Study of the immune response and the impact of memory B cells upon immunization against streptococcus pneumoniae in HIV-1 infected patients

Streptococcus pneumoniae infections account for high morbidity and mortality in HIV-1 patients. The introduction of highly active antiretroviral therapy (HAART) has lead to a decline in the incidence of invasive pneumococcal disease, though it still affects HIV-infected more often than healthy individuals. B cells comprise one the most dysfunctional lymphocyte populations in patients with HIV infection. During chronic viral replication functional perturbations of B-cells occur. The loss of memory B cells is one aspect of dysfunction in HIV infection. Moreover, there is evidence for alterations in B cell populations against T-cell–independent antigens such as pneumococcal polysaccharides. Although antibody levels are useful as a surrogate marker of protection, they have limitations and they cannot fully describe the immune response to vaccines. Aim of this study was to fully assess immunogenicity of 23-PPV in HIV patients. Specifically, we tried to record and evaluate associations between circulating B cell subpopulations and antibody response during a 48 week period, pre and post immunological stimulation with the recommended vaccine against Streptococcus pneumoniae in HIV-1 patients. We studied two patient groups with distinguished infection status, those successfully treated with HAART and those being HAART naïve. This is a longitudinal study including 66 HIV-1 patients, of whom 31 were antiretroviral naïve and 35 under successful HAART, matched for age, CD4 cell count and duration of HIV infection. All patients were immunized for the first time against Streptococcus pneumoniae with the 23-valent polysaccharide vaccine. Antibody levels and B cells populations were measured pre, 4 weeks and 48 weeks post vaccination with ELISA and flow cytometry respectively. Phagocytosis was assessed using flow cytometry. Patients under HAART had significantly higher antibody levels in all three time points, at baseline (p=0.0005), 4 weeks (p=0.006) and 48 weeks (p=0.001) post vaccination. 50 patients doubled their initial IgG level (responders), while 16 were non-responders. Though, the vast majority of non-responders were under HAART treatment. Memory B cells were diminished over time in both groups, though treated patients maintained higher levels of all subsets studied, with the exception of activated memory and isotype switched memory B cells. Total B cells, memory B cells and isotype-switched memory B cells before immunization correlated with antibody levels pre 23-PPV administration (p=0.06, p=0.058 και p=0.012 respectively) independently of HAART intake. The vaccine-specific IgG concentration measured 4 weeks post vaccination correlated positively with total baseline B cell (p=0.02)and exhausted memory B cell subset (p=0.07). Phagocytis was higher in treated patients. Despite adequate antibody response, high proportion of these patients presented impaired phagocytotic activity. We found that treated patients had higher levels of several B cell subsets before vaccine administration. Moreover, we showed that naïve patients with continuous viral replication preserved increased activated and isotype-switched memory B cells, while nadir CD4 predicted low resting memory and isotype-switched memory B cells. Finally, HAART was associated with increased total B and exhausted memory B cells, which seemed to predict IgG responses. Despite effective antibody formation, phagocytosis is modest, which clearly denotes the impairment in the immune capacity of HIV-1 patients.