Lack of association between alopecia areata and HLA class I and II in a southeastern Brazilian population

Abstract: Background: Alopecia areata (AA) is a common disorder of unknown etiology that affects approximately 0.7% to 3.8% of patients among the general population. Currently, genetic and autoimmune factors are emphasized as etiopathogenic. Studies linking Human Leukocyte Antigens (HLA) to AA have suggested that immunogenetic factors may play a role in the disease's onset/development. Objectives: To investigate an association between AA and HLA class I/II in white Brazilians. Methods: Patients and control groups comprised 33 and 112 individuals, respectively. DNA extraction was performed by column method with BioPur kit. Allele's classification was undertaken using the PCR-SSO technique. HLA frequencies were obtained through direct counting and subjected to comparison by means of the chi-square test. Results: Most patients were aged over 16, with no familial history, and developed partial AA, with no recurrent episodes. Patients showed a higher frequency of HLA-B*40, HLA-B*45, HLA-B*53 and HLA-C*04 compared with controls, although P was not significant after Bonferroni correction. Regarding HLA class II, only HLA-DRB1*07 revealed statistical significance; nevertheless, it featured more prominently in controls than patients (P=0.04; Pc=0.52; OR=0.29; 95%; CI=0.07 to 1.25). P was not significant after Bonferroni correction. Conclusions: The development of AA does not seem to be associated with HLA in white Brazilians, nor with susceptibility or resistance. The studies were carried out in populations with little or no miscegenation, unlike the Brazilian population in general, which could explain the inconsistency found.

HLA-Bw4-B*57 and Cw*18 alleles are associated with plasma viral load modulation in HIV-1 infected individuals in Salvador, Brazil

Host genetic factors play an important role in mediating resistance to HIV-1 infection and may modify the course of infection. HLA-B alleles (Bw4 epitope; B*27 and B*57) as well as killer cell immunoglobulin-like receptors have been associated with slow progression of HIV-1 infection. OBJECTIVE: To evaluate the association between serological epitopes HLA-Bw4 and HLA-Bw6 and prognostic markers in AIDS. METHODS: 147 HIV-infected individuals in Bahia, Northeast Brazil, were genotyped for HLA class I locus. HLA class I genotyping was performed by hybridization with sequence-specific oligonucleotide probes following amplification of the corresponding HLA-A, HLA-B and HLA-C genes. Statistical analysis was performed using Fisher's exact and ANOVA tests for categorical and continuous variables, respectively. RESULTS: We detected a significant association (χ2 = 4.856; p = 0.018) between the presence of HLA-Bw4 and low levels of viremia. Eighteen out of the 147 HIV-infected individuals presented viremia <1,800 copies/mL and 129 presented viremia > 2,000 copies/mL. Ninety and four percent (17/18) of all individuals with viremia < 1,800 copies/mL carried HLA-Bw4, compared to 67.4 percent (87/129) of individuals with viremia > 2,000 copies/mL. Additionally, we found a significantly higher frequency of B*57 (OR = 13.94; 95 percent CI = 4.19-46.38; p < 0.0001) and Cw*18 (OR = 16.15; 95 percent CI = 3.46-75.43; p < 0.0001) alleles, favoring the group with lower viremia levels, in comparison with those with higher viral load. CONCLUSION: HLA-Bw4-B*57 and Cw*18 alleles are associated with lower level of viral load in HIV-infected Brazilian patients. These findings may help us in understanding the determinants of HIV evolution in Brazilian patients, as well as in providing important information on immune response correlates of protection for such population.

Association of HLA-*08:DRB1*03 with immunoglobulin A-deficiency.

OBJECTIVE: Susceptibility to IgA deficiency (IgAD) is strongly associated with alleles of HLA, but it is not equally strong in different human populations. Therefore, the goal of this study was to determine the HLA-A, -B and -DRB1 antigenic and haplotypic frequencies in unrelated Polish Caucasian IgA-deficient patients who had never been examined so far in this respect. METHODS: The HLA alleles were determined by means of low resolution polymerase chain reaction with sequence specific primers (PCR-SSP) method in a group of IgA-deficient patients and control subjects from the same area. RESULTS: The HLA-DRB1*03 allele showed the strongest association with IgA deficiency in the Polish population (OR=6.6, p cor=0.0084). The HLA-B*08 allele was also associated with predisposition to the disease (OR=6.22, p cor=0.033). These significant associations could be explained in the context of a positive association of IgAD with the HLA-B*08:DRB1*03 haplotype, previously reported in other Caucasoid populations from Northern and Central Europe. In our group the HLA-B*08:DRB1*03 haplotype was present in 52.9% of IgA-deficient patients comparing to 9.9% in controls (p< 0.00011). A positive association of HLA-B*08 and DRB1*03 was stronger in IgA-deficient males than in females from the same group. CONCLUSION: Immunoglobulin A deficiency in Polish population is strongly associated with HLA-B*08:DRB1*03 haplotype rather than with single alleles.

