Changes of CD4/CD8 ratio and interleukin-16 in systemic lupus erythematosus

Leptin antagonism attenuates hypertension and renal injury in an experimental model of autoimmune disease

Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder that is characterized by B- and T-lymphocyte dysfunction and altered cytokine production, including elevated levels of the adipocytokine leptin. Leptin has various immunomodulatory properties, including promoting the expansion of proinflammatory T lymphocytes and the proliferation and survival of B cells. In the present study, we hypothesized that leptin antagonism would improve B- and T-cell dysfunction and attenuate hypertension in an experimental model of SLE, the NZBWF1 mouse. To test this hypothesis, 28-week-old female control and SLE mice were administered 5 mg/kg of murine leptin superantagonist (LA) or vehicle via ip injection every other day for four weeks. Analysis of peripheral blood immune cell populations showed no changes in total CD45R+ B and CD3+ T cell percentages after treatment with LA. However, SLE mice treated with LA had an improved CD4/CD8 ratio and decreased CD3+CD4-CD8- double negative (DN) T cells. Blood pressure was higher in SLE than in control, and treatment with LA decreased blood pressure in SLE mice. Treatment with LA also delayed the onset of albuminuria and decreased glomerulosclerosis in SLE mice. Renal immune cell infiltration was significantly higher in SLE mice as compared with control, but LA treatment was associated with decreased levels of renal CD4+ T cells. In conclusion, these data suggest that leptin plays a pathogenic role in the development of hypertension in SLE, in part, by promoting the expansion of inflammatory DN T cells and the infiltration of T cells into the kidneys.

Antibodies against neutrophil extracellular traps (NETs) potentiate clinical performance of anti-double-stranded DNA antibodies in systemic lupus erythematosus

Autoantibodies against NETs (ANETA) are present in SLE patients. We aimed to determine the clinical relevance of ANETA in SLE. Serum from 129 SLE patients, 161 patients with various rheumatoid diseases (DC), and 53 healthy controls (HC) were tested by a home-made ANETA ELISA platform. ANETA showed a sensitivity of 35.7% and a specificity of 92.5%, respectively, in the diagnosis of SLE. The combination of ANETA with anti-dsDNA antibody increased the diagnostic sensitivity from 49.6% to 62.8% for SLE. The presence of ANETA potentiates the clinical utility of anti-dsDNA antibodies in identifying a subset of SLE patients with higher disease activity and hematological abnormalities. The binding of ANETA to NETs did not inhibit the immunostimulatory effect of NETs. Our findings suggested that ANETA have potential as clinically relevant biomarkers that potentiate the clinical performance of anti-dsDNA antibodies in the diagnosis, risk stratification and subtyping of patients with SLE.

Association of the IL16 Asn1147Lys polymorphism with intravenous immunoglobulin resistance in Kawasaki disease

Kawasaki disease (KD) is an acute, self-limited vasculitis, mainly affecting children younger than 5 years old, with accompanying fever and signs of mucocutaneous inflammation. Intravenous immunoglobulin (IVIG) is the standard treatment for KD; however, ~15% of patients are resistant to IVIG treatment. To identify protein coding genetic variants influencing IVIG resistance, we re-analyzed our previous genome-wide association study (GWAS) data from 296 patients with KD, including 101 IVIG non-responders and 195 IVIG responders. Five nonsynonymous SNPs (nsSNPs) in five immune-related genes, including a previously reported SAMD9L nsSNP (rs10488532; p.Val266Ile), were associated with IVIG non-response (odds ratio [OR] = 1.89-3.46, P = 0.0109-0.0035). In a replication study of the four newly-identified nsSNPs, only one in the interleukin 16 (IL16) gene (rs11556218, p.Asn1147Lys) showed a trend of association with IVIG non-response (OR = 1.54, P = 0.0078). The same IL16 nsSNP was more significantly associated with IVIG non-response in combined analysis of all data (OR = 1.64, P = 1.25 × 10^-4). Furthermore, risk allele combination of the IL16 CT and SAMD9L TT nsSNP genotypes exhibited a very strong effect size (OR = 9.19, P = 3.63 × 10^-4). These results implicate IL16 as involved in the mechanism of IVIG resistance in KD.

