Human Herpesvirus 8 (HHV-8), also known as Kaposi’s Sarcoma-associated Herpesvirus (KSHV), is a type of herpesvirus that can establish a lifelong infection in humans. This virus is recognized for its ability to cause several different conditions, particularly in individuals whose immune systems are weakened.
The HHV-8 Virus and Asymptomatic Infection
HHV-8 often remains in a latent state within infected cells, meaning it remains inactive and does not cause disease in most carriers. Transmission of HHV-8 occurs through various routes, including saliva, particularly through deep kissing, and sexual contact. The virus can also be transmitted through organ transplantation or blood transfusions.
While many individuals carry HHV-8 asymptomatically, symptoms emerge when an individual’s immune system becomes compromised. This is often observed in people living with HIV/AIDS, as their weakened immune defenses allow the virus to reactivate. Individuals undergoing immunosuppressive therapies, such as organ transplant recipients, are also at higher risk for HHV-8-related diseases due to their suppressed immune responses.
Symptoms of Kaposi’s Sarcoma
Kaposi’s Sarcoma (KS) is the most common disease linked to HHV-8, characterized by the appearance of distinct lesions. These lesions often present as purple, red, or brown patches that can evolve into raised nodules or tumors on the skin. Common locations for these skin lesions include the legs, feet, face, and mucous membranes such as the inside of the mouth or nose. The progression of these lesions varies, sometimes appearing slowly over months or rapidly in more aggressive forms.
Beyond the skin, Kaposi’s Sarcoma can affect internal organs, leading to a range of symptoms depending on the affected site. Lung involvement can cause shortness of breath, persistent cough, or chest pain. When the gastrointestinal tract is affected, individuals might experience abdominal pain, bleeding, or diarrhea. Swelling of lymph nodes can also occur in various parts of the body.
The presentation of Kaposi’s Sarcoma differs across its various forms. Classic KS typically affects older men of Mediterranean or Eastern European descent, manifesting as slow-growing skin lesions on the lower extremities. Endemic KS is prevalent in equatorial Africa, often affecting younger individuals and presenting with more aggressive skin lesions or significant lymph node involvement. Iatrogenic KS develops in individuals receiving immunosuppressive drugs, with symptoms often improving upon reduction of immunosuppression. AIDS-associated KS, the most common form in many regions, typically presents with widespread skin lesions and frequent internal organ involvement due to severe immune suppression.
Symptoms of Other HHV-8 Associated Conditions
HHV-8 is also associated with other less common but severe conditions, each with distinct symptomatic profiles.
Primary Effusion Lymphoma (PEL)
Primary Effusion Lymphoma (PEL) is a rare form of non-Hodgkin lymphoma primarily affecting body cavities. Individuals with PEL often experience symptoms related to fluid accumulation, such as shortness of breath and chest pain due to pleural effusions around the lungs. Pericardial effusions, fluid around the heart, can lead to chest discomfort or heart function issues. Abdominal swelling and discomfort may indicate peritoneal effusions, which is fluid in the abdominal cavity. Systemic symptoms, often referred to as “B symptoms,” are also common in PEL. These include persistent fevers, drenching night sweats, and unexplained weight loss.
Multicentric Castleman Disease (MCD)
Multicentric Castleman Disease (MCD) is another HHV-8-associated disorder characterized by widespread enlargement of lymph nodes and systemic inflammation. Symptoms of MCD can be generalized and debilitating, including persistent fever and drenching night sweats. Profound fatigue and unexplained weight loss are also frequently reported. Patients often present with enlarged lymph nodes in multiple areas of the body, such as the neck, armpits, and groin. Beyond lymphadenopathy, MCD can lead to the enlargement of organs like the spleen or liver. Other systemic manifestations may include anemia or kidney dysfunction.
Detecting HHV-8 and Its Associated Diseases
Detecting HHV-8 infection and its related conditions typically involves a combination of laboratory tests and tissue analysis. Blood tests can identify antibodies to HHV-8, indicating past or present exposure to the virus. While antibody detection suggests infection, it does not confirm active disease or predict symptom development. Molecular tests, such as polymerase chain reaction (PCR), are used to detect the virus’s genetic material directly in tissue or fluid samples. This method helps confirm active viral presence in symptomatic lesions or effusions.
For a definitive diagnosis of Kaposi’s Sarcoma, Primary Effusion Lymphoma, or Multicentric Castleman Disease, a biopsy is often required. A small sample of affected tissue or fluid is removed and examined under a microscope by a pathologist. This examination confirms the presence of characteristic cellular changes and viral components, leading to a precise diagnosis.