Monocyte Gene Expression Distinguishes Enhancing Brain Parenchymal Cysticercal Granulomas From Tuberculomas

Abstract

Abstract Background In patients with enhancing brain parenchymal lesions, parenchymal neurocysticercosis (pNCC) is often difficult to distinguish from tuberculoma, necessitating biopsy or empirical therapy. Methods In a prospective study, peripheral blood monocytes were isolated from patients with definitive pNCC (n = 39) and brain tuberculomas (n = 20). Patients with tuberculomas were diagnosed by the presence of concurrent systemic tuberculosis (n = 7), pathological or bacteriological confirmation (n = 5), and resolution of typical brain lesions following a therapeutic trial of antituberculous therapy (n = 8). Expressions of 14 NCC-associated monocyte genes were determined by quantitative polymerase chain reaction and analyzed for diagnostic usefulness between the 2 groups. Results Expression of 7 genes (TAX1BP1, RAP1A, PLCG2, TOR3A, GBP1P1, LRRFIP2, and FEZ2) was significantly higher in pNCC patients than in tuberculoma patients, with TAX1BP1 and RAP1A expressions more than 22- and 5-fold higher in pNCC patients. TAX1BP1 had the highest sensitivity of 66.7% at a specificity of 100% in discriminating pNCC from tuberculoma. A combination of TAX1BP1 and RAP1A increased the sensitivity to 84.6%, and including GBP1P1 with TAX1BP1 and RAP1A further increased sensitivity to 87.2% while maintaining specificity of 100%. Conclusions Expression of a panel of genes in blood monocytes distinguishes pNCC from brain tuberculomas in patients with enhancing brain lesions.