Distribution of PTPN22 polymorphisms in SLE from western Mexico: correlation with mRNA expression and disease activity

Relative CTLA-4, PTPN-22, and interleukin 37 mRNA expressions in patients with lupus nephritis

OBJECTIVES

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by T-cell immune-dysregulation and loss of tolerance to self-antigens. CTLA-4 and PTPN-22 are involved in the inhibition of T-lymphocytes activation. IL-37 is an anti-inflammatory cytokine that suppresses innate immunity. The relative expression of CTLA-4, IL-37 and PTPN-22 were evaluated as negative regulators of immune response in SLE patients, lupus nephritis (LN) and disease activity.

METHODS

Real-Time PCR was performed to determine relative CTLA-4, IL-37, and PTPN-22 mRNA expressions in fifty-eight SLE patients, who were divided into two groups: 29 SLE patients without nephritis and 29 patients with LN, versus fifty controls.

RESULTS

There was a significantly high-expression of CTLA-4 and IL-37 genes in SLE patients compared to controls (p=0.005; 0.018 respectively). There was no difference in relative PTPN-22 mRNA expression between the SLE patients and controls. Relative CTLA-4 mRNA expression decreased in LN patients (p=0.044), however, relative IL-37 mRNA over-expressed in LN patients (p=0.001) compared to those without LN. There was a significant over-expression of relative IL-37 andPTPN-22 mRNA in active SLE patients. But, there was a non-significant difference in CTLA-4 expression with disease activity. Regression analysis revealed patients with relative IL-37 mRNA over-expression had two times more to develop lupus nephritis (OR=1.906, 95% CI=1.218-2.983, p=0.005).

CONCLUSIONS

Relative IL-37mRNA expression was elevated in SLE patients and associated with renal involvement and disease activity. It could be considered as a new promising predicting tool for LN. Relative PTPN-22 mRNA expression was correlated with disease activity only in SLE patients.

Analysis of PTPN22 -1123 G>C, +788 G>A and +1858 C>T Polymorphisms in Patients with Primary Sjögren's Syndrome

BACKGROUND

Primary Sjögren's syndrome (pSS) is an autoimmune exocrinopathy characterized by lymphocytic infiltration, glandular dysfunction and systemic manifestations. Lyp protein is a negative regulator of the T cell receptor encoded by the tyrosine phosphatase nonreceptor-type 22 (PTPN22) gene. Multiple single-nucleotide polymorphisms (SNPs) in the PTPN22 gene have been associated with susceptibility to autoimmune diseases. This study aimed to investigate the association of PTPN22 SNPs rs2488457 (-1123 G>C), rs33996649 (+788 G>A), rs2476601 (+1858 C>T) with pSS susceptibility in Mexican mestizo subjects.

METHODS

One hundred fifty pSS patients and 180 healthy controls (HCs) were included. Genotypes of PTPN22 SNPs were identified by PCR-RFLP. PTPN22 expression was evaluated through RT-PCR analysis. Serum anti-SSA/Ro and anti-SSB/La levels were measured using an ELISA kit.

RESULTS

Allele and genotype frequencies for all SNPs studied were similar in both groups (p > 0.05). pSS patients showed 17-fold higher expression of PTNP22 than HCs, and mRNA levels correlated with SSDAI score (r² = 0.499, p = 0.008) and levels of anti-SSA/Ro and anti-SSB/La autoantibodies (r² = 0.200, p = 0.03 and r² = 0.175, p = 0.04, respectively). Positive anti-SSA/Ro pSS patients expressed higher PTPN22 mRNA levels (p = 0.008), with high focus scores by histopathology (p = 0.02). Moreover, PTPN22 expression had high diagnostic accuracy in pSS patients, with an AUC = 0.985.

CONCLUSIONS

Our findings demonstrate that the PTPN22 SNPs rs2488457 (-1123 G>C), rs33996649 (+788 G>A) and rs2476601 (+1858 C>T) are not associated with the disease susceptibility in the western Mexican population. Additionally, PTPN22 expression may be helpful as a diagnostic biomarker in pSS.

