Risk of Toxicity From Topical 5-Fluorouracil Treatment in Patients Carrying DPYD Variant Alleles

Patients carrying DPYD variant alleles have increased risk of severe toxicity from systemic fluoropyrimidine chemotherapy. There is a paucity of data regarding risk of toxicity from topical 5-fluorouracil (5-FU) treatment in these patients, leading to inconsistent guideline recommendations for pretreatment testing and topical 5-FU dosing. The objective of this retrospective cohort study was to investigate whether DPYD variant allele carriers have increased risk of toxicity from topical 5-FU. Treatment and toxicity data were retrospectively abstracted from the electronic medical records. Genotypes for the five DPYD variants that are associated with increased toxicity from systemic fluoropyrimidine chemotherapy (DPYD*2A, DPYD*13, DPYD p.D949V, DPYD HapB3, and DPYD p.Y186C) were collected from a genetic data repository. Incidence of grade 3+ (primary end point) and 1+ (secondary end point) toxicity was compared between DPYD variant carriers vs. wild-type patients using Fisher's exact tests. The analysis included 201 patients, 7% (14/201) of whom carried a single DPYD variant allele. No patients carried two variant alleles or experienced grade 3+ toxicity. DPYD variant allele carriers did not have a significantly higher risk of grade 1+ toxicity (21.4% vs. 10.2%, odds ratio = 2.40, 95% confidence interval: 0.10-2.53, P = 0.19). Given the low toxicity risk in patients carrying a single DPYD variant allele, there is limited potential clinical benefit of DPYD genetic testing prior to topical 5-FU. However, the risk of severe toxicity in patients with complete DPD deficiency remains unknown and topical 5-FU treatment should be avoided in these patients.

Cytokines and growth factors in a biologic product obtained from patients' urine as immune-modulators to treat autoimmune and allergic diseases

At "Instituto de Alergias y Autoinmunidad Dr. Maximiliano Ruiz Castañeda, A.C." in Mexico City, a non-traditional health care center focused on the treatment of autoimmune and allergic diseases using personalized medicine, an alternative treatment referred to as an "immune-modulator" has been developed. In this study, we will refer to this treatment substance as the "immune-modulator." In brief, a urine sample is collected from the patient and processed to obtain the peptide fraction, which is conditioned and then administered sublingually to the patient. Sample processing involves multiple steps aimed at the removal of toxic compounds and enrichment for cytokines, growth factors, and other immune peptides that may contribute to the function of the immune-modulator. This treatment has been administered for many years, and patients testify that it is useful and reliable. Despite the benefits of this treatment, the molecular mechanisms underlying its effects have not been thoroughly investigated. Therefore, this study aims to identify immunoregulatory peptides, such as cytokines and growth factors, in the immune-modulator. Urine and immune-modulator concentrations of cytokines and growth factors were assessed using a Luminex assay. Twenty-one cytokines and growth factors were identified in immune-modulator samples. MCP-1 was identified in 100% of the samples; MIP-1β, IL-8, RANTES, INF-γ, and IP-10 were identified in approximately 65-70% of samples; IL5, IL-1B, and IL-17 in 50-60%; eotaxin, VEGF, IL-6, and FGF in about 40%; MIP-1α, IL-9, GM-CSF, G-CSF, IL-12, and IL-15 in about 20-30%; and IL-13 and PDGF-bb were identified in <6% of samples. Additionally, patients exhibited significant changes in IL-1β, IFN-γ, and MCP-1 concentrations after treatment with the immune-modulator, whereas healthy individuals showed no significant change in response to the treatment. The immune-modulator is an alternative treatment based on the administration of cytokines and growth factors obtained from the urine of patients. In this study, its composition was characterized. The isolated products could be responsible for the effects of the immune-modulator. Further trials are required to evaluate the effective delivery of these molecules by the administration route described.

Comparison of the Effects of Endotracheal Intubation of Wistar Rats Using the Conventional Technique vs. a New Modified Technique Using a 3D Mouth-Piece

AIMS

Endotracheal intubation in rats is challenging due to the difficult anatomical characteristics of the airway. The success rate at first attempt is low and airway damage is a common complication. We aimed to compare and evaluate the conventional intubation method with a modified procedure using an inclined plate, headlamp (700-Lumen), and 3D mouth-piece designed with a 20° curvature. Both techniques were conducted by laboratory personnel with and without previous experience in airway management of laboratory rats.

MATERIAL AND METHODS

In this study, we used 36 Wistar rats of both genders. Three groups of laboratory personnel (anesthesiologists, medical students, and laboratory technicians) performed both endotracheal intubation techniques, i.e., blind intubation at supine position and endotracheal intubation at 70° supine position with a 3D mouth-piece and direct illumination of the glottis.

RESULTS

The modified technique had a significantly higher success rate and shorter procedure duration. Moreover, there was no significant difference in the procedure duration between personnel with and without previous training in airway management.

CONCLUSION

Previous knowledge and experience in airway management are required when performing conventional endotracheal intubation; moreover, its success rate is low. Contrastingly, using proper instruments and the 3D mouth-piece facilitated easier and quicker airway management regardless of previous experience.

Effect and associated factors of a clinical pharmacy model in the incidence of medication errors (EACPharModel) in the Hospital Pablo Tobón Uribe: study protocol for a stepped wedge randomized controlled trial (NCT03338725)

BACKGROUND

According to WHO, medication error (ME) is a subject that requires attention at all levels of care to reduce severe and preventable damage related to medication use. Clinical pharmacy practice standards have been proposed around the world so that the pharmacist, as part of a multidisciplinary health team, can help improve patient safety; however, further evidence derived from adequate studies is needed to demonstrate this. This study aims to assess the effect of a clinical pharmacy practice model (CPPM) in preventing MEs associated with the medication use process.

METHODS

A prospective, stepped-wedge, cluster-randomized, controlled trial with a duration of 14 months will be performed to compare the effect of a CPPM along with the usual care process of patients in the Pablo Tobón Uribe Hospital (Medellin, Colombia). The study is designed as a cluster-randomized controlled trial, involving five hospital wards (clusters) and 720 patients. Medical wards are allocated to interventions using a stepped-wedge design. Clusters are initially assigned to the control group. After a 2-month observation period, hospital clusters were randomly allocated to the intervention group. Study outcomes will be assessed at baseline and at 2, 4, 6, 8, 10, and 12 months after randomization. The primary outcome will be to assess the effect of a CPPM on the incidence of medication errors associated with the medication use process. Drug-related problems and factors that contribute to the occurrence of MEs will be assessed as secondary outcomes. Statistical analyses will be performed using a mixed model, with the treatment group and time as fixed effects and the clustering structure as a random effect. Statistical analysis will be performed using Pearson chi-square tests and Student's t-tests, and a P value < 0.05 will be considered statistically significant.

DISCUSSION

As far as we know, this is the first stepped-wedge, cluster-randomized, controlled trial designed to assess the change of a CPPM on the incidence of medication errors in a hospital in Colombia, and it could generate valuable information about a standardized and patient-centered clinical pharmacy model to improve the safety of inpatient care.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03338725. Registered on 9 November 2017. The first patient was randomized on 2 February 2018.

PROTOCOL VERSION

0010112018JG.

