COVID-19 Infection Risk Following Elective Arthroplasty and Surgical Complications in COVID-19 Vaccinated Patients: A Multicenter Comparative Cohort Study

Background

We aimed to determine symptomatic Coronavirus disease 2019 (COVID-19) rates within 1 month of elective arthroplasty for vaccinated individuals and to determine whether vaccination guarantees protection against COVID-19 after arthroplasty (primary outcome). In addition, the 90-day surgical complications were compared to those of an unvaccinated group (secondary outcome).

Methods

A prospective cohort study was conducted on elective joint arthroplasty patients at 3 tertiary hospitals in 2 major cities (Tehran and Isfahan) in our country (Iran). The outcomes of the COVID-19-vaccinated group were assessed between October 2021 and March 2022. Ninety-day surgical complications were compared with a historical cohort of unvaccinated patients treated earlier in the pandemic (April 2020-March 2021).

Results

The study included 1717 consecutive patients: 962 vaccinated and 755 unvaccinated. In the vaccinated group, 38 patients (3.9%) contracted COVID-19, 4 (10.5%) were hospitalized again, and none required intensive care unit admission. The multivariate logistic regression analysis revealed that COVID-19-positive cases are more likely to be female (odds ratio [OR] = 12.5), to have visitors to their home (OR = 4.7), and to stay longer in the hospital (OR = 1.2) than COVID-19-negative cases. Compared to unvaccinated patients, the postoperative COVID-19 rate was not significantly different (3.9% vs 2.4%, P = .07). The incidence of surgical complications was similar between the 2 groups (P > .05).

Conclusions

The vaccination does not provide a guarantee that a patient will not contract COVID-19 following their arthroplasty surgery, especially in a region with a high rate of COVID-19. We believe reasonable perioperative COVID-19 precautions may be warranted even in vaccinated patients.

Comparing the Outcomes of Surgical and Non-Surgical Approaches in Management of Older Patients with Distal Radius Fracture; a Retrospective Cohort Study

INTRODUCTION

Distal radius fractures (DRFs) are the most common orthopedic injuries in emergency department. This study aimed to compare the outcomes of conservative and surgical managements of DRFs in the aged population.

METHODS

In this retrospective cohort study, ninety patients with unilateral DRFs were treated using either surgical or conservative (casting) approach and the management outcomes as well as complications were compared between the two groups at 3 and 6-month follow-ups.

RESULTS

A total of 90 patients over 70 years old were included (45 treated with cast immobilization, and 45 using the surgical method). The mean age (p = 0.56) and gender (p = 0.85) was similar in the two groups. Except for quality of life in both follow-up times, patients treated with surgical methods showed better outcomes in other aspects, including 3-month (p = 0.042) and 6-month (p = 0.022) mean Disability of the Arm Shoulder Hand (DASH) score, 3-month (p = 0.013) and 6-month (p = 0.006) mean range of motion (ROM), and 3-month (p = 0.003) and 6-month (p = 0.033) pain intensity based on Visual Analogue Scale (VAS). A total of 70 (77.77%) adverse events were registered (33 (36.6%) in the casting group and 37 (41.1%) in the surgical group; p = 0.05). The rate of mal-union (p = 0.021) and superficial radial nerve injury (p = 0.026) were significantly lower in the surgical group.

CONCLUSION

The findings suggest that surgical approach for management of DRFs in elder cases has better clinical and functional outcomes than cast immobilization.

Antioxidants and their role in the prevention and treatment of chronic kidney disease (CKD), perspective of complementary nursing and medicine: a review

BACKGROUND

Chronic kidney disease (CKD) is a progressive and irreversible disease that leads to end-stage renal disease. Many factors such as increased oxidative stress play a role in the occurrence of this complication. Due to the effective role of the antioxidant defense system in controlling many of the complications in which oxidative stress is involved, the present study was conducted to evaluate the role of antioxidants in the prevention and treatment of chronic kidney disease.

METHODS

In this review study, studies using standard keywords in internal and external databases including: SID, Magiran, IranDoc, Medlib, Science Direct, PubMed, Scopus, Embase, Web of Science, Medline and Google Scholar search engine, were retrieved and selected without time limit.

