Association of L-ficolin levels and FCN2 genotypes with chronic Chagas disease.

BACKGROUND: L-ficolin (encoded by FCN2) binds to acetylated sugar moieties of many pathogens, including Trypanosoma cruzi, promoting their phagocytosis and lysis by the complement system. METHODS: We investigated L-ficolin levels in 160 T. cruzi infected patients with chronic Chagas disease and 71 healthy individuals, and FCN2 polymorphisms (-986 G>A, -602 G>A, and -4 A>G in the promoter and A258S in exon 8) in 243 patients, being 88 indeterminate (asymptomatic), 96 with cardiac, 23 with digestive and 33 with cardiodigestive manifestations (two were unspecified) and 305 controls (135 for A258S). RESULTS: Patients presented lower L-ficolin plasma levels than controls (p<0.0001). Among the different groups of cardiac commitment, individuals with moderate forms had higher L-ficolin levels than the severe forms (P = 0.039). Lower L-ficolin levels were found associated with the 258S variant in the patients (P = 0.034). We found less -4A/G heterozygotes in the cardiac patients, than in the controls (OR = 0.56 [95% CI = 0.33-0.94], P = 0.034). Heterozygote -4A/G genotypes with the 258S variant and 258SS homozygotes were nevertheless more frequent among cardiodigestive patients than in controls (OR = 14.1 [95% CI = 3.5-56.8], P = 0.0001) and in indeterminate patients (OR = 3.2 [95% CI = 1.1-9.4], P = 0.037). We also found an association of the allelic frequency of the 258S variant with cardiodigestive Chagas disease compared to controls (OR = 2.24 [95% CI = 1.1-4.5], P = 0.037). Thus, decreased patient levels of L-ficolin reflect not only protein consumption due to the disease process, but also the higher frequency of the 258S variant in patients with cardiodigestive symptoms. CONCLUSION: The very first study on Brazilian cohort associates both L-ficolin plasma levels and FCN2 variants to Chagas disease and subsequent disease progression. The prognostic value of L-ficolin levels and the FCN2*A258S polymorphism should be further evaluated in other settings

Mannose binding lectin and susceptibility to rheumatoid arthritis in Brazilian patients and their relatives.

INTRODUCTION: Rheumatoid arthritis (RA) is a commonly occurring systemic inflammatory auto immune disease and is believed to be associated with genetic factors. The innate immune complement protein Mannose binding lectin (MBL) and their MBL2 genetic variants are associated with different infectious and autoimmune diseases. METHODS: In a Brazilian cohort, we aim to associate the functional role of circulating MBL serum levels and MBL2 variants in clinically classified patients (n = 196) with rheumatoid arthritis including their relatives (n = 200) and ethnicity matched healthy controls (n = 200). MBL serum levels were measured by ELISA and functional MBL2 variants were genotyped by direct sequencing. RESULTS: The exon1+54 MBL2*B variant was significantly associated with an increased risk and the reconstructed haplotype MBL2*LYPB was associated with RA susceptibility. Circulating serum MBL levels were observed significantly lower in RA patients compared to their relatives and controls. No significant contribution of MBL levels were observed with respect to functional class, age at disease onset, disease duration and/or other clinical parameters such as nodules, secondary Sjögren syndrome, anti-CCP and rheumatoid factor. Differential distribution of serum MBL levels with functional MBL2 variants was observed in respective RA patients and their relatives. CONCLUSIONS: Our results suggest MBL levels as a possible marker for RA susceptibility in a Brazilian population

Distribution of L-ficolin levels based on genotypic variant and disease stages.

<p>(A) L-ficolin levels in Chagas patients and controls by the presence of <i>258S</i> variant and (B) Distribution of L-ficolin levels in Chagas patients and controls by disease stages. The statistical distribution is shown with median and interquartile range. Closed dots: samples with −<i>4 A/G</i> genotype. Closed boxes: samples with −<i>4 A/G</i> and <i>258A/S</i> (<i>AGGA/GGAS</i> genotype) or <i>258S/S</i> homozygotes (<i>GGAS/GGAS</i> genotype).</p

Demographic and clinical parameters of chronic Chagas patients.

*<p>MBL levels were determined by ELISA and C-reactive protein (hs-CRP) by nephelometry as previously described <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0060237#pone.0060237-Luz1" target="_blank">[6]</a> n number of investigated samples; N.d. not determined.</p>&<p>some patients were unspecified.</p

L-ficolin levels in Chagas patients and controls.

<p>The statistical distribution is shown with median (line in the box), box indicating the 25–75 percentiles, whiskers the 5–95 percentile and arithmetic mean (cross inside the box).</p

<i>FCN2</i> genotype frequencies (%) in Chagas patients and controls.

<p>In bold: genotypes with −<i>4 A/G</i> heterozygosity, whose summed frequencies differ between cardiac patients and controls. Gray-shadowed: genotypes <i>AGGA/GGAS</i> and <i>GGAS/GGAS</i> (homozygote for <i>A258S</i>), whose summed frequencies differ between cardiodigestive patients and indeterminate patients or controls (see text).</p>*<p><i>A258S</i> was investigated by sequencing in a subset of 135 controls. n number of individuals.</p

Distribution of L-ficolin levels based on age and clinical classification.

<p>(A) L-ficolin levels in Chagas patients and controls according to age (B) L-ficolin levels in Chagas patients and controls based on class of cardiac commitment. The statistical distribution is shown with median and interquartile range. One outlier (18880.7 ng/ml) was excluded for better visualization in the 45–59 group of patients.</p

Distribution of MBL levels in different <i>MBL2</i> haplotypes and diplotypes.

<p><i>MBL2</i> diplotypes were reconstructed from promoter variant −221X/Y and variants in exon1 (Codon 52+54+57, A/O) and divided into high MBL producers (<i>YA/YA</i>), intermediate (<i>YA/YO</i>, <i>XA/XA</i> and <i>XA/YA</i>) and low MBL producers (<i>YO/YO</i>, <i>XA/YO</i>). Serum MBL levels were segregated according to different <i>MBL2</i> diplotypes in patients and relatives (A), and different <i>MBL2 </i>secretor haplotypes in RA patients (B) and relatives (C).</p

Correlations between anti-CCP and patient’s age and age at disease onset.

<p>Anti-CCP correlated with the age of patients (A) and age at disease onset (C). Anti-CCP studied according to patient’s age (B) and age at disease onset (D).</p

Distribution of MBL levels in different <i>MBL2</i> genotypes.

<p>Serum MBL levels according to different genotypes of studied <i>MBL2</i> variants in RA patients (A) and relatives (B).</p