Οι λοιμώξεις από τον Streptococcus pneumoniae ευθύνονται για υψηλή νοσηρότητα και θνητότητα στους HIV-1 ασθενείς. Η είσοδος της υψηλής δραστικότητας αντιρετροϊκής αγωγής (HAART) οδήγησε σε μείωση της επίπτωση πνευμονιοκοκκικής νόσου, ωστόσο εξακολουθεί να πλήττει συχνά αυτούς τους ασθενείς. Τα Β λεμφοκύτταρα αποτελούν έναν από τους πιο δυσλειτουργικούς πληθυσμούς κυττάρων στην HIV λοίμωξη. Υπάρχουν στοιχεία για σημαντική διαταραχή σε Β λεμφοκυτταρικούς πληθυσμούς με δράση ενάντια σε Τ-ανεξάρτητα αντιγόνα, όπως είναι ο Streptococcus pneumoniae. Σκοπός της παρούσας μελέτης ήταν να αξιολογήσει πλήρως την ανοσογονικότητα του 23-PPV σε ασθενείς με HIV. Ειδικότερα, προσπαθήσαμε να καταγράψουμε και να αξολογήσουμε τους αριθμούς των κυκλοφορούντων Β κυτταρικών υποπληθυσμών στο περιφερικό αίμα και της αντισωματικής απάντησης κατά τη διάρκεια μιας περιόδου 48 εβδομάδων μετά τον εμβολιασμό με το πολυσακχαριδικό εμβόλιο έναντι του Streptococcus pneumoniae σε HIV-1 ασθενείς. Ταυτόχρονα, εκτιμήσαμε την φαγοκυτταρική λειτουργία, ως έμμεσο δείκτη και προγνωστικό παράγοντα της ανοσιακής επάρκειας. 35 ΗΙV-1 ασθενείς υπό θεραπεία και 31 χωρίς θεραπεία εμβολιάστηκαν με το 23-PPV. Οι υποπληθυσμοί των Β λεμφοκυττάρων προσδιορίστηκαν με κυτταρομετρία ροής σε τρία διαφορετικά στιγμιότυπα: πριν τον εμβολιασμό, 4 και 48 εβδομάδες μετά τον εμβολιασμό. Ο έλεγχος του τίτλου των IgG αντισωμάτων για τους ορότυπους του εμβολίου έγινε με χρήση ELISΑ. Η φαγοκυτταρική ικανότητα των ουδετερόφιλων και των μονοκυττάρων εκτιμήθηκε πριν και 48 εβδομάδες μετά τον εμβολιασμό. Τα επίπεδα των αντισωμάτων ήταν υψηλότερα στους θεραπευόμενους ασθενείς, πριν τον εμβολιασμό (p=0,0005) ,την 4η εβδομάδα (p=0,006) και την 48η εβδομάδα ( p=0,001 ).Οι δυο ομάδες ασθενών διέφεραν ακόμα ως προς την ανταπόκριση στον εμβολιασμό (p=0.047), ενώ και η διαχρονική τους εξέλιξη παρουσίαζε σημαντικές διαφορές(p=0.009). Καμιά στατιστική διαφορά στα επίπεδα των ολικών Β και των άλλων υποπληθυσμών μνήμης δεν ανιχθεύθηκε ανάμεσα στους θεραπευόμενους και μη θεραπευόμενους ασθενείς πριν τον εμβολιασμό. Οι μη θεραπευόμενοι ασθενείς διατηρούσαν αυξημένα επίπεδα ενεργοποιημένων και λεμφοκυττάρων μνήμης με μεταστροφή ισοτύπου, ενώ ο αριθμός των ναδίρ CD4 Τ λεμφοκυττάρων προέβλεπε χαμηλές συγκεντρώσεις ηρεμούντων Β λεμφοκυττάρων και λεμφοκυττάρων μνήμης με μεταστροφή ισοτύπου στην πορεία του χρόνου. Τα ολικά Β λεμφοκύτταρα, τα Β λεμφοκύτταρα μνήμης και τα Β λεμφοκύτταρα μνήμης με μεταστροφή ισοτύπου, συσχετίστηκαν με τις συγκεντρώσεις των αντισωμάτων πριν τον εμβολιασμό, ανεξάρτητα από τη λήψη HAART(p=0.059, p=0.058 και p=0.012 αντίστοιχα). Η HAART συσχετίστηκε με αυξημένες συγκεντρώσεις ολικών Β κυττάρων(p=0.02) και εξουθενωμένων Β λεμφοκυττάρων μνήμης(p=0.07), που φάνηκε να προβλέπουν την IgG αντισωματική απάντηση στο εμβόλιο. Η φαγοκυτταρική δραστηριότητα ήταν αποτελεσματικότερη στους ασθενείς που ελάμβαναν θεραπεία. Διαχρονικά παρατηρήθηκε μείωση της φαγοκυτταρικής ικανότητας και στις δύο ομάδες των ασθενών. Παρά τη διαμόρφωση ικανών αντισωματικών συγκεντρώσεων, υψηλά ποσοστά αυτών εμφάνισαν ελαττωμένη φαγοκυτταρική δραστηριότητα, ιδίως μεταξύ των ασθενών που ελάμβαναν θεραπεία. Οι μεταβολές υποπληθυσμών των Β λεμφοκυττάρων φαίνεται να επιδρούν στην αντισωματική απάντηση στο 23-δύναμο πολυσακχαριδικό εμβόλιο στους ασθενείς με HIV-1 λοίμωξη. Οι επιδράσεις στους διάφορους Β κυτταρικούς πληθυσμούς δεν αποκαθίστανται πλήρως με τη θεραπεία. Τα αποτελέσματά μας επισημαίνουν την ανάγκη για προσδιορισμό κι άλλων δεικτών ανοσογονικότητας και προστασίας, συνεπώς, η ολοκληρωμένη μελέτη όλων των πιθανά εμπλεκόμενων παραμέτρων της ανοσιακής απόκρισης, ίσως αποτελέσει μια καλύτερη προσέγγιση της αξιολόγησης της ανοσογονικότητας του 23-PPV στους ασθενείς με HIV-1 λοίμωξη

