Using serial observations to identify predictors of progression to AIDS in the Toronto Sexual Contact Study

Distinct Immunological Profiles Help in the Maintenance of Salivary Secretory IgA Production in Mild Symptoms COVID-19 Patients

Background

Relevant aspects regarding the SARS-CoV-2 pathogenesis and the systemic immune response to this infection have been reported. However, the mucosal immune response of the upper airways two months after SARS-CoV-2 infection in patients with mild/moderate symptoms is still not completely described. Therefore, we investigated the immune/inflammatory responses of the mucosa of the upper airways of mild/moderate symptom COVID-19 patients two months after the SARS-CoV-2 infection in comparison to a control group composed of non-COVID-19 healthy individuals.

Methods

A cohort of 80 volunteers (age 37.2 ± 8.2), including non-COVID-19 healthy individuals (n=24) and COVID-19 patients (n=56) who presented mild/moderate symptoms during a COVID-19 outbreak in Brazil in November and December of 2020. Saliva samples were obtained two months after the COVID-19 diagnosis to assess the levels of SIgA by ELISA and the cytokines by multiplex analysis.

Results

Salivary levels of SIgA were detected in 39 volunteers into the COVID-19 group and, unexpectedly, in 14 volunteers in the control group. Based on this observation, we distributed the volunteers of the control group into without SIgA or with SIgA sub-groups, and COVID-19 group into without SIgA or with SIgA sub-groups. Individuals with SIgA showed higher levels of IL-10, IL-17A, IFN-γ, IL-12p70, IL-13, and IFN-α than those without SIgA. In intergroup analysis, the COVID-19 groups showed higher salivary levels of IL-10, IL-13, IL-17A, and IFN-α than the control group. No statistical differences were verified in the salivary levels of IL-6 and IFN-β. Lower IL-12p70/IL-10 and IFN-γ/IL-10 ratios were found in the control group without SIgA than the control group with SIgA and the COVID-19 group with SIgA.

Conclusion

We were able to present, for the first time, that associations between distinct immunological profiles can help the mucosal immunity to maintain the salivary levels of SIgA in COVID-19 patients two months after the SARS-CoV-2 infection.

An Inflammatory Story: Antibodies in Tuberculosis Comorbidities

Mycobacterium tuberculosis (Mtb) resides in a quarter of the world's population and is the causative agent for tuberculosis (TB), the most common infectious reason of death in humans today. Although cellular immunity has been firmly established in the control of Mtb, there is growing evidence that antibodies may also modulate the infection. More specifically, certain antibody features are associated with inflammation and are divergent in different states of human infection and disease. Importantly, TB impacts not just the healthy but also those with chronic conditions. While HIV represents the quintessential comorbid condition for TB, recent epidemiological evidence shows that additional chronic conditions such as diabetes and kidney disease are rising. In fact, the prevalence of diabetes as a comorbid TB condition is now higher than that of HIV. These chronic diseases are themselves independently associated with pro-inflammatory immune states that encompass antibody profiles. This review discusses isotypes, subclasses, post-translational modifications and Fc-mediated functions of antibodies in TB infection and in the comorbid chronic conditions of HIV, diabetes, and kidney diseases. We propose that inflammatory antibody profiles, which are a marker of active TB, may be an important biomarker for detection of TB disease progression within comorbid individuals. We highlight the need for future studies to determine which inflammatory antibody profiles are the consequences of comorbidities and which may potentially contribute to TB reactivation.

The Multifaceted Nature of Immunoglobulin A and Its Complex Role in HIV

IgA is the most abundant immunoglobulin in mucosal secretions, and understanding the role of IgA in both protection from HIV acquisition and modulation of HIV disease progression is a field of considerable controversy and renewed research interest. Analysis of the RV144 clinical trial associated plasma HIV envelope-specific monomeric IgA from vaccines with reduced vaccine efficacy. The RV144 trial, however, only assessed for plasma IgA, which was not further subclassed, and the role of mucosal IgA was not addressed as mucosal samples were not collected. On the other hand, several studies have detected envelope-specific IgA in mucosal secretions of highly exposed persistently seronegative cohorts, while recent macaque simian-HIV passive immunization studies have suggested a potentially protective role for mucosal IgA. It is well established that total IgA in serum appears to correlate with HIV disease progression. In contrast, a selective deficit of anti-HIV IgA responses in HIV infection is apparent, with a number of recent studies beginning to elucidate the mechanisms behind these dysfunctional IgA responses. In this review, we highlight the dichotomy that exists in the literature as to whether anti-HIV IgA is protective or harmful to the host. Herein, we emphasize the importance of distinguishing between monomeric, multimeric, and isoforms of IgA and review what is known about the complex and diverse interactions of various molecular forms of IgA with HIV in both the systemic circulation and mucosal compartments.

