Public Health

Kit created by USP in Ribeirão Preto facilitates the identification of the retrovirus HTLV

With cost 17 times less than similar imported, the national confirmatory test will reduce the window period

Researchers from the Blood Center of Ribeirão Preto, connected to the Hospital of the Faculty of Medicine of Ribeirão Preto (HCFMRP) USP, in partnership with Gene ID SA have developed a molecular diagnostic kit to confirm infection by the retrovirus HTLV 1 and 2 in case of positive results of tests done on the routine serologic blood centers and blood banks. Confirmatory testing domestic, and more sensitive, which allows to reduce the window period (the time between infection and antibody production against retroviruses), will cost 17 times less than that currently used, called Western blot (WB) which is imported.

An estimated 2.5 million people in Brazil have the retroviruses but only between 1% and 5% develop some kind of disease. The price of imported WB test is about $ 170.00 and also, in many cases, can not solve the patient diagnosis. Due to price sensitivity and the fact it is not mandatory, only a few institutions perform the confirmatory test. The national under development, uses a different methodology and beyond more efficient, will cost about $ 10.00, ie, only 6% of the value of imports. Another factor as important as the cost is to reduce the window period, which now ranges from 36 to 72 days.

Since 1993, blood centers are tests to identify blood donors among possible carriers of retroviruses HTLV. If the first test for the presence of HTLV constada, the stock is discarded and the donor is called by the medical staff of blood banks. But some institutions make to reduce doubts about the initial result, another test to confirm the result of the first. But most institutions does not perform the second test, considering only the result of the first.

These factors allow the safe completion of diagnosis for proper counseling and treatment of patients, increased security in transplants and blood transfusions and prevent vertical transmission (mother to child), the main route of transmission, explains the researcher Mauricio Rocha, Laboratory of Molecular Biology of the Blood Center, led by researcher Simone Haddad. The coordination of the research is Professor Dimas Tadeu Covas, of the Faculty of Medicine of Ribeirão Preto (FMRP) USP.


Studies indicate that in the world there are about 20 million people infected with HTLV. Of these, approximately two and a half million are in Brazil, which has the largest absolute number of infected worldwide. Between 1% and 5% of this total will develop some disease related to HTLV. Among them, myelopathy tropical spastic paraparesis associated with HTLV, one prevalent in Brazil, for which there is no cure, but if discovered early-stage treatment provides an improvement in the patient's condition.

It is a neurological disorder that affects the bone marrow in adults between 50 and 60 years, and that leads to muscle weakness of the legs. The person has difficulty walking and difficulty in controlling urine. It is a slowly progressive disease. It is a disease with rapid evolution, the patient takes many years to need wheel chair. The infection is transmitted by several mechanisms, including, breast milk, blood transfusion and sexual intercourse. There is no specific treatment. What you do is physical therapy and other rehabilitation measures, explains neurologist HCFMRP, Osvaldo Massaiti Takayanagui expert in treating the disease.

The next step in the research is to test blood samples from Salvador (Bahia), South Africa and Peru. The proposal is to expand the number of exams from other regions to ensure the efficiency of the test. The samples tested show 100% efficiency, however, other samples need to be examined, since no diagnostic test is 100% efficient, Rocha explained. In this first phase were conducted 180 tests on samples from the database of the Blood Center of Ribeirão Preto.

The Financier of Studies and Projects (FINEP) is investing £ 1m in the production of national confirmatory test. The company Gene ID will be responsible for producing the kit, on completion of the survey. With lower price and more efficient outcome, we hope that after completing all steps of the research kit to be used in routine diagnostic confirmatory of all blood centers in the country, says Rocha.

Source: USP