Fungal Infection Susceptibility

June 4, 2026 updated by: National Institute of Allergy and Infectious Diseases (NIAID)

Cryptococcosis in Previously Healthy Adults

The protocol will be carried out in accordance with International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) Good Clinical Practice (GCP) and the following United States Code of Federal Regulations (CFR) applicable to clinical studies: 45 CFR Part 46, 21 CFR Part 50, 21 CFR Part 56, 21 CFR Part 312, and/or 21 CFR Part 812.

NIH-funded investigators and study site staff who are responsible for the conduct, management, or oversight of NIH-funded studies have completed Human Subjects Protection and ICH GCP Training.

The protocol, informed consent form(s), recruitment materials, and all participant materials will be submitted to the Institutional Review Board (IRB) for review and approval. Approval of both the protocol and the consent form must be obtained before any participant is enrolled. Any amendment to the protocol will require review and approval by the IRB before the changes are implemented to the study. In addition, all changes to the consent form will be approved by the IRB; an IRB determination will be made regarding whether a new consent needs to be obtained from participants who provided consent, using a previously approved consent form.

Study Overview

Status

Recruiting

Conditions

Detailed Description

Cryptococcus is a fungus that causes infections most commonly in immunocompromised patients, such as those with AIDS and solid organ transplant recipients, particularly renal transplant recipients (1-3). However, approximately one-third of cases fall outside these groups and, overall, 12.9 percent to 17.9 percent have no readily identifiable immune defect (4, 5). The genetic factors, which may predispose to cryptococcosis and the immune response in these patients, have not been extensively studied.

This protocol is designed to examine the immune deficits that predispose to cryptococcosis as well as the clinical and immune responses among previously healthy adults. The patients included will have an unknown predisposing condition and cryptococcosis. Patients will undergo various sampling procedures, including saliva, blood, eyebrow hair, CSF, and nail clipping collection. Throughout the study, patients will be provided with standard medical care and will be seen as often as necessary to manage their condition. Patients in whom microbiologic control of the infection has occurred but in whom inflammation is causing neurologic damage may be treated with corticosteroids or other immunosuppressive agents. Genetically related family members of patients will also be screened for clinical, in vitro, immune, and genetic correlates of immune abnormalities. Healthy adult volunteers, as a comparison group, will be enrolled as a source of blood samples, saliva samples, CSF samples, and eyebrow hair samples for research testing. Moreover, with respect to cryptococcosis, patients with isolated non-central nervous system (CNS) disease (e.g., pulmonary) may serve as a subset comparator to those with CNS involvement-a major tissue tropism for Cryptococcus.

Genetic and immunologic testing will be performed on all subjects (patients, relatives, and healthy volunteers) to evaluate for possible immunogenetic factors that lead to susceptibility to cryptococcosis. Among the aims of this protocol are to better understand the pathophysiology and genetic factors that lead to defects in host defense and to use modern and evolving methods in molecular and cellular biology to elucidate the pathogenesis of this particular susceptibility. A better understanding of the underlying pathophysiology of immune defects and genetic susceptibility to fungal infections could allow for the rational development of novel therapies for such diseases and to benefit future patients.

Study Type

Observational

Enrollment (Estimated)

800

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

Study subjects will consist of previously healthy adults without known prior conditions who have cryptococcosis, blood relatives of these patients, and healthy adult volunteers. Potential Cryptococcus patients must be 18 or older with evidence of positive Cryptococcus infection results as shown through their medical records, telephone interviews or referring physician. This includes a positive Cryptococcus culture (neoformans or gattii), a positive cryptococcal antigen from serum or CSF with CSF cell count and chemistry consistent with Cryptococcus infection, or histopathology showing cryptococci. Blood relatives and healthy volunteers must be 18 years or older.

Description

  • INCLUSION CRITERIA:

Patients

Patients must:

  1. Have cryptococcosis as determined by information collected from their medical records, telephone interviews, or from a referring physician:

    • histopathology showing cryptococci; or
    • culture of C. neoformans or C. gattii
    • a positive cryptococcal antigen in the serum and/or CSF, together with CSF cell count and chemistry consistent with cryptococcal meningitis.
  2. Be over the age of 18 years old.
  3. Have a primary physician outside of the NIH.
  4. Agree to undergo genetic testing that will include WES and high density SNP arrays as appropriate for possible WES linkage studies.
  5. Allow samples to be stored for future research.
  6. Pregnant patients will not be excluded. However, research procedures greater than minimal risk including bone marrow biopsy and apheresis would not be performed on pregnant subjects. Otherwise, pregnant patients with cryptococcus would be treated with as per standard of care, minimizing teratogenic potential of drugs and ionizing radiation whenever possible.

