Effect of Magnesium Supplementation on Circulating Biomarkers of Cardiovascular Disease

(1) Background: Magnesium supplementation may be effective for the prevention of cardiometabolic diseases, but the mechanisms are unclear. Proteomic approaches can assist in identifying the underlying mechanisms. (2) Methods: We collected repeated blood samples from 52 individuals enrolled in a double-blind trial which randomized participants 1:1 to oral magnesium supplementation (400 mg magnesium/day in the form of magnesium oxide) or a matching placebo for 10 weeks. Plasma levels of 91 proteins were measured at baseline with follow-up samples using the Olink Cardiovascular Disease III proximity extension assay panel and were modeled as arbitrary units in a log₂ scale. We evaluated the effect of oral magnesium supplementation for changes in protein levels and the baseline association between serum magnesium and protein levels. The Holm procedure was used to adjust for multiple comparisons. (3) Results: Participants were 73% women, 94% white, and had a mean age of 62. Changes in proteins did not significantly differ between the two intervention groups after correction for multiple comparisons. The most statistically significant effects were on myoglobin [difference −0.319 log₂ units, 95% confidence interval (CI) (−0.550, −0.088), p = 0.008], tartrate-resistant acid phosphatase type 5 (−0.187, (−0.328, −0.045), p = 0.011), tumor necrosis factor ligand superfamily member 13B (−0.181, (−0.332, −0.031), p = 0.019), ST2 protein (−0.198, (−0.363, −0.032), p = 0.020), and interleukin-1 receptor type 1 (−0.144, (−0.273, −0.015), p = 0.029). Similarly, none of the associations of baseline serum magnesium with protein levels were significant after correction for multiple comparisons. (4) Conclusions: Although we did not identify statistically significant effects of oral magnesium supplementation in this relatively small study, this study demonstrates the value of proteomic approaches for the investigation of mechanisms underlying the beneficial effects of magnesium supplementation. Clinical Trials Registration: ClinicalTrials.gov NCT02837328.

Altered circulating levels of B cell growth factors and their modulation upon anti-tuberculosis treatment in pulmonary tuberculosis and tuberculous lymphadenitis

B cell activating factor/a proliferation-inducing ligand (BAFF/APRIL) are members of the tumor necrosis factor alpha (TNF) α family of ligands, which are essential for B cell survival, development, and modulation of the immune system. To examine the association of circulating levels of BAFF and APRIL with pulmonary tuberculosis (PTB) and tuberculous lymphadenitis (TBL), we measured the systemic levels of APRIL and BAFF in individuals with PTB, TBL, latent tuberculosis (LTB) and healthy controls (HC). Further, we also examined the pre and post-treatment plasma levels of above-mentioned parameters in PTB and TBL individuals upon completion of anti-TB chemotherapy. Next, the association of these cytokines either with extent of disease, disease severity, bacterial burden in PTB and lymph node culture grade or the lymph node size in TBL was also assessed. Finally, ROC analysis was performed to examine the discrimination capacity of APRIL and BAFF between PTB or TBL with LTB. Our study revealed significantly diminished plasma levels of APRIL in PTB and higher plasma levels of BAFF in both PTB and TBL individuals compared to LTB and HC. Furthermore, we observed a significant increase in APRIL levels in TBL and significantly decreased plasma levels of BAFF in both PTB and TBL after the completion of successful anti-TB treatment. There was no statistically positive relationship between BAFF and APRIL levels and the extent of disease, disease severity and bacterial burden in PTB. In TBL, there was a significant correlation between APRIL (but not BAFF) levels with lymph node culture grades. In contrast, APRIL in PTB and BAFF in TBL were able to clearly discriminate from LTB in ROC analysis. In summary, our results showed altered levels of BAFF/APRIL and their modulation upon chemotherapy, suggesting that these cytokines might be involved in the immune-modulation of TB infection.

Modulation of Mycobacterium tuberculosis-specific humoral immune responses is associated with Strongyloides stercoralis co-infection

Background / Objectives

Helminth infections are known to influence T cell responses in latent tuberculosis (LTBI). Whether helminth infections also modulate B cell responses in helminth-tuberculosis co-infection is not known.