Human Leukocyte Antigen Typing Proficiency Surveys in Korea, 2005-2006 / 대한진단검사의학회지

BACKGROUND: To monitor the performance of histocompatibility testing laboratories, HLA proficiency survey in Korea has been conducted biannually since 1996. In this report, we summarized the results of the surveys performed in recent two years (2005-2006). METHODS: A total of four proficiency surveys were performed, in which 59-61 laboratories participated. Each survey included three tests for HLA class I (serology and DNA) and class II (DNA) typing and six tests for HLA crossmatch. RESULTS: The overall concordance of serologic typing was 98.9% (355/359) for HLA-A, 97.5% (350/ 359) for HLA-B, and 94.7% (337/356) for HLA-C. The antigens assigned correctly by less than 95% of the participating laboratories were A26 (93.8%), B38 (94.2%), Cw3/Cw10 (90.9%), Cw6 (94.4%), and Cw8 (74.3%). The overall concordance rates of DNA typing were 99.6% (533/535) for HLA-A, 99.8% (539/540) for HLA-B, and 100% (392/392) for HLA-C. Correct assignment of HLA-DRB1 and -DQB1 was reported by 99.2% (98.1-100%) and 96.7% (88.9-100%) for the generic level and 100% and 95.8% (75-100%) for the allelic level, respectively. On the average 3.8% (0-7.7%) of the total laboratories showed unacceptable results in the crossmatch tests. CONCLUSIONS: The rates of correct antigen identification and of unacceptable crossmatch were similar to those of previous surveys, which were considered satisfactory. The Korean proficiency survey program may have contributed to a high quality of HLA tests today and should be continued for further improvements of the tests tomorrow.

Serological analysis of human leukocyte antigens-A and -B antigens in Thai patients with nasopharyngeal carcinoma.

OBJECTIVE: To study the distribution of human leukocyte antigens (HLA) -A and -B antigens by standard microlymphocytotoxicity assay in Thai nasopharyngeal carcinoma (NPC) patients compared to normal controls in order to identify the alleles associated with NPC in Thailand. DESIGN: Retrospective-Analytical study. SUBJECTS: Fifty-three unrelated Thai patients with histologically confirmed NPC diagnosed at King Chulalongkorn Memorial Hospital and 70 healthy unrelated Thai individuals served as controls. METHOD: Lymphocyte separation and HLA typing were performed from freshly drawn blood by standard microlymphocytotoxicity assay. The significance of differences between the two groups was analyzed by the chi-square test. RESULTS: HLA-A2 was observed at a greater frequency in patients being found in 31/53 (58%) NPC patients compared to 27/70 (38%) controls (p = 0.02). An increase in HLA-B46 was also demonstrated. HLA-B46 was present in 16/53 (30%) NPC patients but was observed in 10/70 (14%) in controls (p = 0.03). CONCLUSIONS: This study reported two susceptible, HLA-A2 and HLA-B46 antigens, for NPC in a Thai population.

Prevalence of HLA- [B5andB27] in the Jordanian poplulation

screening for HLA- [B5andB27] is routinely carried out for kidney and bone marrow donors. The purpose of this study is to determine the prevalence of HLA- [B5andB27] among the Jordanian population compared with other population. patients and methods the present study was conducted on seven hundred and fifty four healthy kidney and bone marrow donors visiting the King Hussein Medical Center [K.H.M.C.], in the period from January 1994 to December 1998. This group was typed for both HLA- [B5andB27] antigens by serological method. the frequencies of HLA- [B5and B27] were 27% and 3.4% respectively. the frequency of HLA- [B5and B27] was higher in the Jordanian population compared with other population, such as the Caucasian who showed a prevalence of 6% and the African blacks who had a prevalence of 3% and close to the Japanese population, where a prevalence of 0.9% was reported. The frequency of [HLA-B27] on the other hand was low in the Jordanian population, compared to the Caucasian 6-10% and higher than the Japanese population where a prevalence of 0.3% was reported