Fungal infection as a risk factor for HIV disease progression among patients with a CD4 count above 200/microl in the era of cART

The identification of clinical risk factors for AIDS in patients with preserved immune function is of significant interest. We examined whether patients with fungal infection (FI) and CD4 cell count >or=200/microl were at higher risk of disease progression in the era of cART. 11,009 EuroSIDA patients were followed from their first CD4 cell count >or=200/microl after 1 January 1997 until progression to any non-azoles/amphotericin B susceptible (AAS) AIDS disease, last visit or death. Initiation of antimycotic therapy (AMT) was used as a marker of FI and was modelled as a time-updated covariate using Poisson regression. After adjustment for current CD4 cell count, HIV-RNA, starting cART and diagnosis of AAS-AIDS, AMT was significantly associated with an increased incidence of non-AAS-AIDS (IRR=1.55, 95% CI 1.17-2.06, p=0.0024). Despite low incidence of AIDS in the cART era, FI in patients with a CD4 cell count >or=200/microl is associated with a 55% higher risk of non-AAS-AIDS (95% confidence interval 1.17-2.06, p=0.0024). These data suggest that patients with FI are more immune compromized than would be expected from their CD4 cell count alone. FI can be used as a clinical marker for disease progression and indirect indicator for initiation/changing cART in settings where laboratory facilities are limited.

Quantitative trait loci on chromosomes 1, 2, 3, 4, 8, 9, 11, 12, and 18 control variation in levels of T and B lymphocyte subpopulations

Lymphocyte subpopulation levels are used for prognosis and monitoring of a variety of human diseases, especially those with an infectious etiology. As a primary step to defining the major gene variation underlying these phenotypes, we conducted the first whole-genome screen for quantitative variation in lymphocyte count, CD4 T cell, CD8 T cell, B cell, and natural killer cell numbers, as well as CD4:CD8 ratio. The screen was performed in 15 of the CEPH families that form the main human genome genetic project mapping resource. Quantitative-trait loci (QTLs) that account for significant proportions of the phenotypic variance of lymphocyte subpopulations were detected on chromosomes 1, 2, 3, 4, 8, 9, 11, 12, and 18. The most significant QTL found was for CD4 levels on chromosome 8 (empirical P=.00005). Two regions of chromosome 4 showed significant linkage to CD4:CD8 ratio (empirical P=.00007 and P=.003). A QTL for the highly correlated measures of CD4 and CD19 levels colocalized at 18q21 (both P=.003). Similarly, a shared region of chromosome 1 was linked to CD8 and CD19 levels (P=.0001 and P=.002, respectively). Several of the identified chromosome regions are likely to harbor polymorphic candidate genes responsible for these important human phenotypes. Their discovery has important implications for understanding the generation of the immune repertoire and understanding immune-system homeostasis. More generally, these data show the power of an integrated human gene-mapping approach for heritable molecular phenotypes, using large pedigrees that have been extensively genotyped.

Prognostic value of single measurements of beta-2-microglobulin, immunoglobulin A in HIV disease after controlling for CD4 lymphocyte counts and plasma HIV RNA levels

The interrelationships between the CD4 lymphocyte count, plasma viral load [human immunodeficiency virus (HIV) RNA], beta-2-microglobulin (beta2-M) and immunoglobulin A (IgA) and the mortality risk was explored in 234 HIV-infected individuals (median CD4 count 230 cells/mm3, range 1-1,247). Product-moment correlation analysis was used to study the association between beta2-M, IgA and HIV RNA. A proportional hazards Cox model was used to estimate the relative hazard (RH) of death. Both beta2-M (r = 0.49, p < 0.0001) and IgA (r = 0.42, p < 0.0001) were positively correlated with HIV RNA. High beta2-M levels were associated with an increased risk of death in both univariate Cox analysis and after adjustment for HIV RNA, CD4 lymphocyte count and age [RH = 1.16 per 100 nmol/l higher beta2-M, 95% confidence interval (CI) 1.05-1.27]. Raised IgA levels were associated with shorter survival in individuals with a CD4 count above 50 cells/mm3 in univariate analysis as well as after adjusting for age and CD4 lymphocyte count (RH = 1.19 per 10 micromol/l higher IgA, 95% CI 1.01-1.39). However, this association was no longer significant after further adjusting for HIV RNA. In conclusion, beta2-M levels provided additional prognostic information for survival to the information obtained by CD4 count and HIV RNA levels, whereas serum IgA only was a weak prognostic marker in this fairly progressed cohort.