RESULTS

Among the selected articles, 14 articles were eligible for inclusion in the study, which was performed on more than 20,000 people and several animal models of rats from 2005 onwards. The results showed that there is an inverse relationship between the concentration of antioxidant enzymes in the body and the intensity and progression of CKD. In severe cases, a significant decrease in the concentration of antioxidant enzymes in the body, as well as cofactors such as selenium, iron and zinc in the progressive and severe course of CKD has been observed.

CONCLUSIONS

The positive and significant effect of antioxidant compounds in chronic kidney disease is evident. The use of these compounds in the diet in the form of fruits, vegetables and grains, as well as the supply of iron and zinc and other minerals elements as cofactors for the action of enzymatic antioxidants has an effective role in the prevention and treatment of diseases by controlling free radicals.

High risk of drug toxicity in social isolation stress due to liver dysfunction: Role of oxidative stress and inflammation

BACKGROUND

Previous studies have shown that social isolation stress (SIS) could associate with several systemic diseases; however, the role of SIS on liver dysfunction has yet to be established. This study aimed to investigate the effect of SIS on liver function and possible drug toxicity through liver inflammation and oxidative stress.

METHODS

Male Naval Medical Research Institute mice in two groups of SIS and control were treated with typical anti-depressant and anxiolytic agents including fluoxetine, norfluoxetine, desipramine, and imipramine in both groups. Then blood concentrations (or their active metabolites) of these drugs were assessed. Liver function test, including aspartate transaminase (AST), alanine aminotransferase (ALT), total bilirubin, and conjugated bilirubin), oxidative activity, inflammatory cytokines, and the gene expression of cytochrome P450 enzymes were assessed.

RESULTS

We observed that the liver enzymes including AST and ALT was slightly higher in SIS animals. The blood concentrations of fluoxetine, norfluoxetine, desipramine, and imipramine were significantly higher in SIS animals. The gene expression of CYP1A2, CYP2A6, CYP2C9, CYP2C29, and CYP2D were significantly decreased in SIS animals. Our results showed that SIS animals had significantly higher level of tumor necrosis factor-α, interleukin-1β, and interleukin-6. SIS could significantly decrease the activity of antioxidant agent (Glutathione).

CONCLUSION

We hypothesized that SIS could induce liver dysfunction and decrease the rate of drug clearance through liver inflammation and oxidative stress; therefore, the blood concentration of anti-depressant/anxiolytic agents should closely monitor in SIS due to the high toxicity of these agents.

Ivermectin-functionalized multiwall carbon nanotube enhanced the locomotor activity and neuropathic pain by modulating M1/M2 macrophage and decrease oxidative stress in rat model of spinal cord injury

Since the inflammation and oxidative stress is the main pathophysiological pathway of neural damage in spinal cord injury (SCI), we tried to evaluate the role of ivermectin (IVM) combined with multi-walled carbon nanotube (MWCNT) in the treatment settings of SCI and its underlying mechanism. Wistar rats with T9 vertebra laminectomy in five groups of: sham-operated, vehicle, IVM (0.1 mg/kg), IVM-MWCNT (0.1 mg/kg), and minocycline (90 mg/kg) were used. We evaluated the locomotor scaling and other behavioral tests for neuropathic pain. Also, tissue samples were obtained to evaluate the expression of M1 and M2 macrophage marker, concentration of TNF-α, IL-1β, and IL-1, and oxidative stress level to assess neuroinflammatory changes. Both IVM and IVM-MWCNT after induction of SCI significantly enhanced the experimental tasks’ outcomes, including locomotion and neuropathic tests. Also, decreasing in pro-inflammatory cytokines including TNF-α, IL-1β, and IL-1 in the spinal cord and dorsal root ganglion tissues was also notable in both IVM and IVM-MWCNT-treated groups 28 days after induction of SCI in compared to the vehicle-treated SCI group. Both IVM and IVM-MWCNT significantly decreased oxidative stress, induced by SCI, based on the results of ROS and NADPH activity. IVM-MWCNT-treated animals indicated better outcome in every previous experiment in comparison to IVM-treated animals. The effectiveness of IVM-MWCNT was similar to minocycline treatment in all experimental task (as positive control group). IVM-MWCNT might be a novel treatment in spinal cord injury, which could act through decreasing the oxidative stress and increase the polarization of M1 in comparison to M2 macrophages.

microRNA expression signatures of gastrointestinal stromal tumours: associations with imatinib resistance and patient outcome

BACKGROUND

Gastrointestinal stromal tumour (GIST) is mainly initialised by receptor tyrosine kinase gene mutations. Although the tyrosine kinase inhibitor imatinib mesylate considerably improved the outcome of patients, imatinib resistance still remains a major therapeutic challenge in GIST therapy. Herein we evaluated the clinical impact of microRNAs in imatinib-treated GISTs.