The Relationship between strength and academic performance: A new reason to promote physical activity

Background

Experimental studies have determined that higher strength values are associated with more efficient cognitive function and better academic performance. In spite of this, the universities in Colombia are decreasing the time available for physical activity in favour of increasing the time devoted to theoretical subjects. This is one of the reasons why in Colombia, only 18% of young people complied with the world recommendations of physical activity. To examine this problem, the objective of this research was to establish the relationship between strength and academic performance in university students.

Methods

A cross-sectional study was developed in 135 (21.8 ± 4.5 yr; 78.69 ± 9.1kg) students of the fifth semester of the Areandina University in Bogota, Colombia. Each participant developed incremental protocols to determine the maximum weight that he or she could move in six different exercises: squat in smith machine, leg press, leg extension, bench press, pull down and military press. The average of the results of these tests was taken as the value of maximum strength. To determine academic performance, the average of the scores accumulated in the five semesters of their university studies was evaluated. Pearson correlation coefficient was used to find the linear relationship between strength and academic performance.

Results

Overall, 70.3 % of the participants were men and 29.7% were women. The results of the maximum strength tests were significantly higher in the male group than in the female group (P &lt; 0.05). Academic performance was similar in both genders (P &gt; 0.05). A positive correlation was established between maximum strength and academic performance. (r = 0.64 P &lt; 0.05).

Conclusions

The conclusion of this research was that there is a significant relationship between strength and academic performance. These results are fundamental to justify the inclusion of spaces for the promotion of physical activity in public and private universities.

Key messages

Universities are institutions that only focus on academic training and generate contexts in which sedentary behaviours are promoted. Sedentary lifestyles are a public health problem in Colombia.

Susceptibility background for type 2 diabetes in eleven Mexican Indigenous populations: HNF4A gene analysis

The genetic risk of developing type 2 diabetes (T2D) increases in parallel with the proportion of Native American ancestry. Mestizo Mexicans have a 70% Native Amerindian genetic background. The T130I polymorphism in the HNF4A gene has been associated with early-onset T2D in mestizo Mexicans. Thus, the aim of the present study was to evaluate the frequency and relationship of the T130I variant in the HNF4A gene with risk factors for developing T2D in eleven indigenous groups from Mexico. In two groups, all exons of the HNF4A gene were directly sequenced; in the remaining the T130I polymorphism was analyzed by restriction fragment length polymorphism. Ancestry informative markers were assessed to confirm the Amerindian component. An additional analysis of EHH was carried out. Interestingly, HNF4A gene screening revealed only the presence of the T130I polymorphism. The range frequency of the risk allele (T) in the indigenous groups was from 2.7 to 16%. Genotypic frequencies (T130I/I130I) were higher and significantly different from those of all of the populations included in the HapMap Project (P < 0.005). EHH scores suggest a positive selection for T130I polymorphism. Metabolic traits indicate a relationship between the T130I/I130I genotypes with high triglyceride concentrations in the indigenous groups (P < 0.005). These results strongly suggest that the high frequency of the T130I polymorphism and its biological relationship with dysfunction in lipid metabolism in Mexican indigenous groups is a risk factor for the developing of T2D in Mexicans.

Expression of interleukin (IL)-19 and IL-24 in inflammatory bowel disease patients: a cross-sectional study

Interleukin (IL)-19 and IL-24 belong to the IL-20 subfamily, and are involved in host defence against bacteria and fungi, tissue remodelling and wound healing. Nevertheless, no previous studies have explored their expression in Mexican mestizo patients with inflammatory bowel disease (IBD). The aim of the study was to characterize and to enumerate peripheral and tissue IL-19- and IL-24-producing cells, as well as gene expression in patients with IBD with regard to its clinical activity. We studied a total of 77 patients with ulcerative colitis (UC), 36 Crohn's disease (CD) and 33 patients as control group (without endoscopic evidence of intestinal inflammation). Gene expression was measured by real-time-polymerase chain reaction (RT-PCR). Protein expression was detected in biopsies by immunohistochemistry and in freshly isolated peripheral blood mononuclear cells by flow cytometry. IL-19 and IL-24 gene expression was elevated significantly in patients with active IBD versus the inactive disease and non-inflammatory control groups (P < 0·05). However, IL-19- and IL-24-producing cells were only increased in active CD versus active UC and non-inflammatory tissues (P < 0·05). IL-19 was produced conspicuously by circulating B cells and monocytes in patients with inactive disease (P < 0·05). Conversely, IL-24 was noticeably synthesized by peripheral B cells, CD4(+) T cells, CD8(+) T cells and monocytes in patients with active disease. In conclusion, IL-19- and IL-24-producing cells in active CD patients were increased compared with active UC and non-inflammatory tissues. These cytokines could significantly shape and differentiate inflammatory process, severity and tolerance loss between UC and CD pathophysiology.

Analysis of genetic polymorphism of the HLA-B and HLA-DR loci in patients with dermatophytic onychomycosis and in their first-degree relatives

Onychomycosis is known to have predisposing factors and a high prevalence within families that cannot be explained by within-family transmission. We determined the frequency of HLA-B and HLA-DR haplotypes in 25 families of Mexican patients with onychomycosis in order to define the role of the class II major histocompatibility complex (MHC) in genetic susceptibility to this infection. Seventy-eight subjects participated in the study, 47 with onychomycosis and 31 healthy individuals. The frequencies of the HLA-B and HLA-DR haplotypes were compared with those found in first-degree relatives without onychomycosis and in a historic control group of healthy individuals. The frequencies in the controls were similar to those of the healthy relatives of the patients. However, on comparison of the patients with historic controls, we detected a higher frequency of the HLA-DR8 haplotype (P=.03; odds ratio, 1.89; 95% confidence interval, 0.98-36). These findings suggest that there are polymorphisms in genes of the MHC that increase susceptibility to onychomycosis, particularly haplotype HLA-DR8.

HLA Genes in Mayos Population from Northeast Mexico

HLA class I and class II alleles have been studied in 60 unrelated people belonging to Mayos ethnic group, which lives in the Mexican Pacific Sinaloa State. Mayos HLA profile was compared to other Amerindians and worldwide populations’ profile. A total of 14,896 chromosomes were used for comparisons. Genetic distances between populations, Neigbour-Joining dendrograms and correspondence analyses were performed to determine the genetic relationship among population. The new specific Mayo HLA haplotypes found are: HLA-A*02-B*35-DRB1*1406-DQB1*0301; HLA-A*02-B*48-DRB1*0404-DQB1*0302; HLA-A*24-B*51-DRB1*0407-DQB1*0302 and HLA-A*02-B*08-DRB1*0407-DQB1*0302. However, the typical Meso American HLADRB1*0407 represents a 40% of all DRB1 alleles. While common HLA characteristics are found in Amerindian distant ethnic groups, still new group specific HLA haplotypes are being found, suggesting that a common founder effect (i.e. high DRB1*0407) is noticed. Moreover, new HLA haplotypes are almost certainly appearing along time probably due to specific pathogen (?) selection for diversity. Mayo language is close to the Tarahumara one (another geographically close group); notwithstanding both groups are not genetically close according to our results, showing again the different evolution of genes and languages, which do not correlate. Finally, Sinaloa is one of the Mexican States in which more European genes are found. However, the results presented in this paper, where no European HLA genes are seen in Mayos, should have a bearing in establishing transplant programs and in HLA and disease studies.

