Delta-like 1 protein, vitamin D binding protein and fetuin for detection of Mycobacterium tuberculosis meningitis

AIM

Tuberculosis meningitis (TBM) diagnosis is difficult, new biomarkers are needed. We evaluated the diagnostic utility of delta-like 1 protein (DLL1), vitamin D binding protein (VDBP) and fetuin.

METHODS

Biomarker concentrations were measured by ELISA in cryopreserved cerebrospinal fluid from 139 HIV-infected Ugandans with suspected meningitis. TBM was diagnosed by GeneXpert MTB/Rif or culture. Cohort diagnoses included TBM (n = 22), cryptococcal (n = 71), or aseptic meningitis (n = 16) and no meningitis (n = 30).

RESULTS

DLL1 (cut-off value 1150 pg/ml) provided 32% sensitivity and 98% specificity. Adding fetuin, cryptococcal antigen and IFN-γ resulted in sensitivities of 36, 63 and 76% with specificities of 98, 90 and 92%, respectively. VDBP (cut-off value 2.0 μg/ml) provided 81% sensitivity and 68% specificity while fetuin (cut-off value 2 μg/ml) provided a sensitivity of 86% and specificity of 68%.

CONCLUSION

CSF DLL1, VDBP and fetuin exhibited fair diagnostic performance for TBM diagnosis.

Seroprevalence of histoplasmosis in Kampala, Uganda

Histoplasmosis is endemic to the Midwestern United States, but cases have been reported nearly worldwide. A 1970 study found 3.8% skin test sensitivity to Histoplasma capsulatum in Uganda but no systemic study of histoplasmosis exposure has occurred since the onset of the human immunodeficiency virus (HIV) pandemic. This study investigated the seroprevalence of H. capsulatum and sought previously undetected cases of histoplasmosis in Kampala, Uganda. Serum, cerebrospinal fluid (CSF) and/or urine specimens were obtained from HIV-infected persons with suspected meningitis. Specimens were tested for H. capsulatum IgG and IgM by enzyme immune assay and Histoplasma antigen. 147 of the 257 subjects who were enrolled had cryptococcal meningitis. Overall, 1.3% (2/151) of subjects were serum Histoplasma IgG positive, and zero of 151 were IgM positive. Antigen was not detected in any serum (n = 57), urine (n = 37, or CSF (n = 63) samples. Both subjects with serum Histoplasma IgG positivity had cryptococcal meningitis. Histoplasma capsulatum IgG was detected at low levels in persons with HIV/AIDS in Kampala, Uganda. Histoplasmosis is not widespread in Uganda but microfoci do exist. There appears to be no cross-reactivity between Cryptococcus neoformans and Histoplasma antigen testing, and cryptococcosis appears to be at most, a rare cause of positive Histoplasma IgG.