Summary about Disease
Kaposi sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus 8 (HHV-8), is a gammaherpesvirus that is the causative agent of Kaposi sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman disease (MCD). While infection with KSHV is relatively common, especially in certain populations, these diseases are less frequent. KSHV can establish lifelong latency in infected cells, and reactivation can lead to the development of KS, PEL, or MCD, particularly in individuals with weakened immune systems.
Symptoms
Symptoms vary depending on the disease manifestation caused by KSHV.
Kaposi Sarcoma (KS): Most commonly presents as painless, flat or raised lesions on the skin, often purple, red, or brown in color. Lesions can also occur in the mouth, gastrointestinal tract, and lungs.
Primary Effusion Lymphoma (PEL): Characterized by malignant B-cells accumulating in body cavities, such as the pleural or peritoneal spaces, leading to effusions (fluid buildup).
Multicentric Castleman Disease (MCD): Involves enlarged lymph nodes throughout the body, along with systemic symptoms like fever, fatigue, weight loss, and organ dysfunction.
Causes
KSHV infection is the necessary cause of Kaposi sarcoma, primary effusion lymphoma, and some forms of multicentric Castleman disease. However, KSHV infection alone is not sufficient to cause these diseases. Immune suppression (e.g., HIV/AIDS, organ transplant recipients) is a major risk factor for developing KSHV-associated malignancies. The virus infects cells, including B lymphocytes and endothelial cells, and can establish latency. Reactivation of the virus, combined with immune dysfunction, contributes to the development of these diseases.
Medicine Used
Treatment for KSHV-associated diseases depends on the specific condition and its severity.
Kaposi Sarcoma (KS):
Antiretroviral therapy (ART): For HIV-associated KS, ART to improve immune function is crucial.
Local therapies: Cryotherapy, surgical excision, radiation therapy, topical retinoids (for localized skin lesions).
Systemic chemotherapy: Liposomal anthracyclines (e.g., liposomal doxorubicin), paclitaxel, are used for more advanced or aggressive KS.
Immunomodulatory agents: Interferon-alpha may be used in some cases.
Primary Effusion Lymphoma (PEL):
Chemotherapy: Combination chemotherapy regimens are typically used.
Antiviral therapy: Ganciclovir or foscarnet may be added to chemotherapy.
Rituximab: May be used if PEL cells express CD20.
Multicentric Castleman Disease (MCD):
Rituximab: Targets CD20-positive B cells, often effective in KSHV-associated MCD.
Chemotherapy: May be used in combination with rituximab or as a single agent.
Antiviral therapy: Ganciclovir or foscarnet may be used.
Siltuximab: Anti-IL-6 monoclonal antibody which may be helpful in controlling symptoms.
Corticosteroids: To manage inflammatory symptoms.
Is Communicable
Yes, KSHV is communicable. The exact modes of transmission are not fully understood, but it is thought to be transmitted through saliva, sexual contact, and potentially blood transfusion or organ transplantation. Transmission is more likely to occur between individuals in close contact, especially in areas where the virus is endemic.
Precautions
Avoid sharing personal items: Such as toothbrushes, razors, and eating utensils.
Safe sex practices: Use condoms during sexual activity.
For healthcare workers: Standard infection control precautions, including hand hygiene and the use of personal protective equipment, should be followed.
For individuals with HIV/AIDS: Adherence to antiretroviral therapy (ART) is crucial to maintain a healthy immune system and reduce the risk of KSHV reactivation and associated diseases.
Avoidance of Deep Kissing: May reduce the risk of transmission from saliva.
How long does an outbreak last?
KSHV establishes a lifelong infection. There are not outbreaks in the same way as other viral infections like herpes simplex virus. If a KSHV-associated condition like Kaposi Sarcoma presents, it is more of a chronic condition, and the duration of symptoms depends on the specific disease, its severity, and the effectiveness of treatment. Untreated KS can progress, while treatment can control the disease and improve symptoms.
How is it diagnosed?
KSHV infection:
Serology: Blood tests to detect antibodies against KSHV.
PCR: Polymerase chain reaction to detect KSHV DNA in blood or tissue samples.
Kaposi Sarcoma (KS):
Physical examination: Observation of characteristic skin lesions.
Biopsy: A tissue sample from a lesion is examined under a microscope.
Primary Effusion Lymphoma (PEL):
Cytology: Analysis of fluid from body cavity effusions to identify malignant cells.
Immunohistochemistry: Staining of cells to identify specific markers.
KSHV testing: Detection of KSHV DNA in effusion fluid.
Multicentric Castleman Disease (MCD):
Lymph node biopsy: Examination of a lymph node tissue sample.
Blood tests: To assess for systemic inflammation and organ dysfunction.
KSHV testing: Detection of KSHV DNA in blood or tissue samples.
Timeline of Symptoms
KSHV infection itself usually doesn't cause symptoms. The timeline of symptoms relates to the development of KSHV-associated diseases, which can vary:
Initial KSHV infection: Often asymptomatic.
Latency: The virus remains dormant in the body for years or decades.
Immune suppression (e.g., due to HIV/AIDS): Increases the risk of reactivation.
Kaposi Sarcoma (KS): Lesions may appear gradually over weeks to months.
Primary Effusion Lymphoma (PEL): Can develop relatively quickly, with rapid accumulation of fluid in body cavities.
Multicentric Castleman Disease (MCD): Symptoms can develop gradually over weeks to months, or more acutely in some cases.
Important Considerations
KSHV infection is more prevalent in certain geographic regions and populations (e.g., men who have sex with men, individuals with HIV/AIDS).
Immune suppression is a major risk factor for the development of KSHV-associated diseases.
Early diagnosis and treatment are crucial for managing KSHV-associated diseases and improving outcomes.
Individuals with KSHV infection should be monitored for signs and symptoms of associated diseases, especially if they are immunocompromised.
Research is ongoing to develop more effective treatments and prevention strategies for KSHV-associated diseases.