Pathology of human immunodeficiency virus infection: infectious conditions

Atypical Prolonged Viral Shedding With Intra-Host SARS-CoV-2 Evolution in a Mildly Affected Symptomatic Patient

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is caused by a respiratory virus with a wide range of manifestations, varying from asymptomatic to fatal cases, with a generally short outcome. However, some individuals present long-term viral shedding. We monitored 38 individuals who were mildly affected by the SARS-CoV-2 infection. Out of the total studied population, three (7.9%) showed atypical events regarding the duration of positivity for viral RNA detection. In one of these atypical cases, a previously HIV-positive male patient presented a SARS-CoV-2 RNA shedding and subgenomic RNA (sgRNA) detected from the upper respiratory tract, respectively, for 232 and 224 days after the onset of the symptoms. The SARS-CoV-2 B.1.1.28 lineage, one of the most prevalent in Brazil in 2020, was identified in this patient in three serial samples. Interestingly, the genomic analyses performed throughout the infectious process showed an increase in the genetic diversity of the B.1.1.28 lineage within the host itself, with viral clearance occurring naturally, without any intervention measures to control the infection. Contrasting widely spread current knowledge, our results indicate that potentially infectious SARS-CoV-2 virus might be shed by much longer periods by some infected patients. This data call attention to better adapted non-pharmacological measures and clinical discharge of patients aiming at preventing the spread of SARS-CoV-2 to the population.

Pathogenic mechanisms of HIV disease

Human immunodeficiency virus (HIV) infection is generally characterized by inefficient viral transmission; an acute phase of intense viral replication and dissemination to lymphoid tissues; a chronic, often asymptomatic phase of sustained immune activation and viral replication; and an advanced phase of marked depletion of CD4(+) T cells that leads to acquired immune deficiency syndrome. Major insight into HIV transmission and each phase of infection has been gained from studies on blood and tissue specimens obtained from HIV-infected individuals, as well as from animal and ex vivo models. Not only has the introduction of effective antiretroviral therapy greatly diminished the morbidity and mortality associated with HIV disease progression, it has also provided new avenues of research toward delineating the mechanisms of HIV-induced pathogenesis. Further advances in therapeutics and informative technologies, combined with a better understanding of the immunologic and virologic components of HIV disease, hold promise for new preventative and even curative strategies.

PLUNC protein expression in major salivary glands of HIV-infected patients

OBJECTIVE

To analyse and compare the expression of Palate, Lung, and Nasal Epithelium Clone (PLUNC) proteins in salivary glands from patients with and without AIDS (control group) using autopsy material.

METHODS

We analysed the expression of PLUNCs using immunohistochemistry in parotid (n = 45), submandibular (n = 47) and sublingual gland (n = 37) samples of AIDS patients [30 with normal histology, 21 with mycobacteriosis, 14 with cytomegalovirus (CMV) infection, 30 with chronic non-specific sialadenitis, and 30 HIV-negative controls. In situ hybridization (ISH) for SPLUNC 2 in the HIV-negative group was performed.

RESULTS

  SPLUNC 1 expression was detected in the mucous acini of submandibular and sublingual glands, and SPLUNC 2 were seen in the serous cells. LPLUNC 1 expression was only positive in the salivary ducts. There was a higher expression of SPLUNC 2 in AIDS patients with CMV infection and mycobacteriosis when compared with all other groups. The intensity of staining for SPLUNC 2 was greater around the lesions than the peripheral ones. ISH for SPLUNC 2 showed perinuclear positivity in the serous cells in all HIV-negative cases.

CONCLUSIONS

  SPLUNC 1 and LPLUNC 1 proteins were similarly expressed in the salivary glands of AIDS patients and non-HIV patients. CMV infection and mycobacteriosis increase SPLUNC 2 expression in serous cells in the salivary gland of AIDS patients.

Oral bacteria induce a differential activation of human immunodeficiency virus-1 promoter in T cells, macrophages and dendritic cells

INTRODUCTION

The human immunodeficiency virus (HIV) can integrate into T cells, macrophages and dendritic cells resulting in a latent infection. Reports have also demonstrated that various microbial and host cell factors can trigger HIV reactivation leading to HIV recrudescence, potentially undermining highly active antiretroviral therapies.