Beta 2-microglobulin and immunoglobulins are more useful markers of disease progression in HIV than neopterin and adenosine deaminase

Reference change values of six biochemical quantities (beta 2-microglobulin, neopterin, adenosine deaminase and immunoglobulins IgA, IgG and IgM) have been established in asymptomatic human immunodeficiency virus (HIV)-infected patients following the method described by Harris and Yasaka in 1983. Patients included in the evaluation were classified as A1, A2 or A3 according to the classification of the Centers for Disease Control (CDC) (January 1993). All patients were followed-up quarterly, with a minimum of four samples each available for statistical analysis. The main objective of this paper was to study whether differences found to be greater than calculated reference change values could predict clinical or immunological worsening in patients' status. Retrospective analysis was made in asymptomatic patients (n = 256) included in an HIV infection protocol carried out in our hospital. Of these patients, 179 showed clinical or immunological worsening during the study period and 77 maintained their clinical and immunological status. Changes in beta 2-microglobulin showed the greatest sensitivity to detect clinical or immunological worsening (43.0%), whereas changes in adenosine deaminase showed the lowest (21.8%). Clinical or immunological worsening in 169 of the 179 patients was detected by one of the six biochemical quantities evaluated. Ten patients showed clinical or immunological worsening, although differences between measurements were lower than the reference change values calculated. Of 77 patients whose clinical state did not deteriorate, there was a change in biochemical analytes greater than the reference value calculated in 29 patients (a period of 12 months had elapsed since detection). In 48 patients, no increases greater than calculated reference change values were detected. The sensitivity obtained using the six analytes was 94.4% and the specificity was 62.3%.

The predictive value of several markers in the progression to acquired immunodeficiency syndrome

Serum beta 2-microglobulin, neopterin, immunoglobulins A, G and M, adenosine deaminase and CD4+ lymphocyte count were evaluated as predictors of progression of HIV-1 infection to AIDS. A population of HIV-1 seropositive, initially asymptomatic men (n = 213) and women (n = 101) was followed up quarterly. We estimated the AIDS-free time using the actuarial method (median survival time 47.2 months). Cox proportional hazard analysis revealed that all markers studied were significant (p < 0.05) in relation to progression to AIDS. The best markers for predicting progression to AIDS were, in descending order, CD4+ lymphocyte count, beta 2-microglobulin, IgA, neopterin, IgG, IgM and adenosine deaminase. On stratifying population into four groups (divided at percentiles 25, 50 and 75--from group 1, with values nearest to reference ranges, to group 4, with most abnormal values) we observed statistically significant differences (p < 0.05) for all markers except for adenosine deaminase. The relative risk from the Cox proportional hazards model were used to quantify the effects of the best markers and compared to the risk obtained in group 1. CD4+ lymphocyte count was the best predictor of progression to AIDS. When considering beta 2-microglobulin and CD4+ together, the relative risk in the group with lowest CD4+ cell count (group 4) ranged from 25.6% (with lower beta 2-microglobulin values) to 41.1% (with higher beta 2-microglobulin values). Similar results were obtained when considering neopterin and CD4+ together. The addition of beta 2-microglobulin or neopterin values to CD4+ lymphocyte count improved the predictive value of CD4+ lymphocyte count.

