Juvenile lupus and serum vitamin D levels: A cross-sectional study

Serum levels of CXCL5 are decreased and correlate with circulating platelet counts in systemic lupus erythematosus

OBJECTIVE

To identify disease-specific serum chemokine profiles and potential anti-inflammatory chemokines in three rheumatic diseases.

METHODS

The discovery cohort included 18 patients with rheumatoid arthritis (RA), 20 patients with primary Sjögren's syndrome (pSS), 24 patients with systemic lupus erythematosus (SLE) and 28 healthy subjects. Findings from the discovery cohort were validated in two replication cohorts, consisting of 23 patients with SLE matched with 23 healthy subjects and 62 patients with SLE, 16 patients with ANCA-associated vasculitis (AAV), and 32 healthy controls, respectively. Serum levels of chemokines were determined using multiplex assay or ELISA.

RESULTS

In the discovery cohort, serum levels of multiple chemokines were increased in one or more diseases in comparison to healthy subjects, including CCL2, CCL20, CXCL9, CXCL10, and CXCL11 in SLE, CCL2, CCL4, and CXCL11 in pSS, and CCL2, CCL4, and CXCL9 in RA. Notably, serum levels of CCL3 (p = .0003) and CXCL5 (p = .0003) were decreased in SLE. The SLE-specific decrease in CXCL5 serum levels was confirmed in the two replication cohorts, with p = .0034 and p = .0006, respectively. Moreover, a positive correlation between serum levels of CXCL5 and circulating platelet counts (R = .71, p = .00018) in SLE observed in the discovery cohort was confirmed in both replication cohorts (R = .52, p = .011 and R = .49, p = .00005, respectively).

CONCLUSION

In the present study, we demonstrate that serum levels of CXCL5 are decreased in patients with SLE and positively correlated with circulating platelet count. These findings suggest that platelet-associated CXCL5 is presumably involved in the development of SLE.

Can vitamin D be an adjuvant therapy for juvenile rheumatic diseases?

Vitamin D, known for its essential role in calcium and bone homeostasis, has multiple effects beyond the skeleton, including regulation of immunity and modulation of autoimmune processes. Several reports have shown suboptimal serum 25 hydroxyvitamin D [25(OH)D] levels in people with different inflammatory and autoimmune rheumatic conditions, and an association between 25(OH)D levels, disease activity and outcomes. Although most available data pertain to adults, insights often are extended to children. Juvenile rheumatic diseases (JRDs) are a significant health problem during growth because of their complex pathogenesis, chronic nature, multisystemic involvement, and long-term consequences. So far, there is no definitive or clear evidence to confirm the preventive or therapeutic effect of vitamin D supplementation in JRDs, because results from randomized controlled trials (RCTs) have produced inconsistent outcomes. This review aims to explore and discuss the potential role of vitamin D in treating selected JRDs. Medline/PubMed, EMBASE, and Scopus were comprehensively searched in June 2023 for any study on vitamin D supplementary role in treating the most common JRDs. We used the following keywords: "vitamin D" combined with the terms "juvenile idiopathic arthritis", "juvenile systemic scleroderma", "juvenile systemic lupus erythematosus", "juvenile inflammatory myopathies", "Behcet disease", "periodic fever syndromes" and "juvenile rheumatic diseases". Observational studies have found that serum 25(OH)D concentrations are lower in juvenile idiopathic arthritis, juvenile systemic lupus erythematosus, juvenile systemic scleroderma, Behcet disease and proinflammatory cytokine concentrations are higher. This suggests that vitamin D supplementation might be beneficial, however, current data are insufficient to confirm definitively the complementary role of vitamin D in the treatment of JRDs. Considering the high prevalence of vitamin D deficiency worldwide, children and adolescents should be encouraged to supplement vitamin D according to current recommendations. More interventional studies, especially well-designed RCTs, assessing the dose-response effect and adjuvant effect in specific diseases, are needed to determine the potential significance of vitamin D in JRDs treatment.

Association of the polymorphism of the vitamin D receptor gene (VDR) with the risk of leprosy in the Brazilian Amazon

The transmission and evolution of leprosy depends on several aspects, including immunological and genetic factors of the host, as well as genetic factors of Mycobacterium leprae. The present study evaluated the association of single nucleotide polymorphisms (SNPs) on the FokI (rs2228570), TaqI (rs731236), ApaI (rs7975232) regions of the vitamin D receptor (VDR) gene with leprosy. A total of 405 individuals were evaluated, composed by groups of 100 multibacillary (MB) and 57 paucibacillary (PB) patients, and 248 healthy contacts. Blood samples were collected from patients and contacts. The genotyping was performed by sequencing of the interest regions. The alleles of the studied SNPs, and SNP FokI genotypes, were not associated with leprosy. For the SNP on TaqI region, the relationship between the tt genotype, and for the SNP ApaI, the AA genotype, revealed an association with susceptibility to MB form, while Aa genotype with protection. The extended genotypes AaTT and AaTt of ApaI and TaqI were associated with protection against MB form. Further studies analyzing the expression of the VDR gene and the correlation with its SNPs might help to clarify the role of polymorphisms on the immune response in leprosy.