METHODS

This study evaluated the capacity of oral bacteria associated with chronic periodontal infections to stimulate HIV promoter activation in various cell models of HIV latency.

RESULTS

T cells (1G5) challenged with oral bacteria demonstrated a dose-response of HIV promoter activation with a subset of the bacteria, as well as kinetics that were generally similar irrespective of the stimuli. Direct bacterial challenge of the T cells resulted in increased activation of approximately 1.5- to 7-fold over controls. Challenge of macrophages (BF24) indicated different kinetics for individual bacteria and resulted in consistent increases in promoter activation of five fold to six fold over basal levels for all bacteria except Streptococcus mutans. Dendritic cells showed increases in HIV reactivation of 7- to 34-fold specific for individual species of bacteria.

CONCLUSION

These results suggested that oral bacteria have the capability to reactivate HIV from latently infected cells, showing a relationship of mature dendritic cells > immature dendritic cells > macrophages > or = T cells. Expression of various pattern recognition receptors on these various cell types may provide insight into the primary receptors/signaling pathways used for reactivation by the bacteria.

Submandibular and sublingual glands involvement in advanced acquired immunodeficiency syndrome (AIDS): an autopsy-based study

OBJECTIVE

To assess the histopathological, immunohistochemical (IHC), and in situ hybridization (ISH) features found in the submandibular (SM) and sublingual (SL) glands of 105 acquired immunodeficiency syndrome (AIDS) patients at autopsy.

STUDY DESIGN

Gender, age, CD4 cell level, and clinical histories were obtained from clinical charts (SM: n = 103; SL: n = 92). Histologic analysis of hematoxylin and eosin, Gomori-Grocott, and Ziehl-Neelsen stained tissues, IHC to detect infectious agents and characterize inflammatory cells in sialadenitis, and ISH for EBER-1/2 were performed.

RESULTS

The mean age of the patients and CD4 cell count were 36 years and 76 cells/microL, respectively. Fifty-eight cases (SM: n = 51 [49%]; SL: n = 54 [59%]) were considered to be microscopically normal. The most common infectious conditions were mycobacteriosis (SM: n = 11 [10%]; SL: n = 7 [7%]), followed by cytomegalovirus (CMV) (SM: n = 14 [13%]; SL: n = 2 [2%]), and cryptococcosis (SM: n = 3 [3%]; SL: n = 4 [4%]). Human immunodeficiency virus (HIV) p24 (SM: n = 2 [2%]; SL: n = 1 [1%]) and EBER-1/2 (SM: n = 9 [39%]; SL: n = 4 [20%]) were seen only in macrophages and lymphocytes, respectively. The most prevalent cells seen in chronic nonspecific sialadenitis (SM: n = 25; SL: n = 25) were CD8+ T lymphocytes, whereas CD68+ macrophages were predominant in the mycobacteriosis-associated granulomatous and nonspecific diffuse macrophagic sialadenitis. Concomitant infections occurred in 5 cases (SM: n = 4; SL: n = 1) and non-Hodgkin lymphoma in 1 case.

CONCLUSIONS

Infectious diseases and chronic nonspecific sialadenitis were the main alterations found in the SM and SL glands. These alterations were greater in the SM than in the SL glands. CD8+ T lymphocytes and CD68+ macrophages might be relevant to the pathogenesis of the sialadenitis. Clinicians should consider these diseases when assessing the major salivary glands in advanced AIDS patients and follow biosafety procedures to avoid contamination by HIV, CMV, mycobacteriosis, and cryptococcosis.

Parotid mycobacteriosis is frequently caused by Mycobacterium tuberculosis in advanced AIDS

BACKGROUND

Tuberculosis is one of the leading infectious diseases in the world, with more than 2 million new cases annually. It is one of the main causes of death of human immunodeficiency virus (HIV)-positive patients, involving multiple organs and particularly the lungs. Nevertheless there are few consistent studies about tuberculosis involving the parotid of HIV patients. The objective of this work was to describe the histological and immunohistochemical characteristics of 10 cases of mycobacteriosis involving the parotid of autopsied patients with advanced acquired immunodeficiency syndrome (AIDS), including identification of the Mycobacterium species.

