Human T-cell leukemia virus type 1

Alternate names

HTLV-1; Human T lymphotropic virus type 1

Definition

Human T-cell leukemia virus, type 1 (HTLV-1) is a retroviral infection that affect the T cells (a type of white blood cell).

Cause

• Human T-cell leukemia virus, type 1 (HTLV-1) occurs when a person is infected by the human T-cell leukemia retrovirus.
• HTLV-1 is spread by blood transfusions, sexual contact and sharing needles.
• It can also be spread from mother to child during birth or breast-feeding.
• It is unclear why some people with HTLV-1 develop adult T-cell leukemia (ATL), HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP) or other medical conditions, while others remain asymptomatic (show no signs or symptoms) their entire lives.

Signs and symptoms

• Human T-cell leukemia virus, type 1 (HTLV-1) generally causes no signs or symptoms.
• However, some affected people may later develop adult T-cell leukemia (ATL), HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP) or other medical conditions.
• Approximately 2-5% of people with HTLV-1 will develop ATL, a cancer of the T-cells (a type of white blood cell).
• The signs and symptoms of this condition and the disease progression vary from person to person.

Affected people may have the following features:

• Fatigue
• Lymphadenopathy (swollen lymph nodes)
• Thirst
• Nausea and vomiting
• Fever
• Skin and bone abnormalities
• Enlarged liver and/or spleen
• Frequent infections
• Roughly .25-2% of people with HTLV-1 will develop HAM/TSP, a chronic, progressive disease of the nervous system. Signs and symptoms of this condition vary but may include:
• Progressive weakness
• Stiff muscles
• Muscle spasms
• Backache
• 'Weak' bladder
• Constipation

Diagnosis

• Human T-cell leukemia virus, type 1 (HTLV-1) is usually diagnosed based on blood tests that detect antibodies to the virus.
• However, HTLV-1 is often never suspected or diagnosed since most people (95%) never develop any signs or symptoms of the infection.
• Diagnosis may occur during screening for blood donation, testing performed due to a family history of the infection, or a work-up for an HTLV-1-associated condition such as adult T-cell leukemia (ATL) or HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP).

Treatment

• No cure or treatment exists for human T-cell leukemia virus, type 1 (HTLV-1).
• Management is focused on early detection and preventing the spread of HTLV-1 to others.
• Screening blood donars, promoting safe sex and discouraging needle sharing can decrease the number of new infections.
• Mother-to-child transmission can be reduced by screening pregnant women so infected mothers can avoid breastfeeding.

Prognosis

• Ninety-five percent of people with human T-cell leukemia virus, type 1 (HTLV-1) never have any signs of symptoms of the infection and do not go on to develop medical problems.
• Approximately 2 to 5% of infected people will develop adult T-cell leukemia (ATL).
• Depending on the subtype of ATL, people usually live an average of 6 months to 2 years following diagnosis.
• Although chemotherapy can produce a complete remission, it does not alter the life expectancy.
• About .25 to 2% of people with HTLV-1 infection will develop HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP).
• People with HAP/TSP are often unable to walk unassisted within 10 years of onset and need to use a wheelchair within 21 years.

NIH genetic and rare disease info

• NIH info on Human T-cell leukemia virus type 1

Human T-cell leukemia virus type 1 is a rare disease.

Human T-cell leukemia virus type 1 Resources
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