METHODS

The expression levels of microRNAs were quantified using microarray and RT-qPCR in GIST specimens from patients treated with neoadjuvant imatinib. The functional roles of miR-125a-5p and PTPN18 were evaluated in GIST cells. PTPN18 expression was quantified by western blotting in GIST samples.

RESULTS

We showed that overexpression levels of miR-125a-5p and miR-107 were associated with imatinib resistance in GIST specimens. Functionally, miR-125a-5p expression modulated imatinib sensitivity in GIST882 cells with a homozygous KIT mutation but not in GIST48 cells with double KIT mutations. Overexpression of miR-125a-5p suppressed PTPN18 expression, and silencing of PTPN18 expression increased cell viability in GIST882 cells upon imatinib treatment. PTPN18 protein levels were significantly lower in the imatinib-resistant GISTs and inversely correlated with miR-125a-5p. Furthermore, several microRNAs were significantly associated with metastasis, KIT mutational status and survival.

CONCLUSIONS

Our findings highlight a novel functional role of miR-125a-5p on imatinib response through PTPN18 regulation in GIST.

MICA gene polymorphism in the pathogenesis of type 1 diabetes

Type 1 diabetes mellitus (T1DM) is a typical autoimmune disease and results from the destruction of insulin-producing beta cells of the pancreas. It develops in the presence of genetic susceptibility, even though more than 85% of patients with T1DM do not have a close relative with the disorder. The etiology of T1DM is complex, and both genetic and environmental factors play important roles. A permissive genetic background is required for the development of the islet autoimmune process. The strongest genetic association idengified is that with HLA class II genes located on the short arm of chromosome 6. It is well known that both HLA DRB1*04-DQA1*0301-DQB1*0302 (DR4-DQ8) and DRB1*03-DQA1*0501-DQB1*0201 (DR3-DQ2) are positively, and DRB1*15-DQA1*0102-DQB1*0602 is negatively, associated with T1DM. However, only a minority of the subjects carrying the high-risk haplotypes/genotypes develops the disease, which suggests that additional genes play a crucial role in conferring either protection or susceptibility to T1DM. Major histocompatibility complex (MHC) class I chain-related A (MICA) is located in a candidate susceptibility region and activates natural killer (NK) cells, T cells and gammadelta CD8 T cells by its receptor NKG2D. The polymorphism of the MICA gene is associated with T1DM in different populations as demonstrated in several papers published in the last 7 years.

Contribution of MHC class I chain-related A (MICA) gene polymorphism to genetic susceptibility for systemic lupus erythematosus

OBJECTIVE

To evaluate the contribution of the MHC class I chain-related A (MICA) gene polymorphism to the genetic risk of systemic lupus erythematosus (SLE).

METHODS

HLA-DRB1-DQA1-DQB1 genotyping, MICA exon 5 microsatellite genotyping and HLA-B8 genotyping were performed in 48 Italian SLE patients and in 158 healthy control subjects.

