Related Experiment Video

Updated: Sep 3, 2026

Macrophage Cholesterol Depletion and Its Effect on the Phagocytosis of Cryptococcus neoformans
11:07

Macrophage Cholesterol Depletion and Its Effect on the Phagocytosis of Cryptococcus neoformans

Published on: December 19, 2014

A cryptic cause of cryptococcal meningitis

Matthew C Cheung1, Anita R Rachlis, Steven L Shumak

  • 1Division of General Internal Medicine, Department of Medicine, Sunnybrook & Women's College Health Sciences Centre, University of Toronto, Toronto, ON.

CMAJ : Canadian Medical Association Journal = Journal De L'Association Medicale Canadienne
|February 20, 2003
PubMed

Insights

Idiopathic CD4+ T-lymphocytopenia (ICL) can cause opportunistic infections like cryptococcal meningitis, even without HIV. Evaluating T-cell subsets is crucial for diagnosing immunodeficiency in unusual infections.

Area of Science:

  • Immunology
  • Infectious Diseases
  • Clinical Medicine

Background:

  • Cryptococcus neoformans is a common opportunistic pathogen in immunocompromised individuals, particularly those with AIDS.
  • CD4+ T-lymphocyte counts are critical indicators of immune function and opportunistic infection risk in HIV-infected patients.

Observation:

  • A case of cryptococcal meningitis occurred in a patient with persistently low CD4+ T-cell counts.
  • This patient did not have evidence of Human Immunodeficiency Virus (HIV) infection.

Findings:

  • The patient's immunocompromised state was diagnosed as idiopathic CD4+ T-lymphocytopenia (ICL).
  • ICL is a syndrome defined by low CD4+ T-cell subsets without HIV infection.
  • This case demonstrates that immunodeficiency can occur independently of HIV infection.

Implications:

  • Highlights the importance of assessing T-cell subsets in patients presenting with atypical infections.
  • Broadens the differential diagnosis for opportunistic infections beyond HIV-related immunosuppression.
  • Underscores the need for comprehensive immunological evaluation in unexplained immunodeficiency states.

More Related Videos

Automated Measurement of Cryptococcal Species Polysaccharide Capsule and Cell Body08:08

Automated Measurement of Cryptococcal Species Polysaccharide Capsule and Cell Body

Published on: January 11, 2018

Size Matters: Measurement of Capsule Diameter in Cryptococcus neoformans08:24

Size Matters: Measurement of Capsule Diameter in Cryptococcus neoformans

Published on: February 27, 2018

Related Concept Videos

Bacterial Meningitis01:24

Bacterial Meningitis

Bacterial meningitis is a severe infectious disease involving inflammation of the meninges, the protective membranes surrounding the brain and spinal cord. It occurs when pathogenic bacteria cross the blood–brain barrier and enter the cerebrospinal fluid. Common causative organisms include Neisseria meningitidis, Streptococcus pneumoniae, Haemophilus influenzae type b, Listeria monocytogenes, and Escherichia coli K1. The exact route of entry varies by pathogen and host condition.Routes of Entry...
Viral Meningitis01:18

Viral Meningitis

Viral meningitis is the most common form of meningitis and is often referred to as aseptic meningitis to indicate the absence of bacterial involvement. It is generally milder than bacterial meningitis, with symptoms including fever, headache, stiff neck, drowsiness, nausea, photophobia, and vomiting. Rarely, more severe manifestations or death may occur. Common causative agents include enteroviruses, particularly coxsackie A and B viruses and echoviruses, all members of the Enterovirus genus...
Cryptococcal Meningitis01:27

Cryptococcal Meningitis

Cryptococcal meningitis is a life-threatening opportunistic infection predominantly associated with HIV/AIDS, accounting for over 100,000 deaths annually worldwide. However, it also affects individuals with other forms of immunosuppression, including those undergoing immunosuppressive therapy, organ transplant recipients, patients with innate immunodeficiencies, and individuals with hematological disorders. The infection is caused mainly by Cryptococcus neoformans and Cryptococcus gattii,...
Bacterial Meningitis I: Introduction01:22

Bacterial Meningitis I: Introduction

Bacterial meningitis is a severe, life-threatening inflammation of the meninges, particularly the pia mater and arachnoid mater, affecting the subarachnoid space, ventricles, and cerebrospinal fluid (CSF). If untreated, it can lead to significant neurological complications or death.Causative AgentsCommon pathogens vary with age and immune status. In adults, major organisms include Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae. Streptococcus agalactiae (group B...
Bacterial Meningitis II: Pathophysiology01:26

Bacterial Meningitis II: Pathophysiology

Bacterial meningitis typically begins when pathogens such as Neisseria meningitidis and Streptococcus pneumoniae colonize the nasopharynx and invade the bloodstream. This process is facilitated by bacterial virulence factors, such as polysaccharide capsules, which resist phagocytosis and complement-mediated killing. Less commonly, bacteria reach the central nervous system via contiguous spread from infections like otitis media or sinusitis, through congenital or acquired dural defects, or...
Encephalitis l: Introduction01:19

Encephalitis l: Introduction

Encephalitis is inflammation of the brain parenchyma, most often due to infections or autoimmune processes. It presents with neuropsychiatric features such as fever, altered mental status, behavioral changes, cognitive dysfunction, seizures, focal deficits, and sometimes autonomic instability. In some cases, the meninges are also involved, resulting in meningoencephalitis.Infectious CausesInfectious encephalitis is most commonly viral but can also result from bacterial, fungal, or parasitic...