Altered PTPN22 and IL10 mRNA Expression Is Associated with Disease Activity and Renal Involvement in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a complex autoimmune disease with very heterogeneous clinical behavior between affected individuals. Therefore, the search for biomarkers clinically useful for the diagnosis, prognosis, and monitoring of the disease is necessary. Here, we determined the association between PTPN22, IL10, OAS2, and CD70 mRNA expression with the clinical characteristics and with the serum levels of IL-10, IFN-γ, and IL-17 in SLE patients. Forty patients with SLE and 34 control subjects (CS) were included, mRNA expression was determined by real-time qPCR and cytokine levels were quantified by a multiplex bead-based immunoassay. Compared to CS, SLE patients showed increased IL10 mRNA and high IL-10 and IL-17 serum levels; in contrast, PTPN22 mRNA and IFN-γ were decreased. PTPN22 and IL10 gene expression was negatively correlated with Mex-SLEDAI score and were notably downregulated in SLE patients with lupus nephritis. Interestingly, SLE patients with renal damage were the ones with the lowest levels of PTPN22 and IL10 mRNA and the highest SLEDAI scores. No associations were observed for OAS2 and CD70 mRNA and IL-10, IL-17, and IFN-γ. In conclusion, we suggest that the assessment of IL10 and PTPN22 mRNA could be useful for monitoring disease activity in SLE patients showing renal involvement.

Tumor necrosis factor receptor II and PTPN22 genes polymorphisms and the risk of systemic lupus erythematosus in Egyptian children

BACKGROUND

Many genes have been implicated in the pathogenesis of systemic lupus erythematosus (SLE). Tumor necrosis factor (TNF) is a potent cytokine stimulator acting through 2 cell surface receptors (TNFR I and II). TNFRII gene which controls expression of these receptors has been linked to SLE susceptibility through promoting apoptosis. Also; Protein tyrosine phosphatase non receptor 22 (PTPN22) gene enhances intrinsic phosphatase activity of T lymphocytes leading to their dysregulation and stimulates autoimmune process of lupus and its rs2476601 has been linked to susceptibility to thyroiditis in SLE patients in few studies.

OBJECTIVES

(i) to investigate the correlation between 2 SNPs of TNFR II and PTPN22 genes and SLE susceptibility in a cohort of Egyptian children compared to controls (ii) and to investigate their possible association with different clinical presentations of the disease in children.

SUBJECTS AND METHODS

Typing of TNFR II rs1061622 and PTPN22 rs2476601 SNPs were done using polymerase chain reaction-restriction fragment length polymorphism for 74 children with SLE and 100 matched healthy controls.

RESULTS

Children with SLE had more frequent G allele and GG genotype of TNFR II rs1061622 (p < 0.001) and more T allele and TT genotype of PTPN22 rs2476601 (p = 0.012 and <0.001, respectively) compared to controls. Only 6 patients (8%) had thyroiditis (hypothyroidism) with T allele and TT genotype of PTPN22 1858 T more prevalent in those patients versus those without thyroiditis (p ≤ 0.001). Apart from, thyroiditis, no significant association was found between genotypes and alleles frequencies of the 2 studied SNPs and other clinical manifestations of the disease.

CONCLUSION

The G allele and GG genotype of TNFR II rs1061622 and T allele and TT genotype of PTPN22 rs2476601 genes polymorphism can be considered as risk factors for the development of SLE. The presence of the T allele of PTPN22 rs2476601 may increase the risk of concomitant thyroiditis in Egyptian children with SLE but further studies are required to confirm this finding as thyroiditis was reported only in few cases in this study.

Association between complement 4 copy number variation and systemic lupus erythematosus: a meta-analysis