The evaluation of cellular immune function in elderly patients with systemic lupus erythematosus

BACKGROUND/AIMS

To evaluate cellular immune function in systemic lupus erythematosus (SLE) patients over 60 years old, the association between antinuclear antibody (ANA) titers and the ratio of CD4+ /CD8+ was analyzed in this study. The distribution of ANAs and extractable nuclear antibodies (ENAs) in a healthy elderly population was also investigated.

METHODS

Serum ANA titers were assayed by indirect immunofluorescence (IIF) and the CD4+ /CD8+ T-cell ratio was determined by flow cytometry in 76 SLE patients and 30 healthy control individuals. IIF of cytoplasm and nuclear and nucleolar staining were performed on samples taken from 286 healthy elderly individuals. ENA levels were determined using a strip enzyme immunoassay among patients that tested positive for ANAs.

RESULTS

ANA titers were negative in the 30 control individuals, but were positive in the 76 SLE patients. Based on ANA titers, the SLE patients were stratified to low (≤ 1:320), medium (1:640 to 1:1,280), and high (≥ 1:2,560) titer groups. The average CD4+ /CD8+ ratio of the SLE group was significantly lower than that of the control group. Among the 286 healthy elderly volunteers, 59 (20.63%) tested positive for ANAs. A homogeneous pattern was present in 47.46% of those 59 patients and a granule pattern in the karyoplasm was present in 33.90%. Furthermore, of the 59 patients, ENAs immunoassay was positive in 18 (30.51%); Sjogren syndrome-related antigen A (SSA)/52 kd and Sjogren syndrome antigen B (SSB)/La were the two major antibodies.

CONCLUSION

The significantly lower CD4+ /CD8+ ratio among SLE patients over 60 years old is associated with deregulated immune responses and the development of SLE. A low ANA titer (1:160) is common in healthy elders, emphasizing the importance of considering age when determining if the evaluation of ANA titers is to be included in autoimmune disease diagnosis.

Vincristine-cyclophosphamide combination therapy positively affects T-cell subset distribution in systemic lupus erythematosus patients

Background

This study aimed to analyze the T-cell subset distribution in systemic lupus erythematosus (SLE) patients and determine whether vincristine-cyclophosphamide combination therapy can positively affect their T-cell subset distribution to keep the disease in remission.

Material/Methods

Thirteen SLE patients with ‘low activity’ (SLE Disease Activity Index (SLEDAI)≤9), 17 SLE patients with ‘high activity’ (SLEDAI>9), and 15 healthy controls were recruited. SLE patients were treated with vincristine-cyclophosphamide combination therapy. CD3⁺, CD4⁺, and CD8⁺ T-cell percentages were analyzed by flow cytometry at baseline, 3 months, 6 months, 12–24 months, and >24 months.

Results

Significantly negative correlations were observed between the CD3⁺ and CD4⁺ T-cell percentages and SLEDAI scores at baseline (r=−0.471, P=0.015; r=−0.473, P=0.015, respectively). A significantly positive correlation was observed between CD4⁺ T-cell percentage and the complement component C3 at baseline (r=0.612, P=0.002). After 3 months of combination therapy, the CD3⁺ and CD4⁺ T-cell percentages were significantly higher than the high activity baseline (P<0.01, P<0.05, respectively). After 6 months, the CD3⁺, CD4⁺, and CD8⁺ T-cell percentages were all significantly higher than the high activity baseline (P<0.01, P<0.05, P<0.05, respectively).

Conclusions

T-cell subset distributions vary across different levels of SLE disease activity with higher CD3⁺ T-cell and CD4⁺ Th cell percentages favoring lower SLE activity. As CD3⁺ T-cell and CD4⁺ Th cell percentages negatively correlate with SLEDAI, vincristine-cyclophosphamide combination therapy appears to positively affect the T-cell subset distribution in SLE patients to keep the disease in remission by increasing their CD3⁺ T-cell and CD4⁺ Th cell percentages.