Methods

We assessed Mycobacterium tuberculosis (Mtb)–antigen specific IgM and IgG levels, circulating levels of the B cell growth factors, BAFF and APRIL and the absolute numbers of the various B cell subsets in individuals with LTBI, LTBI with coincident Strongyloides stercoralis (Ss) infection (LTBI/Ss) and in those with Ss infection alone (Ss). We also measured the above-mentioned parameters in the LTBI-Ss group after anthelmintic therapy.

Results

Our data reveal that LTBI-Ss exhibit significantly diminished levels of Mtb-specific IgM and IgG, BAFF and APRIL levels in comparison to those with LTBI. Similarly, those with LTBI-Ss had significantly diminished numbers of all B cell subsets (naïve, immature, classical memory, activated memory, atypical memory and plasma cells) compared to those with LTBI. There was a positive correlation between Mtb—antigen specific IgM and IgG levels and BAFF and APRIL levels that were in turn related to the numbers of activated memory B cells, atypical memory B cells and plasma cells. Finally, anthelmintic treatment resulted in significantly increased levels of Mtb—antigen specific IgM and IgG levels and the numbers of each of the B cell subsets.

Conclusions

Our data, therefore, reveal that Ss infection is associated with significant modulation of Mtb-specific antibody responses, the levels of B cell growth factors and the numbers of B cells (and their component subsets).

Helminth infections and tuberculosis are two of the major health care problems worldwide and share a great deal of geographical overlap. Moreover, helminth infections are known to induce immune responses that are antagonistic to the protective immune responses elicited by Mycobacterium tuberculosis. Having previously demonstrated that helminth infections can profoundly alter protective T cell responses needed to control tuberculosis infection, we examined how Strongyloides stercoralis (Ss) infection influences B cell responses in latent tuberculosis infection (LTBI) in the context of co-infection and showed the Ss infection is associated with dramatic alterations in mycobacterial-specific IgG and IgM responses and levels of B cells and their growth factors BAFF and APRIL. These alterations in B cell responses could have implications for vaccine-induced immune responses to tuberculosis in helminth—endemic countries.

Increased APRIL Expression Induces IgA1 Aberrant Glycosylation in IgA Nephropathy

Aberrant glycosylated IgA1 molecules, mainly galactose-deficient IgA1 (Gd-IgA1), are important causal factors in IgA nephropathy; however, the underlying mechanism for the production of aberrantly glycosylated IgA1 is unknown. A recent genome-wide association study identified a novel IgAN susceptibility gene, TNFSF13, which encoded a proliferation-inducing ligand (APRIL) that promotes lymphocyte proliferation and IgA class switching. We aimed to explore the mechanism of APRIL's involvement in IgAN. We enrolled 166 patients with IgAN and 77 healthy controls and detected the plasma APRIL levels by the ELISA method, identified the mRNA expression of APRIL and its receptors by relative quantitative PCR, and confirmed by in vitro experiment. We identified increased plasma APRIL levels in IgAN, which was further proved by upregulated mRNA expression in B-lymphocytes from 27 IgAN patients. Analysis of the clinical characteristics of patients with IgAN showed that higher plasma APRIL level was associated with more severe clinical presentations (high proteinuria and low eGFR). The plasma APRIL level was positively correlated with Gd-IgA1 levels. Furthermore, exogenous APRIL could induce more production of Gd-IgA1 in cultured lymphocytes from patients with IgAN, compared with that from healthy controls. And, the relative higher expression of receptors of APRIL, that is, BCMA and TACI, in B-lymphocytes from IgAN patients were observed. Our findings implied that in patients with IgAN, increased APRIL is accompanied elevated expression of its receptors in B-lymphocytes, which induces overproduction of Gd-IgA1, ultimately contributing to the pathogenesis of IgAN.

