HLA-A*01 allele: a risk factor for dengue haemorrhagic fever in Brazil's population

Severe forms of dengue, such as dengue haemorrhagic fever (DHF) and dengue shock syndrome, are examples of a complex pathogenic mechanism in which the virus, environment and host immune response interact. The influence of the host's genetic predisposition to susceptibility or resistance to infectious diseases has been evidenced in several studies. The association of the human leukocyte antigen gene (HLA) class I alleles with DHF susceptibility or resistance has been reported in ethnically and geographically distinct populations. Due to these ethnic and viral strain differences, associations occur in each population, independently with a specific allele, which most likely explains the associations of several alleles with DHF. As the potential role of HLA alleles in the progression of DHF in Brazilian patients remains unknown, we then identified HLA-A alleles in 67 patients with dengue fever and 42 with DHF from Rio de Janeiro, Brazil, selected from 2002-2008 by the sequence-based typing technique. Statistical analysis revealed an association between the HLA-A*01 allele and DHF [odds ratio (OR) = 2.7, p = 0.01], while analysis of the HLA-A*31 allele (OR = 0.5, p = 0.11) suggested a potential protective role in DHF that should be further investigated. This study provides evidence that HLA class I alleles might be important risk factors for DHF in Brazilian patients.

Experience of HLA Antibody Testing in the International Serum Exchange Program / 대한진단검사의학회지

BACKGROUND: When organ transplantation or HLA-matched platelet transfusion is considered, accu-rate identification of HLA antibody specificity in the recipient's serum is very important. In this study, we report our experience in an international quality control program. METHODS: For external quality control in a HLA antibody test, the International Serum Exchange Program distributes serum samples, generally showing polyspecific reactivity for cross-reactive epitope groups (CREGs), to participating laboratories: 4 samples per survey, 10 surveys per year. Participating in the program from May 1998 to August 2000 (24 surveys), we performed HLA antibody identification of 96 serum samples by the AHG-CDC (anti-human globulin-complement dependent cytotoxicity) method using frozen lymphocyte trays (36 lymphocyte panels). We compared the results of our laboratory with those of the total participants (all methods combined, 72 to 92 laboratories per survey) using the analyzed survey results distributed by the program organizer. RESULTS: We analyzed the survey results for the antibodies to relatively common HLA antigens in Koreans (antigen frequency >1%). For the HLA antibodies detected in >or=20% of participants, our detection rate was higher by 10-15% than that of all laboratories (HLA-A, 76% vs 65%; HLA-B, 73% vs 57%). And for the HLA antibodies detected in >or=50% of the participants, our detection rate was as high as 88% for HLA-A and 87% for HLA-B. Our detection rate for a few antibody specificities was lower than that of all laboratories, namely HLA-A1, A3, B35, and B55. Among these, A1, A3, and B55 were of lower incidence antigens in Koreans (antigen frequency 3-4%), indicating that the low detection rate was due to a limitation in the composition of lymphocyte panels. CONCLUSIONS: In general, our detection rate of HLA antibodies was superior to the average detection rate of the total participant laboratories. We would be able to improve the low detection rate for a few antibody specificities to lower incidence antigens by refining the composition of lymphocyte panels.

Human leucocyte antigen [HLA] class one [A1, B7] and class two [DR-11] are new factors affecting the incidence of colonic carcinoma

The problem of colonic carcinoma is still a dilemma regarding, diagnostic and therapeutic strategy. Many factors have been found to affect the incidence of this type of cancer such as age, sex, diet and previous abdominal surgery. A survey study revealed that in normal [control] population HLA-A1 was positive in about 50%. HLA-B7 was positive in about 8% and HLA-DR11 was positive in about 40%. The aim of this study was to find a relation between the above-mentioned types of HLA and the increased or decreased risk of incidence of colonic carcinoma. Thirty patients were diagnosed after using: careful history taking, clinical examination, laboratory, and radiological investigations. Finally colonoscopy and biopsy were done. Detection of [HLA- A1. B7] was done serologically using Sigma USA. Detection of [HLA-DR 11] was done using lymphobeads method [Biotest Great Britain [UK] Itd]. HLA-A1 was found to be positive in eight patients while HLA-B7 was positive in seven patients, and HLA-DR 11 was positive in ten patients. HLA-A1 positive results were associated with increased risk of incidence of colonic carcinoma by 45%, while HLA-B7 positive results were associated with increased risk of incidence by 233% and presence of HLA-DR11 positive results were associated with decreased risk incidence by 80%. So we can consider the above-mentioned HLA types as new factors affecting the incidence of colonic carcinoma

