Mannan-binding lectin (MBL) and ficolins distinguish between self, non-self and altered-self by recognizing patterns of ligands on the surface of microorganisms or aberrant cells. When this happens MBL-associated serine protease-2 (MASP-2) is activated and cleaves complement factors to start inflammatory actions. We examined human populations for MASP-2 levels, MASP-2 function and for the presence of mutations in coding exons of MASP2. The MASP-2 levels were lowest in Africans from Zambia (median, 196 ng/ml) followed by Hong Kong Chinese (262 ng/ml), Brazilian Amerindians (290 ng/ml) and Danish Caucasians (416 ng/ml). In the Chinese population, we uncovered a novel four amino-acid tandem duplication (p.156_159dupCHNH) associated with low levels of MASP-2.

Chemokines play a major role in leukocyte recruitment during the formation of tuberculous granulomas. We studied the association between genetic polymorphisms of three chemokines, monocyte chemoattractant protein-1 (MCP-1), RANTES (regulated on activation, normal T cell expressed and secreted) and macrophage inflammatory protein-1a (MIP-1a), and tuberculosis (TB). The distribution of five functionally significant single-nucleotide polymorphisms (SNPs), MCP-1 À2518A/G, RANTES À403G/A, À28C/G and In1.1T/C as well as MIP-1a þ 459C/T was not found to be different between patients with TB and healthy control subjects of the Hong Kong Chinese population. However, differences in linkage disequilibrium (LD) of the SNPs of RANTES and in distribution of the haplotypes of RANTES between patients with TB and healthy controls (Po0.0001) were found. Two risk haplotypes of RANTES, A-C-T and G-C-C, at positions À403, À28 and In1.1, respectively, were identified. Furthermore, combining the genotypes of RANTES À403 and In1.1, two diplotypes GA/TT (Po0.001) and GG/ TC (Po0.0001) showed strong association with TB. Our findings support the association between RANTES functional polymorphisms and TB.

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