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BACKGROUND:Cancer patients who undergo tumor removal, and reconstructive surgery by transfer of a free tissue flap, are at high risk of surgical site infection and ischemia-reperfusion injury. Complement activation through the lectin pathway (LP) may contribute to ischemia-reperfusion injury. Remote ischemic preconditioning (RIPC) is a recent experimental treatment targeting ischemia-reperfusion injury. The study aims were to investigate LP protein plasma levels in head and neck cancer patients compared with healthy individuals, to explore whether RIPC affects LP protein levels in head and neck cancer surgery, and finally to examine the association between postoperative LP protein levels and the risk of surgical site infection. METHODS:Head and neck cancer patients (n = 60) undergoing tumor resection and reconstructive surgery were randomized 1:1 to RIPC or sham intervention administered intraoperatively. Blood samples were obtained preoperatively, 6 hours after RIPC/sham, and on the first postoperative day. LP protein plasma levels were measured utilizing time-resolved immunofluorometric assays. RESULTS:H-ficolin and M-ficolin levels were significantly increased in cancer patients compared with healthy individuals (both P ≤ 0.02). Conversely, mannan-binding lectin (MBL)-associated serine protease (MASP)-1, MASP-3, collectin liver-1 (CL-L1), and MBL-associated protein of 44 kilodalton (MAp44) levels were decreased in cancer patients compared with healthy individuals (all P ≤ 0.04). A significant reduction in all LP protein levels was observed after surgery (all P < 0.001); however, RIPC did not affect LP protein levels. No difference was demonstrated in postoperative LP protein levels between patients who developed surgical site infection and patients who did not (all P > 0.13). CONCLUSIONS:The LP was altered in head and neck cancer patients. LP protein levels were reduced after surgery, but intraoperative RIPC did not influence the LP. Postoperative LP protein levels were not associated with surgical site infection.

Collectin liver 1 (CL-L1, alias CL-10) and collectin kidney 1 (CL-K1, alias CL-11), encoded by the COLEC10 and COLEC11 genes, respectively, are highly homologous soluble pattern recognition molecules in the lectin pathway of complement. These proteins may be involved in anti-microbial activity and in tissue development as mutations in COLEC11 are one of the causes of the developmental defect syndrome 3MC. We studied variations in COLEC10 and COLEC11, the impact on serum concentration and to what extent CL-L1 and CL-K1 serum concentrations are correlated. We sequenced the promoter regions, exons and exon-intron boundaries of COLEC10 and COLEC11 in samples from Danish Caucasians and measured the corresponding serum levels of CL-L1 and CL-K1. The median concentration of CL-L1 and CL-K1 was 1.87 μg/ml (1.00-4.14 μg/ml) and 0.32 μg/ml (0.11-0.69 μg/ml), respectively. The level of CL-L1 strongly correlated with CL-K1 (ρ = 0.7405, P T (rs3820897) was associated with decreased levels of CL-K1 (P = 0.044). In conclusion, COLEC10 and COLEC11 are highly conserved, which may reflect biological importance of CL-L1 and CL-K1. Moreover, the strong inter individual correlation between the two proteins suggests that a major proportion are found as heterooligomers or subjected to the same regulatory mechanisms.

BackgroundThe gene MASP2 (mannan-binding lectin (MBL)-associated serine protease 2) encodes two proteins, MASP-2 and MAp19 (MBL-associated protein of 19 kDa), bound in plasma to MBL and ficolins. The binding of MBL/MASP-2 and ficolin/MASP-2 complexes to microorganisms activates the lectin pathway of complement and may increase the ingestion of intracellular pathogens such as Mycobacterium leprae.MethodsWe haplotyped 11 MASP2 polymorphisms with multiplex sequence-specific PCR in 219 Brazilian leprosy patients (131 lepromatous, 29 borderline, 21 tuberculoid, 14 undetermined, 24 unspecified), 405 healthy Brazilians and 291 Danish blood donors with previously determined MASP-2 and MAp19 levels. We also evaluated MASP-2 levels in further 46 leprosy patients and 69 Brazilian controls.ResultsTwo polymorphisms flanking exon 5 of MASP2 were associated with a dominant effect on high MASP-2 levels and an additive effect on low MAp19 levels. Patients presented lower MASP-2 levels (P = 0.0012) than controls. The frequency of the p.126L variant, associated with low MASP-2 levels (below 200 ng/mL), was higher in the patients (P = 0.0002, OR = 4.92), as was the frequency of genotypes with p.126L (P = 0.00006, OR = 5.96). The *1C2-l [AG] haplotype, which harbors p.126L and the deficiency-causing p.439H variant, has a dominant effect on the susceptibility to the disease (P = 0.007, OR = 4.15). Genotypes composed of the *2B1-i and/or *2B2A-i haplotypes, both associated with intermediate MASP-2 levels (200-600 ng/mL), were found to be protective against the disease (P = 0.0014, OR = 0.6). Low MASP-2 levels (P = 0.022), as well as corresponding genotypes with *1C2-l and/or *2A2-l but without *1B1-h or *1B2-h, were more frequent in the lepromatous than in other patients (P = 0.008, OR = 8.8).ConclusionsIn contrast with MBL, low MASP-2 levels increase the susceptibility to leprosy in general and to lepromatous leprosy in particular. MASP2 genotypes and MASP-2 levels might thus be of prognostic value for leprosy progression.

