Black individuals who are HIV-positive may have a decreased ratio of influenza-specific immunoglobulin G (IgG) vs IgM after influenza vaccination, suggesting impaired class-switching, according to study results published in Vaccine.
In black women and men who have sex with men (MSM), race and race-associated behavioral changes are potential drivers of increased HIV-1 acquisition compared with white women and MSM. In the black population, increased HIV incidence has been associated with factors including circumcision, access to HIV care and antiretroviral therapy (ART) treatment, addictive drug abuse, social and psychosocial factors, and social networks. Furthermore, black individuals have less pooled prevalence of the favorable IL-28B genotype and are also more susceptible to AIDs-related cancer and opportunistic infection and have a higher mortality rate compared with white individuals.
Individuals who have HIV are susceptible to influenza infection and are therefore recommended to receive vaccination seasonally. In the general population, the IL-28B gene, age, and sex are factors related to the robustness of response to the influenza vaccine. In people with HIV, these factors are low CD4+ T-cell counts, B-cell perturbations, HIV viral replication, and chronic immune activation. However, whether or not there are racial differences in influenza vaccine responses in HIV remains unclear. Therefore, this study evaluated racial differences in seasonal influenza vaccine responses.
A total of 16 healthy controls (9 white and 7 black individuals) and 26 individuals (11 white and 15 black individuals) with HIV who were aviremic and receiving ART (plasma HIV RNA <50 copies/mL) were included in the study. Blood samples were obtained pre-vaccination (day 0) and 14 days after the administration of the seasonal influenza vaccine. Flow cytometry was used to assessed B and T cells ex vivi; enzyme-linked immunosorbent assay (ELISA) was used to characterize serologic responses in plasma. All participants were vaccinated during the 2012 to 2013 season and received the 2013/2014 influenza vaccine, which included A/Christchurch/16/2010 (H1N1); A/Texas/50/2012 (H3N2); and 1 B subtype virus, B/Massachusetts/2/2012.
The results showed that blacks individuals with HIV had decreased fold induction of IgG vs IgM after influenza vaccination, which is directly correlated with a reduced ratio of influenza-specific IgG vs IgM induction. Absolute counts of CD19+ B cells and CD4+ CD3+ T cells were similar between healthy control participants and participants with HIV, as well as between white and black participants in the 2 study groups. However, compared with white individuals with HIV, the percentage of peripheral T follicular helper (pTfh) cells was decreased in black individuals with HIV. Similarly, compared with white individuals with HIV the ratio of anti-influenza-specific IgG vs IgM induction following vaccination was decreased in black with HIV, which was directly correlated with the percentage of pTfh cells. This racial difference and correlation were not seen among the control participants.
Overall, the study authors concluded that, “To the best of our knowledge, this is the first reported racial differences in the frequencies of pTfh cells and ratio of influenza-specific IgG versus IgM in response to influenza vaccination in ART-treated HIV disease. This study may provide some information for vaccine design.”
Ma P, Luo Z, Qian J, et al. Decreased ratio of influenza-specific IgG versus IgM in response to influenza vaccination in antiretroviral-treated HIV-infected African Americans compared to Caucasians, and its direct correlation with the percentages of peripheral Tfh cells [published online January 14, 2020] . Vaccine. doi:10.1016/j.vaccine.2020.01.002