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by multiple genetic mutations. Complement 4 (C4) copy number variation (CNV) is a target-of-interest located on chromosome 6. C4 encodes for either of the two C4 paralogs, C4A or C4B, and low C4 levels have been associated with SLE activity. In this study, we conducted a meta-analysis to comprehensively understand the role of C4 CNV in SLE. Three databases (PubMed, Embase, and Web of Science) were searched for relevant studies. Two investigators independently extracted and evaluated data from eligible studies. Associations between C4 CNV and SLE were estimated by odds ratios (OR) and 95% confidence intervals (95% CI). Further analysis was conducted using the STATA 12.0 software. A total of eight case-control studies were included in the analysis with 4107 SLE patients and 5889 healthy controls. Six studies used TaqMan real-time PCR to genotype C4 CNV, with 1 study used paralog ratio test and other one used multiplex ligation-dependent probe amplification (MLPA). Lower total C4 CNV and C4A CNV were associated with SLE in the overall analysis (pooled OR: 1.55, 95% CI: 1.23-1.95; pooled OR: 1.86, 95% CI: 1.51-2.29). The subgroup analysis found that total C4 CNV and lower C4A CNV were significantly associated with SLE in Caucasians (pooled OR: 1.84, 95% CI: 1.60-2.12; pooled OR: 2.23, 95% CI:1.92-2.59). However, the association was not detected in East Asians. Lastly, SLE was not associated with C4B CNV, long C4 CNV, or short C4 CNV. The meta-analysis confirmed that lower total C4 CNV and lower C4A CNV are associated with SLE in certain populations. Future studies should consider other ethnic groups to further investigate the relationship between the C4 gene and SLE.

ITGAM is a risk factor to systemic lupus erythematosus and possibly a protection factor to rheumatoid arthritis in patients from Mexico

Introduction

ITGAM has consistently been associated with susceptibility to systemic lupus erythematosus (SLE) in many ethnically diverse populations. However, in populations with higher Amerindian ancestry (like Yucatan) or highly admixed population (like Mexican), ITGAM has seldom been evaluated (except few studies where patients with childhood-onset SLE were included). In addition, ITGAM has seldom been evaluated in patients with rheumatoid arthritis (RA). Here, we evaluated whether four single nucleotide polymorphisms (SNPs), located within ITGAM, were associated with SLE and RA susceptibility in patients from Mexico.

Methods

Our study consisted of 1,462 individuals, which included 363 patients with SLE (292 from Central Mexico and 71 from Yucatan), and 621 healthy controls (504 from Central Mexico and 117 from Yucatan). Our study also included 478 patients with RA from Central Mexico. TaqMan assays were used to obtain the genotypes of the four SNPs: rs34572943 (G/A), rs1143679 (G/A), rs9888739 (C/T), and rs1143683 (C/T). We also verified the genotypes by Sanger sequencing. Fisher's exact test and permutation test were employed to evaluate the distribution of genotype, allele, and haplotype between patients and controls.

Results

Our data show that all four ITGAM SNPs are significantly associated with susceptibility to SLE using both genotypic and allelic association tests (corrected for multiple testing, but not for population stratification). A second study carried out in patients from Yucatan, a southeastern part of Mexico (with a high Amerindian ancestry), also replicated SLE association with all four SNPs, including the functional SNP, rs1143679 (OR = 24.6 and p = 9.3X10^-6). On the other hand, none of the four SNPs are significant in RA after multiple testing. Interestingly, the GACC haplotype, which carries the ITGAM rs1143679 (A) minor allele, showed an association with protection against RA (OR = 0.14 and p = 3.0x10^-4).

Conclusion

Our data displayed that ITGAM is a risk factor to SLE in individuals of Mexican population. Concurrently, a risk haplotype in ITGAM confers protection against RA.

Identification of susceptibility SNPs in CTLA-4 and PTPN22 for scleritis in Han Chinese

The aim of this study was to determine the association between 13 single nucleotide polymorphisms (SNPs) in the cytotoxic T lymphocyte-associated antigen-4 (CTLA4) and protein tyrosine phosphatase non-receptor type 22 (PTPN22) genes with scleritis in a Chinese Han population. We recruited 432 scleritis patients and 710 healthy controls. Four tag SNPs of CTLA4 and nine tag SNPs of PTPN22 were selected using Haploview. Genotyping was performed with the Sequenom MassArray® iPLEX GOLD Assay. Genotype and allele frequency differences were analyzed by χ² test and Bonferroni correction. Haplotype analysis was performed to further evaluate the association of these two genes with scleritis. In this study, CTLA4/rs3087243 G allele frequency and GG genotype frequency were significantly increased in scleritis patients compared to healthy controls [corrected P-value (Pc) = 0·02, odds ratio (OR) = 1·475, 95% confidence interval (CI) = 1·175-1·851; Pc = 0·04, OR = 1·546, 95% CI = 1·190-2·008, respectively]. None of the tested SNPs in the PTPN22 gene showed an association with scleritis. Haplotype analysis revealed a lower frequency of a CTLA4 TCAA haplotype (order of SNPs: rs733618, rs5742909, rs231775, rs3087243) (Pc = 4·26 × 10^-3 , OR = 0·618, 95% CI = 0·540-0·858) and a higher frequency of a PTPN22 TTATACGCG haplotype (order of SNPs: rs3789604, rs150426536, rs1746853, rs1217403, rs1217406, rs3789609, rs1217414, rs3789612, rs2488457) (Pc = 2·83 × 10^-4 , OR = 1·457, 95% CI = 1·210-1·754) in scleritis patients when compared to healthy controls. In conclusion, our findings indicate that CTLA4 and PTPN22 might confer genetic susceptibility to scleritis in a Chinese Han population.

