I. Rumba

EULAR/PRINTO/PRES criteria for Henoch–Schönlein purpura, childhood polyarteritis nodosa, childhood Wegener granulomatosis and childhood Takayasu arteritis: Ankara 2008. Part II: Final classification criteria

Objectives To validate the previously proposed classification criteria for Henoch–Schönlein purpura (HSP), childhood polyarteritis nodosa (c-PAN), c-Wegener granulomatosis (c-WG) and c-Takayasu arteritis (c-TA). Methods Step 1: retrospective/prospective web-data collection for children with HSP, c-PAN, c-WG and c-TA with age at diagnosis ≤18 years. Step 2: blinded classification by consensus panel of a representative sample of 280 cases. Step 3: statistical (sensitivity, specificity, area under the curve and κ-agreement) and nominal group technique consensus evaluations. Results 827 patients with HSP, 150 with c-PAN, 60 with c-WG, 87 with c-TA and 52 with c-other were compared with each other. A patient was classified as HSP in the presence of purpura or petechiae (mandatory) with lower limb predominance plus one of four criteria: (1) abdominal pain; (2) histopathology (IgA); (3) arthritis or arthralgia; (4) renal involvement. Classification of c-PAN required a systemic inflammatory disease with evidence of necrotising vasculitis OR angiographic abnormalities of medium-/small-sized arteries (mandatory criterion) plus one of five criteria: (1) skin involvement; (2) myalgia/muscle tenderness; (3) hypertension; (4) peripheral neuropathy; (5) renal involvement. Classification of c-WG required three of six criteria: (1) histopathological evidence of granulomatous inflammation; (2) upper airway involvement; (3) laryngo-tracheo-bronchial involvement; (4) pulmonary involvement (x-ray/CT); (5) antineutrophilic cytoplasmic antibody positivity; (6) renal involvement. Classification of c-TA required typical angiographic abnormalities of the aorta or its main branches and pulmonary arteries (mandatory criterion) plus one of five criteria: (1) pulse deficit or claudication; (2) blood pressure discrepancy in any limb; (3) bruits; (4) hypertension; (5) elevated acute phase reactant. Conclusion European League Against Rheumatism/Paediatric Rheumatology International Trials Organisation/Paediatric Rheumatology European Society propose validated classification criteria for HSP, c-PAN, c-WG and c-TA with high sensitivity/specificity.

Polymorphism at NRAMP1 and D2S1471 loci associated with juvenile rheumatoid arthritis

OBJECTIVE To examine the role of NRAMP1 in susceptibility to juvenile rheumatoid arthritis (JRA). METHODS DNA from 119 JRA patients (72 pauciarticular, 47 polyarticular) and 111 healthy controls from Latvia was genotyped for a functional repeat polymorphism in the promoter of NRAMP1 and a linked (<150 kb) microsatellite D2S1471. The findings were compared with those from HLA-DQ alleles typed previously. Chi-square analyses were performed using the Mantel-Haenszel test and stratification according to pure Latvian or pure Russian descent. Haplotype analysis was performed using the Associate program to implement the expectation-maximization algorithm based on the gene-counting technique. RESULTS Allele 3 at NRAMP1 conferred increased risk (odds ratios [ORs] 2.26, 2.31, and 2.19; P = 0.0006, 0.003, and 0.019) of disease in the JRA, pauciarticular, and polyarticular patient groups, respectively. Allele 2 conferred protection (OR 0.44, 0.43, and 0.46). Alleles at D2S1471 that conferred susceptibility (6 and 12) or protection (11) did so only when on a haplotype with alleles 3 or 2, respectively, at NRAMP1. Allele 3 at NRAMP1 was additive with HLA-DQ7 for susceptibility (OR 3.71, 3.71, and 4.02), and allele 2 at NRAMP1 was additive with HLA-DQ5 for protection (OR 0.19, 0.08, and 0.12). CONCLUSION The NRAMP1 allele conferring susceptibility to JRA drives high levels of NRAMP1 expression, while the allele associated with protection drives low levels. These 2 alleles are inversely associated with susceptibility to infectious disease, consistent with their maintenance in populations through balancing selection.