Doenca de Jorge Lobo e sua relacao com os antigenos do sistema HLA / Disease Jorge Lobo and his relationship with the antigens of the HLA system

A doenca de Jorge Lobo e uma micose causada pelo fungo Lacazia loboi (L.loboi), o qual se assemelha filogenetica e antigeneticamente ao Paracoccidioides brasiliensis (P.brasiliensis). Devido as caracteristicas epidemiologicas e aos poucos estudos relacionados aos apectos imunologicos dessa doenca, o objetivo desse trabalho foi pesquisar a frequencia dos antigenos HLA de classe I e classe II em 21 pacientes portadores da doenca de Jorge Lobo e comparar com populacao controle. As tipagens HLA de classe I foram realizadas pela tecnica de microlinfocitotoxicidade e as de classe II pelo metodo de PCR-SSP. Como controles, utilizaram-se duas populacoes: uma do Estado do Acre e outra da populacao brasileira, segundo os dados publicados no 11th IHW no Japao

HLA na dermatologia: o que existe de concreto / HLA in dermatology: what there are of real

A participaçäo genética nas doenças auto-imunes torna-se cada vez mais evidente. A imunogenética compreende a análise de genes e seus produtos, localizados na regiäo 6p21, no braço curto do cromossomo 6, que também é conhecida como complexo principal de histocompatibilidade (CPH). Antígenos HLA de classe I, II e III säo altamente polimórficos. Um grande número de doenças dermatológicas está associado ao HLA. Essas associaçöes variam em diferentes populaçöes e grupos étnicos. A determinaçäo do HLA pode estar associada ao curso da doença, predileçäo anatômica podendo ser utilizado como subsídio para o diagnóstico. Entretanto, o papel patogênico do HLA na suscetibilidade ou resistência a determinadas doenças cutâneas permanece incerto. Nesta revisäo, discutem-se alguns aspectos do sistema HLA, o papel patogênico dos antígenos HLA e sua associaçäo com doenças dermatológicas.

Lack of association between paracoccidioidomycosis and HLA histocompatibility antigens

Foi realizado um estudo de associaçäo HLA e doença, onde 40 pacientes com diagnóstico clínico e laboratorial de Paracoccidioidomicose (PCM) e, 80 indivíduos brancos, clinicamente saudáveis, usados como controles, foram tipados para os antígenos HLA-A, -B, -Cw, -DR e - DQ. Os resultados obtidos mostraram uma associaçäo positiva dos antígenos HLA-A1 (P = 0.050), -A3 (P = 0.014), -B8 (P = 0.014), -Cw7 (P = 0.020), - DQw2 (P = 0.014) e DQw3 (P = 0.019) nos pacientes e uma associaçäo negativa dos antígenos HLA-Cw3 (P = 0.032), -DR1 (P = 0.019) e -DQw1 (P = 0.003) no mesmo grupo, comparados aos controles e, sem correçäo pelo número de antígenos testados (50). Os resultados sugerem uma fraca associaçäo destes antígenos HLA com a doença, uma vez que outros fatores podem também estar influenciando na susceptibilidade genética à PCM. Se corrigido o valor de P, segundo Svejgaard e Ryder (HLA and disease, J, Dausset and A. Svejgaard, eds., 1977), nenhuma associaçäo é demonstrada neste estudo

On the association between HLA-A1 and B5 and clinical forms of schistosomiasis mansoni

The association between both HLA-A1 and B5 antigens and chronic forms of human schistosomiasis was studied in 64 patients and 26 normal controls from a southern Brazilian hospital. No apparent correlation between the chronic forms of the disease and the expression of those antigens was detected. However, the analysis of these date together with those observed on an Egyptian sample suggests that the presence of either of the antigens and the hepatomegalic forms of schistosomiasis is significant, without heterogeneity. Converseley, the association of histocompatibility antigens with splenogegaly is consistent and significant only for HLA-B5, but not HLA-A1