Interleukin-1beta exon 5 and interleukin-1 receptor antagonist in children with immune thrombocytopenic purpura

Interleukin-1 Receptor Antagonist Gene Polymorphisms in Egyptian Children and Adolescents With Primary Immune Thrombocytopenia: Association With Disease Susceptibility, Response to Therapy, and Outcome

Immune thrombocytopenia (ITP) is one of the most common hematologic disorders with poorly predictable clinical course and outcome. We studied the distribution of interleukin 1 receptor antagonist (IL-1Ra) gene polymorphism (intron-2) among children and adolescents with ITP and correlated IL-1Ra gene polymorphism to disease susceptibility, response to therapy, and outcome. Sixty children with ITP (mean age: 9.2±4.5 y) and 100 healthy controls (mean age: 8.83±4.05 y) were enrolled. The frequencies of the allele A2 and genotype A1A2 were significantly higher in patients compared with controls ( P <0.0001, P =0.0008, respectively). Allele A2 conferred 3.1 times increased relative risk for disease development. Allele A2 and genotypes A1A2 and A2A2 were significantly more frequent among remitted patients ( P =0.028 and 0.024, respectively). There was no significant difference between different genotypes and alleles regarding bleeding score ( P >0.05). Patients with polymorphic allele A2 (A1A2/A2A2) showed significantly better response to steroids than those with homozygous wild allele A1 ( P =0.028). IL-1Ra polymorphism might contribute to the susceptibility to ITP in Egyptian children. The presence of A2 polymorphic allele of IL-1Ra gene was found to be associated with better disease outcome and response to steroids than those with homozygous wild allele.

Impact of IL-1Ra Gene Polymorphism on the Etiology and Fate of Disease in Children with Immune Thrombocytopenic Purpura

Background. Immune thrombocytopenic purpura (ITP) is considered to be one of the common childhood autoimmune diseases, and the current study was initiated to study the effect of various factors, particularly interleukin 1 receptor antagonist (IL-1Ra) gene polymorphism, on the course of the disease. Methods. The current case-control study involved 60 newly diagnosed children presented with ITP (also included 60 age- and sex-matched healthy children). All enrolled individuals had complete blood count and molecular study to determine the polymorphic state of IL-1Ra gene using conventional polymerase chain reaction. Results. Sixty patients with ages 1-14 years and having a male/female ratio of 1 : 1.61 were enrolled in the current study. Forty-five children (75%) recovered within the first year, and 15 (25%) children developed chronic ITP. IL-1Ra $\ast$ 2 variant was found to be significantly associated with control groups ( $P=0.011$ ), while IL-1Ra $\ast$ 3 was significantly associated with patients ( $P=-0.0163$ ). Other factors having significant association with the remission rate include a previous history of immunization ( $P<0.0001$ ) and the symptoms at presentation ( $P=0.0009$ ). Conclusions. The current study revealed a significant correlation of IL-1Ra gene polymorphism to the etiology and the course of the disease.

Distinct alterations of CD68+CD163+ M2-like macrophages and myeloid-derived suppressor cells in newly diagnosed primary immune thrombocytopenia with or without CR after high-dose dexamethasone treatment

Background

Although impaired myeloid-derived suppressor cells (MDSCs) recently have been studied in immune thrombocytopenia (ITP), another myeloid-derived cell population signified as M2 macrophages has not been investigated properly in ITP patients. In the present study, we intended to determine the features of circulating M2-like macrophages, to examine its relationship with MDSCs, and to explore their prognostic values in ITP.

Methods

Peripheral blood mononuclear cells from healthy controls and primary ITP patients were isolated to test the circulating M2-like macrophages and MDSCs. The circulating M2-like macrophage population defined as CD68⁺CD163⁺ and circulating MDSC population as CD11b⁺CD33⁺HLA-DR⁻ were determined by flow cytometry. Plasma inflammatory cytokines were measured by multiplex ELISA.

Results

The percentages of MDSCs were found to be expanded in newly diagnosed patients of ITP, especially among those of the complete response (CR) group (p < 0.0001). Positive linear correlation was verified between percentages of M2-like macrophages and MDSCs. The same correlation was also determined in the CR group. After treatment, the percentages of M2-like macrophages and MDSCs were both increased significantly in CR group, while those patients among the PR + NR group manifested a significant numeric decrease of MDSCs but only a moderate decrease in M2-like macrophages. MIP-1α/CCL3 was negatively correlated with M2-like macrophages while MCP-1 possessed a positive correlation with M2-like macrophages, eotaxin-1/CCL11 was negatively correlated with MDSCs and interleukin-1β (IL-1β) was found to be negatively correlated with both M2-like macrophages and MDSCs.