BACKGROUND: In HIV-infected patients, prediction of Cytomegalovirus (CMV) disease remains difficult. A protective role of mannan-binding lectin (MBL) and ficolins against CMV disease has been reported after transplantation, but the impact in HIV-infected patients is unclear. METHODS: In a case-control study nested within the Swiss HIV Cohort Study, we investigated associations between plasma levels of MBL/ficolins and CMV disease. We compared HIV-infected patients with CMV disease (cases) to CMV-seropositive patients without CMV disease (controls) matched for CD4 T-cells, sampling time, and use of combination antiretroviral therapy. MBL and M-ficolin, L-ficolin, and H-ficolin were quantified using ELISA. RESULTS: We analysed 105 cases and 105 matched controls. CMV disease was neither associated with MBL (odds ratio [OR] 1.03 per log(10) ng/mL increase (95% CI 0.73-1.45)) nor with ficolins (OR per log(10) ng/mL increase 0.66 (95% CI 0.28-1.52), 2.34 (95% CI 0.44-12.36), and 0.89 (95% CI 0.26-3.03) for M-ficolin, L-ficolin, and H-ficolin, respectively). We found no evidence of a greater association between MBL and CMV disease in patients with low CD4 counts; however in the multivariable analysis, CMV disease was more likely in patients with an increased HIV RNA (OR 1.53 per log(10) copies/mL; 95% CI 1.08-2.16), or a shorter duration of HIV-infection (OR 0.91 per year; 95% CI 0.84-0.98). CONCLUSIONS: CMV disease is not associated with low levels of MBL/ficolins, suggesting a lack of a protective role in HIV-infected patients.

MASP-1 is the first protein in the activation of the lectin pathway and MASP-1 is, like its isoforms MASP-3 and MAp44, encoded by the MASP1 gene. Our aim was to explore associations between polymorphisms in MASP1 and corresponding concentrations of MASP-1, MASP-3, and MAp44 in plasma as well as the genetic contribution to the equilibrium between the three proteins.Fifteen SNPs were genotyped in the MASP1 gene in 350 blood donors. Corresponding plasma concentrations of MASP-1, MASP-3, and MAp44 were measured.A total of 10 different SNPs showed associations with the concentration of one or some of the three proteins (rs113938200, rs190590338, rs35089177, rs3774275, rs67143992, rs698090, rs72549154, rs72549254, rs75284004, rs7625133), and several of these were in strong linkage. SNPs located in the mutually exclusive splice region had opposite effects on the protein concentrations. Being e.g. homozygote for the minor allele of rs3774275 was associated with an increase in median concentration of 13% in MASP-1(P=0.03), 29% in MAp44 (P

BackgroundThe innate immune system encompasses various recognition molecules able to sense both exogenous and endogenous danger signals arising from pathogens or damaged host cells. One such pattern-recognition molecule is M-ficolin, which is capable of activating the complement system through the lectin pathway. The lectin pathway is multifaceted with activities spanning from complement activation to coagulation, autoimmunity, ischemia-reperfusion injury and embryogenesis. Our aim was to explore associations between SNPs in FCN1, encoding M-ficolin and corresponding protein concentrations, and the impact of non-synonymous SNPs on protein function.Principal findingsWe genotyped 26 polymorphisms in the FCN1 gene and found 8 of these to be associated with M-ficolin levels in a cohort of 346 blood donors. Four of those polymorphisms were located in the promoter region and exon 1 and were in high linkage disequilibrium (r(2)≥0.91). The most significant of those were the AA genotype of -144C>A (rs10117466), which was associated with an increase in M-ficolin concentration of 26% compared to the CC genotype. We created recombinant proteins corresponding to the five non-synonymous mutations encountered and found that the Ser268Pro (rs150625869) mutation lead to loss of M-ficolin production. This was backed up by clinical observations, indicating that an individual homozygote of Ser268Pro would be completely M-ficolin deficient. Furthermore, the Ala218Thr (rs148649884) and Asn289Ser (rs138055828) were both associated with low M-ficolin levels, and the mutations crippled the ligand-binding capability of the recombinant M-ficolin, as indicated by the low binding to Group B Streptococcus.SignificanceOverall, our study interlinks the genotype and phenotype relationship concerning polymorphisms in FCN1 and corresponding concentrations and biological functions of M-ficolin. The elucidations of these associations provide information for future genetic studies in the lectin pathway and complement system.