Decreased Circulating Levels of APRIL: Questioning Its Role in Diabetes

Diabetes mellitus is a chronic disease that affects over 382 million people worldwide. Type-1 Diabetes (T1D) is classified as an autoimmune disease that results from pancreatic β-cell destruction and insulin deficiency. Type-2 Diabetes (T2D) is characterized principally by insulin resistance in target tissues followed by decreased insulin production due to β-cell failure. It is challenging to identify immunological markers such as inflammatory molecules that are triggered in response to changes during the pathogenesis of diabetes. APRIL is an important member of the TNF family and has been linked to chronic inflammatory processes of various diseases since its discovery in 1998. Therefore, this study aimed to evaluate APRIL serum levels in T1D and T2D. For this, we used the ELISA assay to measure serum APRIL levels of 33 T1D and 30 T2D patients, and non-diabetic subjects as control group. Our data showed a decrease in serum APRIL levels in T1D patients when compared with healthy individuals. The same pattern was observed in the group of T2D patients when compared with the control. The decrease of serum APRIL levels in diabetic patients suggests that this cytokine has a role in T1D and T2D. Diabetes is already considered as an inflammatory condition with different cytokines being implicated in its physiopathology. Our data suggest that APRIL can be considered as a potential modulating cytokine in the inflammatory process of diabetes.

APRIL Level as a Marker of Disease Activity in Treated Rheumatoid Arthritis Patients: Association with Disease Activity and Anti-CCP Antibody

Rheumatoid arthritis (RA) is a chronic autoimmune disease with joint inflammation and autoantibody production. Cytokines play an important role in the pathogenesis of RA. Among the cytokines that regulate B cell homeostasis is the "A Proliferation-Inducing Ligand" (APRIL). To determine the differences in APRIL in response to treatment in anti- cyclic citrllinated peptides (anti-CCP) positive versus anti-CCP negative patients with established RA. Concentrations of APRIL in sera of 10 anti-CCP positive RA patients, 18 anti-CCP negative RA patients, and 12 healthy controls were measured by enzyme-linked immunosorbent assay (ELISA) at treatment initiation and after 6 months of treatment with methotrexate and hydroxychloroquine. Correlations between serum anti-CCP, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), 28-joint Disease Activity Score (DAS28), and serum level of APRIL were analyzed. Serum APRIL levels were increased in rheumatoid arthritis patients in comparison with healthy volunteers. APRIL correlated positively with disease activity; swollen joint count, visual analog score and simplified disease activity index (all P < 0.05). In addition, APRIL was significantly higher in patients with positive anti-CCP. After treatment, APRIL levels significantly decreased in the anti-CCP positive RA patients than in anti-CCP negative RA patients. In conclusions, serum APRIL may be a good predictor marker for joint injury and therapeutic response in patients with RA.

TNF superfamily proteins in the serum of patients with B-ALL--preliminary study

BACKGROUND

TNF superfamily ligands such as B cell-activating factor (BAFF), a proliferation inducing ligand (APRIL) and TNF-related apoptosis inducing ligand (TRAIL), can play an important role in the pathogenesis and development of various B cell malignancies involving B-ALL.

METHODS

The study group consisted of 25 children suffering from newly diagnosed B cell precursor ALL (B- ALL), involving immunophenotype pre-B and common-cALL. Peripheral blood samples were collected at the time of diagnosis, before any treatment, and after treatment. Soluble APRIL, soluble BAFF, and soluble TRAIL concentrations were assessed using ELISA kits.

RESULTS

The concentrations of sAPRIL and sBAFF in the sera of the patient group were higher compared to the values of the control specimens. Among all molecules examined, the highest concentrations were found for the sAPRIL molecule. Furthermore, sAPRIL and sBAFF concentrations were higher in patients with ALL-pre B than in patients with cALL. After the treatment, the sera of patients with ALL-pre B contained lower concentrations of sAPRIL, sBAFF, and sTRAIL than those of the same patients before therapy.

CONCLUSIONS

Contrary to earlier indications of the key function of BAFF in B-ALL, the quantitative dominance of APRIL in the serum suggests that this molecule can play an equivalent or even more significant role in this patient group than BAFF.

