Decreased HIV diversity after allogeneic stem cell transplantation of an HIV-1 infected patient: a case report.

The human immunodeficiency virus type 1 (HIV-1) coreceptor use and viral evolution were analyzed in blood samples from an HIV-1 infected patient undergoing allogeneic stem cell transplantation (SCT). Coreceptor use was predicted in silico from sequence data obtained from the third variable loop region of the viral envelope gene with two software tools. Viral diversity and evolution was evaluated on the same samples by Bayesian inference and maximum likelihood methods. In addition, phenotypic analysis was done by comparison of viral growth in peripheral blood mononuclear cells and in a CCR5 (R5)-deficient T-cell line which was controlled by a reporter assay confirming viral tropism. In silico coreceptor predictions did not match experimental determinations that showed a consistent R5 tropism. Anti-HIV directed antibodies could be detected before and after the SCT. These preexisting antibodies did not prevent viral rebound after the interruption of antiretroviral therapy during the SCT. Eventually, transplantation and readministration of anti-retroviral drugs lead to sustained increase in CD4 counts and decreased viral load to undetectable levels. Unexpectedly, viral diversity decreased after successful SCT. Our data evidence that only R5-tropic virus was found in the patient before and after transplantation. Therefore, blocking CCR5 receptor during stem cell transplantation might have had beneficial effects and this might apply to more patients undergoing allogeneic stem cell transplantation. Furthermore, we revealed a scenario of HIV-1 dynamic different from the commonly described ones. Analysis of viral evolution shows the decrease of viral diversity even during episodes with bursts in viral load.

Bichat guidelines for the clinical management of viral encephalitis and bioterrorism-related viral encephalitis.

Most of the viruses involved in causing encephalitis are arthropod-borne viruses, with the exception of arenaviruses that are rodent-borne. Even if little information is available, there are indications that, most of these encephalitis-associated viruses could be used by aerosolisation during a bioterrorist attack. Viral transfer from blood to the CNS through the olfactory tract has been suggested. Another possible route of contamination is by vector-borne transmission such as infected mosquitoes or ticks. Alphaviruses are the most likely candidates for weaponisation. The clinical course of the diseases caused by these viruses is usually not specific, but differentiation is possible by using an adequate diagnostic tool. There is no effective drug therapy for the treatment of these diseases and treatment is mainly supportive, but vaccines protecting against some of these viruses do exist.

Bichat guidelines for the clinical management of Q fever and bioterrorism-related Q fever.

Q fever is a zoonotic disease caused by Coxiella burnetii. Its interest as a potential biological weapon stems from the fact that an aerosol of very few organisms could infect humans. Another route of transmission of C. burnetii could be through adding it to the food supply. Nevertheless, C. burnetii is considered to be one of the less suitable candidate agents for use in a bioterrorist attack; the incubation is long, many infections are inapparent and the mortality is low. In the case of an intentional release of C. burnetii by a terrorist, clinical presentation would be similar to naturally occurring disease. It may be asymptomatic, acute, normally accompanied by pneumonia or hepatitis, or chronic, usually manifested as endocarditis. Most cases of acute Q fever are asymptomatic and resolve spontaneously without specific treatment. Nevertheless, treatment can shorten the duration of illness and decrease the risk of complications such as endocarditis. Post-exposure prophylaxis is recommended after the exposure in the case of a bioterrorist attack.

Bichat guidelines for the clinical management of glanders and melioidosis and bioterrorism-related glanders and melioidosis.

Glanders and melioidosis are two infectious diseases that are caused by Burkholderia mallei and Burkholderia pseudomallei respectively. Infection may be acquired through direct skin contact with contaminated soil or water. Ingestion of such contaminated water or dust is another way of contamination. Glanders and melioidosis have both been studied for weaponisation in several countries in the past. They produce similar clinical syndromes. The symptoms depend upon the route of infection but one form of the disease may progress to another, or the disease might run a chronic relapsing course. Four clinical forms are generally described: localised infection, pulmonary infection, septicaemia and chronic suppurative infections of the skin. All treatment recommendations should be adapted according to the susceptibility reports from any isolates obtained. Post-exposure prophylaxis with trimethoprim-sulfamethoxazole is recommended in case of a biological attack. There is no vaccine available for humans.