PTPN22 +788 G>A (R263Q) Polymorphism is Associated with mRNA Expression but it is not a Susceptibility Marker for Rheumatoid Arthritis Patients from Western Mexico

PTPN22 represents an important non-HLA gene that has been strongly associated with rheumatoid arthritis (RA) pathogenesis. Several studies have reported a specific genetic variant for PTPN22 (+788 G>A; rs33996649) that might be associated with decreased RA risk in Caucasian population; nevertheless, its specific role in western Mexican population has not been yet described. A case-control study with 443 RA patients and 317 control subjects (CS) was conducted. The genotyping was performed by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) technique and the PTPN22 mRNA expression was determined by SYBR Green-based real-time quantitative-PCR assay. No association between the PTPN22 +788 G>A polymorphism and RA susceptibility in western Mexican population was found when comparing genotype and allelic frequencies between RA patients and CS (G/G vs. G/A: OR 0.55, p = 0.14, 95% CI 0.22-1.32; G vs. A: OR 0.56, p = 0.14, 95% CI 0.23-1.36). The PTPN22 mRNA expression increased 4.6-fold more in RA patients than in CS, and RA patients, carriers of PTPN22 +788 G/A genotype, expressed 15.6-fold more than RA patients carrying the homozygous G/G genotype. Overall, these results showed that the PTPN22 +788 G>A polymorphism is not associated with RA susceptibility in western Mexican population, whereas the presence of G/A genotype is associated with increased PTPN22 mRNA expression in RA patients.

High prevalence of protein tyrosine phosphatase non-receptor N22 gene functional variant R620W in systemic lupus erythematosus patients from Kuwait: implications for disease susceptibility

Background

Systemic lupus erythematosus (SLE) is an autoimmune inflammatory disease which involves the loss of self-tolerance with hyperactivation of autoreactive T- and B-cells. Protein tyrosine phosphatase non-receptor type 22 (PTPN22) encodes for lymphoid specific phosphatase (LYP) which is a key negative regulator of T lymphocyte activation. The aim of this study was to investigate the association between PTPN22 gene functional variant R620W and systemic lupus erythematosus (SLE) by comparing its prevalence in Kuwaiti SLE patients and controls.

Methods

The study included 134 SLE patients and 214 controls from Kuwait. The genotypes of PTPN22 gene functional variant R620W were determined by PCR-RFLP and confirmed by DNA sequence analysis in both SLE patients and the controls.

Results

A relatively high prevalence of the variant 620 W (T-allele) of the PTPN22 gene was detected in the SLE patients from Kuwait. 35.7% of the SLE patients had at least one variant allele (T-allele) compared to 15.9% in the controls. A statistically significant difference was detected in the frequency of variant genotypes, TT and CT between SLE patients and the controls (p < 0.0001). No association was detected between the PTPN22 gene variant and the Raynaud’s phenomenon, renal involvement and severity of the SLE.

Conclusions

The frequency of PTPN22 gene functional variant R620W reported in this study is amongst the highest compared to other world populations. A high prevalence of this variant in SLE patients in comparison to the healthy controls suggests its significant contribution in conferring susceptibility to SLE together with other factors.