Increased serum APRIL differentially correlates with distinct cytokine profiles and disease activity in systemic lupus erythematosus patients

Cytokines play an important role in the pathogenesis of systemic lupus erythematosus (SLE). Among the cytokines that regulate B cell homeostasis is a proliferation-inducing ligand (APRIL). This study aimed to determine whether serum levels of APRIL are raised in patients with SLE and correlate with disease activity or proinflammatory cytokines production, or both. Serum APRIL, interleukin-17 (IL-17), IL-4 and interferon gamma (IFN-γ) levels were measured in forty patients with SLE and 30 healthy controls. Disease activity was assessed by SLE disease activity index (SLEDAI), and results were correlated with serum APRIL levels. Serum APRIL levels were significantly higher in patients with SLE than in healthy controls. Positive correlation was found between serum APRIL levels and total SLEDAI score and anti-dsDNA antibody titers. Moreover, serum APRIL levels was significantly higher in patients with arthritis, mucocutaneous manifestations and proteinuria. APRIL is increased in patients with active SLE accompanying the increase of IL-17 and IFN-γ. Significant positive correlations between serum levels of APRIL and IL-17 and IFN-γ and a negative correlation between serum levels of APRIL and IL-4 were found. The results suggest that APRIL may be an important marker of disease activity in patients with SLE. We provide the analyses of APRIL levels in patients with SLE, suggesting new tools for the diagnosis, prognosis and possible therapeutic management of SLE.

Serum sAPRIL: a potential tumor-associated biomarker to colorectal cancer

OBJECTIVE

The purpose of our study was to investigate the serum levels of soluble a-proliferation-inducing ligand (sAPRIL) in patients with colorectal cancer (CRC), benign intestinal disease and healthy volunteers and explore the potential possibility of sAPRIL severing as a CRC biomarker.

METHODS

Our investigation was conducted on 35 blood samples obtained from CRC patients, 32 blood samples from patients with benign intestinal diseases and 31 blood samples from healthy volunteers. The sAPRIL concentrations were examined by an enzyme-linked immunosorbent assay (ELISA) and data were analyzed with non-parametric Mann-Whitney U-test and X²-test. The correlation relationship between sAPRIL and CEA, as well as sAPRIL and CA19-9 was assessed by non-parametric Spearmen's correlation test, respectively.

RESULTS

The median value of sAPRIL in the malignant group was 10.43 ng/mL, compared with those of the benign group (4.89 ng/mL) and control group (3.30 ng/mL), respectively, which had an obvious significance (P<0.0003). Area under the receiver-operating characteristic (ROC) curve for sAPRIL was 0.854 (95% CI, 0.776-0.933). The optimal cut-off level of sAPRIL was 5.49 ng/mL. Serum sAPRIL had a positive correlation with CEA (r=0.637, P=0.000) and CA19-9 (r=0.357, P=0.008) in 35 patients with colorectal cancer. sAPRIL showed higher sensitivity (82.9%) than those of CEA (74.3%) and CA19-9 (65.7%) in CRC, respectively.

CONCLUSION

The results indicated that serum sAPRIL, as a potential biomarker, had a positive diagnostic value for colorectal cancer.

Serum BAFF and APRIL might be associated with disease activity and kidney damage in patients with anti-glomerular basement membrane disease

AIM

B cell activating factor belonging to the tumour necrosis factor family (BAFF) and a proliferation inducing ligand (APRIL) are two tumour necrosis factor (TNF)-like cytokines that were found to be elevated in many autoimmune diseases. Anti-glomerular basement membrane (GBM) disease is a typical severe autoimmune disease characterized by raised serum anti-GBM antibodies. In this study we aimed to detect the serum levels of BAFF and APRIL in patients with anti-GBM disease, and their clinical significance was further analyzed.

METHODS

Forty-seven patients with anti-GBM disease were enrolled in this study. Forty-eight healthy individuals were used as normal controls. The levels of serum BAFF and APRIL were assessed using commercially available enzyme linked immunosorbent assay kits. The association between the levels of serum BAFF and APRIL, and the clinical and pathological parameters were further evaluated.

