Association between circulating exhausted CD4+ T cells with poor meningococcal C conjugate vaccine antibody response in HIV-infected children and adolescents

OBJECTIVES: To investigate the expression levels of surface markers of activation (CD38 and HLA-DR), inhibition (PD-1, TIGIT and CD57) and co-stimulation (CD28 and CD127) on CD4+ T cells of children/adolescents with vertical HIV infection (HI patients) and HIV-uninfected (HU) controls vaccinated with the meningococcal C conjugate vaccine (MCC). METHODS: HI patients (n=12), aged 8-17 years, were immunized with two MCC injections, while HU controls (n=9), aged 5.3-10.7 years, received a single MCC dose (as per national recommendation at the time of this study, a single MCC vaccine dose should be given for healthy children and youth aged 1-18 years). The HI patients were categorized according to the combined antiretroviral therapy (cART) treatment. Blood samples were obtained before vaccination, after priming, and after the administration of a booster dose of vaccine to determine the serum bactericidal antibody (SBA) titers and the expression levels of surface markers on CD4+ T cells by flow cytometry. The levels of serum cytokines, IL-4 and CXCL-13 were also measured using Luminex kits. RESULTS: The co-expression of the TIGIT-HLA-DR-CD38 molecules increased in the CD4+ T cells of HI patients/no-cART who also showed a lower frequency of CD127+CD28+ CD4+ T cells than HI patients/cART and HU group subjects. There were significant negative correlations between the frequency of exhausted CD4+ T cells and the SBA response. IL-4 levels were higher in HI patients/cART and positively correlated with SBA titers but negatively associated with the expression of exhaustion markers. Moreover, the CXCL-13 levels were positively correlated with the exhausted CD4+ T cells. CONCLUSION: The results of our study suggest that the co-expression of exhaustion markers and/or loss of co-stimulatory molecules influence the SBA response in HI patients.

Antibody persistence following meningococcal C conjugate vaccination in children and adolescents infected with human immunodeficiency virus / Persistência de anticorpos seguida de vacina conjugada meningocócica C em crianças e adolescentes infectados por vírus da imunodeficiência humana

Abstract Objective: HIV-infected individuals (HIVI) are threatened by meningococcal infection and presented lower response to vaccines. Data are scarce on long-term persistence of human serum bactericidal antibody (hSBA) after a meningococcal C conjugate (MCC) vaccine in HIVI youth; the authors aimed to describe this persistence in HIVI. Methods: HIVI and HIV uninfected individuals (HIVU), aged 2-18 years, CD4 >15% were recruited. Seroprotection (hSBA ≥1:4) at baseline and at 12-18 months after immunization was evaluated and the association of the different factors with the long-term persistence was calculated using logistic regression. Results: A total of 145 HIVI, 50 HIVU were recruited and immunized, and their median age was 11 years (median age in HIVI group was 12 years, and 10 years in HIVU group, p-value = 0.02). 85 HIVI (44%) had undetectable viral load (UVL). Seroprotection rate was 27.2%: 24.1% in HIVI and 36% in HIVU 12-18 months after immunization (p = 0.14). Baseline immunity (odds ratio [OR] = 70.70, 95% CI: 65.2-766.6); UVL at entry (OR: 2.87, 95% CI: 0.96-8.62) and lower family income (OR: 0.09, 95% CI: 0.01-0.69) were associated with seroprotection among HIVI. Conclusion: Seroprotection at 12-18 months after single dose of MCC was low for both groups, and higher among individuals who presented baseline immunity. Among HIVI, vaccine should be administered after UVL is achieved.

Resumo Objetivo: As pessoas infectadas pelo HIV (HIVI) estão sujeitas a infecção meningocócica e apresentam menor resposta a vacinas. São escassos os dados a respeito da persistência de longo prazo do anticorpo bactericida no soro humano (hSBA) após vacina conjugada meningocócica C (MCC) em HIVI jovens e visamos a descrever essa persistência em HIVI. Métodos: Foram recrutadas pessoas HIVI e pessoas não infectadas por HIV (HIVU), entre 2 e 18 anos, CD4 > 15%. A seroproteção (hSBA ≥ 1:4) basal aos 12-18 meses após a imunização foi avaliada e a associação dos diferentes fatores com a persistência de longo prazo foi calculada com a regressão logística. Resultados: Foram recrutados 145 HIVI e 50 HIVU e imunizados e sua idade média foi determinada em 11 anos (12 no grupo HIVI e 10 no grupo HIVU, valor de p = 0,02); 85 HIVI (44%) apresentaram carga viral indetectável (CVI). A taxa de seroproteção foi 27,2%: 24,1% no grupo HIVI e 36% no grupo HIVU 12-18 meses após imunização (p = 0,14). A imunidade basal [razão de chance (RC) = 7070, IC: 65,2-7666]; CVI no momento da participação (RC: 2,87, IC de 95%: 0,96-8,62) e renda familiar mais baixa (RC: 0,09, IC de 95%: 0,01-0,69) foram associadas a seroproteção entre as pessoas HIVI. Conclusão: A seroproteção aos 12-18 meses após única dose de MCC mostrou-se baixa em ambos os grupos e mais elevada entre as pessoas que apresentaram imunidade basal. Entre as pessoas HIVI, as vacinas devem ser administradas após a CVI ser atingida.

Diphtheria Antibodies and T lymphocyte Counts in Patients Infected with HIV-1

We assessed the IgG levels anti-diphtheria (D-Ab) and T cell counts (CD4+ and CD8+) in HIV-1 infected subjects undergoing or not highly active antiretroviral therapy (HAART). Approximately 70% of all HIV-1 patients were unprotected against diphtheria. There were no differences in D-Ab according to CD4 counts. Untreated patients had higher D-Ab (geometric mean of 0.62 IU/ml) than HAART-patients (geometric mean of 0.39 IU/ml). The data indicated the necessity of keeping all HIV-1 patients up-to-date with their vaccination.