RESULTS

Of HLA class II haplotypes, only DRB1*03-DQA1*0501-DQB1*0201 (DR3-DQ2) was significantly more frequent among SLE patients than among healthy control subjects [odds ratio (OR) = 6.5, corrected P < 0.0026]. HLA-B8 was detected in 31% SLE patients and 13% healthy control subjects (OR = 3.0, P = 0.005). The allele-wise comparison between patients and controls showed that both MICA5 (OR = 2.5, corrected P < 0.0005) and MICA5.1 (OR = 2.4, corrected P < 0.0005) were positively and MICA9 (OR = 0.2, corrected P < 0.0005) was negatively associated with the disease. The MICA5/5.1 genotype was positively associated with SLE (OR = 28.9, corrected P < 0.0015) also in subjects negative for DR3-DQ2 (OR > 22.6, corrected P < 0.011). The simultaneous presence of DR3-DQ2 and MICA5.1 was detected in 15/48 (31%) SLE and in 10/158 (6%) healthy control subjects (OR = 6.7, corrected P < 0.011). The simultaneous combination of DR3-DQ2 and MICA5 was found in 10/48 (21%) SLE patients and in only 1/158 healthy control subjects (OR = 41.3, corrected P < 0.011). Logistic regression analysis showed the independent positive associations of MICA5 and MICA5.1 and negative association of MICA9 with the disease, and revealed that the interaction of the three major markers (DR3-DQ2, MICA5 and MICA5.1) was associated with increasing genetic risk, which was highest (OR > 30.3) in DR3-DQ2-positive subjects carrying the MICA5-5.1 genotype.

CONCLUSIONS

Our study provides the first demonstration of the independent association of the MICA gene polymorphism with genetic risk of SLE.

Lack of association of human chemokine receptor gene polymorphisms CCR2-64I and CCR5-Delta32 with autoimmune Addison's disease

The attraction of leukocytes to tissues is essential for inflammation and the initiation of the autoimmune reaction. The process is controlled by chemokines, which are chemotactic cytokines. We investigated whether human chemokine receptor gene polymorphisms, namely CCR5-Delta32 and CCR2-64I, are associated with susceptibility to autoimmune Addison's disease. Genotyping was performed in 56 patients and 127 healthy controls by a new method using pyrosequencing for CCR2-64I and by polymerase chain reaction and detecting gel for CCR5-Delta32. None of the CCR2 or CCR5 alleles was found to be associated, either positively or negatively, with disease risk. Our results indicate that the CCR2-64I and CCR5-Delta32 gene polymorphisms do not play a major role in conferring genetic risk for, and/or protection against, autoimmune Addison's disease.

MHC class I chain-related gene alleles 5 and 5.1 are transmitted more frequently to type 1 diabetes offspring in HBDI families

Type 1 diabetes mellitus (T1DM) is an autoimmune disease characterized by autoimmune destruction of pancreatic beta cells. Genetic and environmental factors contribute in this disease. There is evidence that MHC class I chain-related gene (MIC-A) plays a role in the susceptibility to this and other autoimmune diseases. There are five alleles of the MIC-A gene, which consist of different repetitions of GCT. In particular, MIC-A alleles 5 and 5.1 (the former with five repetitions of GCT, the latter with five repetitions and one additional insertion of nucleotide G) have been found to be associated with susceptibility to and age at onset of T1DM. The aim of our study was to analyze the transmission of these MIC-A alleles to T1DM-affected offsprings in HBDI families. These are multiplex families with affected offsprings and unaffected parents. DNA samples were amplified for MIC-A using fluorescence-labeled primers and analyzed on an ABI prism DNA sequencer. The transmission of alleles was then analyzed using pedigrees of families also obtained from HBDI. We analyzed 78 families and found that MIC-A alleles 5 and 5.1 are present and transmitted more frequently than expected. Heterozygotic parents for MIC-A alleles 5 and 5.1 were excluded from the study. Our results suggest that MIC-A alleles 5 and 5.1 are associated with susceptibility to T1DM in family studies.

MHC class I chain-related gene a alleles distinguish malnutrition-modulated diabetes, insulin-dependent diabetes, and non-insulin- dependent diabetes mellitus patients from eastern India