RESULTS

The serum levels of BAFF and APRIL in patients with anti-GBM disease were significantly higher than that in normal controls (12.3 ± 14.1 ng/mL vs. 0.9 ± 0.3 ng/mL, P < 0.001; 19.1 ± 22.9 ng/mL vs. 1.6 ± 4.6 ng/mL, P < 0.001), respectively. The levels of serum APRIL were correlated with the titres of anti-GBM antibodies (r = 0.347, P = 0.041), and the levels of serum BAFF were associated with the percentage of glomeruli with crescents (r = 0.482, P = 0.015) in patients with anti-GBM disease.

CONCLUSION

The levels of serum BAFF and APRIL were raised in patients with anti-GBM disease and might be associated with disease activity and kidney damage.

The expression of BAFF, APRIL and TWEAK is altered in eczema skin but not in the circulation of atopic and seborrheic eczema patients

The TNF family cytokines BAFF (B-cell activating factor of the TNF family) and APRIL (a proliferation-inducing ligand) are crucial survival factors for B-cell development and activation. B-cell directed treatments have been shown to improve atopic eczema (AE), suggesting the involvement of these cytokines in the pathogenesis of AE. We therefore analyzed the expression of these TNF cytokines in AE, seborrheic eczema (SE) and healthy controls (HC). The serum/plasma concentration of BAFF, APRIL and a close TNF member TWEAK (TNF-like weak inducer of apoptosis) was measured by ELISA. The expression of these cytokines and their receptors in skin was analyzed by quantitative RT-PCR and immunofluorescence. Unlike other inflammatory diseases including autoimmune diseases and asthma, the circulating levels of BAFF, APRIL and TWEAK were not elevated in AE or SE patients compared with HCs and did not correlate with the disease severity or systemic IgE levels in AE patients. Interestingly, we found that the expression of these cytokines and their receptors was altered in positive atopy patch test reactions in AE patients (APT-AE) and in lesional skin of AE and SE patients. The expression of APRIL was decreased and the expression of BAFF was increased in eczema skin of AE and SE, which could contribute to a reduced negative regulatory input on B-cells. This was found to be more pronounced in APT-AE, the initiating acute stage of AE, which may result in dysregulation of over-activated B-cells. Furthermore, the expression levels of TWEAK and its receptor positively correlated to each other in SE lesions, but inversely correlated in AE lesions. These results shed light on potential pathogenic roles of these TNF factors in AE and SE, and pinpoint a potential of tailored treatments towards these factors in AE and SE.

[Role of measuring the expression levels of a proliferation-inducing ligand and its receptors by real-time fluorescence quantitative method in children with lymphoma]

OBJECTIVE

to investigate the role of a real-time fluorescence quantitative polymerase chain reaction (PCR) in measuring the expression levels of a proliferation-inducing ligand and its receptors expression levels in peripheral blood of children with lymphoma.

METHODS

real-time fluorescence quantitative PCR was used to detect the expression levels of a proliferation-inducing ligand and its receptors in patients with Hodgkin disease (n = 10) or non-Hodgkin lymphoma (n = 37) and healthy control (n = 40). The correlation between the mRNA levels of a proliferation-inducing ligand and its receptors and differential stage of malignant lymphoma was analyzed.

RESULTS

the results of 47 samples showed that the levels of proliferation-inducing ligand, B cell maturation antigen, transmembrane activator and CAML interactor in the peripheral blood of lymphoma in children were significantly higher than those in normal children (1.13 ± 0.09 vs 0.41 ± 0.09, 1.22 ± 0.11 vs 0.43 ± 0.10, 0.89 ± 0.12 vs 0.35 ± 0.08, all P < 0.05). The level of a proliferation-inducing ligand and its receptors had no significant difference between Hodgkin disease and non-Hodgkin lymphoma (P > 0.05). The level of a proliferation-inducing ligand in I-II stage (0.88 ± 0.06, 0.90 ± 0.08) of malignant lymphoma in children was significantly lower than that in III-IV stage (1.21 ± 0.09, 1.23 ± 0.09, P < 0.05) while the level of its receptors between various stages showed no difference (P > 0.05).

