iral agents have been tried in patients with PML (interferon, cidofovir, cytarabine), but only cytarabine, which penetrates the central nervous system poorly, has shown activity against JC virus.

PML has been reported among patients with rheumatic diseases, including SLE and Wegener's granulomatosis. There are a handful of reports of PML among patients with rheumatoid arthritis. No cases of PML have been reported to date among RA patients treated with rituximab. Among patients with immunodeficiencies, patients with AIDS have a greater prevalence of PML than th

The United States Food and Drug Administration issued an alert on December 19, 2006, regarding the use of rituximab (Rituxan) in patients with certain arthritic conditions. This was based on two reports of fatal progressive multifocal leukoencephalopathy (PML) in patients with systemic lupus erythematosus who had received rituximab therapy.

PML is a rare, generally fatal demyelinating disease of the central nervous system similar to multiple sclerosis. It is caused by reactivation of JC polyoma virus infection. Exposure to JC virus is endemic meaning that approximately 80% of healthy adults have been exposed to the virus and actually still carry the virus around. However, PML is rare (approximately 1 in 200,000 persons), and is almost always seen among very immunocompromised individuals, for example AIDS patients and organ transplant patients receiving strong immunosuppressive drugs.

There have been approximately 20 cases of PML reported in the medical literature among patients with systemic lupus erythematosus (SLE) not receiving rituximab. More than 85% of patients reported were receiving one or more immunosuppressive drugs and/or high dose corticosteroids. The outcome was fatal in approximately two thirds of cases. Although rituximab has not yet received regulatory approval for use in SLE, it is estimated that approximately 8,000 SLE patients worldwide have received therapy with rituximab to date.

The symptoms of PML include paralysis, thinking difficulty, memory lapses, and problems with coordination.

Diagnosis can be difficult. Magnetic resonance imaging (MRI) findings consistent with PML include multiple spots in different parts of the brain with the lesions limited to the white matter. The presence of JC virus in the central nervous system (CNS) can be established by a test called the polymerase chain reaction (PCR) on samples of cerebrospinal fluid. Biopsy of brain tissue also will be abnormal. Measurement of the viral load of JC virus in the blood can also be done.

Among AIDS patients, antiretroviral therapy has resulted in a decreased prevalence of PML, indicating that improved immune function can improve outcome. It is not clear whether discontinuation of immunosuppressive therapy might improve the outcome in other conditions. Several anti-viral agents have been tried in patients with PML (interferon, cidofovir, cytarabine), but only cytarabine, which penetrates the central nervous system poorly, has shown activity against JC virus.

PML has been reported among patients with rheumatic diseases, including SLE and Wegener's granulomatosis. There are a handful of reports of PML among patients with rheumatoid arthritis. No cases of PML have been reported to date among RA patients treated with rituximab. Among patients with immunodeficiencies, patients with AIDS have a greater prevalence of PML than tho

y 80% of healthy adults have been exposed to the virus and actually still carry the virus around. However, PML is rare (approximately 1 in 200,000 persons), and is almost always seen among very immunocompromised individuals, for example AIDS patients and organ transplant patients receiving strong immunosuppressive drugs.

There have been approximately 20 cases of PML reported in the medical literature among patients with systemic lupus erythematosus (SLE) not receiving rituximab. More than 85% of patients reported were receiving one or more immunosuppressive drugs and/or high dose corticosteroids. The outcome was fatal in approximately two thirds of cases. Although rituximab has not yet received regulatory approval for use in SLE, it is estimated that approximately 8,000 SLE patients worldwide have received therapy with rituximab to date.

The symptoms of PML include paralysis, thinking difficulty, memory lapses, and problems with coordination.

Diagnosis can be difficult. Magnetic resonance imaging (MRI) findings consistent with PML include multiple spots in different parts of the brain with the lesions limited to the white matter. The presence of JC virus in the central nervous system (CNS) can be established by a test called the polymerase chain reaction (PCR) on samples of cerebrospinal fluid. Biopsy of brain tissue also will be abnormal. Measurement of the viral load of JC virus in the blood can also be done.