Insulin-dependent diabetes mellitus (IDDM) is a polygenic disorder with an autoimmune basis for disease development. In addition to HLA, a second susceptibility locus for IDDM has been identified to lie in the major histocompatibility class III region. MIC-A is located in the MHC class III region and is expressed by monocytes, keratinocytes, and endothelial cells. Sequence determination of the MIC-A gene identifies trinucleotide repeat (GCT) microsatellite polymorphism in exon 5. Five alleles with 4, 5, 6, and 9 repetitions of GCT or 5 repetitions of GCT with 1 additional nucleotide insertion (GGCT) are identified. The alleles are A4, A5, A5.1, A6, and A9. The aim of our study was to find the association of MIC-A alleles with IDDM, malnutrition-modulated diabetes mellitus (MMDM), and non-insulin-dependent diabetes mellitus (NIDDM) patients. IDDM (n = 52), MMDM (n = 41), NIDDM (n = 212), and healthy controls (n = 73) from Cuttack, in eastern India, were studied. Of the 212 NIDDM patients analyzed, 96 of them were found to be positive for either GAD65 or IA-2 antibodies. Autoantibodies to GAD65 and IA-2 were measured by radioligand binding assay using (35)S-labeled recombinant human GAD65 and IA-2 in an in vitro transcription/translation system. Autoantibody-positive NIDDM patients (n = 96) and adult healthy controls for NIDDM (n = 113) were also compared. These autoantibody-positive NIDDM patients are considered as slow-onset IDDM or latent autoimmune diabetes in adults (LADA) patients. The samples were analyzed for MIC-A by PCR amplification, and fragment sizes were determined in an ABI prism DNA sequencer. The results of the MIC-A typing are: allele 9 of MIC-A is positively associated (OR 3.62; P < 0.001), and allele 4 is negatively associated (OR 0.31; P < 0.05) with MMDM patients compared to controls. Allele 5 is positively associated with IDDM (OR 2.64; P < 0.05) when compared to controls. Allele 5.1 is positively associated in the autoantibody-positive NIDDM patients compared to adult controls. Our findings of a significant increase of allele A9 in MMDM patients compared to healthy controls suggest that MMDM is immunogenetically different from IDDM in eastern India. MIC-A is important in the pathogenesis of MMDM patients from Cuttack. MIC-A alleles distinguish acute-onset IDDM from slow-onset IDDM, indicating that this molecule may be important for delaying the onset of IDDM with the result that these patients are diagnosed clinically as NIDDM.

Microsatellite allele 5 of MHC class I chain-related gene a increases the risk for insulin-dependent diabetes mellitus in latvians

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.

Tumor necrosis factor A and MHC class I chain related gene A (MIC-A) polymorphisms in Swedish patients with cervical cancer

Human papillomaviruses type 16 and 18 are the major cause of cervical cancer. However, genetic factors contribute to the propensity of persistent HPV infection and cervical carcinoma. Allelic variants of the human leukocyte genes have shown to be associated with cervical neoplasia. The strongest associations have been found with the genes in the HLA class II region. The aim of this study was to analyze the association of two non-HLA class II markers with invasive cervical cancer. Microsatellite polymorphism of the TNFA gene located in the class III region and a short tandem repeat polymorphism of the MICA gene located in the centromeric end of the HLA class I region were analyzed. Eighty-five patients and 120 matched control individuals from a population-based cohort from Northern Sweden participated in this nested case-control study. MICA was not associated with cervical carcinoma. TNFa-11 frequency was increased in the HPV18 DNA positive patients (OR = 2.84, p = 0.0481, CI = 1.04-7.78, pc = NS). TNFa-11 was not associated with susceptibility to HPV16 infection, but it increased the risk for cervical cancer with the HLA DQ6 (DQA 1*0102-DQB 1*0602) haplotype. Our findings indicate that the association of TNFA with cervical cancer is different with CIN. The extended HLA DQ6-TNFa-11 haplotype is increasing the risk for development of cervical cancer significantly (OR = 3.08, p = 0.0104, CI = 1.30-7.31).