Genetic mapping with multiple levels of phenotypic information reveals determinants of lymphocyte glucocorticoid sensitivity

Clinical response to glucocorticoids, steroid hormones widely used as pharmaceuticals, varies extensively in that many individuals (∼30%) show a weak response to treatment. Although little is known about the molecular basis of this variation, regulatory polymorphisms are likely to play a key role given that glucocorticoids act largely through activation of a transcription factor, the glucocorticoid receptor. In an effort to characterize the molecular basis of variation in glucocorticoid sensitivity, we measured in vitro lymphocyte glucocorticoid sensitivity and transcriptome-wide response to glucocorticoids in peripheral-blood mononuclear cells from African American healthy donors. We found that variation in lymphocyte glucocorticoid sensitivity was correlated with transcriptional response at 27 genes (false-discovery rate < 0.1). Furthermore, a genome-wide association scan revealed a quantitative trait locus (QTL) for lymphocyte glucocorticoid sensitivity (rs11129354, p = 4 × 10(-8)); it was also associated with transcriptional response at multiple genes, including many (14/27) where transcriptional response was correlated with lymphocyte glucocorticoid sensitivity. Using allelic-imbalance assays, we show that this QTL is a glucocorticoid-dependent cis-regulatory polymorphism for RBMS3, which encodes an RNA-binding protein known as a tumor suppressor. We found that siRNA-mediated knockdown of RBMS3 expression increased cellular proliferation in PBMCs, consistent with the role of the gene as a negative regulator of proliferation. We propose that differences in lymphocyte glucocorticoid sensitivity reflect variation in transcriptional response, which is influenced by a glucocorticoid-dependent regulatory polymorphism that acts in cis relative to RBMS3 and in trans to affect the transcriptional response of multiple distant genes.

A candidate gene analysis of canine hypoadrenocorticism in 3 dog breeds

Canine hypoadrenocorticism is believed to be an immune-related condition. It is rare in the overall dog population but shows a breed-related predisposition with Standard poodles and Portuguese water dogs having a greater prevalence of the condition. It shares many similarities with human primary adrenal insufficiency and is believed to be a naturally occurring, spontaneous model for the human condition. Short haplotype blocks and low levels of linkage disequilibrium in the human genome mean that the identification of genetic contributors to the condition requires large sample numbers. Pedigree dogs have high linkage disequilibrium and long haplotypes within a breed, increasing the potential of identifying novel genes that contribute to canine genetic disease. We investigated 222 SNPs from 42 genes that have been associated or may be implicated in human Addison's disease. We conducted case-control analyses in 3 pedigree dog breeds (Labrador retriever: affected n = 30, unaffected = 76; Cocker Spaniel: affected n = 19, unaffected = 53; Springer spaniel: affected n = 26, unaffected = 46) and identified 8 associated alleles in genes COL4A4, OSBPL9, CTLA4, PTPN22, and STXBP5 in 3 pedigree breeds. Association with immune response genes PTPN22 and CTLA4 in certain breeds suggests an underlying immunopathogenesis of the disease. These results suggest that canine hypoadrenocorticism could be a useful model for studying comparative genetics relevant to human Addison's disease.

TRAIL death receptor-4, decoy receptor-1 and decoy receptor-2 expression on CD8+ T cells correlate with the disease severity in patients with rheumatoid arthritis

Background

Rheumatoid Arthritis (RA) is a chronic autoimmune inflammatory disorder. Although the pathogenesis of disease is unclear, it is well known that T cells play a major role in both development and perpetuation of RA through activating macrophages and B cells. Since the lack of TNF-Related Apoptosis Inducing Ligand (TRAIL) expression resulted in defective thymocyte apoptosis leading to an autoimmune disease, we explored evidence for alterations in TRAIL/TRAIL receptor expression on peripheral T lymphocytes in the molecular mechanism of RA development.

