Absence of human leukocyte antigen-B*57:01 amongst patients on antiretroviral therapy in Nigeria: Implications for use of abacavir.

Background: The presence of human leukocyte antigen (HLA) B*57:01 allele predicts hypersensitivity reaction (HSR) to abacavir (ABC), a nucleoside reverse-transcriptase inhibitor used for human immunodeficiency virus (HIV) treatment. However, the prevalence of this allele amongst Nigerians with HIV is yet to be established. We aimed to determine the prevalence of HLA-B*57:01 allele amongst Nigerians with HIV infection. Methods: We conducted a multicentre cross-sectional epidemiologic survey. Between April 2016 and April 2017, patients were enrolled across five HIV treatment facilities in Nigeria. Participants' demographic information and their history of ABC exposure were obtained, and venous blood was obtained for HLA typing. Results: One thousand five hundred and four (1504) adults were enrolled, with a mean age of 44.6 ± 10.7 years, 1078 (71.7%) were female. 1463 (97.3%) were on antiretroviral therapy. ABC use was reported by 12 (0.8%) participants and none reported HSR. Of 1500 blood samples that were processed, 1458 (97.2%) were successfully typed. Of these, 132 (9.1%) were HLA-B*57 positive using non-specific low-resolution HLA-B*5701 primer mix. On further analysis, none of the 132 samples (0%) had the HLA-B*5701 allele. Conclusion: HLA-B*5701allele is rare amongst Nigerians.

A modified anthrax toxin-based enzyme-linked immunospot assay reveals robust T cell responses in symptomatic and asymptomatic Ebola virus exposed individuals.

BACKGROUND: Ebola virus (EBOV) caused more than 11,000 deaths during the 2013-2016 epidemic in West Africa without approved vaccines or immunotherapeutics. Despite its high lethality in some individuals, EBOV infection can produce little to no symptoms in others. A better understanding of the immune responses in individuals who experienced minimally symptomatic and asymptomatic infection could aid the development of more effective vaccines and antivirals against EBOV and related filoviruses. METHODOLOGY/PRINCIPLE FINDINGS: Between August and November 2017, blood samples were collected from 19 study participants in Lagos, Nigeria, including 3 Ebola virus disease (EVD) survivors, 10 individuals with documented close contact with symptomatic EVD patients, and 6 control healthcare workers for a cross-sectional serosurvey and T cell analysis. The Lagos samples, as well as archived serum collected from healthy individuals living in surrounding areas of the 1976 Democratic Republic of Congo (DRC) epidemic, were tested for EBOV IgG using commercial enzyme-linked immunosorbent assays (ELISAs) and Western blots. We detected antibodies in 3 out of 3 Lagos survivors and identified 2 seropositive individuals not known to have ever been infected. Of the DRC samples tested, we detected antibodies in 9 out of 71 (12.7%). To characterize the T cell responses in the Lagos samples, we developed an anthrax toxin-based enzyme-linked immunospot (ELISPOT) assay. The seropositive asymptomatic individuals had T cell responses against EBOV nucleoprotein, matrix protein, and glycoprotein 1 that were stronger in magnitude compared to the survivors. CONCLUSION/SIGNIFICANCE: Our data provide further evidence of EBOV exposure in individuals without EVD-like illness and, for the first time, demonstrate that these individuals have T cell responses that are stronger in magnitude compared to severe cases. These findings suggest that T cell immunity may protect against severe EVD, which has important implications for vaccine development.