Blood Relatives of Patients

Blood relatives must:

  1. Be a genetic relative of a patient enrolled in this study
  2. Be over the age of 18 years old
  3. Agree to undergo genetic testing that may include WES and high density SNP analysis
  4. Allow samples to be stored for future research

Healthy Volunteers

Healthy volunteers must:

  1. Be between the ages of 18 and 70 years old
  2. Allow samples to be stored for future research

EXCLUSION CRITERIA:

Patients

Patients will be excluded for any of the following:

  1. The presence of certain types of acquired abnormalities of immunity due to:

    • HIV
    • Cancer chemotherapeutic agent(s)
    • An underlying malignancy could be grounds for possible exclusion of a patient if, in the opinion of the investigator, the underlying disease predisposed the patient to the infection
    • Monoclonal antibody therapy directed against a patient s immune system
  2. Any condition that in the opinion of the investigator may interfere with the evaluation of a co-existing abnormality of immunity that is the subject of study under this protocol. For example, we may exclude patients with Cushing s disease that have very high cortisol levels at the time of diagnosis of their cryptococcosis.

Genetic Relatives of Patients

Genetic relatives will be excluded for the following:

-Any condition that in the opinion of the investigator may interfere with evaluation of an immune system abnormality that is the subject of study under this protocol.

Healthy Volunteers

Healthy volunteers will be excluded for any of the following:

  1. HIV or viral hepatitis (B or C).
  2. History of recurrent or severe infections.
  3. History of intravenous drug use.
  4. History of engaging in high-risk activities for exposure to HIV.
  5. Receiving chemotherapeutic agent(s), immunosuppressants or have underlying malignancy.
  6. Pregnancy.
  7. Have history of heart, lung, kidney disease, or bleeding disorders.
  8. Any condition that in the opinion of the investigator may interfere with evaluation of an immune system abnormality that is the subject of study under this protocol.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Observational Models: Cohort
  • Time Perspectives: Prospective

Cohorts and Interventions

Group / Cohort
Healthy Volunteers
Will be placed in a control group. Participant age must be 18 years or older. Healthy volunteers will be excluded if they have HIV, viral hepatitis (B or C), history of recurrent or severe infections, history of intravenous drug use, history of engaging in high-risk activities for HIV exposure, receiving chemotherapeutic agents, immunosuppressants, have underlying malignancies, pregnancy, or a history of heart disease, lung disease, kidney disease, or bleeding disorders.
Patient Population
Previously healthy adult patients diagnosed with Cryptococcosis and have no predisposing conditions, such as HIV.
Blood Relatives
Will be placed in a control group. Must be a blood relative of a patient enrolled in the study. Participant age must be 18 years or older. Relatives may be excluded if they have a condition that may interfere with evaluation of an immune system abnormality.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Characterize the full spectrum of clinical disease of Cryptococcosis in previously healthy adults without known immune predisposition.
Time Frame: 1-5 years
1-5 years

Secondary Outcome Measures

Outcome Measure
Time Frame
Characterize the immunological and genetic mechanisms predisposing to disease acquisition.
Time Frame: 1-5 years
1-5 years
Understand the inflammatory response and distinguish its consequences from those directly due to fungal growth.
Time Frame: 1-5 years
1-5 years
Understand the natural history of disease progression or regression over time.
Time Frame: 1-5 years
1-5 years

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

National Institute of Allergy and Infectious Diseases (NIAID)

Investigators

  • Principal Investigator: Peter R Williamson, M.D., National Institute of Allergy and Infectious Diseases (NIAID)

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

April 1, 1993

Study Registration Dates

First Submitted

November 3, 1999

First Submitted That Met QC Criteria

November 3, 1999

First Posted (Estimated)

November 4, 1999

Study Record Updates

Last Update Posted (Actual)

June 5, 2026

Last Update Submitted That Met QC Criteria

June 4, 2026

Last Verified

June 3, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 930106
  • 93-I-0106

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Clinical Trials on Cryptococcosis

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

CROs by country

CROs in Latvia

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

Subscribe