CONCLUSION

the real-time fluorescence quantitative PCR has a high sensitivity and reproducibility. A proliferation-inducing ligand may play a great role in the development and progression of malignant lymphoma in children through its receptors of B cell maturation antigen, transmembrane activator and CAML interactor. A proliferation-inducing ligand and its receptors can be established as target molecules for early diagnosis and anti-cancer therapy.

Serum BAFF and APRIL levels in patients with PBC

B-cell-activating factor belonging to the TNF family (BAFF) and a proliferation-inducing ligand (APRIL) are known to be involved in the occurrence of autoimmune diseases. We assessed serum levels of these cytokines in PBC patients. Serum BAFF levels were significantly higher in PBC patients than in healthy controls (1253.9+/-741.4 vs. 722.8+/-199.2 pg/ml; p<0.0001) and HCV-infected patients (1253.9+/-741.4 vs. 871.0+/-251.1 pg/ml; p=0.015). Whereas changes in serum APRIL levels were not significant among these groups, there was a significant correlation between BAFF and AST (R=0.278, p=0.003) or total bilirubin (R=0.363, p=0.0006) in PBC patients. Furthermore, serum BAFF levels were elevated in PBC patients with advanced interface hepatitis. Our data indicate that serum levels of BAFF and APRIL are differentially regulated and serum BAFF levels are significantly elevated in PBC patients. These findings suggest that BAFF may serve as a modulator of the clinical and/or serological manifestation in PBC patients.

Age-related changes in BAFF and APRIL profiles and upregulation of BAFF and APRIL expression in patients with primary antibody deficiency

In some patients with common variable immunodeficiency (CVID) and immunoglobulin (Ig) A deficiency (IgAD), tumor necrosis factor (TNF) family receptor transmembrane activator and calcium-modulator and cyclophilin ligand interactor (TACI) gene mutations have been reported. B cells from individuals with TACI mutations do not produce IgG and IgA in response to the TACI ligand a proliferation-inducing ligand (APRIL) which probably suggests impaired isotype switching. To clarify the pathogenesis of CVID and IgAD of Japanese patients, we investigated the mutations of TNF family members TACI, APRIL, B-cell activating factor (BAFF), B-cell maturation antigen (BCMA) and BAFF receptor (BAFF-R) genes and the expression levels of BAFF and APRIL in patients with CVID, IgAD and X-linked agammaglobulinaemia (XLA). We also investigated the relationship between age and the blood plasma levels of BAFF and APRIL. The causative gene mutations of TNF family members in our patients were not detected. In healthy subjects, the BAFF and APRIL plasma levels correlated inversely with age. The BAFF and APRIL plasma levels of patients with CVID, IgAD and XLA were significantly higher than those of healthy children. Elevated BAFF and APRIL expression levels might partially reflect the common immunological feature of primary antibody deficiency.

APRIL but not BLyS serum levels are increased in chronic lymphocytic leukemia: prognostic relevance of APRIL for survival

APRIL (a proliferation-inducing ligand) and BLyS (B lymphocyte stimulator) expression have been reported in chronic lymphocytic leukemia (CLL) cells. We examined APRIL and BLyS serum levels in CLL patients and evaluated the prognostic significance of APRIL expression on survival.

Elevated serum APRIL levels in patients with systemic sclerosis: distinct profiles of systemic sclerosis categorized by APRIL and BAFF

OBJECTIVE

Elevated serum concentrations of B cell-activating factor belonging to the tumor necrosis factor family (BAFF) are found in systemic sclerosis (SSc) and are associated with the severity of skin sclerosis. We investigated serum levels of a proliferation-inducing ligand (APRIL), a close homolog to BAFF, and its clinical association in patients with SSc as well as its correlation with BAFF.

