Risk factors in HIV-1-infected patients developing repetitive bacterial infections: toxicological, clinical, specific antibody class responses, opsonophagocytosis and Fc(gamma) RIIa polymorphism characteristics

Of vascular defense, hemostasis, cancer, and platelet biology: an evolutionary perspective

We have established considerable expertise in studying the role of platelets in cancer biology. From this expertise, we were keen to recognize the numerous venous-, arterial-, microvascular-, and macrovascular thrombotic events and immunologic disorders are caused by severe, acute-respiratory-syndrome coronavirus 2 (SARS-CoV-2) infections. With this offering, we explore the evolutionary connections that place platelets at the center of hemostasis, immunity, and adaptive phylogeny. Coevolutionary changes have also occurred in vertebrate viruses and their vertebrate hosts that reflect their respective evolutionary interactions. As mammals adapted from aquatic to terrestrial life and the heavy blood loss associated with placentalization-based live birth, platelets evolved phylogenetically from thrombocytes toward higher megakaryocyte-blebbing-based production rates and the lack of nuclei. With no nuclei and robust RNA synthesis, this adaptation may have influenced viral replication to become less efficient after virus particles are engulfed. Human platelets express numerous receptors that bind viral particles, which developed from archetypal origins to initiate aggregation and exocytic-release of thrombo-, immuno-, angiogenic-, growth-, and repair-stimulatory granule contents. Whether by direct, evolutionary, selective pressure, or not, these responses may help to contain virus spread, attract immune cells for eradication, and stimulate angiogenesis, growth, and wound repair after viral damage. Because mammalian and marsupial platelets became smaller and more plate-like their biophysical properties improved in function, which facilitated distribution near vessel walls in fluid-shear fields. This adaptation increased the probability that platelets could then interact with and engulf shedding virus particles. Platelets also generate circulating microvesicles that increase membrane surface-area encounters and mark viral targets. In order to match virus-production rates, billions of platelets are generated and turned over per day to continually provide active defenses and adaptation to suppress the spectrum of evolving threats like SARS-CoV-2.

Immunogenicity of pneumococcal vaccination in HIV infected individuals: A systematic review and meta-analysis

BACKGROUND

The objective of this systematic review and meta-analysis was to summarise the literature regarding the immunogenicity of pneumococcal conjugate vaccines (PCV) and pneumococcal polysaccharide vaccines (PPSV) in adult people living with HIV (PLWH) in the era of advanced combination antiretroviral therapy (cART).

METHODS

The systematic review protocol was published online (PROSPERO ID: CRD 42020153137). We searched Medline (Ovid), EMBASE (Ovid), and the Global Health Library for publications from 2000 to June 11, 2020. We included all studies in adult PLWH that reported vaccine immunogenicity outcomes. The primary outcome was seroconversion rate (SCR) after PCV, PPSV and PCV/PPSV combined. For random-effects meta-analysis, we included studies defining SCR as a ≥ 2-fold increase in IgG from baseline, and reporting SCR for serotypes 6B, 14, or overall SCR, 1-3 months after vaccination.

FINDINGS

Our search identified 1597 unique studies, of which 115 were eligible for full-text assessment. Of these, 39 met the inclusion criteria (11 RCTs; 28 cohort studies). A high degree of heterogeneity was observed. Nineteen studies were included in the meta-analysis. Pooled overall SCRs were 42% (95% CI 30-56%), 44% (95% CI 33-55%) and 57% (95% CI 50-63%) for PLWH who received PPSV, PCV or a combination of PCV/PPSV, respectively. Compared to PPSV alone, a combination of PCV/PPSV yielded higher SCRs (OR 2.24 95% CI 1.41- 3.58), whereas we did not observe a significant difference in SCR between PCV and PPSV23 alone. There were no statistically significant differences in geometric mean post-vaccination antibody concentrations between vaccination schedules. Vaccination at higher CD4 cell counts improved immunogenicity in 8/21 studies, especially when PCV was administered. No studies assessed the long-term immunogenicity of PCV followed by PPSV23. Quality of evidence ranged from poor (n = 19) to good quality (n = 7). A limited number of pneumococcal serotypes was assessed in the majority of studies.

