27-IgD- and the CD27+IgD- memory B cells revealed that twenty-one genes were differentially expressed between the two B cell subsets (≥ 2-fold, p<0.001). The, IL21R, IL4R, CCL4, CCL3, CD83 and the IKAROS Family Zinc Finger 2 (IKZ2) showed higher expression in the double negative CD27-IgD- B cells.

CONCLUSION

The interactions between B cells and pDCs together with RNA-containing IC led to an expansion of B cells with similar phenotype as seen in SLE, suggesting that the pDC-B cell crosstalk contributes to the autoimmune feed-forward loop in SLE.

Lupus nephritis and B-cell targeting therapy

INTRODUCTION

Lupus Nephritis (LN) is a severe manifestation of Systemic Lupus Erythematosus (SLE) with a significant prognostic impact. Over a prolonged course, an exhaustion of treatment alternatives may occur and further therapeutic options are needed. B cells play a pivotal role in disease pathogenesis and represent an attractive therapeutic target. Areas covered: This review provides an update regarding targeting B cells in LN. The rational for this approach, as well as currently available and future targets are discussed. Expert commentary: Despite its wide clinical use and the encouraging results from retrospective studies, a role of rituximab in LN has not been prospectively confirmed. Trial design methodologies as well as intrinsic limitations of this approach may be responsible and rituximab use is currently limited as a rescue treatment or in settings where a strong steroid sparing effect is warranted. Despite belimumab now being licensed for use in SLE, the evidence in LN is weak although prospective trials are on-going. The combination of different targeted approaches as well as a focus on new clinical end-points may be strategies to identify new therapeutic options.

An investigation of the relationship between recurrent spontaneous abortion and memory T follicular helper cells

PROBLEM

Immune tolerance with respect to a semi-allogeneic fetus plays a key role in the establishment of a pregnancy. Memory T follicular helper (Tfh) cells have a central role in the regulation of the adaptive immune response. Much of our knowledge of memory Tfh cells' function comes from immune-related diseases. However, the true physiological characteristics of memory Tfh cells and their mode of action in pregnancy remain unclear.

METHODS OF STUDY

Deciduas and blood were obtained from 25 recurrent spontaneous abortion (RSA) patients undergoing surgical abortion and 19 normal women in early pregnancy undergoing elective termination. RSA patients were grouped into antibody-positive patients and antibody-negative patients, respectively. The memory Tfh cells with the CD4⁺ CXCR5⁺ PD1⁺ CCR7^- and CD4⁺ CXCR5⁺ PD-1⁺ ICOS⁺ phenotypes were assessed by flow cytometry. The B cells were evaluated by flow cytometry. A correlation analysis of the subsets of memory Tfh cells and B cells in antibody-positive RSA patients was made by the Pearson test.

RESULTS

Memory Tfh cells with the CD4⁺ CXCR5⁺ PD1⁺ CCR7^- and CD4⁺ CXCR5⁺ PD-1⁺ ICOS⁺ phenotypes showed a significant increase in RSA patients compared to women with a normal pregnancy who had chosen termination. When RSA patients were grouped according positive or negative antibodies, it was surprising to find that decidual CD4⁺ CXCR5⁺ PD-1⁺ ICOS⁺ memory Tfh cells significantly increased in RSA patients with positive antibody compared to RSA patients with negative antibody. However, the percentages of CD4⁺ CXCR5⁺ PD1⁺ CCR7^- memory Tfh cells did not change in the deciduas of the two groups. Circulating and decidual B cells significantly increased in antibody-positive RSA patients compared with antibody-negative RSA patients. Correlation analysis indicated a strong association between the decidual CD4⁺ CXCR5⁺ PD-1⁺ ICOS⁺ memory Tfh cells and B cells in antibody-positive RSA patients.

CONCLUSION

These new findings provide unique insights into memory Tfh cells in mediating feto-maternal immune tolerance.

Promoter polymorphisms of the TIM-4 gene are correlated with disease activity in patients with systemic lupus erythematosus

Although the TIM gene family plays important roles in immune responses, little is known about TIM regulation in the development of systemic lupus erythematosus (SLE). This study aimed to investigate the association of two TIM-4 single nucleotide polymorphisms (SNPs) rs6874202 (-1419G>A) and rs62382402 (-1609G>A) with SLE susceptibility in a Chinese Han population. The results showed no significant differences between patients with SLE and control group for rs6874202 and rs62382402 (p = .72, .53 respectively). However, the anti-dsDNA levels in serum from SLE patients with GG genotype of TIM-4 gene at -1419 site were significantly higher than those with GA and AA genotype (p = .0335), and C3 levels of SLE patients with GG and GA genotype were much lower than those with AA genotypes (p = .0187). Moreover, the apoptotic cell levels of SLE patients with AA and GG genotypes were significantly higher than those with GA genotypes in patients with SLE (p = .0393). In addition, the C3 concentration of SLE patients with the GG genotype of TIM-4 gene at -1609 site was found to be significantly higher than those with the GA genotype (p = .0129). The results imply that GG genotype of the TIM-4 gene at -1419 site might be associated with the disease activity of SLE.