Two distinct MICA gene markers discriminate major autoimmune diabetes types

The polymorphism of the major histocompatibility complex class I chain-related A gene is associated with type 1 diabetes mellitus. The major histocompatibility complex class I chain-related A gene 5 allele is significantly more frequent in Caucasian type 1 diabetes mellitus children than in healthy subjects, but no information is available on the association with adult-onset type 1 diabetes mellitus or with the so-called slowly progressive latent autoimmune diabetes of the adult in the same ethnic group. In this study we estimated the frequency of major histocompatibility complex class I chain- related A gene alleles and human leukocyte antigen-DRB1*03-DQA1*0501-DQB1*0201 and human leukocyte antigen-DRB1*04- DQA1*0301-DQB1*0302 in 195 type 1 diabetes mellitus subjects, in 80 latent autoimmune diabetes of the adult subjects, and in 158 healthy subjects from central Italy. Major histocompatibility complex class I chain-related A gene 5 was significantly associated with type 1 diabetes mellitus only in the 1-25 yr age group at diagnosis, and the odds ratio of the simultaneous presence of both major histocompatibility complex class I chain-related A gene 5 and human leukocyte antigen-DRB1*03- DQA1*0501-DQB1*0201 and/or human leukocyte antigen-DRB1*04-DQA1*0301-DQB1*0302 was as high as 54 and higher than 388 when compared with double negative individuals. Adult-onset type 1 diabetes mellitus (age at diagnosis, >25 yr) and latent autoimmune diabetes of the adult were significantly associated with major histocompatibility complex class I chain-related A gene 5.1, which was not significantly increased among diabetic children. Only the combination of major histocompatibility complex class I chain-related A gene 5.1 and human leukocyte antigen-DRB1*03-DQA1*0501-DQB1*0201 and/or human leukocyte antigen-DRB1*04-DQA1*0301-DQB1*0302 conferred increased risk for adult-onset type 1 diabetes mellitus or for latent autoimmune diabetes of the adult. Our study provides demonstration of the existence of distinct genetic markers for childhood/young-onset type 1 diabetes mellitus and for adult-onset type 1 diabetes mellitus/latent autoimmune diabetes of the adult, namely major histocompatibility complex class I chain-related A gene 5 and major histocompatibility complex class I chain-related A gene 5.1, respectively.

Tumor necrosis factor a-11 and DR15-DQ6 (B*0602) haplotype increase the risk for cervical intraepithelial neoplasia in human papillomavirus 16 seropositive women in Northern Sweden

HLA genes have been shown to be associated with cervical intraepithelial neoplasia (CIN), a precursor of cervical cancer. The human papillomaviruses (HPV) types 16 and 18 are the major environmental cause of this disease. Because the immune system plays an important role in the control of HPV infection, the association of polymorphic HLA could lead to a different immune response to control the development of cervical cancer. The aim of this study was to analyze the association between CIN and a microsatellite polymorphism of tumor necrosis factor (TNFa) taking HPV exposure and CIN-associated HLA haplotypes into account. In a nested case-control study in northern Sweden, 64 patients and 147 controls matched for age and sex and derived from the same population-based cohort were typed for TNFA, HLA-DR, and DQ and assayed for antibodies to HPV types 16 and 18. TNFa polymorphism was not associated with CIN per se. However, there was a significant increase in the frequency of TNFa-11 among HPV16-positive and HLA DR15-DQ6 (B*0602) patients compared with HPV16- and HLA-DQ6-negative patients (odds ratios, 5.4 and 9.3, respectively). The relative risk for CIN conferred by the combination of TNFa-11, HLA-DQ6, and HPV 16 positivity was 15. Our study suggests that the TNFa-11 allele is associated with HPV16 infection and associated with CIN in combination with HLA-DQ6 but not by itself.

Association of MHC Class I chain-related A (MIC-A) gene polymorphism with Type I diabetes

AIMS/HYPOTHESIS

A distinct family of MHC genes has been identified in the class III region and denominated MHC Class I chain-related genes (MIC). The MIC-A gene is located between the TNFA and the HLA-B genes. The aim of our study was to test the association of the polymorphism of the MIC-A gene with Type I (insulin-dependent) diabetes mellitus and evaluate the interaction between MIC-A and TNFA, HLA-B, HLA-DR and HLA-DQ gene polymorphism.

METHODS

Type I diabetic (n =95) and healthy (n = 98) Italian subjects were typed for exon 5 of MIC-A and for HLA-DRB1, HLA-DQA1, HLA-DQB1 and TNFA alleles. All subjects were also typed for the presence of HLA-B8 or HLA-B15.