Oral candidiasis in HIV infection: predictive value and comparison of findings in injecting drug users and homosexual men

The objectives of this study were to compare the relationship of oral candidiasis to HIV status, cohort and CD4+ lymphocyte values in injecting drug users and homosexual men and to examine its impact on prognosis. An oral examination was added to an ongoing longitudinal study of HIV infection. Data obtained at 6-month intervals included smoking, illicit drug use, medication use, symptoms and medical diagnoses, physical examination findings and laboratory data. In this study HIV+ subjects were much more likely to present with oral candidiasis than were HIV- subjects (OR = 6.3, P < 0.01). Injecting drug users, regardless of serostatus, were more likely than homosexual men to present with oral candidiasis (OR = 3.0, P = 0.001). In both cohorts oral candidiasis was associated with low CD4+ lymphocyte counts and percent ages, and Kaplan-Meier survival estimates showed that subjects with oral candidiasis had a poorer prognosis than those without candidiasis, even after controlling for CD4+ lymphocyte count.

Sentinels and signposts: the epidemiology and significance of the oral manifestations of HIV disease

A large number of studies attest to the frequency of oral disease in those with HIV infection. Most show that hairy leukoplakia and pseudomembranous candidiasis are the commonest lesions in those with HIV infection and AIDS, with higher prevalence and incidence rates correlating with falling CD4 counts and disease progression. HIV-infected individuals with oral candidiasis or hairy leukoplakia progress to AIDS more rapidly than matched controls without these lesions. Oral candidiasis and hairy leukoplakia increase with time since seroconversion. On the other hand, parotid enlargement in children appears to be associated with slower progression to AIDS. As a consequence of these and other observations, oral lesions are widely included in natural history studies, staging and classification schemes for HIV infection. In addition to their role in the diagnosis of HIV infection and as indicators of the progression of HIV disease, oral lesions are used as clinical correlates of CD4 counts and as criteria for entry into clinical trials.

Oral manifestations of human immunodeficiency virus infection

This article includes the oral manifestations which have been reported to be associated with human immunodeficiency virus (HIV) infection. The clinical appearance, diagnostic criteria and treatment of fungal, viral and bacterial infections, neoplasms and lesions of uncertain etiology are described. Accurate diagnosis of the oral lesions is important in the management of patients infected with HIV. Identification of oral lesions may suggest the need for HIV testing or may be an indicator for preventive intervention. Early identification, diagnosis and treatment may prevent extensive tissue destruction and may improve the quality of life for HIV-infected patients.

Potential application of human interferon-alpha in microbial infections of the oral cavity

We have been evaluating the potential use of interferon-alpha (IFN-alpha) against fungal infections of the oral cavity. IFN-alpha has been reported to enhance the antifungal activity of neutrophils. This cytokine is also known to synergize with interleukin-1 in enhancing a number of immunomodulatory responses. To study cytokine involvement in oral defense mechanisms against microbial infection, we first demonstrated the presence of antimicrobial interleukins (IL)-1 alpha, IL-1 beta, and IL-8 in the saliva, which can all augment the microbicidal activity of neutrophils, and the presence of epithelial cells and neutrophils in oral lavage fluid from healthy volunteers. Immunostaining for cytokines produced by these cells showed that the candidate producers of both IL-1 alpha and IL-8 are epithelial cells, but those of IL-1 beta remained inconclusive. We next found that IFN-alpha enhanced IL-1 alpha-augmented neutrophil-mediated anticandidal action while marginally enhancing IL-8- and IL-1 beta-mediated reactions. These results suggest that IFN-alpha is a potential agent for treating oral mycosis by cooperating with endogenous cytokine(s) in the saliva, in addition to its intrinsic antiviral action.

Hairy leucoplakia and HIV-2--a case report and review of the literature

Type 2 human immunodeficiency virus (HIV-2), originally confined to West Africa, has lately appeared with increasing frequency in Europe. Oral lesions affect a large proportion of patients with AIDS. Hairy leucoplakia (HL), a clinical expression of Epstein-Barr virus (EBV), is a lesion of the oral mucosa (usually the lateral margin of the tongue) that is observed in patients who are immunocompromised due to HIV or, more rarely, due to immunosuppressive medication or other causes. We review the definition, clinical signs, histopathology, diagnosis, prognosis and treatment of HL, and report the (to our knowledge) first detailed description of an HIV-2-seropositive patient with HL, which affected the lateral and dorsal tongue and was the first clinical sign of HIV infection (this patient was at that time only the second native Spaniard in whom unique HIV-2 infection had been detected). EBV detection and subtyping by in situ hybridization and polymerase chain reaction were performed in paraffin-embedded tissue from the HL lesion of the dorsal tongue; EBV-1 and EBV-2 were detected by the latter technique.