METHODS

Serum APRIL levels from 74 patients with SSc, 25 patients with systemic lupus erythematosus, and 25 healthy subjects were examined by ELISA. Clinical and laboratory measures were compared between SSc patients with elevated serum APRIL levels and those with normal levels. We assessed correlation of serum APRIL and BAFF levels in patients with SSc.

RESULTS

Serum APRIL levels were elevated in SSc patients compared to controls. SSc patients with elevated serum APRIL levels had significantly higher incidences of pulmonary fibrosis than those with normal levels. Serum APRIL levels did not correlate with serum BAFF levels in SSc patients, and there were distinct profiles of SSc categorized by serum APRIL and BAFF levels. High APRIL levels served as a marker for involvement of pulmonary fibrosis and high BAFF levels served as a marker for severe skin sclerosis.

CONCLUSION

The results suggest that elevated serum APRIL and BAFF levels were differentially associated with disease severity in SSc.

High serum levels of BAFF, APRIL, and TACI in common variable immunodeficiency

Common variable immunodeficiency (CVID) is characterized by low levels of immune globulins and lack of antibody. Mutations in transmembrane activator and calcium-modulating cyclophilin ligand (TACI), are found in 8-10%, associated with autoimmunity and splenomegaly. Some patients with mutations had increased serum levels of TACI. Because of this, and the prevalence of autoimmunity, splenomegaly, and lymphadenopathy, we quantitated levels of TACI ligands, a proliferation inducing ligand (APRIL) and B cell activating factor (BAFF) and TACI in serum of 77 patients. CVID subjects had markedly increased serum levels of BAFF (p<0.0001), APRIL (p<0.0001), and TACI (p=0.001) but there was no relationship between levels and autoimmunity, lymphadenopathy, splenomegaly, B cell numbers, or mutations in TACI. Peripheral blood mononuclear cells of CVID subjects had increased levels of BAFF mRNA. We conclude that increased constitutive production and/or underlying immuno-regulatory or inflammatory conditions lead to enhanced release of ligands; however, the biological result remains unclear.

Differential effects on BAFF and APRIL levels in rituximab-treated patients with systemic lupus erythematosus and rheumatoid arthritis

The objective of this study was to investigate the interaction between levels of BAFF (B-cell activation factor of the tumour necrosis factor [TNF] family) and APRIL (a proliferation-inducing ligand) and B-cell frequencies in patients with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) treated with the B-cell-depleting agent rituximab. Ten patients with SLE were treated with rituximab in combination with cyclophosphamide and corticosteroids. They were followed longitudinally up to 6 months after B-cell repopulation. Nine patients with RA, resistant or intolerant to anti-TNF therapy, treated with rituximab plus methotrexate were investigated up to 6 months after treatment. The B-cell frequency was determined by flow cytometry, and serum levels of BAFF and APRIL were measured by enzyme-linked immunosorbent assays. BAFF levels rose significantly during B-cell depletion in both patient groups, and in patients with SLE the BAFF levels declined close to pre-treatment levels upon B-cell repopulation. Patients with SLE had normal levels of APRIL at baseline, and during depletion there was a significant decrease. In contrast, patients with RA had APRIL levels 10-fold higher than normal, which did not change during depletion. At baseline, correlations between levels of B cells and APRIL, and DAS28 (disease activity score using 28 joint counts) and BAFF were observed in patients with RA. In summary, increased BAFF levels were observed during absence of circulating B cells in our SLE and RA patient cohorts. In spite of the limited number of patients, our data suggest that BAFF and APRIL are differentially regulated in different autoimmune diseases and, in addition, differently affected by rituximab treatment.

Role of APRIL (TNFSF13) polymorphisms in the susceptibility to systemic lupus erythematosus in Japanese

OBJECTIVES

A polymorphism of APRIL, c.199G > A (Gly67Arg), has been reported to be associated with systemic lupus erythematosus (SLE) in Japanese. To identify the causative polymorphism, we screened for polymorphisms of APRIL as well as TWEAK (TNFSF12), a closely located gene that generates a fusion protein TWE-PRIL by intergenic splicing. Association of APRIL and TWEAK with rheumatoid arthritis (RA) was examined in parallel.