Bichat guidelines for the clinical management of brucellosis and bioterrorism-related brucellosis.

Interest in Brucella species as a biological weapon stems from the fact that airborne transmission of the agent is possible. It is highly contagious and enters through mucous membranes such as the conjunctiva, oropharynx, respiratory tract and skin abrasions. It has been estimated that 10-100 organisms only are sufficient to constitute an infectious aerosol dose for humans. Signs and symptoms are similar in patients whatever the route of transmission and are mostly non-specific. Symptoms of patients infected by aerosol are indistinguishable from those of patients infected by other routes. Regimens containing doxycycline plus streptomycin or doxycycline plus rifampin are effective for most forms of brucellosis. Isolation of patients is not necessary. Trimethoprim-sulfamethoxazole and fluoroquinolones also have good results against Brucella, but are associated with high relapse rates when used as monotherapy. The combination of ofloxacin plus rifampicin is associated with good results. Even if there is little evidence to support its utility for post-exposure prophylaxis, doxycycline plus rifampicin is recommended for 3 to 6 weeks.

Bichat guidelines for the clinical management of botulism and bioterrorism-related botulism.

Botulism is a rare but serious paralytic illness caused by botulinum toxin, which is produced by the Clostridium botulinum. This toxin is the most poisonous substance known. It 100,000 times more toxic than sarin gas. Eating or breathing this toxin causes illness in humans. Four distinct clinical forms are described: foodborne, wound, infant and intestinal botulism. The fifth form, inhalational botulism, is caused by aerosolised botulinum toxin that could be used as a biological weapon. A deliberate release may also involve contamination of food or water supplies with toxin or C. botulinum bacteria. By inhalation, the dose that would kill 50% of exposed persons (LD50) is 0.003 microgrammes/kg of body weight. Patients with respiratory failure must be admitted to an intensive care unit and require long-term mechanical ventilation. Trivalent equine antitoxins (A,B,E) must be given to patients as soon as possible after clinical diagnosis. Heptavalent human antitoxins (A-G) are available in certain countries.

Bichat guidelines for the clinical management of haemorrhagic fever viruses and bioterrorism-related haemorrhagic fever viruses.

Haemorrhagic fever viruses (HFVs) are a diverse group of viruses that cause a clinical disease associated with fever and bleeding disorder. HFVs that are associated with a potential biological threat are Ebola and Marburg viruses (Filoviridae), Lassa fever and New World arenaviruses (Machupo, Junin, Guanarito and Sabia viruses) (Arenaviridae), Rift Valley fever (Bunyaviridae) and yellow fever, Omsk haemorrhagic fever, and Kyanasur Forest disease (Flaviviridae). In terms of biological warfare concerning dengue, Crimean-Congo haemorrhagic fever and Hantaviruses, there is not sufficient knowledge to include them as a major biological threat. Dengue virus is the only one of these that cannot be transmitted via aerosol. Crimean-Congo haemorrhagic fever and the agents of haemorrhagic fever with renal syndrome appear difficult to weaponise. Ribavirin is recommended for the treatment and the prophylaxis of the arenaviruses and the bunyaviruses, but is not effective for the other families. All patients must be isolated and receive intensive supportive therapy.

Bichat guidelines for the clinical management of tularaemia and bioterrorism-related tularaemia.

Francisella tularensis is one of the most infectious pathogenic bacteria known, requiring inoculation or inhalation of as few as 10 organisms to initiate human infection. Inhalational tularaemia following intentional release of a virulent strain of F. tularensis would have great impact and cause high morbidity and mortality. Another route of contamination in a deliberate release could be contamination of water. Seven clinical forms, according to route of inoculation (skin, mucous membranes, gastrointestinal tract, eyes, respiratory tract), dose of the inoculum and virulence of the organism (types A or B) are identified. The pneumonic form of the disease is the most likely form of the disease should this bacterium be used as a bioterrorism agent. Streptomycin and gentamicin are currently considered the treatment of choice for tularemia. Quinolone is an effective alternative drug. No isolation measures for patients with pneumonia are necessary. Streptomycin, gentamicin, doxycycline or ciprofloxacin are recommended for post-exposure prophylaxis.