West Nile Virus Seroprevalence and Behavioral Risks in HIV-1 Infected Individuals, Northern Greece, 2011

Objectives: This study sought to assess the West Nile Virus (WNV) seroprevalence and behavioral risk factors for WNV infection in HIV-1 infected individuals in Northern Greece in 2011. Methods: We prospectively enrolled 91 HIV-1 consecutive patients followed up in the HIV clinic of the AHEPA University Hospital in the period from November to December 2011. Serum samples were tested for the presence of WNV IgG antibodies. All subjects were administered a standardized questionnaire to evaluate for risk factors for WNV infection. Results: WNV IgG antibodies were detected in three subjects (3.3%, 95% CI 0.7-9.3%), two of whom were of African origin. The prevalence of WNV antibodies in HIV patients of Greek origin was 1.2% (95% CI: 0.03% - 6.3%). In the sample surveyed, 53.6% (95% CI: 42.4% to 64.5%) were aware of WNV prevention measures; 2.2% reported no implementation of prevention measures, whereas 46.1% implemented at least three measures. Approximately one half of the patients reported outdoor activities for more than two hours from dusk to dawn. None of the IgG-positive patients reported any symptoms compatible with WNV disease during the season at risk. Conclusions: Among native Greek HIV patients, the WNV seroprevalence is 1.2%. A considerable proportion of patients was aware of WNV prevention measures and implemented some of these. HIV patients and other categories of immunocompromised patients are at increased risk of neuroinvasive disease, and widespread implementation of prevention measures should be strongly encouraged in this patient population

Prolonged and high dosage of tigecycline – successful treatment of spondylodiscitis caused by multidrug-resistant Acinetobacter baumannii: a case report

Abstract Background The incidence of infectious spondylodiscitis has been increasing over the last few years. This reflects the expanding elderly and immunocompromised populations and the rising implementation of invasive spinal procedures. Infection may be inoculated into the disc space directly during invasive spinal procedures. Osteomyelitis caused by Acinetobacter species is rare and mainly caused by multidrug-resistant strains. Case presentation We present the case of a 72-year-old Greek woman with postoperative spondylodiscitis caused by a multidrug-resistant Acinetobacter baumannii strain that was successfully treated, after she declined surgical treatment, with prolonged and high dosage of tigecycline. She received intravenously administered tigecycline 200 mg per day for 60 days and then 100 mg per day for a total of 102 days and was infection-free. Conclusions We reviewed the literature on the role of Acinetobacter baumannii as a cause of osteomyelitis, emphasizing the difficulty of treatment and the potential role of tigecycline in conservative treatment of the infection. We believe that 102 days in total is the longest time that any patient has received tigecycline in the literature, thus our patient is a unique case of successful treatment of spondylodiscitis

The controversial impact of B cells subsets on immune response to pneumococcal vaccine in HIV-1 patients

Background: Chronic HIV infection leads to severe perturbations of the B cell populations and hypo-responsiveness to vaccines. The associations between circulating B cell subpopulations and the antibody response to pneumococcal polysaccharide vaccine in antiretroviral-naïve and treated patients were studied. Methods: Sixty-six HIV-infected adults were grouped according to antiretroviral therapy (ART) and CD4+ cell count; 31 were ART-naïve and 35 were ART-treated, and they were matched for age, CD4 cell count, and duration of HIV infection. All subjects were immunized with the 23-valent polysaccharide vaccine against Streptococcus pneumoniae. Pre- and post-vaccination B cell subpopulations were assessed by flow cytometry. Serum IgG concentrations for vaccine serotypes were quantified by ELISA at baseline and at 4 and 48 weeks post-vaccination. Results: Patients under highly active antiretroviral therapy (HAART) had significantly higher antibody levels against pneumococcal vaccine antigens, while an adequate number of patients responded to vaccination. Memory B cells were diminished over time, although treated patients maintained higher levels of all subsets studied, with the exception of activated memory and isotype-switched memory B cells. Conclusions: Low concentrations of total B cells and exhausted memory B cells was the strongest independent predictor of poor pneumococcal vaccine responsiveness, emphasizing that B cell subset disturbances are associated with a poor vaccine response among HIV-infected patients

Predominance of Clostridioides difficile PCR ribotype 181 in northern Greece, 2016-2019.

