We have shown that circulating CXCL9 levels in TB patients differ according to severity of disease35. In addi-tion, mycobacterial antigen induced CXCL9 responses correlate with IFNγ, and that these are greater in local-ised as compared with disseminated disease36. A recent study has also shown the relevance of using both CCL2 (MCP-2) and CXCL10 (IP-10) as biomarkers for tuberculosis37,38 . In this study we hope to determine immune parameters in patients prior to and post-vitamin D treatment.