METHODS

Polymorphisms were screened by direct sequencing. Association was analysed by case-control analysis using 266 SLE, 298 RA and 208 healthy individuals. Allele-specific difference in the mRNA level was examined using RNA difference plot analysis. Serum APRIL level was measured by ELISA.

RESULTS

The protective effect of APRIL c.199A/A homozygotes in SLE was replicated (odds ratio 0.50, 95% confidence interval 0.30-0.83, P = 0.0073; pooled P = 0.0001, Pcorr = 0.007). In addition, association of c.287A > G (Asn96Ser, P = 0.0064, allele frequency) and c.*263C > T (3' untranslated region, P = 0.025, allele frequency) was detected. c.199G-c.287A (67Gly-96Asn) haplotype was found to confer risk for SLE, while c.199A-c.287G (67Arg-96Ser) was protective. Association of TWEAK was observed neither for SLE nor RA. APRIL mRNA was increased in SLE-associated c.*263T allele. In addition, serum APRIL was undetectable in all six healthy controls homozygous for the protective c.199A-c.287G haplotype (P = 0.015).

CONCLUSIONS

In addition to replicating the protective role of APRIL c.199A/A, two additional SNPs in APRIL were found to be associated with SLE. Presence of a protective haplotype and a risk haplotype was demonstrated. The mechanism of association was suggested to be altered expression at the protein and mRNA levels.

Increased serum levels of a proliferation-inducing ligand in patients with bullous pemphigoid

BACKGROUND

B cells have been demonstrated to have critical roles in developing autoimmune bullous diseases. Recently identified tumor necrosis factor-like molecules, B cell-activating factor of the TNF family (BAFF) and a proliferation-inducing ligand (APRIL) are essential molecules for B cell development, survival, and proliferation. Although the functions of APRIL have not been fully evaluated, recent studies suggest that circulating levels of APRIL are increased in various autoimmune diseases, including systemic lupus erythematosus and rheumatoid arthritis.

OBJECTIVES

To determine serum APRIL levels in patients with pemphigus vulgaris (PV) and bullous pemphigoid (BP), and compare those with clinical findings and laboratory findings.

PATIENTS/METHODS

Sera from 15 PV patients, 43 BP patients, and 15 normal controls were subjected to ELISA assays to measure serum APRIL, BAFF, Dsg3, and BP180 levels.

RESULTS AND CONCLUSIONS

Circulating APRIL levels were significantly elevated in BP patients but not in PV patients, and correlated with serum BAFF levels. Our study revealed that serum APRIL levels tended to be increased in the quite early stage of disease. In conclusion, circulating APRIL levels may be a useful marker for early activation of autoimmune diathesis, and furthermore, an effective therapeutic target molecule in patients with BP.

APRIL is increased in serum of patients with brain glioblastoma multiforme

A PRoliferation-Inducing Ligand (APRIL) is a cytokine with the ability to induce tumorigenesis. The aim of the study was to measure serum APRIL levels in patients with brain glioblastoma multiforme. Twenty five patients with brain tumor and a control group of 25 subjects took part in the study. APRIL was measured by the enzyme-linked immunosorbent method. The study showed increased APRIL levels in the serum of patients with brain glioblastoma multiforme compared to the control group (p < 0.05). However, there was no significant difference in the level of this cytokine between groups of patients divided according to their clinical state and tumor size (p > 0.05). Inflammation parameters such as C-reactive protein (CRP) and polymorphonuclear leucocytes (PMN) were also increased in patients with brain tumor compared to controls (p < 0.05). There was a significant correlation between APRIL and CRP and PMN (p < 0.05). Results from the study suggest that APRIL may play a role in the pathogenesis of brain glioblastoma multiforme. It is possible that anti-APRIL therapy might be useful in this disease. However, this cytokine cannot be regarded as a marker of tumor size or of severity of the clinical condition of patients.