[Analysis of genetic polymorphism of the HLA-B and HLA-DR loci in patients with dermatophytic onychomycosis and in their first-degree relatives]

Onychomycosis is known to have predisposing factors and a high prevalence within families that cannot be explained by within-family transmission. We determined the frequency of HLA-B and HLA-DR haplotypes in 25 families of Mexican patients with onychomycosis in order to define the role of the class II major histocompatibility complex (MHC) in genetic susceptibility to this infection. Seventy-eight subjects participated in the study, 47 with onychomycosis and 31 healthy individuals. The frequencies of the HLA-B and HLA-DR haplotypes were compared with those found in first-degree relatives without onychomycosis and in a historic control group of healthy individuals. The frequencies in the controls were similar to those of the healthy relatives of the patients. However, on comparison of the patients with historic controls, we detected a higher frequency of the HLA-DR8 haplotype (P=.03; odds ratio, 1.89; 95% confidence interval, 0.98-36). These findings suggest that there are polymorphisms in genes of the MHC that increase susceptibility to onychomycosis, particularly haplotype HLA-DR8.

Role of major histocompatibility complex and ethnicity in acute renal graft rejection

BACKGROUND

The major histocompatibility complex (MHC) plays a main role in antigen presentation. Class I, II, and III genes form defined "blocks" of conserved DNA sequences (conserved extended haplotypes) that are useful to follow the ancestry of a population. Each variant encodes a specific peptide that determines a particular individual's immune response. In addition, differential expression of HLA antigens in certain physiological and pathological conditions may participate in the pathogenesis of allograft rejection versus tolerance.

OBJECTIVES

The aim of this study was to determine whether the specific HLA ancestry was associated with acute renal graft rejection among the Mexican mestizo population.

MATERIALS AND METHODS

We studied 544 Mexican mestizo renal donors and their respective recipients for their serologically determined HLA and based on antigens haplotype assignments. The acute rejection group was compared with the nonrejection group among donors and recipients, correspondingly.

RESULTS

Frequent Mexican alleles were observed in this study. Moreover, HLA-B*61/-DR*04, HLA-A*35/-DR*06 (Amerindian ancestry), HLA-A*68/-DR*01, HLA-A*28/-B*65/-DR*01 (African ancestry), and HLA-A*33/-B*65 (Caucasian ancestry) in donors were associated with acute renal graft rejection episodes.

CONCLUSION

Knowing the ancestry of a donor's HLA molecules may help to individualize immunosuppressive therapy for posttransplant surveillance, because they may be more membrane-exposed in parenchymal cells, making them more susceptible of being recognized by the recipient's immune system.

HLA-DRB1 alleles are associated with the clinical course of disease and steroid dependence in Mexican patients with ulcerative colitis

AIM

The aim of this study was to study the association between the HLA-DRB1 alleles and the clinical course of ulcerative colitis (UC).

METHOD

  Seventy-five Mexican patients with UC were studied. High resolution HLA typing was performed using Polymerase Chain Reaction-Sequence Specific Oligonucleotide PCR-SSO reverse dot blot and Polymerase Chain Reaction-single specific primer PCR-SSP. Molecular typing techniques were applied to define HLA-DRB1 alleles.

RESULTS

Seventy-five patients (36 female patients, 39 male patients) were studied. Significant associations were found between some HLA-DRB1 alleles and the clinical course of disease: initial active and then inactive and the HLA-DRB1*14 allele (P = 0.03; OR = 4.63; 95% CI: 1.08-21.23); and HLA-DRB1*08 allele (P = 0.04; OR = 4.34; 95% CI: 1.9-33.3). On the other hand, the HLA-DRB1*07 (P = 0.001; OR = 9.76 95% CI: 1.55-65.56) was significantly associated with steroid dependence in UC patients.

CONCLUSIONS

 This study suggests that HLA-DRB1 alleles were associated with the clinical course of disease and steroid dependence in UC patients.

Human leukocyte antigen typing in tuberculous rheumatism: Poncet's disease

SETTING

Tuberculous rheumatism (Poncet's disease) is a reactive polyarthropathy associated with extra-pulmonary and pulmonary tuberculosis (TB) without evidence of mycobacterial infection of the involved joints. As all patients with TB do not present with this peculiar clinical feature, a genetic susceptibility is suspected.

OBJECTIVE

To determine the major histocompatibility complex (MHC) class I and II alleles in Mexican mestizo patients with Poncet's disease.

DESIGN

In this case-control study of 16 Mexican mestizo patients diagnosed with Poncet's disease and 99 ethnically matched healthy controls, high resolution human leukocyte antigen (HLA) typing was performed for HLA-A, B, DR and DQ by polymerase chain reaction. HLA-DRB1 and HLA-DQB1 subtypes were performed by sequence-specific oligonucleotide probe hybridization.

RESULTS

A significantly increased frequency of HLA-B27 (corrected P = 0.01) and DQB1*0301 (corrected P = 0.0009) alleles and decreased frequency of HLA-DQB1*0302 (corrected P = 0.00001) were identified in patients compared to healthy controls.

CONCLUSION

These data suggest that genes located within the MHC may play a role in the susceptibility to Poncet's disease in patients diagnosed with TB.

Clinical evolution of heart transplantation in patients with previous valvular cardiomyopathy

OBJECTIVE

Heart transplantation (HT) due to valvular cardiomyopathy is rare, namely, about 3% of cases in the Registry of the International Society for Heart and Lung Transplantation (ISHLT). Usually, these patients present some risk factors such as previous valvular operations and pulmonary hypertension. Since there are few studies in the literature, we retrospectively analyzed our early and long-term results.

MATERIALS AND METHODS

We studied our experience in 22 HT cases for valvular cardiomyopathy (9.3% of our total experience), namely, 12 men and 10 women, of overall mean age of 52.6 +/- 10 years. Five patients had mitral; 8, aortic; and 1, tricuspid valve disease; 7 had double valve disease and 1, triple valve disease. Nineteen patients (87%) had been operated previously between 1 and 4 times. The mean ejection fraction was 23% +/- 7.3% and the mean New York Heart Association (NYHA) functional class was 3.7. Fifty-three percent of the patients had pulmonary hypertension. Two patients were operated as an emergency "O." We used the standard HT technique.

RESULTS

Four patients (18%) were reoperated due to hemorrhage. The hospital mortality was 2 cases (9%). Another patients (9%) died on follow-up due to cardiac allograft vasculopathy. All surviving patients have been followed to the end of 2006. The mean follow-up has been 72 +/- 53 months. They are functional class I or II.

CONCLUSIONS

HT for this indication was more frequent in our experience than in the Registry of the ISHLT. The immediate and long-term results were good, with an 82% mean survival at 6 years. HT can be a good treatment for patients with valvular cardiomyopathy and bad ventricular function and/or multiple valvular reoperations.

HLA-DRB1*0101 is associated with the genetic susceptibility to develop lichen planus in the Mexican Mestizo population

The etiology of lichen planus (LP) is still unknown and previous studies have found an association between LP and HLA-DR1, DR2, DR3, DR9 and DR10 in different populations. The aim of this study was to analyze the distribution of the HLA-DRB1 alleles in Mexican Mestizo patients with LP. The aim of this study was to determine the gene frequency of HLA-DR locus in Mexican Mestizo patients with LP. We studied 20 patients with LP and 99 healthy Mexican Mestizo controls. HLA-DRB1 was performed by PCR-SSO reverse dot blot hybridization. High resolution HLA typing was performed by PCR-SSP. The HLA-DRB1*0101 allele was associated significantly in LP patients compared with healthy controls (pC = 0.0007, OR = 5.46, 95% CI = 1.86-16.06). HLA-DRB1*0101 is a marker for the development of LP in Mexican Mestizo population, yet another gene or HLA marker within MHC region may be the causatively associated gene.

