Immune Reconstitution Inflammatory Syndrome (IRIS) Associated Multifocal Leukoencephalopathy (PML) in Patients with Human Immunodeficiency Virus (HIV) Infection: A Case Report
Abstract
Progressive Multifocal Leukoencephalopathy (PML) is seen mostly in advanced human immunodeficiency virus (HIV) infection. In some individuals, especially those with very low CD4+ counts, worsening of PML or new-onset PML can be observed after the initiation of highly active antiretroviral therapy (HAART). A case of IRIS associated PML is reported here which is much more rare as compared to PML in HIV patients unrelated to HAART. This is thought to be secondary to immune reconstitution inflammatory syndrome (IRIS). IRIS is defined as a paradoxical deterioration of a previously existing infection which is related to the immune system recovery. It is suggested to occur due to an imbalance of CD8+ /CD4+ T cells. So in HIV cases with low CD4 counts and if one is on HAART then should be further investigated for IRIS and PML.
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Introduction
Subclinical hypothyroidism (SCH) can be best defined as a high serum thyroid stimulating hormone (TSH) and normal serum total/free thyroxine (T4), triiodothyronine (T3) concentrations associated with few or no symptoms/signs of hypothyroidism. It is referred to as a state of mild thyroid failure and is essentially a laboratory diagnosis.1,2 Subclinical hypothyroidism is much more common than overt hypothyroidism3,4 with a world-wide prevalence of about 7.5% to 8.5% in women and 2.8% to 4.4% in men. 5
In the era of combined antiretroviral therapy, despite a dramatic fall in the incidence of most opportunistic infections, progressive multifocal leukoencephalopathy (PML) continues to occur at a similar frequency in HIV infected patients. PML occurs in up to 5% of patients with Acquired Immunodeficiency Syndrome (AIDS). 1
PML-IRIS may account for up to 18% of HIV-infected patients with PML. Rest 82% PML in HIV is unrelated to HAART treatment. Reactivation of JC virus (JCV), a polyoma virus, leads to PML. JCV infects oligodendrocytes and astrocytes in the CNS and induces a non-inflammatory lytic reaction which leads to demyelination, necrosis, and cell death. In some individuals, especially those with very low CD4+ counts, after the initiation of highly active antiretroviral therapy (HAART) worsening of PML or new-onset PML can be observed.
Conclusion
It can be concluded from this study that subjects with HIV, following the initiation of HAART, reconstitution of immune system may lead to activation of an inflammatory response which may leads to detectable or latent JC virus infection. Early and prolonged treatment with steroids may be useful in patients with PML-IRIS but requires further investigation.