Methods

The expression of TRAIL/TRAIL receptors on T cells in 20 RA patients and 12 control individuals were analyzed using flow cytometry. The correlation of TRAIL and its receptor expression profile was compared with clinical RA parameters (RA activity scored as per DAS28) using Spearman Rho Analysis.

Results

While no change was detected in the ratio of CD4⁺ to CD8⁺ T cells between controls and RA patient groups, upregulation of TRAIL and its receptors (both death and decoy) was detected on both CD4⁺ and CD8⁺ T cells in RA patients compared to control individuals. Death Receptor-4 (DR4) and the decoy receptors DcR1 and DcR2 on CD8⁺ T cells, but not on CD4⁺ T cells, were positively correlated with patients' DAS scores.

Conclusions

Our data suggest that TRAIL/TRAIL receptor expression profiles on T cells might be important in revelation of RA pathogenesis.

Type I interferon in systemic lupus erythematosus and other autoimmune diseases

Different genetic alterations may lead to type I interferon (IFN) overproduction in human systemic lupus erythematosus (SLE). The increased bioavailability of type I IFN contributes to peripheral tolerance breakdown through the activation of immature myeloid dendritic cells (mDCs). IFN-matured mDCs activate autoreactive T cells. These cells, together with plasmacytoid DCs, help expand autoreactive B cells. IFN-matured DCs also activate cytotoxic CD8+ T cells, possibly increasing apoptotic cell availability. The capture of apoptotic cells by mDCs and of nucleic acid-containing immune complexes by plasmacytoid DCs and B cells amplifies the autoimmune reaction leading to disease manifestations. Genetic alterations in lineages other than B cells might explain other autoimmune syndromes where type I IFNs appear to be involved.

PDCD1: a tissue-specific susceptibility locus for inherited inflammatory disorders

Variation in genes encoding costimulatory molecules expressed on lymphocytes has been expected to contribute to the genetic component of inflammatory disease, but only the gene encoding the inhibitory protein, CTLA-4, seems consistently to confer disease susceptibility. Studies in murine models implicate the inhibitory product of the pd1 gene, programmed death-1, in the maintenance of peripheral tolerance to self-antigens. We identify 22 single-nucleotide polymorphisms (SNPs) in the equivalent human gene, PDCD1, a number of which show significant associations with the specific immunoglobulin E response to grass allergens in atopic individuals. Stepwise analyses indicate that four of the disease-associated SNPs have independent effects. The two most common haplotypes show positive and negative associations but rarer haplotypes are also likely to be of influence. In a case-control study, multiple regression analysis of genotypic data implies that PDCD1 also confers susceptibility to rheumatoid arthritis. Along with work linking PDCD1 with susceptibility to another autoimmune condition, systemic lupus erythematosus, our data identify PDCD1 as a second immunomodulatory gene with pleiotropic effects in human disease. Genes encoding negative regulators may generally confer a significant fraction of the genetic risk associated with inherited inflammatory disorders.

Immune abnormalities induced by human endogenous retroviral peptides: with reference to the pathogenesis of systemic lupus erythematosus

P15E is a specific sequence among the envelope gene (env)-encoded transmembrane proteins of exogenous and endogenous retroviruses. A synthetic peptide (CKS- 17) that shows homology to this p15E region in several species of retrovirus is known to induce immune abnormalities. In this study, we examined the effect of a synthetic peptide derived from a region of human endogenous retrovirus (HERV) clone 4-1 (lambda4 - 1) similar to sequences of CKS-17 on the induction of systemic lupus erythematosus (SLE)-related immune abnormalities. Our results indicated that this peptide could induce T-cell activation and anergy in normal peripheral blood mononuclear cells, and the peptide could also promote the production of interleukins IL-6 and IL-16. These phenomena are representative immune abnormalities observed in SLE patients. Thus, our findings support the possibility that HERV acts as a pathogen in human SLE.