P2X7 and NRAMP1/SLC11 A1 gene polymorphisms in Mexican mestizo patients with pulmonary tuberculosis

Tuberculosis remains one of the most important infectious diseases worldwide. Several studies have suggested that genetic factors may affect susceptibility to tuberculosis, but the specific genes involved have not yet been fully characterized. NRAMP1/SLC11 A1 and P2X(7) genes have been linked to increased risk for tuberculosis in some African and Asiatic populations. To explore the potential role of these genes in the susceptibility to pulmonary tuberculosis in a Mexican mestizo population, we evaluated the association of D543N and 3'-UTR polymorphisms in NRAMP1/SLC11 A1 and - 762 and A1513C polymorphisms in P2X(7) genes with the risk for tuberculosis. Polymerase chain reaction (PCR) amplification of genomic DNA followed by restriction fragment length polymorphism analysis, and allelic-specific PCR was employed. We found no significant differences in allelic frequency in NRAMP1/SLC11 A1 gene polymorphisms in 94 patients with tuberculosis compared to 100 healthy contacts. Similarly, no significant association of the P2X(7)-762 gene polymorphism with tuberculosis was detected. In contrast, the P2X(7) A1513C polymorphism was associated significantly with tuberculosis (P = 0.02, odds ratio = 5.28, 95% CI, 0.99-37.69), an association that had not been reported previously. However, when the function of P2X(7) was assessed by an L-selectin loss assay, we did not find significant differences in patients compared to healthy contacts or between PPD(+) and PPD(-) control individuals. This study further supports the complex role of P2X(7) gene in host regulation of Mycobacterium tuberculosis infection, and demonstrates that different associations of gene polymorphisms and tuberculosis are found in distinct racial populations.

Association of HLA-DRB1*16 with chronic discoid lupus erythematosus in Mexican mestizo patients

BACKGROUND

Chronic discoid lupus erythematosus (CDLE) is present in 15-30% of patients with systemic lupus erythematosus (SLE). Approximately 5% of CDLE cases can evolve to SLE at some stage of the disease.

AIM

The aim of this study was to determine gene frequencies of HLA-DRB1 alleles in Mexican mestizo patients with CDLE, irrespective of the presence of systemic disease.

METHODS

The study comprised 28 Mexican mestizo patients with CDLE who were attending the Passover Dermatology Centre, in Mexico City. HLA-DRB1 and DQ allele typing was performed by sequence-specific oligotyping after DNA amplification using PCR. The study also included 99 ethnically matched healthy individuals as controls.

RESULTS

In the patient group, a significantly increased gene frequency was found for the HLA-DR4 (P = 0.016, OR = 2.24, 95% CI 1.14-4.38) and HLA-DR16 alleles (P = 0.005, OR = 5.51, 95% CI 1.49-21.08).

CONCLUSION

HLA-DRB1 alleles seem to be involved in the genetic susceptibility to CDLE in the Mexican mestizo population.

HLA-E polymorphism in Amerindians from Mexico (Mazatecans), Colombia (Wayu) and Chile (Mapuches): evolution of MHC-E gene

Human leukocyte antigen (HLA)-E is a nonclassical class I (Ib) gene with a restricted polymorphism. Only eight DNA alleles and three proteins of this gene have been described and their frequencies analyzed in Caucasian, Oriental, Asian Indian, and Negroid populations. In the present study, HLA-E polymorphism has been analyzed in six Amerindian and Mestizo populations from North and South America and compared with previously described populations. HLA-E*0101 is the most frequent allele found in all populations except in Afrocolombian and Wayu Amerindians, in which blood group analyses show a high admixture with Caucasian and African populations. Mazatecan and Mapuche (two Amerindian groups from North and South America, respectively) presented similar HLA-E frequencies, whereas Wayu Indians are more similar to the Afrocolombian population. The Mexican and Colombian Mestizo show similar allele frequencies to Amerindians with high frequencies of HLA-E*0101 and HLA-E*010302 alleles. Also, frequencies in Negroids and Asian Indians present a similar distribution of HLA-E alleles. These data are in agreement with worldwide restricted polymorphism of HLA-E because no new allele was detected in the six populations studied. The allelic frequencies show differences among Caucasian, Oriental, Mestizo and Indian populations. Ape major histocompatibility complex-E allelism is also very restricted: common chimpanzee (one allele); bonobo (two alleles); gorilla (two alleles); orangutan (one allele); rhesus monkey (eight alleles); cynomolgus monkey (two alleles); and green monkey (two alleles).

Prevalence of HLA Antibodies and Its Impact on Graft Function in a Group of Kidney Transplant Recipients: A Cross-Sectional Study

HLA alloantibodies (Abs) are associated with chronic rejection and poorer graft survival. The current study was designed to document the prevalence of HLA Abs in a group of kidney transplant recipients (KTR) and its impact on graft function.

PATIENTS AND METHODS

283 KTR transplanted between January 1990 and December 2003 who had a functional graft were invited to participate. 198 KTR were enrolled. HLA class I and II Abs were measured by Luminex-One Lambda. Graft function was assessed by DeltaCr and GFR calculated by the Levey formula.

RESULTS

Median post-kidney transplant (post-KT) follow-up was 51.4 (4.3 to 176.3) months. Forty-four (22.2%) KTR were found to have class I and/or class II Abs. Eleven had both class I and II Abs, ten were positive only for class I, and 23 for class II. Overall, no significant difference was seen in renal function. The DeltaCr for Ab positive and Ab negative were -0.24+/-0.84 and -0.17+/-0.60 mg/dL (P=0.54), respectively. The GFR for Ab positive and Ab negative were 64.4+/-26 and 60.2+/-20 mL/min (P=0.25), respectively. No statistically significant difference was found between HLA Abs and number of HLA mismatches, gender, blood transfusions, pre-KT pregnancies, DGF, history of acute rejection, and chronic allograft nephropathy. Adjusting analysis by transplant year showed no significant difference.

CONCLUSION

The prevalence of HLA antibodies was similar to previous reports. In this cross-sectional study, the presence of HLA antibodies was not related to a negative impact on renal function.

Allele frequencies for 15 autosomal STR loci and admixture estimates in Puerto Rican Americans

Allelic frequencies of 15 short tandem repeats (STR) markers (CSF1PO, FGA, THO1, TPOX, VWA, D3S11358, D5S818, D7S820, D8S1179, D13S317, D16S539, D18S51, D21S11, D19S433 and D2S1338) were determined using the AmpFl STR Identifiler PCR Amplification Kit in Puerto Rican American individuals (N=205) from Massachusetts. The FGA, D18S51 and D2S1338 loci had a high power of discrimination (PD) with values of 0.967, 0.965 and 0.961, respectively. Significant deviations from the Hardy-Weinberg (HW) equilibrium were not detected. An important genetic contribution of Caucasian European (76.4%) was detected in Puerto Rican Americans. However, comparative analysis between Puerto Rican American and other neighboring populations from United States mainly with African and Caucasian Americans, revealed significant differences in the distribution of STR markers. Our results are important for future comparative genetic studies of different American ethnic groups, in particular a cultural group called Hispanic-Americans and should be helpful for forensic and paternity testing.

HLA antigens and juvenile onset spondyloarthritides: negative association with non-B27 alleles

OBJECTIVE

To describe the association between HLA-B and HLA-DR genes and juvenile onset spondyloarthritides (SpA) in Mexicans.

