Although everyone is virtually infected with this fungus, a healthy immune system keeps the infection from ever causing disease. But this immunity is weak when people are infected with HIV or if someone uses immunosuppressive drugs after organ transplantation, or for treating autoimmune diseases or cancer. And for this reason, the risk of developing fungal meningitis from Cryptococcus neoformans rises dramatically.

Liise-anne Pirofski, M.D., describes in this study a technique for predicting which HIV-infected patients are at greatest risk for developing fungal meningitis caused by Cryptococcus neoformans. The immune cells are known as IgM memory B cells, and were counted by Dr. Pirofski and her colleagues in the bloodstream of three groups of individuals: people infected with HIV but with no history of the disease caused by Cryptococcus neoformans; those infected with HIV who had a history of fungal meningitis caused by Cryptococcus neoformans; and those with no history of either HIV infection or the disease.

After this experiment, Dr. Pirofski said “We were astounded to find a profound difference in the level of these IgM memory B cells between the HIV-infected groups”. Furthermore, they wanted to find out whether the lower levels of IgM memory B cells in certain HIV-infected individuals resulted from the fungal disease, or they preceded their development of the disease. After tests it resulted that some people are predisposed to develop fungal meningitis, because of low levels of IgM memory B cells.

As a conclusion Dr. Pirofski stated that “We think that knowing whether transplant recipients or other patients taking immunosuppressive drugs have low numbers of IgM memory B cells could be useful in deciding which patients should receive antifungal drugs to prevent meningitis caused by Cryptococcus neoformans.”