INTERPRETATION

We show that the recommended immunisation schedule consisting of a combination of PCV13/PPSV23, is immunogenic in PLWH in the era of advanced cART. However, the durability of this vaccination schedule remains unknown and must be addressed in future research. Vaccination with PCV should be delayed until immunological recovery (CD4>200) in recently diagnosed PLWH for optimal immunogenicity. The evidence gathered here supports wide implementation of the combination of PCV/PPSV23 for all PLWH. We recommend reassessment of this strategy once higher-valent PCVs become available.

FUNDING

HMGG is funded by a public research grant of ZonMw (project number 522004005).

Morphine modulation of toll-like receptors in microglial cells potentiates neuropathogenesis in a HIV-1 model of coinfection with pneumococcal pneumoniae

Chronic drug users account for a third of all cases of AIDS in the United States and the progression to AIDS dementia is accelerated in opiate drug abusers. Clinically, microglial activation better correlates with HIV-associated neurocognitive disorders (HAND) than productive HIV-1 infection in the CNS. Moreover, pneumococcal pneumonia is the most common opportunistic infection in individuals with HAND. We show that coinfection with Streptococcus pneumoniae may be a contributing factor in the increased prevalence of HAND in the opioid-dependent population. To date, there have been no studies published implicating the Toll-like receptors (TLR) in the neurocognitive disorders associated with NeuroAIDS in the context of opportunistic infection. Our studies show for the first time, in a morphine-dependent model, synergistic increase and activation of TLR expression in the presence of HIV-1 protein TAT and S. pneumoniae with a significant increase in proinflammatory cytokines (IL-6, TNF-α) levels. Furthermore, concurrent increases in reactive oxygen species and nitric oxide production leading to increased caspase 3 activation are also observed in both murine and human microglial cells. These effects are recapitulated with TLR 2, 4, and 9 cognate ligands (Pam3CSK4, LPS, and CpG) and significantly attenuated in TLR 2 and 4 knock-out mice and TLR2/4 double knock-out mice. Therefor, our findings clearly suggest for the first time that activation of TLRs on microglia cells by morphine and TAT in the context of S. pneumoniae infection may be a potential mechanism for the increased prevalence of HAND in HIV-infected opioid-dependent patients.

Vaccination in HIV-infected individuals

Vaccinations are key to limiting the increased risk of severe infectious diseases in HIV-infected patients for whom the risk–benefit ratio has been re-evaluated. Vaccine safety and immunogenicity depend on both vaccine type and immune deficiency, while vaccine-induced immune activation promotes a transient increase in viral load. Vaccine immunogenicity is reduced and wanes more rapidly, strengthening the need for revaccination. While inactivated vaccines are safe, attenuated vaccines are theoretically contraindicated, but the risk of infectious diseases outweighs the risks of severe adverse events in endemic areas, where the majority of HIV-infected individuals live, thus allowing their use when immune deficiency is moderate. Immune reconstitution with HAART has improved vaccine immune response, highlighting the importance of global access to and early initiation of therapy.

Effectiveness of polysaccharide pneumococcal vaccine in HIV-infected patients: a case-control study

BACKGROUND

Polysaccharide pneumococcal vaccine (PPV) is recommended among human immunodeficiency virus (HIV)-infected patients, although its effect in reducing the incidence of pneumonia or invasive pneumococcal disease is not well established. Our objective was to determine the effectiveness of 23-valent PPV in HIV-infected adults and the risk factors for pneumococcal pneumonia or invasive pneumococcal disease.

METHODS

We performed a retrospective case-control study in 4 Spanish hospitals for the period from January 1995 through December 2005 using the HIV database from each hospital to identify case patients with Streptococcus pneumoniae disease and control subjects without a history of pneumococcal infection.