METHODS

The study included 66 consecutive patients with SpA (45 with ankylosing spondylitis (AS) and 21 with undifferentiated SpA) and 99 non-related healthy controls. The HLA-A, -B and DR alleles were detected by the polymerase chain reaction with the sequence-specific primers technique. Statistical methods included the Mantel-Haenzel chi2 test, Fisher's exact test, and Woolf method for odds ratio (OR).

RESULTS

The frequency of HLA-B27 was significantly increased in the whole group (pC < 10(-3), OR = 53.0, aetiological fraction = 51%), particularly in AS (pC < 10(-3), OR = 67.42, aetiological fraction 57%). In contrast, the frequencies of HLA-B44, and HLA-B14 were significantly decreased. Also, a weak negative association HLA-DR5 (p < 0.05) was found.

CONCLUSION

Apart from an expected significant association between HLA-B27 and juvenile-onset SpA, particularly AS, we found negative associations with HLA-B44, B14, and DR5. There was also a trend for HLA-B15 and DR1 associations with SpA.

HLA-DRB1 alleles encoding the “shared epitope” are associated with susceptibility to developing rheumatoid arthritis whereas HLA-DRB1 alleles encoding an aspartic acid at position 70 of the β-chain are protective in Mexican mestizos

The risk to develop rheumatoid arthritis (RA) has been associated with the presence of HLA-DRB1 alleles encoding the "shared epitope" (SE). Additionally, HLA-DRB1 alleles encoding an aspartic acid at position 70 (D70+ ) have been associated with protection against the development of RA. In this study we tested the association between either SE or D70+ and rheumatoid arthritis in Mexican Mestizos. We included 84 unrelated Mexican Mestizos patients with RA and 99 unrelated healthy controls. The HLA-typing was performed by PCR-SSO and PCR-SSP. We used the chi-squared test to detect differences in proportions of individuals carrying at least one SE or D70+ between patients and controls. We found that the proportion of individuals carrying at least one HLA-DRB1 allele encoding the SE was significantly increased in RA cases as compared to controls (p(c) = 0.0004, OR = 4.1, 95% CI = 2.2-7.7). The most frequently occurring allele was HLA-DRB1*0404 (0.161 vs 0.045). Moreover, we observed a significantly increased proportion of HLA-DRB1 SE+ cases with RF titers above the median (p = 0.005). Conversely, the proportion of individuals carrying at least one HLA-DRB1 allele encoding the D70+ was significantly decreased (p(c) = 0.004, OR = 0.4, 95% CI 0.2-0.7) among RA patients compared with controls. In conclusion, the SE is associated with RA in Mexican Mestizos as well as with the highest titers of RF.

HLA class II genotypes in Mexican Mestizo patients with myasthenia gravis

Myasthenia gravis is an autoimmune, heterogeneous disorder, characterized by the presence of antibodies against acetylcholine receptors at the neuromuscular junction. There is a strong evidence that an individual's genetic composition is an important predisposing factor for the development of the disease. To correlate HLA class II genotypes with thymic pathology in Mexican Mestizo patients who had been subjected to thymectomy. HLA class II genes were analyzed in 60 patients and in 99 healthy ethnically matched controls. Thymic hyperplasia, atrophy, thymoma, and normal histology were encountered in 56, 33, 8 and 2% of patients, respectively. HLA-DR11 was significantly increased in patients with thymoma compared with healthy controls (pC = 0.001, OR = 13.35, 95% CI 3.5-51.3), compared with the subgroup of hyperplasia patients (pC = 0.005, OR = 15.5, 95% CI 2.78-95.58) and with the atrophy subgroup (pC = 0.04, OR = 10.5, 95% CI 1.75-70.95). This study provides the evidence of an association between HLA class II alleles with clinical and genetic heterogeneity in myasthenia gravis, particularly in those with thymoma (HLA-DR11).

Acute myocardial infarction with cardiogenic shock: treatment with mechanical circulatory assistance and heart transplantation

The mortality of cardiogenic shock (CS) after an acute myocardial infarction (AMI) still remains high. Thrombolysis, PTCA or CABG, when possible, can improve the results, but when all the treatments fail death is almost certain.

OBJECTIVE

We investigate the use of the mechanical circulatory assistance (MCA) and heart transplantation (HT) to improve the adverse results in this irreversible situation.

METHODS

Among 11 patients with irreversible CS after an AMI we used a MCA (Abiomed BVS-5000). After improvement and hemodynamic stabilization, we performed heart transplantation in 7 patients of mean age 52 years (35-60) including two women. The MCA was univentricular in 7 patients and biventricular in 4. Mean duration of the MCA was 5 days (1-12).

RESULTS

Three patients died during the MCA: two due to cerebrovascular accidents and one multiorgan failure. Weaning was possible in one patient. Among Seven transplanted patients one died due to sepsis. Seven (64%) patients are long-term survivors.

CONCLUSION

When all the treatments have failed for CS after an AMI, MCA may be used as a bridge to heart transplantation in a select group of patients where the procedure is not contraindicated. The long-term results of 64% survivors in our experience is satisfactory.

Biological relevance of the polymorphism in the CCR5 gene in refractory and non-refractory rheumatoid arthritis in Mexicans

OBJECTIVE

The aim of this study was to analyze the frequencies of the CCR5 delta 32 deletion and HLA class II alleles in Mexican Amerindian populations and its relevance in the development and severity of RA.

METHODS

We studied 212 Mexican Mestizo subjects (40 patients with refractory RA, 102 patients with non-refractory RA and 70 healthy individuals). At the same time, to evaluate the ethnicity of the CCR5 delta 32 deletion we also studied 192 individuals from three Mexican Amerindian populations (70 Mayo (Capomo) individuals, 61 Teenek individuals, and 61 Mazatecan Indians). The delta 32 deletion in the CCR5 structural gene and HLA-DRB1 were determined by a PCR-SSP and a PCR-SSO procedure, respectively.

RESULTS

In the non-refractory RA group the CCR5 delta 32 gene frequency was 0.019 and the following genotype frequencies were observed: CCR5/CCR5 = 98.0%, CCR5/CCR5 delta 32 = 1.9% and CCR5 delta 32/CCR5 delta = 1.0%. In the refractory RA group the CCR5 delta 32 gene frequency was 0.025 and the genotype distribution was similar to that in the non-refractory RA group. The deletion was not detected in the Mexican Mestizo healthy group, or among the Teenek and Mayo Amerindians, all being individuals homozygous for the wild type allele. In the Mazatecan group the deletion frequency was 1.6% (g.f. = 0.016). We observed a significant increase in the frequency of the DRB1*07 allele in severe RA patients in relation to the non-severe RA group (p = 0.02, OR = 5.65, 95% CI = 0.95-43.05).

CONCLUSION

Our results suggest that the CCR5 delta 32 deletion is not common in Mexican Amerindian populations and this study does not support an important role of CCR5 delta 32 in the pathogenesis of RA or a severe form of the disease in Mexicans.

IgG antibodies to enterobacteria 60 kDa heat shock proteins in the sera of HLA-B27 positive ankylosing spondylitis patients

OBJECTIVE

To study the association of HLA-B27 and the IgG response to the 60 kDa HSPs of Klebsiella pneumoniae, Yersinia enterocolitica, Shigella flexneri, Escherichia coli and Salmonella typhi.