PTPN22 1858C > T polymorphism and susceptibility to systemic lupus erythematosus: a meta-analysis update

Studies performed in the past years showed PTNP22 1858 C > T (rs2476601) polymorphism as associated with systemic lupus erythematosus susceptibility, although conflicting findings are still found. In this context, a powerful statistical study, such as meta-analysis, is necessary to establish a consensus. The aim of this study was to evaluate association studies between the PTPN22 1858 C > T polymorphism and SLE by a meta-analysis update, including three recently published studies in the last three years. A total of 3868 SLE patients and 7458 healthy individuals were considered herein, enclosing 19 studies from Asian, American, European and Latin ethnic groups. Odds ratio (OR) was performed for allelic, dominant and recessive genetic models. Statistically significant association was found between the PTPN22 1858 C > T polymorphism and susceptibility to SLE in all inheritance models. Allelic genetic model data (OR = 1.54, 95% confidence interval (CI) = 1.38-1.72, p value=.000) shows that T allele confers increased SLE susceptibility. As well as recessive genetic model (OR = 2.04, 95% CI = 1.09-3.82, p value = .030) for T/T genotype. Instead, dominant genetic model shows that C/C genotype confers lower susceptibility for SLE development (OR = 0.62, 95% CI = 0.54-0.72, p value = .000). In addition, we provided an ethnicity-derived meta-analysis. The results showed association in Caucasian (OR = 1.47, p value = .000) and Latin (OR = 2.41, p value = .000) ethnic groups. However, rs2476601 polymorphism is not associated nor in Asian (OR= 1.31; p value = .54) and African (OR = 2.04; p value=.22) populations. In conclusion, present meta-analysis update confirms that T allele and T/T genotype in PTPN22 1858 C > T polymorphism confers SLE susceptibility, particular in Caucasian and Latin groups, suggesting PTPN22 1858 C > T as a potential genetic marker in SLE susceptibility.

Protein tyrosine phosphatase non-receptor 22 and C-Src tyrosine kinase genes are down-regulated in patients with rheumatoid arthritis

Several protein tyrosine phosphatase non-receptor 22 (PTPN22) single-nucleotide polymorphisms (SNPs) have been significantly related with rheumatoid arthritis (RA) susceptibility. Nevertheless, its potential influence on PTPN22 expression in RA has not been completely elucidated. Furthermore, PTPN22 binds to C-Src tyrosine kinase (CSK) forming a key complex in autoimmunity. However, the information of CSK gene in RA is scarce. In this study, we analyzed the relative PTPN22 and CSK expression in peripheral blood from 89 RA patients and 43 controls to determine if the most relevant PTPN22 (rs2488457, rs2476601 and rs33996649) and CSK (rs34933034 and rs1378942) polymorphisms may influence on PTPN22 and CSK expression in RA. The association between PTPN22 and CSK expression in RA patients and their clinical characteristics was also evaluated. Our study shows for the first time a marked down-regulation of PTPN22 expression in RA patients carrying the risk alleles of PTPN22 rs2488457 and rs2476601 compared to controls (p = 0.004 and p = 0.007, respectively). Furthermore, CSK expression was significantly lower in RA patients than in controls (p < 0.0001). Interestingly, a reduced PTPN22 expression was disclosed in RA patients with ischemic heart disease (p = 0.009). The transcriptional suppression of this PTPN22/CSK complex may have a noteworthy clinical relevance in RA patients.

Novel biomarkers for systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a complex and highly heterogeneous disease. By now, no novel drug has been approved by the US FDA in the past 50 years, except Belimumab, a monoclonal antibody to inhibit B-cell activating factor. The stagnating drug development of lupus may be due to our limited understanding of disease etiopathogenesis and the extreme heterogeneity of patient population. Thus, the individualized treatment for SLE becomes necessary. Recently, biomarkers have shown potential in individualized treatment. This review comprehensively summarizes novel potential biomarkers, discusses their current status in preclinical studies and clinical use, sensitivity to treatments and correlation with the disease activity, and provides an insight into the possibility of biomarkers in the utilization of individualized treatment for SLE.