Among AIDS patients, antiretroviral therapy has resulted in a decreased prevalence of PML, indicating that improved immune function can improve outcome. It is not clear whether discontinuation of immunosuppressive therapy might improve the outcome in other conditions. Several anti-viral agents have been tried in patients with PML (interferon, cidofovir, cytarabine), but only cytarabine, which penetrates the central nervous system poorly, has shown activity against JC virus.

PML has been reported among patients with rheumatic diseases, including SLE and Wegener's granulomatosis. There are a handful of reports of PML among patients with rheumatoid arthritis. No cases of PML have been reported to date among RA patients treated with rituximab. Among patients with immunodeficiencies, patients with AIDS have a greater prevalence of PML than th

r high dose corticosteroids. The outcome was fatal in approximately two thirds of cases. Although rituximab has not yet received regulatory approval for use in SLE, it is estimated that approximately 8,000 SLE patients worldwide have received therapy with rituximab to date.

The symptoms of PML include paralysis, thinking difficulty, memory lapses, and problems with coordination.

Diagnosis can be difficult. Magnetic resonance imaging (MRI) findings consistent with PML include multiple spots in different parts of the brain with the lesions limited to the white matter. The presence of JC virus in the central nervous system (CNS) can be established by a test called the polymerase chain reaction (PCR) on samples of cerebrospinal fluid. Biopsy of brain tissue also will be abnormal. Measurement of the viral load of JC virus in the blood can also be done.

Among AIDS patients, antiretroviral therapy has resulted in a decreased prevalence of PML, indicating that improved immune function can improve outcome. It is not clear whether discontinuation of immunosuppressive therapy might improve the outcome in other conditions. Several anti-viral agents have been tried in patients with PML (interferon, cidofovir, cytarabine), but only cytarabine, which penetrates the central nervous system poorly, has shown activity against JC virus.

PML has been reported among patients with rheumatic diseases, including SLE and Wegener's granulomatosis. There are a handful of reports of PML among patients with rheumatoid arthritis. No cases of PML have been reported to date among RA patients treated with rituximab. Among patients with immunodeficiencies, patients with AIDS have a greater prevalence of PML than th

tter. The presence of JC virus in the central nervous system (CNS) can be established by a test called the polymerase chain reaction (PCR) on samples of cerebrospinal fluid. Biopsy of brain tissue also will be abnormal. Measurement of the viral load of JC virus in the blood can also be done.

Among AIDS patients, antiretroviral therapy has resulted in a decreased prevalence of PML, indicating that improved immune function can improve outcome. It is not clear whether discontinuation of immunosuppressive therapy might improve the outcome in other conditions. Several anti-viral agents have been tried in patients with PML (interferon, cidofovir, cytarabine), but only cytarabine, which penetrates the central nervous system poorly, has shown activity against JC virus.

PML has been reported among patients with rheumatic diseases, including SLE and Wegener's granulomatosis. There are a handful of reports of PML among patients with rheumatoid arthritis. No cases of PML have been reported to date among RA patients treated with rituximab. Among patients with immunodeficiencies, patients with AIDS have a greater prevalence of PML than th

iral agents have been tried in patients with PML (interferon, cidofovir, cytarabine), but only cytarabine, which penetrates the central nervous system poorly, has shown activity against JC virus.

PML has been reported among patients with rheumatic diseases, including SLE and Wegener's granulomatosis. There are a handful of reports of PML among patients with rheumatoid arthritis. No cases of PML have been reported to date among RA patients treated with rituximab. Among patients with immunodeficiencies, patients with AIDS have a greater prevalence of PML than those with other immune deficiencies.

PML is a rare condition. So far two cases of PML have been described in patients with SLE treated with rituximab. The overall and long-term risk of PML in patients with rheumatic diseases treated with rituximab is unknown. Patients should be counseled about the potential risk. As with any treatment, the potential risks must be weighed against the potential benefits of therapy.