Conclusions

The present findings indicated critical roles of both circulating M2-like macrophages and MDSCs in ITP. The positive correlation between them might be related to inflammatory factors-mediated bidirectional interactions or partially due to their similar background patterns during differentiation. MIP-1α/CCL3, MCP-1, eotaxin-1/CCL11 and IL-1β might play a critical role in the expansion of both M2 macrophages and MDSCs population in ITP patients, which deserves further investigation.

Electronic supplementary material

The online version of this article (10.1186/s12967-018-1424-8) contains supplementary material, which is available to authorized users.

Interleukin-1B (IL-1B-31 and IL-1B-511) and interleukin-1 receptor antagonist (IL-1Ra) gene polymorphisms in primary immune thrombocytopenia

Background

Immune thrombocytopenia (ITP) is an immune-mediated disease caused by autoantibodies against platelets membrane glycoproteins GPIIb/IIIa and GPIb/IX. The etiology of ITP remains unclear. This study evaluated the association of polymorphisms in interleukin (IL)-1B-31, IL-1B-511, and IL-1Ra with ITP.

Methods

Genotyping of IL-1B-31, IL-1B-511, and IL-1Ra was performed in 118 ITP patients and 100 controls by polymerase chain reaction restriction fragment length polymorphism and detection of variable number tandem repeats.

Results

Genotype differences in IL-1B-31 and IL-1Ra were significantly associated with ITP. Patients showed a higher frequency of the IL-1B-31 variant allele (T) and a 1.52-fold greater risk of susceptibility to ITP (odds ratio [OR]=1.52, 95% confidence interval [CI]=1.04–2.22, P=0.034). The frequencies of both homozygous and heterozygous variant genotypes of IL-1B-31 were higher (OR=2.33, 95% CI=1.069–5.09, P=0.033 and OR=2.044, 95% CI=1.068–39, P=0.034) among patients and were significantly associated with ITP susceptibility. Both homozygous and heterozygous variant genotypes of IL-1Ra were also more frequent (OR=4.48, 95% CI=1.17–17.05, P=0.0230 and OR=1.80, 95% CI=1.03–3.14, P=0.0494) among patients and were associated with ITP risk. IL-1B-31 and IL-1Ra also showed significant association with severe ITP. However, IL-1B-511 was not associated with ITP.

Conclusion

IL-1B-31 and IL-1Ra polymorphisms may significantly impact ITP risk, and they could be associated with disease severity, which may contribute to the pathogenesis of ITP.

Expression of IL4 (VNTR intron 3) and IL10 (-627) genes polymorphisms in childhood immune thrombocytopenic purpura

OBJECTIVE

Immune thrombocytopenic purpura (ITP) is an acquired autoimmune disorder caused by the production of antiplatelet antibodies. These autoantibodies opsonize platelets for splenic clearance, resulting in low levels of circulating platelets. Interleukin 4 (IL4) and interleukin 10 (IL10) are important immunoregulatory cytokines mainly produced by macrophages, monocytes, T cells, B cells, and mast cells. Our study was aimed at detecting the frequency of IL4 (VNTR intron 3) and IL 10 (-627) gene polymorphisms in Egyptian ITP children as genetic markers for ITP risk and clarifying their possible role in the pathogenesis of ITP as well as their correlation with the clinical presentation and laboratory data.

METHODS

IL4 (VNTR intron 3) and IL10 (-627) gene polymorphisms were studied in 70 ITP patients and 50 age- and sex-matched healthy controls using polymerase chain reaction-restriction fragment length polymorphism assay (PCR-RFLP).

RESULTS

IL4 RP2 and IL10 A alleles were detected more frequently among ITP patients compared to controls. A statistically significant difference was observed in IL10 and IL4 gene polymorphism distribution between acute and chronic ITP patients, with higher A allele and RP2 allele among chronic ITP patients versus acute ITP patients. Combined polymorphisms of IL4 and IL10 genes were associated with greater risk of ITP.