METHODS

IgG against the 60 kDa HSPs of enterobacteria was determined by ELISA in the sera from 49 HLA-B27+ ankylosing spondylitis (AS) patients; 41 HLA-B27+ healthy relatives of AS patients and 101 HLA-B27-unrelated healthy individuals.

RESULTS

HLA-B27+ patients and healthy individuals, showed significantly higher IgG antibody levels to the Klebsiella, Yersinia and Salmonella HSPs than HLA-B27- healthy controls. B27+ patients had a significantly higher response to E. coli HSP than the two other groups. IgG response anti-Shigella HSP was similar in the three groups.

CONCLUSIONS

There is a relationship between HLA-B27 and the response to HSPs 60 from Klebsiella, Yersinia, Escherichia and Salmonella, that may be important in the initiation of AS.

Clinical and immunogenetic characterization of Mexican patients with 'rhupus'

The coexistence of systemic lupus erythematosus and rheumatoid arthritis (rhupus), is a rare clinical condition. To date, 50 cases of rhupus have been described worldwide; however, the lack of clinical criteria for this rheumatic condition has created confusion in the characterization of this disorder. Nevertheless, in this paper we describe a comprehensive clinical and serological characterization of a cohort of 22 Mexican patients with rhupus, supported by generic HLA-DR phenotyping. We found that rhupus patients have a special clinical behavior. In this setting, the signs and symptoms of rheumatoid arthritis prevail, little organic damage associated with systemic lupus erythematosus (SLE) exists and none of the cases present thrombosis or morbidity during pregnancy in spite of presenting a high frequency of anticardiolipin antibodies. We also found an increased frequency of HLA-DR1 and HLA-DR2 alleles compared to healthy ethnically matched controls, systemic lupus erythematosus and rheumatoid arthritis patients.

Identification of two homologous antigenic peptides derived from L1 HPV-16 and 18 proteins specific for the HLA-B*3901 allele

In this work we present evidence that the homologous peptides IHSMNSTIL and IHSMNSSIL derived from L1 HPV-16 and 18 proteins respectively, and with high specificity for the allele HLA-B*3901, according with an algorithm prediction program, induced T cell stimulation in patients with advanced cervical cancer positive for HPV-16 or 18 infection and for the HLA-B*3901 allele. Interestingly, T lymphocytes derived from a patient with HPV-18 infection and stimulated with the peptide IHSMNSTIL were capable to kill a cervical cancer cell line named Rova, derived from the tumor of the same patient. In addition, the cytotoxic activity was strongly increased when this cell line was previously treated with hrIFN-gamma. These results suggest that the CTL immune response to L1 HPV-16 and 18 protein derived epitopes is maintained in patients with advanced cervical cancer within specific alleles, and opens the possibility that homologous epitopes may be used in the generation of prophylactic vaccines for cervical tumors bearing different HPV-types.

LMP2 and LMP7 gene polymorphism in Mexican populations: Mestizos and Amerindians

Low molecular weight polypeptide (LMP) genes are located within the major histocompatibility complex and have been associated with autoimmune diseases such as ankylosing spondylitis. In order to define the distribution of LMP genes in Mexican populations, the LMP2 and LMP7 polymorphism was analyzed in 312 Mexican individuals (95 Mexican Mestizos, 48 Nahuas, 56 Mazatecans, 50 Teenek, and 63 Mayos) belonging to different ethnic groups. In Mexican populations both Mestizos and Amerindians presented similar distribution of LMP2 and LMP7 polymorphisms, except Nahuas and Mayos who presented the higher frequencies of LMP2-H/H and the lowest frequencies of LMP2-H/R genotypes (P < 0.05 when compared with Mexican Mestizos). The LMP7-K/K genotype was absent in Nahuas, Teenek and Mayos and only one Mazatecan individual presented this genotype. Differences with other populations were found in Mexicans. An increased frequency of LMP2-H and a decreased frequency of LMP2-R alleles were observed in Mexican Amerindians (Nahuas and Mayos) when compared with Brazilian Amerindians (Kaingang and Guarani) and Caucasians (Spaniards) (P < 0.05). All Mexican populations (Mestizos and Amerindians) presented an increased frequency of LMP7-Q allele and a decreased frequency of LMP7-K allele when compared to Brazilian Amerindians (Kaingang), Caucasians (United States) and Asian (Japan) populations (P < 0.05). Genetic distances showed that Mexican Mestizos have an important relation with Spaniards and with all Mexican Amerindians. The present data corroborate the influence of Spaniard and Amerindian genes in the Mexican Mestizo population and could help to define the true significance of LMP polymorphism as genetic and evolutive marker in the Amerindian populations.

Effect of HLA-B and HLA-DR genes on susceptibility to and severity of spondyloarthropathies in Mexican patients

OBJECTIVE

To investigate the role of HLA-B and HLA-DR genes as contributors to genetic susceptibility and clinical expression of the spondyloarthropathies (SpA) in the Mexican population.

METHODS

The study included 172 patients with SpA (undifferentiated SpA 83, ankylosing spondylitis (AS) 64, and reactive arthritis 25) and 99 healthy controls. The HLA-B and HLA-DR alleles were detected by the polymerase chain reaction with sequence-specific primers technique. Patient assessment included demographic data, diagnostic categories, and disease patterns. Statistical methods included the Mantel-Haenzel chi(2) test, Fisher's exact test, and Woolf method for odds ratio (OR). Differences of continuous variables between HLA allele groups were calculated by Student's t test.

RESULTS

Increased frequencies of HLA-B27 (pCh10(-3), OR=28.7), HLA-DR1 (pC=0.045, OR=2.77), and HLA-B15 (p=0.034, pC=NS, OR=2.04) alleles in the whole group were found. HLA-B27 strength of association (OR) was 41.4 in AS; 20.9 in undifferentiated SpA; 27.2 in reactive arthritis. HLA-DR1 and HLA-B15 were increased in undifferentiated SpA (pC=0.045, OR=2.98 and p=0.004, pC=NS, OR=2.75). By analysing 58 HLA-B27 negative patients it was found that HLA-B15 and HLA-DR1 associations with SpA were independent of HLA-B27; increased frequencies of HLA-B15 were found in the whole SpA group and in patients with undifferentiated SpA (pC=0.03, OR=3.09 and pCh0.01, OR=3.77) and of HLA-DR1 in the latter (p=0.04, pC=NS, OR=3.15). HLA-B27 positive patients were younger than HLA-B27 negative patients at onset (p=0.03), but HLA-DR1 positive patients were older than HLA-DR1 negative patients (p=0.03). Bath indices for disease activity and functioning were higher in HLA-B27 positive patients (p=0.006 and p=0.004 v HLA-B27 negative patients). In contrast, neither HLA-DR1 nor HLA-B15 influenced these indices.

CONCLUSION

Apart from HLA-B27, there is a significant association of HLA-DR1 and HLA-B15 with SpA in Mexicans which is independent of B27. HLA-B27 is associated with younger age at onset and increased disease severity and HLA-DR1 with older age at onset. The strength of HLA-B15, HLA-B27, and HLA-DR1 associations varied in different forms of SpA.