Sex Association with HLA-A, -B and -C antigens among bahrainis

This is the first study of HLA class I antigens among Bahrainis, which will indicate the HLA -A, -B, and -C amongst Bahrainis in correlation with sex of the population. Six hundred and five Bahrainis were included in the study [303 males: 302 females]. The complement-dependent microcytotoxicity [CDC] was used. The study showed that there are unique HLA antigens, which show Bahrainis relation to the Middle East, with the following characteristics of high frequencies: A2, Al, A19, A9, Al0, All, B12, B7, B8, B2, B5, B13, Cw4, Cw3, Cw1, Cw2, and Cw6. Some of the antigens were shared with other countries. The results showed that some HLA -A, -B and -C antigens are sex associated

HLA-B27 typing by flow cytometery to identify high risk group for ankylosing spondylitis among patients with low back pain

The human leucocyte antigens [HLA] are known to be associated with some diseases, the most common is HLA-B27 and ankylosing spondylitis [AS]. We studied hundred patients suffering from low back pain and radiologic sacroiliitis and 260 normal healthy individuals. Two methods were used for HLA-B27 typing namely complement mediated lymphocytotoxicity and flow cytometery. Results obtained by the two methods were in agreement. The percentage of B27 individuals among the total number of patients with back pain was 25% while in the control group it was 2.7% [p< 0.001]. Among patients suffering from AS, the percentage of B27 was 96% and relative risk was 85%. Flow cytometery had the advantages of being rapid, simple and accurate. The monoclonal antibody used had the ability to identify all subtypes of B27 known to be associated with AS. It is concluded that HLA - B27 is a rare allele among healthy individuals in Bahrain and that flow cytometery is an excellent method for HLA-B27 typing to identify patients at high risk for AS

Anti-insulin antibodies and retinopathy in juvenile onset type-1 diabetes.

Juvenile diabetics have severe loss of beta cell function and require replacement therapy with insulin. Insulin antigenicity can produce anti-insulin antibodies resulting in allergic reactions and insulin resistance. The role of insulin-anti-insulin antibody complexes in the development and progress of chronic diabetic complications like microangiopathy is not very clear. In the present study, there was statistically a significant trend of higher insulin antibody binding levels in IDDM patients who developed retinopathy. Though there was a trend of higher insulin antibody in IDDM patients with retinopathy, there was no association between insulin antibody and HLA antigen which some authors have reported.

Histocompatibility in couples with habitual abortion

Thirty couples suffering from habitual abortion as well as thirty normal fertile couples as a control group were subjected to HLA typing and one way mixed lymphocyte culture reaction [MLC] between females and their husbands in each group and between "females and husbands in the other groupo. There was no significant difference in the frequency, of any of the HLA-A or B antigens in females or males of recurrent abortions compared to the normal control group and another larger control group representing the general Egyptian population. However a significant increase was found in sharing of antigens as regards locus A and B and combined at both loci in habitual abortion group compared to the control group. Mothers in the abortion group were found to be significantly hyporesponsive to stimulation by their husband's lymphocytes specifically. There was no significant association between the sharing of HLA antigens and depression in MLC on individual basis, abortions. Their ages ranged from 21-35 years and the number of living children ranged from 3 to 6 children. All wives of abortion and control groups were non pregnant at the time of the study. HLA Typing: Tissue typing for HLA-A and HLA-B antigens for both partners was performed with the use of two stages lymphocyte microcytotoxicity technique [Terasaki et al, 1978] Mixed lymphocyte culture [MLC] reactivity: One way mixed lymphocyte culture was performed [Hartzman et al, 1971] and the following responses were studied: 1.Cellular response of cells from the wives: each stimulated, by her husband in both study and control groups 2.Cellular response of the wives in the abortion group stimulated by men from the control group 3 Cellular response of the wives in the control group stimulated by men from the study group N.Bs:Every MLC combination was done in triplicate. Results of MLC were expressed as stimulation index [SI] and relative response [RR] as follows: SI = Test mean count per minute [cpm] Autologous mean [cpm] Where: Test cpm = Mean counts per minute for a woman's cells [female responder] against mitomycin treated husband's stimulator cells [male stimulator]