C-reactive protein, Neopterin and Beta2 microglobulin levels pre and post TB treatment in The Gambia. Issue 1 (December 2016) - Mendy, Joseph
Abstract Background Tuberculosis is one of the leading causes of morbidity and mortality in developing countries. Analysis of the host immune response may help with generating point-of-care tests for personalised monitoring. Thus, the aim of this study was to assess the relationship between immune activation markers: C-reactive protein (CRP), Beta2 microglobulin (B2 M) and Neopterin, disease severity prior to treatment and response to therapy in adult pulmonary TB patients. Methods HIV negative adult pulmonary TB index cases (n = 91) were recruited from the TB clinic at MRC, The Gambia. Plasma samples were collected at enrolment and at 2 and 6 months following TB treatment initiation. An enzyme linked immunosorbent assay (ELISA) was performed for evaluation of CRP, B2 M and Neopterin levels and correlated with clinical and microbiological parameters including strain of infection. Disease severity was determined using Chest X-ray (CXR), Body Mass Index (BMI) and sputum smear grade. Results Plasma levels of all three markers were highly elevated in patients at recruitment and declined significantly during TB therapy. No correlation with disease severity was seen at recruitment. CRP showed the most significant decrease by 2 months of treatment (p < 0.0001) whereas levels of B2 M and Neopterin showed little change by 2 months but a significant decrease by 6 months of treatment (p = 0.0002 andp < 0.0001 respectively). At recruitment, B2 M levels were significantly higher in subjects infected withMycobacterium africanum (Maf) compared with those infected withMycobacterium tuberculosis sensu stricto(Mtb) (p = 0.0075). In addition, while CRP and Neopterin showed a highly significant decline post-treatment regardless of strain (p < 0.0001 for all), B2 M showed differential decline depending on strain (p = 0.0153 forMtb andp = 0.0048 forMaf ) and levels were still significantly higher at 6 months inMaf compared toMtb infected subjects (p = 0.0051). Conclusion Our findings suggest that activation markers, particularly CRP, may have a role in identifying good response to TB therapy regardless of the strain of infection and could be further developed as point-of-care tests. In addition, B2 M levels may allow differentiation betweenMtb andMaf -infected subjects.