Influence of glucose on the sex ratio of bovine IVM/IVF embryos cultured in vitro

The effect of glucose in the medium used during in vitro culture on the sex ratio of bovine blastocysts derived from in-vitro-matured and in-vitro-fertilized oocytes was evaluated. Oocytes were matured and inseminated with mixed sperm from three bulls and were cultured in vitro in modified synthetic oviducal fluid medium with 10% fetal calf serum, with or without glucose supplementation. The overall rate of cleaved embryos that developed to expanded blastocyst in the medium without glucose (27.0%) was significantly greater (P < 0.05) than the percentage observed when embryos were cultured in medium with glucose (17.5%). Analysis of variance was performed to analyse the effect of glucose on the proportion of male embryos reaching the blastocyst stage (or arrested at the morula stage) during Days 7 to 10. Regardless of the presence or absence of glucose in the medium, significantly (P < 0.05) more male than female embryos were harvested as expanded blastocysts on Day 7 and on Day 8 of culture. On Days 9 plus 10 of culture, a sex ratio imbalance only occurred in the absence of glucose in the culture medium (P < 0.05). Glucose did not produce any significant effect on the sex ratio of the overall number of expanded blastocysts harvested by Day 10 of in vitro culture. However a significantly greater proportion of females (P < 0.01) were found among those embryos that developed only to the morulae stage after 10 days in vitro. These results show that glucose supplementation of culture media produces a preferential loss of female embryos during culture to the blastocyst stage.

[Alleles of the major histocompatibility system associated with susceptibility to the development of Takayasu's arteritis]

OBJECTIVE

Since 1972, the relationship between HLA alleles and the susceptibility for Takayasu arteritis (TA) has been studied on different populations. Hence the results up to date are heterogeneous, the objective of the present review is to analyze the relationship between the presence of HLA alleles and the susceptibility for the development of TA considering the ethnic origin of the studied populations.

MATERIAL AND METHODS

We carried out a bibliographic review from clinical articles of case and controls studies on different populations on which the relationship between HLA alleles and the susceptibility for TA was studied, published since 1972 until February 2000.

RESULTS

We reviewed articles of studies on Asian, Arab, North-American and Mexican Mestizo populations. On Asian populations TA was associated with HLA-A31, -B52, -B39, -B5 and -DR2, on Arabs with HLA-A2, -A9, -B35 and -DR7, on North-Americans with HLA-DR4 and on Mexican Mestizo with HLA-B5, -B52 and -DR6. On the other hand, recent reports establish that several HLA-B alleles (HLA-B52 and HLA-B39) associated with the disease share some residues important on the antigen presentation.

CONCLUSIONS

Hence the heterogeneity of the results obtained up to date, it stands out the increase on HLA-B52 and HLA-DR4 reported on ethnically different populations. More recent data point the possible participation of an epitope located on the peptide-binding site of the HLA-B molecule (positions 63 and 67) that seems to be shared by several alleles associated with the disease. These residues might be participating on the presentation of an unknown antigen that would unchain the disease on the genetically susceptible individuals group.

Heat shock protein 70 gene polymorphisms in Mexican patients with spondyloarthropathies

OBJECTIVE

To investigate the role of HSP70 genes as contributors to genetic susceptibility of the spondyloarthropathies (SpA) in the Mexican population.

METHODS

The study included 150 patients with SpA (undifferentiated spondyloarthropathy (uSpA) 68, ankylosing spondylitis (AS) 60, and reactive arthritis 22) and 158 healthy controls. HSP70-1, HSP70-2 and HSP70-hom genotypes were analysed by the polymerase chain reaction-restriction fragment length polymorphism technique. Statistical methods included the Mantel-Haenzel, chi(2), Fisher's exact test, and Woolf's method for odds ratio (OR).

RESULTS

HSP70-2 B/B genotype frequency was increased in the whole group of patients with SpA (pC<0.05, OR=4.3), as well as in the different clinical subgroups (pC<0.05, OR=4.2 for AS; pC<0.05, OR=4.4 for uSpA; and pC<0.05, OR=4.1 for ReA). This frequency remained significantly increased when the patients with B27 negative SpA were analysed. On the other hand, HSP70-hom locus analysis showed significantly increased frequency of A allele in the whole group of SpA (pC<0.05, OR=3.4), as well as in the groups with AS (pC<0.05, OR=5.6) and with uSpA (pC<0.05, OR=3.1), when compared with healthy controls. In this case, also, the genotype A/A was increased in the whole group of SpA (pC<0.05, OR=4.5), as well as in patients with AS (pC<0.05, OR=6.4) and with uSpA (pC<0.05, OR=3.7). When the patients with B27 negative SpA were analysed the frequencies of HSP70-hom A allele and A/A genotype remained significantly increased in the whole group of SpA (pC<0.05, OR=3.2 for the A allele and pC<0.05, OR=4.2 for the A/A genotype) and in the uSpA subgroup (pC<0.05, OR=3.8 for the A allele and pC<0.05, OR=4.3 for the A/A genotype).

CONCLUSION

In addition to the association of SpA with HLA-B27, there is a significant association of HSP70-2 and HSP70-hom alleles with SpA in Mexicans. This association seems to be independent of the susceptibility conferred by HLA-B27 in the group of patients with uSpA.

Pacemaker endocarditis: approach for lead extraction in endocarditis with large vegetations

We present the case of a patient with vegetations on a pacing lead from a pacemaker implanted 13 years previously. A new surgical technique for removal of infected leads was developed to avoid the increased risk of septic pulmonary embolism. The electrode with vegetations was removed without cardiopulmonary bypass using the direct surgical approach described.

Tumor necrosis factor-alpha promoter polymorphisms in Mexican patients with systemic lupus erythematosus (SLE)

The major histocompatibility (MHC) genes including TNF-alpha, HSP70 and HLA genes have been associated with systemic lupus erythematosus (SLE) in several populations. In this study we analyze the polymorphism of TNF-alpha promoter in 51 Mexican Mestizo SLE patients and 55 ethnically-matched healthy controls by polymerase chain reaction methods. No statistically significant differences were observed in the TNF -308 allele and genotype distribution between patients and healthy controls. However, we found a significant increase in the TNF G/A -238 genotype and in the TNFA -238 allele frequencies in the SLE group when compared with healthy controls (Pc = 0.03, OR = 4.77 and Pc = 0.02, OR = 3.62, respectively). DRB1 analysis showed a similar distribution in patients and controls. Linkage disequilibrium was observed for five haplotypes: DRB1*1401-TNFA-238 (D = 0.84; D' = 1.0; P = 0.015); DRB1*0301-TNFA-238 (D = 1.38; D' = 0.41; P = 0.042); DRB1*1106-TNF2-308 (D = 0.9; D' = 1.0; P = 0.0006); DRB1*1104-TNF2-308 (D = 0.83; D' = 0.45; P = 0.02) and DRB1*1406-TNF2-308 (D = 0.83; D' = 0.45; P = 0.02). Our data suggest that the association between the TNF-alpha -238 polymorphism and SLE could play a major role in disease susceptibility.

Melatonin protects against renal oxidative stress after obstructive jaundice in rats

The goals of this study were to analyze the renal oxidative status in experimental biliary obstruction and to evaluate the impact of melatonin on renal oxidative stress. Cholestasis was done by double ligature and section of the extra-hepatic biliary duct. Melatonin was injected i.p. (500 microg/kg/day). Malondialdehyde, reduced glutathione, catalase, superoxide dismutase, glutathione reductase, glutathione peroxidase and glutathione transferase were determined in the renal tissue. After biliary obstruction, an increase in malondialdehyde (P<0.0001) and a fall in reduced glutathione (P<0.0001) were seen. Moreover, the scavenger enzyme activity had significantly diminished. After melatonin administration, the malondialdehyde fell significantly (P<0.0001), whereas reduced glutathione showed an important increase (P<0.0001) compared with the ligated bile duct group. Experimental bile duct obstruction was associated to an increase of renal oxidative stress. Treatment with melatonin decreased the renal lipid peroxidation, and both the reduced glutathione as well as the scavenger enzyme activity recovered.

