Association of HLA antigens with differential responsiveness to Mycobacterium w vaccine in multibacillary leprosy patients

HLA class II and TNF genes in African Americans from the Southeastern United States: regional differences in allele frequencies

Knowledge of population major histocompatibility complex gene frequencies is important for construction of organ donor pools and for studies of disease association. Human leukocyte antigen DRB1 (HLA-DRB1), HLA-DQB1, and TNFalpha -308 (G-A) promoter genetic typing was performed in 112 healthy, unrelated African Americans (AAs) from the southeastern United States. Allele frequencies were compared with published frequency data from other AA populations. Our AA population had the highest frequency of HLA- DRB1*09 (6.7%) reported in any AA population. The frequency of the TNF alpha -308A polymorphism was also high (14.4%), when compared with published frequencies in AAs. Significant regional differences in the distribution of most HLA-DRB1 and HLA-DQB1 alleles were observed in all AA populations examined. The AA HLA-DRB1 and -DQB1 frequencies also differed from published Caucasian frequencies. This is the first report describing the distribution of TNF alpha promoter alleles in the Southeastern United States. The high DRB1*09 and TNF alpha -308A allele frequencies of our population most resemble the frequencies of these alleles in certain West African populations. These varying major histocompatibility complex gene frequencies may reflect different regional population structures among AAs in the United States, which may be due to differences in ancestral origins, migration, and racial admixture.

Host genes and infectious diseases. HIV, other pathogens, and a public health perspective

INTRODUCTION

The global impact of infectious diseases is tremendous. In 1996, the 17 million deaths from infectious diseases accounted for one third of all deaths worldwide, while the acute and chronic morbidity from infectious diseases adds an additional great burden on global health. Multiple factors, host and nonhost, influence the susceptibility of individuals and populations to infectious diseases, as well as the severity of the illness once infected.

METHODS

We review the influence of host genes on the susceptibility to and severity of viral, bacterial, parasitic and fungal infectious diseases, on vaccine responsiveness and on treatments for infections. HIV/AIDS is discussed in detail because it is an example of an infectious disease influenced by multiple host genes and because of its impact. Although the HIV/AIDS pandemic dates only since the late 1970s, it has claimed the lives of 11 million people worldwide and, today, more than 30 million people are estimated to be HIV infected.

CONCLUSION

Our greater understanding of the genetic factors that influence morbidity and mortality of infectious disease leads to new avenues of prevention and treatment that can improve the health of individuals and populations.

Association of leprosy with HLA-DR2 in a Southern Brazilian population

The association between HLA specificities and leprosy was investigated in a southern Brazilian population. One hundred and twenty-one patients and 147 controls were typed for HLA-A, B, Cw, DR and DQ. Patients were subdivided into the following subgroups, according to clinical, histological and immunological criteria: lepromatous (N = 55), tuberculoid (N = 32), dimorphous (N = 20), and indeterminate (N = 14). The frequencies of HLA specificities were compared between the total group of patients and controls, and between the same controls and each subgroup of patients. After correction of the probabilities, deviations, were not significant, except for the DR2 specificity, which presented a frequency of 44.2% in the total group of patients and 56.3% in the subgroup of individuals with the tuberculoid form of the disease, compared to 23.3% in the controls. Stratified analysis showed that the increased DR2 frequency in the total group of patients was due to the subgroups with tuberculoid and dimorphous forms. The relative risk of tuberculoid leprosy for DR2-positive individuals was 4.2, and the etiologic fraction of DR2 was 0.429. In conclusion, a positive association of the DR2 specificity with the tuberculoid form of leprosy, but not with the lepromatous, dimorphous, or indeterminate forms, was demonstrated in this Southern Brazilian population.

Do human leukocyte antigens have a role to play in differential manifestation of multibacillary leprosy: a study on multibacillary leprosy patients from north India

118 multibacillary leprosy patients with differential manifestations were studied for the antigens they expressed at MHC loci to investigate the role of human leukocyte antigens in the differential response to the same causative agent. While the lepromatous leprosy (LL) patients showed a significant increase of Bw60, DR2, DRw8 and DQw1, borderline lepromatous (BL) patients had Bw52, DR9 and DQw7 significantly more often as compared to the normal controls. A comparison of LL, BL and mid-borderline (BB) patients showed a significantly higher frequency of Bw60 in LL patients as compared to the BL. However, Bw52, Bw53, DR9 and DQw7 were found significantly more often in the BL patients as compared to the LL patients but the difference failed to reach significance after pc. A comparison of HLA antigens in BB patients with those of either the LL or BL patients did not show any significant differences.