[Idiopathic CD4-positive lymphocytopenia-associated progressive multifocal leukoencephalopathy confirmed by brain biopsy following negative results of repeated CSF-JC-virus tests: a case report]

Progressive multifocal leukoencephalopathy secondary to idiopathic CD4 lymphocytopenia treated with pembrolizumab

BACKGROUND

Progressive multifocal leukoencephalopathy (PML) is a rare demyelinating disease due to a lytic infection of oligodendrocytes caused by John Cunningham polyoma virus (JCV) infection. Idiopathic CD4+ T-cell lymphocytopenia (ICL) is a very rare cause of PML.

METHODS

We present an individual with PML secondary to ICL treated with 3 doses of pembrolizumab, a Programmed-Death-1 Immune Checkpoint Inhibitor following with complete resolution of symptoms and conduct a review of the literature.

CONCLUSION

This report illustrates the objective clinical and radiological improvement in a patient with PML due to ICL and suggests further study of immune checkpoint inhibitors as potential treatment for patients with PML.

Progressive multifocal leukoencephalopathy without overt immunosuppression

Progressive multifocal leukoencephalopathy (PML) is a central nervous system disease caused by the human polyomavirus 2 that usually occurs in a setting of immunodeficiency. PML without overt immunosuppression is considered a rare occurrence but has been described in multiple previous case reports and series. Its prevalence, overall frequency, and prognosis are largely unknown. This is a single-center retrospective review of all University of Florida cases with the ICD10 PML diagnosis code (A81.2). PML without overt immunosuppression was defined as absence of human immunodeficiency virus (HIV) infection, hematological malignancy, immunomodulatory/-suppressive medications, autoimmune conditions with a propensity for PML (sarcoidosis, systemic lupus erythematosus). Cases that did not fulfill criteria for clinically or histologically definite PML were excluded. Of 52 patients with the ICD10 code A 81.2, 17 fulfilled definite diagnostic criteria for PML. Overt immunosuppression was identified in 15/17 (88.2%) cases (10/17 (58.8%): human immunodeficiency virus; 5/17 (29.4%): immunomodulatory/-suppressive medication). Two/seventeen (11.8%) cases were consistent with PML without overt immunosuppression. Possible contributing factors were a preceding dog bite and mild hypogammaglobulinemia M (39 mg/dL) in case 1 and significant alcohol use without evidence for liver disease in case 2. Both cases were fatal within 6 (case 1) and 2 (case 2) months. The results suggest that PML without overt immunosuppression may be more common than previously described. Therefore, PML should be considered even in the absence of overt immunosuppression if clinical and radiographic findings are suggestive of the diagnosis.

Undetectable JC virus CSF PCR in patients with JC virus-induced progressive multifocal leukoencephalopathy

The diagnosis of progressive multifocal leukoencephalopathy (PML) is based on a combination of clinical, radiographic, and laboratory findings. However, negative JC polyomavirus (JCPyV) PCR in CSF does not always rule out JCPyV-related PML. In this narrative review, we sought to examine the characteristic of biopsy-proven PML in patients with undetectable JCPyV CSF PCR and provide alternative approaches in this scenario.