CONCLUSION

IL4 and IL10 gene polymorphisms may contribute to susceptibility for ITP in children.

Clinical and laboratory predictors of chronic immune thrombocytopenia in children: a systematic review and meta-analysis

Childhood immune thrombocytopenia (ITP) is a rare autoimmune bleeding disorder. Most children recover within 6 to 12 months, but individual course is difficult to predict. We performed a systematic review and meta-analysis to identify predictors of chronic ITP. We found 1399 articles; after critical appraisal, 54 studies were included. The following predictors of chronic ITP in children, assessed in at least 3 studies, have been identified: female gender (odds ratio [OR] 1.17, 95% confidence interval [CI] 1.04-1.31), older age at presentation (age ≥11 years; OR 2.47, 95% CI 1.94-3.15), no preceding infection or vaccination (OR 3.08, 95 CI 2.19-4.32), insidious onset (OR 11.27, 95% CI 6.27-20.27), higher platelet counts at presentation (≥20 × 10(9)/L: OR 2.15, 95% CI 1.63-2.83), presence of antinuclear antibodies (OR 2.87, 95% 1.57-5.24), and treatment with a combination of methylprednisolone and intravenous immunoglobulin (OR 2.67, 95% CI 1.44-4.96). Children with mucosal bleeding at diagnosis or treatment with intravenous immunoglobulin alone developed chronic ITP less often (OR 0.39, 95% CI 0.28-0.54 and OR 0.71, 95% CI 0.52-0.97, respectively). The protective effect of intravenous immunoglobulin is remarkable and needs confirmation in prospective randomized trials as well as future laboratory studies to elucidate the mechanism of this effect.

DNA methyltransferase 3B gene promoter and interleukin-1 receptor antagonist polymorphisms in childhood immune thrombocytopenia

Primary immune thrombocytopenia (ITP) is one of the most common blood diseases as well as the commonest acquired bleeding disorder in childhood. Although the etiology of ITP is unclear, in the pathogenesis of the disease, both environmental and genetic factors including polymorphisms of TNF-a, IL-10, and IL-4 genes have been suggested to be involved. In this study, we investigated the rs2424913 single-nucleotide polymorphism (SNP) (C46359T) in DNA methyltransferase 3B (DNMT3B) gene promoter and the VNTR polymorphism of IL-1 receptor antagonist (IL-1 Ra) intron-2 in 32 children (17 boys) with the diagnosis of ITP and 64 healthy individuals. No significant differences were found in the genotype distribution of DNMT3B polymorphism between the children with ITP and the control group, whereas the frequency of allele T appeared significantly increased in children with ITP (P = 0.03, OR = 2, 95% CI: 1.06-3.94). In case of IL-1 Ra polymorphism, children with ITP had a significantly higher frequency of genotype I/II, compared to control group (P = 0.043, OR = 2.60, 95% CI: 1.02-6.50). Moreover, genotype I/I as well as allele I was overrepresented in the control group, suggesting that allele I may have a decreased risk for development of ITP. Our findings suggest that rs2424913 DNMT3B SNP as well as IL-1 Ra VNTR polymorphism may contribute to the susceptibility to ITP.

Genetic studies in pediatric ITP: outlook, feasibility, and requirements

The genomic revolution in medicine has not escaped attention of clinicians and scientists involved in medical management and research studies of immune thrombocytopenic purpura (ITP). In principle, ITP biology and care will benefit greatly from modern methods to understand the patterns of gene expression and genetic markers associated with fundamental parameters of the disease including predictors of remission, risk factors for severity, determinants of response to various therapies, and possibly biological sub-types. However, applying modern genetics to ITP carries severe challenges: (a) Achieving adequate sample sizes is a fundamental problem because ITP is rare (and in pediatric ITP, chronic cases constitute only about one fourth of the total); (b) familial transmission of childhood ITP is so rare that a convincing pedigree requires consideration of other immunologic or hematologic disorders; (iii) ITP is probably biologically heterogeneous, based on clinical observations, immunological studies, and animal models. Here we review the advantages and disadvantages of potential genetic approaches. Sufficient information is available to set reasonable bounds on which genetic analyses of ITP are feasible and how they are most likely to be accomplished. The highest priority is for accurate phenotypes to compare to genetic analyses. Several registries worldwide hold promise for accomplishing this goal.