RESULTS

A total of 184 case patients and 552 control subjects were identified. The factors associated with pneumococcal disease in bivariate analysis were active injection drug use (odds ratio [OR], 3.33; 95% confidence interval [CI], 2-5.55), alcoholism (OR, 3.03; 95% CI, 1.86-4.91), chronic obstructive pulmonary disease (OR, 2.58; 95% CI, 1.3-5.1), cirrhosis (OR, 6.05; 95% CI, 3.2-11.4), antiretroviral therapy (OR, 0.23; 95% CI, 0.16-0.32), trimethoprim-sulfamethoxazole prophylaxis (OR, 0.66; 95% CI, 0.45-0.97), viral load <5000 copies/mL (OR, 0.38; 95% CI, 0.26-0.54), and previous PPV (OR, 0.39; 95% CI, 0.24-0.65). Risk factors for pneumococcal disease in multivariate analysis were cirrhosis (OR, 5.64; 95% CI, 2.53-12.53), chronic obstructive pulmonary disease (OR, 2.90; 95% CI, 1.21-6.94), and alcoholism (OR, 2.15; 95% CI, 1.11-4.19), whereas protective factors were receipt of antiretroviral therapy (OR, 0.23; 95% CI, 0.14-0.36) and receipt of pneumococcal vaccine (OR, 0.44; 95% CI, 0.22-0.88), even in patients with CD4 lymphocyte counts <200 cells/microL.

CONCLUSIONS

Antiretroviral therapy and PPV have a significant, independent protective effect against pneumococcal disease, regardless of CD4 lymphocyte count; thus, all patients with HIV infection should be vaccinated with PPV to prevent pneumococcal disease.

Acute bacterial meningitis in HIV, pacients in southern Brazil: Curitiba, Paraná, Brazil

Acute communitarian bacterial meningitis and AIDS are prevalent infectious disease in Brazil. The objective of this study was to evaluate the frequency of acute communitarian bacterial meningitis in AIDS patients, the clinical and cerebrospinal fluid (CSF) characteristics. It was reviewed the Health Department data from city of Curitiba, Southern Brazil, from 1996 to 2002. During this period, 32 patients with AIDS fulfilled criteria for acute bacterial meningitis, representing 0.84% of the AIDS cases and 1.85% of the cases of bacterial meningitis. S. pneumoniae was the most frequent bacteria isolated. The number of white blood cells and the percentage of neutrophils were higher and CSF glucose was lower in the group with no HIV co-infection (p 0.12; 0.008; 0.04 respectively). Bacteria not so common causing meningitis can occur among HIV infected patients. The high mortality rate among pneumococcus meningitis patients makes pneumococcus vaccination important.

Global strategies to prevent bacterial pneumonia in adults with HIV disease

We examined the peer-reviewed literature on the burden of bacterial pneumonia and the effectiveness of interventions for its prevention among HIV-infected adults in developed and developing countries. Bacterial pneumonia rates were up to 25-fold higher among HIV-infected adults than in the general community, with rates increasing as CD4+ T-cell count decreases. In developed countries, cohort studies showed that highly active antiretroviral therapy (HAART) had the most consistent effect on reducing pneumonia. In a prospective cohort and case-control studies from these regions, pneumococcal polysaccharide vaccine reduced pneumococcal disease in certain subgroups, particularly those with higher CD4+ T cells/microL. In patients with fewer than 200 CD4+ T cells/microL, antimicrobial prophylaxis was usually effective in reducing pneumonia. In sub-Saharan Africa, randomised controlled trials concluded that co-trimoxazole prophylaxis decreased rates of bacterial pneumonia, but pneumococcal polysaccharide vaccine prevented neither pneumonia nor invasive pneumococcal disease. Although not yet fully evaluated in Africa, based on experience in industrialised nations, use of HAART in Africa may have substantial potential to prevent bacterial pneumonia.

Immunization of immunocompromised persons

Advances in medicine, science, and technology have led to increasing numbers of people in the general population with altered host defenses. The risk for clinical infection in an immunocompromised host, such as a person who has received a solid organ transplant, is determined largely by the interaction between two factors: the epidemiologic exposures the person encounters and the person's net state of immunosuppresson. Vaccination represents a crucial approach for preventing infection in the general public and immunocompromised persons. This article reviews the benefits of and risks for immunization in immunocompromised persons and provides recommendations for the use of specific vaccines.