RESULTS

The frequency of MIC-A5 was increased in diabetic subjects (53 % vs 15 %) (OR = 6.1) (corrected p, p(c) < 0.0005). Among HLA class II haplotypes, both HLA-DRB1*03-DQA1*0501-DQB1*0201 (DR3-DQ2) and DRB1*04-DQA1*0301-DQB1*0302 (DR4-DQ8) ("at-risk class II haplotypes") were positively associated with diabetes (OR = 6.7 and 6.0, respectively) (p(c) < 0.003). Also HLA-B8 was more frequent among Type I diabetic subjects than among healthy control subjects (OR = 2.8, p = 0.01). None of the TNFA alleles were statistically significantly associated with Type I diabetes. The MIC-A5 exon was negatively associated with age at clinical onset of diabetes (p = 0.012). Thus, 68 % diabetic subjects younger than 25 years and 29 % older than 25 years were carrying this allele. Both MIC-A5 and the at-risk class II haplotypes were independently associated with Type I diabetes and the combined association of the two markers had the highest relative risk (OR = 172). In subjects younger than 25 years, the OR of MIC-A5 was as high as 21.7 and was more than twofold that of at-risk class II haplotypes (OR = 9.5). The MIC-A5 exon was not in linkage disequilibrium with any of the HLA-class I, class II or TNFA alleles studied.

CONCLUSIONS/INTERPRETATION

The MIC-A gene polymorphism is associated with genetic risk for Type I diabetes and the combination of MIC-A5 and at-risk class II haplotypes is now to be seen as the strongest genetic marker for this disease.

MICA gene polymorphism and the risk to develop cervical intraepithelial neoplasia

Cervical intraepithelial neoplasia (CIN) is associated with human papillomaviruses (HPV) and the HLA genes. The MICA (MHC class I chain-related gene A) is expressed by keratinocytes and epithelial cells and interacts with gamma delta T cells. It is therefore possible that MICA might influence the pathogenesis of CIN and cervical cancer through presentation of viral or tumor antigens. To investigate this, we determined the MICA transmembrane allele frequencies in a prospective population-based cohort study from the Västerbotten County in northern Sweden. 74 women developed CIN. 153 control women who remained healthy during follow up were matched for age. Five polymorphic microsatellite alleles of MICA were identified by a polymerase chain reaction-based (PCR) technique using fluorescent-labeled primers. MICA A5 and A5.1 were the most common alleles in this population. None of the alleles of MICA were associated with disease. The frequency of MICA allele A5 was higher among HPV 18 seropositive than HPV 18 seronegative patients but this difference was not significant after the correction of p value. In conclusion, microsatellite allele polymorphism of MICA transmembrane part is not associated with cervical intraepithelial neoplasia.

Microsatellite polymorphism of the MHC class I chain-related (MIC-A and MIC-B) genes marks the risk for autoimmune Addison's disease

The major histocompatibility complex class I chain-related MIC-A and MIC-B genes are located on chromosome 6 between the histocompatibility leucocyte antigen (HLA)-B and the B-associated transcript genes. The presence of 21-hydroxylase autoantibodies is a sensitive and specific marker of autoimmune Addison's disease. We studied the polymorphism of exon 5 of the MIC-A gene, of intron 1 of the MIC-B gene, and of HLA-DRB1, -DQA1, and -DQB1 genes in 28 autoimmune (21-hydroxylase autoantibody positive) Addison's disease patients and in 75 healthy subjects from central Italy. The MIC-A5.1 allele was significantly more frequent in Addison's disease patients (79%) than in healthy subjects (36%) [odds ratio (OR) = 6.52, corrected P (Pc) = 0.0015], whereas MIC-A6 was significantly reduced in affected subjects (15% vs. 56%, OR = 0.13, Pc = 0.002). The A5.1/A5.1 genotype had an OR for autoimmune Addison's disease as high as 18.0 and an absolute risk of 1 per 1131. In the presence of MIC-A5.1, MICB-CA-25 was significantly increased in Addison's disease patients (25% vs. 4%, OR = 8.0, P = 0.0039, Pc = 0.047). The MICB-CA-17 allele was absent in Addison's disease patients, but present in more than 25% healthy individuals (OR = 0.10, P = 0.0025, Pc = 0.03). Among HLA-DR and -DQ haplotypes, only DRB1*03-DQA1*0501-DQB1*0201 (DR3/DQ2) was significantly more frequent in Addison's disease patients than in healthy subjects, but only in the presence of MIC-A5.1. The frequency of MIC-A5.1 was significantly increased in Addison's disease patients only in the presence of HLA-DR3-DQ2. Our study demonstrates that susceptibility to autoimmune Addison's disease is linked to the MIC-A microsatellite allele 5.1 and that both MIC-A5.1 and HLA-DR3/DQ2 are necessary to confer increased genetic risk for Addison's disease.