METHODS

Detection of 'M. tuberculosis complex' was performed by polymerase chain reaction (PCR) and ligase chain reaction (LCR) and Mycobacterium avium by PCR.

RESULTS

All cases showed involvement of intraparotid lymph nodes, but the glandular parenchyma was affected in only three cases. Most of the cases (80%) presented a chronic non-caseating granulomatous inflammation, and in two cases predominated foamy macrophages, full of bacteria, and no granuloma formation. In areas of mycobacteriosis, macrophages predominated followed by TCD8, B and TCD4 lymphocytes. All cases were infected by Mycobacterium genus and 'M. tuberculosis complex' was detected in five cases by LCR and in eight by PCR, while M. avium was positive in one case only, which was also positive for M. tuberculosis.

CONCLUSIONS

Parotid mycobacteriosis in advanced AIDS is characterized by intraparotid lymph node non-caseating inflammatory granulomatous lesion, caused mainly by M. tuberculosis.

Infectious disease pathology

The anatomic pathologist performs an important role in the diagnosis or exclusion of infectious diseases. The morphologic interpretation of biopsies and cytologic preparations allows for the definitive establishment or exclusion of a wide variety of diseases. Once the pathologist has determined that a disease is likely to be due to an infection and has characterized the inflammatory response, associated microorganisms or viral-associated cytopathic effects should be recorded. Although some microorganisms or their cytopathic effects may be clearly visible on routine hematoxylin and eosin-stained sections, additional histochemical stains are often needed for their complete characterization. Highly specific molecular techniques, such as immunohistochemistry, in situ hybridization, and nucleic acid amplification, may be needed in certain instances to establish the diagnosis of infection. Through appropriate morphologic diagnoses and interlaboratory communication and collaboration, the anatomic pathologist contributes greatly to the diagnosis and treatment of infectious diseases.

Colon carcinoid tumors. A population-based study

PURPOSE

The aim of our investigation was to evaluate the clinical presentation of patients with carcinoid tumors of the colon and to estimate the survival and potential prognostic factors of this tumor type.

METHODS

A population-based study was performed using data from the Alberta Cancer Registry between 1964 and 1988 (inclusive). The clinical records and the pathologic material of eligible patients were reviewed. Survival was estimated both as crude survival and with the Kaplan-Meier method.

RESULTS

During the 25-year study period (1964-1988), 36 true carcinoid tumors of the colon were diagnosed in Alberta. Carcinoids of the ileocecal region and of the rectum were excluded from the study. The average age at time of diagnosis was 68.4 years; there were 20 males and 16 females. Symptoms (abdominal pain, diarrhea, weakness, anorexia) occurred late in the course of the disease: 64 percent of the lesions were in Dukes D stage and 22 percent were Dukes C at diagnosis. Only one patient presented with a malignant carcinoid syndrome. Lesions occurred most frequently in the cecum (39 percent), followed by transverse and sigmoid colon. Most of the patients were managed surgically. The perioperative mortality rate was with 22 percent, which is quite high. The average size of the lesions was 5.8 (range, 2-10) cm, and most tumors (31/36) had invaded the pericolic fat. The most common immunohistochemical pattern was argentaffin/argyrophil negative and neuron-specific enolase positive. Two-year and five-year actuarial (Kaplan-Meier) survival was 34 percent and 26 percent, respectively. Survival for carcinoids of the colon was significantly lower compared with carcinoids of the rectum or appendix, and with colon adenocarcinomas. Size of the tumor and tumor invasion into the muscularis propria--the two major histopathologic prognostic factors for carcinoids of the gastrointestinal tract--were not found to influence survival significantly. Rather, tumor stage, histologic pattern, tumor differentiation, nuclear grade, and mitotic rate were found to significantly influence the survival rate.

CONCLUSION

Carcinoid tumors of the colon are extremely rare tumors, diagnosed late in the course of the disease, and they carry a bad prognosis. Prognostic factors are tumor stage, histologic pattern, differentiation, nuclear grade, and mitotic rate of the tumor.