Correct!
5. All of the above

The most frequent cause of immunocompromise in a patient with cryptococcosis is AIDS. Our patient’s HIV was negative as was his anti-HTLV I/II. Crytococcosis has been reported in patients with hypogammaglobulinemia but the patient’s immunoglobulins were normal. However, his CD4 count was low at 154 cells/mm3. Our infectious disease consultant thought this likely represented idiopathic CD4 lymphocytopenia (ICL).

ICL is a rare disorder with a poorly defined incidence (2). There is no gender bias and the mean age in one review was 43 years. There is no evidence of any transmissible agent as a cause but the underlying mechanism is unknown. The most common clinical presentation is opportunistic infections particularly with Cryptococcus or atypical Mycobacteria sp. Pneumocystis, human papilloma virus, and shingles have also been reported to be associated with ICL. The CDC has defined ICL by 3 criteria:

  1. Absolute CD4 T-lymphocytes < 300 on two occasions 6 weeks apart
  2. HIV negative.
  3. Absence of any defined immunodeficiency or therapy associated with reduced CD4 counts.

Cryptococcal meningitis can be particularly difficult to diagnose in this population (3) and was the reason for the diagnosis of cryptococcal meningitis with the minimal CSF findings.

The patient was being treated with fluconazole at last report and stable. There is no specific treatment for ICL although the National Institutes of Health has an ongoing clinical trial with IL-7 treatment. Prophylaxis against Pneumocystis is recommended with CD4 < 200 cells/mm3. 

References

  1. Smith JA, Kauffman CA. Pulmonary fungal infections. Respirology. 2012;17(6):913-26.[CrossRef] [PubMed]
  2. Luo L and Li T, Idiopathic CD4 lymphocytopenia and opportunistic infections – an update. FEMS Immunol Med Microbiol. 2008;54:283-9. [CrossRef] [PubMed]
  3. Sancesario G, Palmieri G, Viola G, Fontana C, Perfetti A, Anemona L, Floris R, Marziali S, Bernardi G, Spagnoli LG. Difficultry diagnosing chronic cryptococcal meningitis in idiopathic CD4 lymphocytopenia. Neurol Sci 2011:32(3):519-24. [CrossRef] [PubMed]

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