Human T-Cell Lymphotropic Virus (HTLV) 1,2

What is HTLV?

HTLV, otherwise known as the human T-lymphotropic virus, is the first type of human retrovirus infection and leads to diseased T-cells. T-cells are a kind of white blood cells that play an important role in our immune system responses. There are two types of HTLV, which are type I and type-II, that are infecting more than 15-20 million people worldwide.

Both types of HTLV infect the lymphocytes and show minimal symptoms. But, even if symptoms are not exacerbated, an infected person can still pass the virus to others. Once the virus enters the body, it remains in it (dormant or active). Up until now, there is no treatment that can cure HTLV. In some cases, the virus can turn into an acute or chronic illness. A study showed that HTLV-2 can also lead to premature death, possibly due to myelopathy.

Just like any other sexually-transmitted disease, HTLV can be passed through having unprotected sexual relations. The risk increases when an individual has multiple sex partners; when he or she comes in close contact with contaminated blood, like the case of drug users; or, getting in contact with genital sores and ulcers. The risk also exists through receiving a blood transfusion of units that were not tested for HTLV as well as through organ transplants. The last two route of transmission are becoming somehow rare on the USA as all donors (blood or organs) are getting tested for both types of HTLV.

An infected mother can pass the infection (only the HTLV-I) to her child through breastfeeding or during the intrauterine and peripartum period. The transmission depends on many factors such as the viral load, as well as the duration of breastfeeding. The Centers For Disease Control And Prevention explains that 5% of babies born to infected pregnant women, acquire HTLV even with not breastfed.

In the United States, 22 out of 100,000 individuals get tested positive for this infection. HTLV type-2 is more common than HTLV type-1. It is usually found in older women who are not white, with lower educational levels and possibly residing in the western and southwestern part of the USA. The virus is a prevalent endemic among Native Americans and drug users who use needles.

When the body gets exposed to any of the two types of HTLV, it produces antibodies. An HTLV blood test can detect these antibodies and assess the infection status.

Why take the HTLV test?

The HTLV test can help detect an HTLV infection for those who are at high risk of being infected. You need to take the HTLV test if you are at high risk of contracting the infection. Risk factors include living in areas where the infection is prevalent or having a partner who came from such areas. Having many sexual partners, being an IV drug user and being a Native American Indian can increase the risks of having the HTLV; therefore, the need to get tested.

According to the National Center for Human Retrovirology at the Imperial College Healthcare, (NHS), one in four babies born to HTLV infected mothers become infected. Also, while most infected people do not experience complications caused by this uncurable infection; others, may experience many health deteriorating illnesses like adult T-cell leukemia, lymphoma, which is a rare kind of cancer that might require a bone marrow transplant. Complications may also include myelopathy, which is when the nerves of the spinal cord become inflamed, which causes weakness and stiffness in the legs, backaches, constipation and a weakened bladder. Other side effects of this infection comprise the inflammation of the eyes, joints, muscles and lungs. Dermatitis can also be the result of a complicated HTLV infection. To prevent all these complications, early detection is essential.

You need the HTLV test, as a follow up, if you have abnormal results for WBC differential and complete blood count (CBC). It also used in the diagnostic test to identify the possible causes of numerous illnesses, including leukemia and lymphoma; or for those who are showing signs and symptoms of HTLV-1 and 2. These latter include fever, night sweats, fatigue, enlarged lymph nodes, weakened lower limbs, lower back pain, muscle stiffness, sexual dysfunctions, and urinary infections.

While donated blood is getting tested for HTLV, if you received blood and was told that the donor was found positive; then, you need to get tested.

Also, a person whose partner tested positive for HTLV, need to be tested to have an early diagnosis and be protected for future complications of this retrovirus.

What can cause the levels to rise?

There is no evidence of any medication or natural supplement that can lead to false results.

What your HTLV test results mean?

This retrovirus is tested using a two-step method. First, an initial test is performed; followed by a confirmatory test in case the health care professional was not completely satisfied with the initial results. This test shows results that are either positive or negative.

If the initial HTLV test was shown negative; then, you do not have the HTLV virus; and, if you have symptoms, they are more likely caused by other illnesses. In that case, the initial test is the only one needed.

If the initial test gave a positive result for antibodies on the initial test; then, a confirmatory test might be needed to make a more accurate diagnosis. In case both the initial and confirmatory tests gave positive results; then, it is very likely that you are infected with HTLV. In case you were also showing symptoms of any of the HTLV-associated complications; then, your chronic illness is most probably caused by the HTLV.

If the initial test and confirmatory tests showed a positive result but the test was not done due to any associated symptoms; then, most probably you are infected with HTLV. This is the case of people who got tested because they may be at high risk. They are more likely to carry the infection; but, have it somehow dormant and not leading to any illness. They are, however, very likely to pass on the infection to others.

If the initial test was positive but the confirmatory test was negative; then, it is called a false negative and you most probably do not have the HTLV virus. If the second results were indeterminate; then you need to get retested. If the test came negative once again; then, you are certainly negative for HTLV.

Where can I get a HTLV test near me?

Please use our Lab Locator to find find a convenient testing location.

Reviewed By: Dr. Kurt Kloss, MD
Last Reviewed Date: Mar 03, 2022