Thirty-five different PCR ribotypes were identified. The most common RTs identified were: 181 (36%, 80/221), 017 (10%, 21/221), 126 (9%, 19/221), 078 (4%, 9/221) and 012 (4%, 8/221). Notably, the predominant RT181, with toxin profile tcdA + tcdB + cdtA + cdtB+, was identified in seven out of ten participating hospitals

Denosumab versus zoledronate for the treatment of low bone mineral density in male HIV-infected patients

Introduction: We aimed to compare annual changes in the bone mineral density (BMD) at the lumbar spine (LS) and the femoral neck (FN) in males with HIV-associated osteoporosis treated with either zoledronate (ZOL) or denosumab (Dmab). Methods: In this open label, 12-month, prospective, multicenter, cohort study, 23 male people living with HIV (PLWH) under antiretroviral therapy (ART) with low BMD were administered either a single iv infusion of ZOL 5 mg (n = 10) or Dmab 60 mg sc injections biannually (n = 13). Fourteen age-matched male PLWH with normal BMD served as controls. BMD was measured at baseline and at 12 months. Results: LS-BMD increased within both treatment groups at 12 months (ZOL 5.43% +/- 3.60%, p = 0.001; Dmab 5.76% +/- 3.44%, p < 0.005) and decreased in controls ( 2.58% +/- 4.12, p = 0.04). FN-BMD increased in both treatment groups at 12 months (ZOL 7.23% +/- 5.46%, p = 0.003; Dmab 3.01% +/- 2.46%, p < 0.005), and remained unchanged in controls (1.22% +/- 2.09, p = 0.06). LS-BMD changes did not differ between the two treatment groups, but FN-BMD changes were more prominent in the ZOL group (p < 0.05). None of our study cohort sustained new fragility fractures during the 12-month study period, and no case of acute phase response was recorded in the ZOL group. Conclusions: In male PLWH under ART requiring osteoporosis treatment both ZOL and Dmab are efficient and well tolerated therapeutic options achieving BMD increases at least for the first year of treatment

Circulating microRNAs Related to Bone Metabolism in HIV-Associated Bone Loss

The pathophysiology of human immunodeficiency virus (HIV)-associated bone loss is complex and to date largely unknown. In this study, we investigated serum expression of microRNAS (miRNAs) linked to bone metabolism in HIV-associated bone loss. This was a case-control study. Thirty male individuals with HIV infection (HIV+) and osteoporosis/osteopenia (HIV+/OP+) (cases) and 30 age-matched male HIV+ individuals with normal bone mass (HIV+/OP−) (controls) were included in the analysis. Thirty male individuals matched for age without HIV infection (HIV−), were also included as second controls. The selected panel of miRNAs was as follows: hsa-miRNA-21-5p; hsa-miRNA-23a-3p; hsa-miRNA-24-2-5p; hsa-miRNA-26a-5p; hsa-miRNA-29a-3p; hsa-miRNA-124-3p; hsa-miRNA-33a-5p; and hsa-miRNA-133a-3p. Within the cohort of HIV+ individuals, relative serum expression of miRNA-21-5p and miRNA-23a-3p was significantly lower (p < 0.001) while the expression of miRNA-24-2-5p was significantly higher (p = 0.030) in HIV+/OP+ compared to HIV+/OP−. Expression of miRNA-21-5p demonstrated a sensitivity of 84.6% and a specificity of 66.7 in distinguishing HIV+/OP+ individuals. Expression of circulating miRNAs related to bone metabolism; miRNA-23a-3p, miRNA-24-2-5p, and miRNA-21-5p is significantly altered in HIV+OP+ individuals, in line with data on other causes of osteoporosis, suggesting a common pattern of circulating miRNAs independent of the underlying cause

Coxiella Endocarditis as the Cause of Recurrent Fever and Brain Abscess in a Patient with Complex Congenital Heart Disease: A Case Report and Literature Review

Introduction. Blood culture-negative infective endocarditis (BCNIE) can present subtly and is associated with a diagnostic delay leading to increased morbidity and mortality. Case Report. We present the case of an 18-year-old male with a history of complex congenital heart disease and 3-year intermittent episodes of fever of unknown origin, who was referred to our hospital for upper and lower extremity focal seizures. Laboratory blood tests were normal, blood cultures were negative, and brain imaging revealed an abscess. Cardiology consultation was requested, and transthoracic echocardiography revealed an intracardiac vegetation. Empiric antibiotic treatment with sultamicillin, gentamycin, and meropenem was initiated. Serology testing was positive for Coxiella burnetii, and the diagnosis of BCNIE was established. The antibiotic course was changed to oral doxycycline for 36 months and led to resolution of IE, with no vegetation detected on TTE after 15 months. Conclusion. BCNIE is a life-threatening disease entity that can lead to severe complications, such as valve regurgitation, emboli, and death. Patients with congenital heart disease are particularly vulnerable to IE. Timely diagnosis and antibiotic management are of paramount importance in order to avoid the potentially fatal sequelae