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The course of hepatitis B virus (HBV) infection may be influenced by the host immune response. A prospective study was carried out in ninety-eight subjects (mean age = 23 years) HBs antigens carriers of hepatitis B and living in Dakar, Senegal. We analysed the HLA-A, -B, and C antigens distribution compared to that one of a control (HBs negative) healthy senegalese population (n = 96) living in Dielmo village where a longitudinal study was set-up since 1990. The HLA class I typing was performed by microlymphocytotoxicity assays. The most frequent HLA-A, -B, -C antigens found were: locus A: A23 (33.6%), A2 (25%), A30 (25%), locus B: B8 (31%), B7 (16.3%), B58 (11.9%), B35 (11%), B49 (11%), B53 (10.8%) and locus C: Cw7 (39.1%), Cw17 (39.1%), Cw3 (36.9%), Cw4 (36.6%). Significant differences (P < 0.001) were found between the donors and the control group for the following HLA antigens: A1, A23, B8 and Cw3. The detection of HBe antigen was positive in 26/84 blood donors. It was observed a significant difference (p < 0.01) between positive and negative HBe donors for HLA-A1 allele with an odds ratio of 6.25. All the donors carrying the HLA haplotype: A1-B8-Cw7 (11.5%) were positive in HBe antigen. HLA: B8-Cw7 haplotype (detected in 8.5% of positive donors) seems to be likely associated with a liver cancer according to many reports. An adequate follow-up should be set-up for positive HBe subjects carrying a susceptible HLA type.

In this study, we compared the serological standard typing method and the DNA genotyping PCR-SSP for the characterization of HLA-DQ alleles in a senegalese population. For this purpose, 120 individuals leaving in Dielmo were typed using the microlymphocytotoxicity assay and the PCR-SSP DQ low Resolution method. A discordance of 42.5% (51/120) was found between these two methods. Thirty % (36/120) of serological typed persons failed to be typed by PCR-SSP method whereas 1% (1/120) assigned by PCR-SSP failed to be characterized by serology. Advantages and limits of these two typing methods and also the genetic background of our study population were valid arguments to comment our findings. The PCR-SSP, as suggested by several authors, is reliable, accurate and fast for HLA class II alleles characterization. Nevertheless, it needs, to become an alternative HLA typing method, available primers adapted to genetic background of study population.

41 patients senegalese patients suffering from clinically defined severe malaria were studied in the intensive medical care unit of the Hôpital Principal in Dakar, Senegal. All of these individuals lived in Dakar, an area of low and seasonal Plasmodium falciparum transmission. In this study, we aim to determine in one hand, the cytokine levels of TNF-alpha, TNF-alpha sRI, TNF-alpha sRII, IL-2 sR, IL-6, IL-6 sR, and IL-10 to evaluate their prognostic value in the course of the disease; in the other hand, the influence of the HLA-DR alleles in the susceptibility to get severe malaria. At the day of admission (day 0) and 3 days later, one or two blood samples were collected for each patient to assess different biological parameters. Plasma samples were tested for cytokines cited above by ELISA (Medegenix EASIA kits) and DNA samples for HLA-DR by PCR-SSP genotyping. The concentrations of all the cytokines and/or their receptors were significantly increased at day 0 in the patients who died (TNF-alpha = 455 +/- 480 pg/ml, IL6 = 511 +/- 396 pg/ml) and decreased rapidly in the patients who survived from the disease (TNF-alpha = 354 +/- 629 pg/ml, IL6 = 453 +/- 706 pg/ml). A fatal issue seems likely related to the age of patients (20 +/- 12 years for surviving patients and 31 +/- 16 years for patients who died) and the kinetic of the cytokines. Significant differences were observed (pc < 0.001) between patients with severe malaria and a control group for the following HLA alleles: DR3, DR10 and DR13. The HLA-DR13 allele was found positively and highly associated with severe malaria.

In this study, we reported the HLA-class II genotyping by PCR-SSP (PCR-Sequence Specific Primers). This method was used to subtype the HLA-DRB1*13 and 11 alleles in Dielmo population. The most frequent DRB1*11 subtypes were 1101, 1102 et 1104; the frequency of 1102 was the highest (18.5%). The DRB1*13 subtypes were more polymorphic in the population and DRB*1304 was the most common subtype (15%). There were significant differences between the ethnic groups for some subtypes of DRB1*11 and 13 alleles.