Multi-state Markov models for analysing incomplete disease history data with illustrations for HIV disease

Multi-state Markov models can be useful in analysing disease history data. We apply the general estimation methods of Kalbfleisch and Lawless to panel data in which individuals are viewed over only a portion of their life history and complete information about transition times between states is unavailable. Methods to assess goodness-of-fit are proposed. To illustrate the methods, we consider models of HIV disease relating important immunological marker measurements to the onset of AIDS.

Practical problems in fitting a proportional hazards model to data with updated measurements of the covariates

We review and discuss the practical problems encountered when analysing the effect on survival of covariates which are measured repeatedly over time. Specific issues arise over and above those met with the standard proportional hazards model and concern all stages of data preparation, data analysis and interpretation of the results. Data from a randomized clinical trial of patients with primary biliary cirrhosis, on whom several measurements were taken at regular intervals after entry, are presented as an illustration.

Markers predicting progression of human immunodeficiency virus-related disease

Human immunodeficiency virus (HIV) interacts with the immune system throughout the course of infection. For most of the disease process, HIV activates the immune system, and the degree of activation can be assessed by measuring serum levels of molecules such as beta 2-microglobulin and neopterin, as well as other serum and cell surface phenotype markers. The levels of some of these markers correlate with clinical progression of HIV disease, and these markers may be useful as surrogate markers for development of clinical AIDS. Because the likelihood and timing of development of clinical AIDS following seroconversion, for any particular individual, are not readily predictable, the use of nonclinical disease markers has become critically important to patient management. Surrogate markers of HIV infection are, by definition, measurable traits that correlate with disease progression. An ideal marker should identify patients at highest risk of disease progression, provide information on how long an individual has been infected, help in staging HIV disease, predict development of opportunistic infections associated with AIDS, monitor the therapeutic efficacy of immunomodulating or antiviral treatments, and the easily quantifiable, reliable, clinically available, and affordable. This review examines the current state of knowledge and the role of surrogate markers in the natural history and treatment of HIV infection. The clinical usefulness of each marker is assessed with respect to the criteria outlined for the ideal surrogate marker for HIV disease progression.

Oral manifestations in HIV-infected patients: diagnosis and management

Oral lesions have been observed since the beginning of the AIDS epidemic. The number of HIV-infected patients is still increasing, especially in the heterosexual population. Oral diseases in HIV-infected patients are often more difficult to diagnose because the clinical presentations may differ from the same diseases in HIV-negative patients. HIV-associated oral lesions have diagnostic, prognostic, and therapeutic impact. Approximately 10% of the HIV-infected population will have oral manifestations as a first sign of their disease. In HIV-infected men oral hairy leukoplakia and oral candidiasis are useful markers for disease progression. This article summarizes the oral manifestations and the management of oral health in persons with HIV infection.

The effect of age on the course of experimental feline immunodeficiency virus infection in cats

Neonatal, young adult, and aged specific pathogen-free cats were experimentally infected with cat-passaged Petaluma strain of feline immunodeficiency virus. The primary stage of illness occurred 6-8 weeks following infection in cats of all ages, but it differed in severity and clinical signs. Generalized lymphadenopathy persisted for the entire 42-week study period in neonatally infected cats, was transient in young adults, but inapparent in aged cats. Only two aged cats became chronically and severely ill during the study. One aged cat died with severe necrotizing transmural enteritis, while a second developed chronic generalized staphylococcal pyoderma that was partially controlled with antibiotics. Neutropenia appeared 6-8 weeks following infection in cats of all ages, but was more severe in newborn and aged cats than in young adults. A persistent decrease in CD4+/CD8+ T lymphocyte ratios, due to both increased CD8+ and decreased CD4+ T lymphocytes, occurred in the neonatal and aged cats. Decreased CD4+/CD8+ T lymphocyte ratios in the young adult cats was due solely to decreased CD4+ T lymphocytes. Antibody response to FIV virus, as measured by ELISA to recombinant FIV p24 antigen, was lower in aged cats than the other age groups during the first 6 weeks after infection. Antibody levels were not significantly different among the three age groups thereafter. Although there are some differences between FIV infection of cats and HIV infection of human beings, age at infection influences the severity of disease in both species.