Bichat guidelines for the clinical management of smallpox and bioterrorism-related smallpox.

Smallpox is a viral infection caused by the variola virus. It was declared eradicated worldwide by the Word Health Organization in 1980 following a smallpox eradication campaign. Smallpox is seen as one of the viruses most likely to be used as a biological weapon. The variola virus exists legitimately in only two laboratories in the world. Any new case of smallpox would have to be the result of human accidental or deliberate release. The aerosol infectivity, high mortality, and stability of the variola virus make it a potential and dangerous threat in biological warfare. Early detection and diagnosis are important to limit the spread of the disease. Patients with smallpox must be isolated and managed, if possible, in a negative-pressure room until death or until all scabs have been shed. There is no established antiviral treatment for smallpox. The most effective prevention is vaccination before exposure.

Bichat guidelines for the clinical management of anthrax and bioterrorism-related anthrax.

The spore-forming Bacillus anthracis must be considered as one of the most serious potential biological weapons. The recent cases of anthrax caused by a deliberate release reported in 2001 in the United States point to the necessity of early recognition of this disease. Infection in humans most often involves the skin, and more rarely the lungs and the gastrointestinal tract. Inhalational anthrax is of particular interest for possible deliberate release: it is a life-threatening disease and early diagnosis and treatment can significantly decrease the mortality rate. Treatment consists of massive doses of antibiotics and supportive care. Isolation is not necessary. Antibiotics such as ciprofloxacin are recommended for post-exposure prophylaxis during 60 days.

Bichat guidelines for the clinical management of plague and bioterrorism-related plague.

Yersinia pestis appears to be a good candidate agent for a bioterrorist attack. The use of an aerosolised form of this agent could cause an explosive outbreak of primary plague pneumonia. The bacteria could be used also to infect the rodent population and then spread to humans. Most of the therapeutic guidelines suggest using gentamicin or streptomycin as first line therapy with ciprofloxacin as optional treatment. Persons who come in contact with patients with pneumonic plague should receive antibiotic prophylaxis with doxycycline or ciprofloxacin for 7 days. Prevention of human-to-human transmission via patients with plague pneumonia can be achieved by implementing standard isolation procedures until at least 4 days of antibiotic treatment have been administered. For the other clinical types of the disease, patients should be isolated for the first 48 hours after the initiation of treatment.

Characterization of a chemokine receptor CCR5-negative T cell line and its use in determining human immunodeficiency virus type 1 phenotype.

A human CD4-positive T cell line from a donor homozygous negative for the chemokine receptor CCR5 was established, characterized, and used for determining the coreceptor usage of human immunodeficiency virus type 1 (HIV-1) isolates. Clones of this IL-2 dependent human T-cell lymphotropic virus type 1 (HTLV-I) immortalized cell line, named IsnoR5 clones 1 and 2, are susceptible to infection by HIV-1 isolates that use CXCR4 as a coreceptor but resistant to infection by CCR5 tropic HIV-1 viruses. HIV-1 isolates whose replication is inhibited in IsnoR5 cells in the presence of the bicyclam AMD 3100, a CXCR4 specific inhibitor, utilize a coreceptor distinct from CCR5 and CXCR4. Using a panel of primary HIV-1 isolates we have shown that a single T cell line is sufficient to discriminate between use of CCR5, CXCR4 or an alternative coreceptor. As IsnoR5 clone 1 cells revealed the existence of even minor populations of CXCR4-using virus variants, they could be useful for the early identification of changes in coreceptor usage in HIV infected individuals facilitating the timely introduction of appropriate clinical treatments.