Associations between PTPN22 and TLR9 polymorphisms and systemic lupus erythematosus: a comprehensive meta-analysis

Previous studies have explored the relationship of PTPN22 and TLR9 polymorphisms with systemic lupus erythematosus (SLE). In consideration of the population stratification, conflicting results and updating data, we conducted a comprehensive meta-analysis, which consists of a total of 17 research articles (9120 cases and 11,724 controls) for PTPN22 and 20 articles (including up to 2808 cases and 3386 controls) for TLR9. Significant association was verified between PTPN22 rs2476601 and SLE in the overall population (OR = 1.511 per T allele, 95% CI 1.338-1.706, P = 2.931 × 10^-11) and under dominant model of T allele (TT+CT vs. CC: OR = 1.531, 95% CI 1.346-1.742, P = 9.17 × 10^-11). Analysis after stratification by ethnicity indicated that PTPN22 rs2476601 was related to SLE in Americans (OR = 2.566, 95% CI 1.796-3.665, P = 2.219 × 10^-7), Europeans (OR = 1.399, 95% CI 1.261-1.552, P = 2.153 × 10^-10), and Africans (OR = 4.14, 95% CI 1.753-9.775, P = 1.0 × 10^-3). We did not observe any association between TLR9 polymorphisms (rs187084, rs352140, rs5743836 and rs352139) and SLE under any model, after excluding the data that were inconsistent with Hardy-Weinberg equilibrium (HWE). In summary, PTPN22 rs2476601 was significantly interrelated with SLE and contributed to susceptibility and development of SLE in Americans, Europeans and Africans in this analysis, while their relationship needs to be validated in Africans by future research.

The PTPN22 R263Q polymorphism confers protection against systemic lupus erythematosus and rheumatoid arthritis, while PTPN22 R620W confers susceptibility to Graves' disease in a Mexican population

OBJECTIVE

The functional PTPN22 R620W polymorphism (rs2476601) is clearly associated with susceptibility to several autoimmune diseases (ADs). However, the PTPN22 R263Q polymorphism (rs33996649) has been scarcely explored in different ADs. Here we aimed to examine the associations of the PTPN22 R620W and R263Q polymorphisms with susceptibility to or protection against rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and Graves' disease (GD) among Mexican patients.

METHODS

We conducted a case-control study including 876 patients (405 with SLE, 388 with RA, and 83 with GD) and 336 healthy control individuals. PTPN22 genotypes were determined using the TaqMan 5' allele discrimination assay.

RESULTS

PTPN22 R620W was associated with GD susceptibility (OR 4.3, p = 0.004), but was not associated with SLE (OR 1.8, p = 0.19). We previously demonstrated that this polymorphism is associated with RA susceptibility (OR 4.17, p = 0.00036). Moreover, PTPN22 R263Q was associated with protection against SLE (OR 0.09, p = 004) and RA (OR 0.28, p = 0.045), but was not associated with GD.

CONCLUSIONS

Our data provide the first demonstration that PTPN22 R620W confers GD susceptibility among Latin-American patients. Moreover, this is the second report documenting the association of PTPN22 R263Q with protection against SLE and RA.

BLK pathway-associated rs13277113 GA genotype is more frequent in SLE patients and associated with low gene expression and increased flares

We aimed to evaluate the relationship between some important genetic variations and expressions of these genes in our SLE population. We also determined their association with clinical parameters. Eighty-four SLE patients (79 F, 5 M) and 105 healthy controls (98 F, 7 M) were included in the study. rs13277113, rs2736340, rs7829816, rs6983130, rs2613310, and rs704853 polymorphisms, gene expressions of Src family kinases (Blk, Hck, Lck, and Lyn), and Syk kinases (Syk, ZAP70) were studied by real-time PCR. The heterozygous genotypic pattern (GA) for rs13277113 polymorphism was more frequent in patients with SLE when compared to that in controls (48.8 vs. 31.4%, p = 0.035). Other genotype variants were similar in SLE patients and controls. In the SLE group, the heterozygous genotype for rs13277113 was significantly less frequent in active SLE patients (58.8 vs. 26.7%, p = 0.01). SLE flares according to the SELENA-SLEDAI flare index were significantly more frequent in GA (rs13277113) (70 vs. 37%) and CT (rs2736340) genotypes (66.7 vs. 35.2%) than those in other genotypes (p values <0.01). The relative expression of Blk gene was significantly decreased in the SLE group as compared to that in controls (0.52 times, 95%CI 0.19-0.85). The gene expressions of Blk and ZAP70 were significantly lower in SLE patients who had flares according to the SELENA-SLEDAI flare index when compared to those in others (p values 0.01 and 0.017). We observed more frequent heterozygous GA genotypic pattern (rs13277113) in our SLE patients compared to that in controls; and it was associated with disease flares. Blk gene expression in SLE was lower, especially in relapsing patients.