Cryptococcosis in Anti-Interferon-Gamma Autoantibody-Positive Patients: a Different Clinical Manifestation from HIV-Infected Patients.

Disseminated nontuberculous mycobacterial (NTM) infection is the most common feature of patients who test positive for anti-interferon-gamma autoantibodies (IFN-γ Ab). Cryptococcus co-infects these patients. A retrospective, matched case-control study was conducted at Srinagarind Hospital between 1992 and 2013. We reviewed the medical records of non-HIV-infected patients with cryptococcosis and disseminated NTM infection (case) and matched 2 HIV-infected patients (control) with cryptococcosis to each case. There were 16 patients in the case group and 32 in the control group. Ten of the 16 patients in the case group had sera available for testing, and all tested positive for IFN-γ Ab. Compared to those in the control group, patients in the case group were significantly older, had a longer of illness duration and were less likely to present with meningitis but more likely to present with bone and/or joint, lung/pleura, and skin infections. Based on culture and staining results, patients in the case group were significantly less likely to test positive for the cryptococcal antigen in cerebrospinal fluid and serum samples, but were more likely to test positive in pus and skin lesion(s), compared to control patients. This is the first study of cryptococcosis in patients with disseminated NTM infection who tested positive for IFN-γ Ab. The clinical manifestations of cryptococcosis are different in these patients compared to those in HIV-infected patients. Recognizing the clinical features of these patients may improve diagnosis and promote timely treatment.