Class II allele and haplotype frequencies in Mexican systemic lupus erythematosus patients: the relevance of considering homologous chromosomes in determining susceptibility

The aim of the present study was to determine the relevant major histocompatibility complex (MHC) class II alleles in the genetic susceptibility to systemic lupus erythematosus (SLE) in Mexican Mestizo patients. We examined the gene and haplotype frequencies of the HLA-DRB1, DQA1 and DQB1 alleles by polymerase chain reaction-sequence-specific oligonucleotide probes in 81 Mexican SLE Mestizo patients and 99 ethnically matched controls. We found a significantly increased frequency of the HLA-DRB1*0301 (p(c) = 0.031, odds ratio = 2.63) allele and significantly decreased frequencies of the DRB1*0802 (p(c) = 0.035) and DRB1*1101 (p(c) = 0.037) alleles in the SLE group. Haplotype analysis showed increased frequencies of DRB1*0301-DQA1*0501-DQB1*0201 (p(c) = 0.017, odds ratio = 2.97), and decreased frequency of DRB1*0802-DQA1*0401-DQB1*0402 (p(c) = 0.034) in SLE patients. The most frequently detected haplotypes in SLE patients showed different haplotypic combinations in the homologous chromosome from those found in controls. Thus, the combinations detected in SLE patients were either not detected in the control group or infrequently found. The results suggest that the DRB1*0301 is the principal class II allele associated with the genetic susceptibility to SLE in Mexican patients and that the presence of a specific haplotype of the homologous chromosome in patients with DRB1*0407-DQA1*03-DQB1*0302 and DRB1*1501-DQA1*0102-DQB1*0602 haplotypes could have an additive effect on the susceptibility to the disease. Finally, the low frequency of the DRB1*0301 and DRB1*1501 alleles in the control population suggests that the genetic admixture between Mexican Indians and Caucasian populations was an event that could have increased the risk of Mexicans to develop SLE.

Immunogenetics and clinical aspects of Takayasu's arteritis patients in a Mexican Mestizo population

OBJECTIVE

The aim of the present work was to study the association between HLA alleles and Takayasu's arteritis in Mexican Mestizo patients.

METHODS

The study included 26 Mexican Mestizo patients with Takayasu's arteritis and 99 healthy unrelated individuals. HLA-A, -B and -DR alleles were determined by polymerase chain reaction PCR-SSP RESULTS: Increased gene frequencies were demonstrated for HLA-B15(p=0.009,pC=0.020,OR=3.24,EF=11.9%) and HLA-B52 (p=0.008, pC=0.027, OR=5.16, EF=7.7%), and a decreased frequency for the HLA-A24 allele in patients compared to normal controls (p=0.035, pC=NS, PF=11.1%). When HLA typing was correlated to clinicalfeatures in 24 cases, wefound an increasedfrequencies of HLA-DR14 in patients with systemic arterial hypertension (p=0.005, pC=0.004, OR=24.6, EF=38.3%) and HLA-A2 on patients with pulmonary involvement (p=0.034, pC=0.036, OR=3.67, EF=40.4%) when compared to patients without these clinical manifestations.

CONCLUSION

These data confirm HLA-B52 as a relevant susceptibility allele for Takayasu's arteritis and suggest that HLA-B15 could be important as a marker of the disease in Mexican patients. Other class I and/or class II alleles could also be relevant as markers for the clinical features present in these patients.

Major histocompatibility complex and tumor necrosis factor-alpha polymorphisms in pigeon breeder's disease

Pigeon breeders disease (PBD) is caused by the exposure of a susceptible host to avian antigens. However, genetic factors determining individual predisposition are unknown. In this work, polymorphisms of the major histocompatibility complex (MHC) class II alleles and tumor necrosis factor alpha (TNF-alpha) promoter were evaluated in 44 patients with PBD, 99 healthy unrelated controls (HC), and 50 exposed but asymptomatic subjects (EAS). MHC typing was performed by PCR-specific sequence oligonucleotide analysis, and TNF-alpha polymorphism at -238 and -308 positions by amplification refractory mutation system-PCR. PBD patients showed a significant increase of the alleles HLA-DRB1*1305 (p < 0.001, OR = 15.4, 95% CI = 3.18-102.6 [HC], and OR = 17.05, 95% CI = 2.25-357.8 [EAS]) and HLA-DQB1*0501 (p < 0.05, OR = 2.93, 95% CI = 1.21-7.15 [HC], and OR = 2.96, 95% CI = 1.0-9.14 [EAS]). A decrease of HLA-DRB1*0802 was also noticed in patients when compared with both control groups (p < 0.05). Haplotype analysis revealed an increase of DRB1*1305-DQB1*0301 and a decrease of DRB1*0802-DQB1*0402. PBD patients had an increased frequency of TNF-2(-)(308) compared with both control groups (p < 0.05). Patients exhibiting the TNF-2(-)(308) allele were younger (33.9 +/- 14.6 versus 44.2 +/- 10.4 yr; p < 0.05), and displayed more lymphocytes in their bronchoalveolar lavages (88.0 +/- 12.1 versus 68.9 +/- 17.2; p < 0.05). These results suggest that genetic factors located within the MHC region contribute to the development of PBD.

Polymorphism and distribution of HLA-DR2 alleles in Mexican populations

DRB1*15/16 nucleotide polymorphism was analyzed in 68 DR2 positive individuals (18 Mexican Mestizos, 30 Mazatecans and 20 Nahuas), carrying a total of 75 DR2 haplotypes. HLA-DR2 was one of the most frequent specificities detected in Mazatecans and Nahuas with gene frequency (gf) of 0.232 and 0.141, respectively. In these populations DRB1*16 was the most frequent DR2 split (gf = 0.183 in Mazatecans and gf = 0.135 in Nahuas), whereas in Mexican Mestizos the most frequent was DRB1*15 (gf = 0.065). Four DRB1-DQB1 combinations in Mexican Mestizos, two in Mazatecans and one in Nahuas were in linkage disequilibrium. In spite of the restricted polymorphism, there were differences on DRB1*15/16 alleles found in Mexicans. DRB1*1501 a Caucasian allele was predominant in Mexican Mestizos, whereas DRB1*1602 an Amerindian allele was characteristic on Indian populations. An important difference was detected among the Amerindian populations studied since DRB1*1502 was only present in Mazatecans. This data corroborates the restricted polymorphism of DRB1*15/16 and the high frequency of DRB1*16 subtype in autochthonous American populations and suggest that the differences in gene frequencies of DRB1*15/16 alleles could be helpful in distinguishing each of these population.

HLA class II genotypes in Mexican Mestizos with familial and nonfamilial multiple sclerosis

Predisposition to MS is associated with the HLA-DR2 antigen in white patients. The authors investigated the genetic factors behind the increasing frequency of MS in the Mexican population. HLA-DR and DQ were analyzed in 17 patients with MS, 15 of their first-degree relatives, and 99 healthy ethnically matched controls. DR2 or DR3 was found in 15 of 17 patients. In controls, both alleles had frequencies less than 0.05. MS in Mexican patients was associated with HLA-DR2 and DR3.