Killer Cell Immunoglobulin-like Receptor Genes in Latvian Patients with Type 1 Diabetes Mellitus and Healthy Controls

Abstract: T1DM is very common in Sweden and is positively associated with HLA class II genes. Approximately 89% of the newly diagnosed patients carry the high‐risk HLA DR4‐DQ8 and DR3‐DQ2. The remaining 11% develop T1DM without them. This can be due to involvement of other genes and environmental factors. Natural killer (NK) cells of the innate immune system are important in antiviral and antitumor immunity. They are implicated in the etiology of autoimmune T1DM. Human NK cells express killer cell immunoglobulin‐like receptors (KIR) that belong to the polymorphic multigene family in chromosome 19q3.4. They modulate NK cell response by interacting with HLA class I. In addition, polymorphic MICA in HLA class I interacts with non‐polymorphic NKG2D receptor on NK cells. We have studied, in addition to HLA‐DR and ‐DQ, genes of the innate immune system MICA and KIR in Latvian patients (n= 98) with T1DM and controls (n= 100). They were genotyped using standard PCR‐based typing methods. MICA allele 5 is positively associated with T1DM. KIR2DL2 and KIR2DS2 were both positively associated. Combined association of MICA4 and KIR2DL2 gave an odds ration (OR) of 26.7. However, the combined risk of KIR2DL2 and HLA class II genes, HLADR3 (OR = 73.4), DR4 (OR = 66.8), and DR3 and DR4 (OR = 88.3), was higher. The maximum risk was when KIR2DL2, MICA5, and DR3/DR4 were in combination. In conclusion, our results suggest that a balance between innate and acquired immunity is important, and an imbalance coud lead to T1DM.

Major histocompatibility complex class I chain related (MIC) A gene, TNFa microsatellite alleles and TNFB alleles in juvenile idiopathic arthritis patients from Latvia

In order to analyze involvement of major histocompatibility complex class I chain-related gene A (MICA) and tumor necrosis factor a (TNFa) microsatellite polymorphisms as well as TNFB gene in juvenile idiopathic arthritis (JIA), we studied 128 patients divided into groups according to clinical features [monoarthritis (n = 14), oligoarthritis (n = 58), polyarthritis (n = 50), and systemic (n = 6)], and 114 age- and sex-matched healthy controls from Latvia. DNA samples were amplified with specific primers and used for genotyping of MICA and TNFa microsatellite. Typing for a biallelic NcoI polymerase chain reaction RFLP polymorphism located at the first intron of TNFB gene was done as follows: restriction digests generated fragments of 555bp and 185bp for TNFB*1 allele, and 740bp for TNFB*2 allele. The results were compared between cases and controls. We found significant increase of MICA allele A4 (p = 0.009; odds ratio [OR] = 2.3) and allele TNFa2 (p = 0.0001; OR = 4.4) in patients compared with controls. The frequency of allele TNFa9 was significantly decreased (p = 0.0001; OR = 0.1) in patients with JIA. No significant differences of TNFB allele frequency were found. Our data suggest that MICA and TNFa microsatellite polymorphisms may be used as markers for determination of susceptibility and protection from JIA.

Combination of KIR 2DL2 and HLA-C1 (Asn80) confers susceptibility to type 1 diabetes in Latvians

Killer immunoglobulin‐like receptors (KIRs) are known to modulate natural killer (NK) and NK T‐cell function by interacting with human leucocyte antigen (HLA) class I ligands on target cells. The aim of our study was to investigate the influence of KIR2D genes with their HLA‐C ligands in susceptibility to type 1 diabetes. A total of 98 type 1 diabetes patients and 70 healthy subjects from Latvia were typed for KIR genes and HLA‐C ligands using polymerase chain reaction‐based genotyping. The HLA C1+/C2+ combination was positively, and C1–/C2+ combination was negatively, associated with type 1 diabetes. Stratification analysis of KIR/HLA‐C ligand combinations showed 2DL2+/C1+, 2DL3+/C1+, and 2DS2+ /C1+ to be positively, and 2DL2–/C1– and 2DS2–/ C1– to be negatively, associated. The presence of 2DL2‐HLA‐C1 in the absence of 2DS1, 2DS2 confers maximum susceptibility. Absence of 2DL2 and HLA‐C1 along with absence of 2DS1 and 2DS2 confer maximum protection. A hypothetical model of KIR/ligand combinations on immune responses and type 1 diabetes susceptibility is proposed. Our results suggest that a combination KIR2DL2‐ HLA‐C1 plays a critical role in susceptibility or protection in Latvians against type 1 diabetes.

Helicobacter pylori infection among children with gastrointestinal symptoms: a high prevalence of infection among patients with reflux oesophagitis

Aim: To investigate the link between H.pylori infection and dyspepsia in children, and association with reflux oesophagitis.

Microsatellite Allele 5 of MHC Class I Chain-Related Gene A Increases the Risk for Insulin-Dependent Diabetes Mellitus in Latvians

Abstract: Insulin‐dependent diabetes mellitus (IDDM) is one of the most common chronic diseases. It is an autoimmune, polygenic disease, associated with several genes on different chromosomes. The most important gene is human leukocyte antigen (HLA), also known as major histocompatibility complex (MHC), which is located on chromosome 6p21.3. HLA‐DQ8/DR4 and DQ2/DR3 are positively associated with IDDM and DQ6 is negatively associated with IDDM in most Caucasian populations. The MICA gene is located in the MHC class I region and is expressed by monocytes, keratinocytes, and endothelial cells. Sequence determination of the MICA gene identifies 5 alleles with 4, 5, 6, and 9 repetitions of GCT or 5 repetitions of GCT with 1 additional insertion (GGCT), and the alleles are referred to as A4, A5, A5.1, A6, and A9. Analysis of allele distribution among 93 Latvian IDDM patients and 108 healthy controls showed that allele A5 of MICA is significantly increased in IDDM patients [33/93 (35%)] compared to healthy controls [22/108 (20%)] (OR = 2.15; P= 0.016). In conclusion, we believe that MICA may play an important role in the etiopathogenesis of IDDM.

A relatively low prevalence of Helicobacter pylori infection in a healthy paediatric population in Riga, Latvia: a cross-sectional study

The aim of this study was to investigate the prevalence, age of acquisition and risk factors for Helicobacter pylori (H. pylori) among asymptomatic children. 13C‐urea breath tests and questionnaires were obtained from 142 children and 40 parents. The prevalence of H. pylori was 19%. H. pylori positivity was higher in children with a positive parent (p= 0.003) and independently inversely related to antibiotic treatment during the previous year in preschool children (p= 0.045).

Different KIRs Confer Susceptibility and Protection to Adults with Latent Autoimmune Diabetes in Latvian and Asian Indian Populations

KIRs (killer Ig‐like receptors) expressed on natural killer (NK) cells are an important component of innate (and adaptive) immunity. They are either activatory or inhibitory, and certain KIRs are known to interact with specific motifs of HLA Class I molecules, which is very crucial in determining whether a cell is targeted to lysis or otherwise. Latent autoimmune diabetes in adults (LADA) is a slowly progressive form of autoimmune diabetes, with an adult onset (>30 years). Because autoantibodies and autoimmunity involved are involved in the etiology of LADA, KIRs might play an important role in conferring susceptibility to or protection against the disease. The purpose of this study was to identify killer immunoglobulin‐like receptor (KIR) genes, which are associated with susceptibility to and protection against type 1 diabetes in Latvian and Asian Indian patients with LADA. KIR and HLA‐C ligand genotyping was performed using PCR‐SSP in LADA patients from Latvia (n= 45) with age‐ and sex‐matched controls (n= 92) and from India (n= 86) with controls (n= 98). Results showed that in Latvian patients with LADA, KIRs 2DL1, 2DS2, and 2DS4 were associated with susceptibility and KIR 2DS5 with protection. In Asian Indian LADA patients, KIRs 2DL5 and 3DL1 were associated with susceptibility and KIRs 2DS1 and 2DS3 with protection. Stratification analyses for KIRs that bind to HLA‐C1 and C2 were performed. We concluded that KIRs are important in conferring susceptibility (or protection) to adult patients with LADA in both our study populations. However the KIR genes (and their HLA‐C ligands) conferring susceptibility or protection in these two populations differ, showing a role of ethnicity in disease susceptibility.

Association of SUMO4 M55V polymorphism with autoimmune diabetes in Latvian patients.

Abstract:  Small ubiquitin‐related modifier (SUMO4), located in IDDM5, has been identified as a potential susceptibility gene for type 1 diabetes mellitus (T1DM). The novel polymorphism M55V, causing an amino acid change in the evolutionarily conserved met55 residue has been shown to activate the nuclear factor κB (NF‐κB), hence the suspected role of SUMO4 in the pathogenicity of T1DM. The M55V polymorphism has been shown to be associated with susceptibility to T1DM in Asians, but not in Caucasians. Latent autoimmune diabetes in adults (LADA) is a slowly progressive form of T1DM and SUMO4 M55V has not been studied in LADA to date. The current study aims to test whether Latvians are similar to Caucasians in susceptibility to autoimmune diabetes (T1DM and LADA), with respect to SUMO4 M55V. We studied, age‐ and sex‐matched, Latvian T1DM patients (n= 100) and healthy controls (n= 90) and LADA patients (n= 45) and healthy controls (n= 95). SUMO4 M55V polymorphism was analyzed using polymerase chain reaction (PCR)–restriction fragment length polymorphism (RFLP) . The allelic frequencies of the A and G alleles were compared with HLA DR3–DR4‐positive and HLA DR3‐DR4‐negative patients to identify any potential relation between HLA DR3–DR4 and SUMO4 M55V. We found no significant association between SUMO4 M55V and T1DM susceptibility in Latvians, the results being in concurrence with the previous studies in Caucasians of British and Canadian origin. Comparison of the A and G alleles with HLA DR3–DR4 did not result in any significant P values. No significant association was found between SUMO4 M55V and LADA. SUMO4 M55V is not associated with susceptibility to T1DM and LADA in Latvians, and Latvians exhibit similarity to other Caucasians with respect to association of SUMO4 M55V with autoimmune diabetes.