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Chronic fatigue syndrome (CFS) is a severe disease characterized by various symptoms of immune dysfunction. CFS onset is typically with an infection and many patients suffer from frequently recurrent viral or bacterial infections. Immunoglobulin and mannose binding lectin (MBL) deficiency are frequent causes for increased susceptibility to infections. In this study we retrospectively analysed 300 patients with CFS for immunoglobulin and MBL levels, and B-cell subset frequencies. 25% of the CFS patients had decreased serum levels of at least one antibody class or subclass with IgG 3 and IgG 4 subclass deficiencies as most common phenotypes. However, we found elevated immunoglobulin levels with an excess of IgM and IgG 2 in particular in another 25% of patients. No major alteration in numbers of B cells and B-cell subsets was seen. Deficiency of MBL was found in 15% of the CFS patients in contrast to 6% in a historical control group. In a 2nd cohort of 168 patients similar frequencies of IgG subclass and MBL deficiency were found. Thus, humoral immune defects are frequent in CFS patients and are associated with infections of the respiratory tract. [ABSTRACT FROM AUTHOR]

Abstract: Susceptibility to systemic lupus erythematosus (SLE) has been associated with immunologic, environmental, and genetic factors. To uncover a possible association between MBL2 gene polymorphisms and SLE, we analyzed functional polymorphisms in the promoter and first exon of the MBL2 gene in 134 Brazilian SLE patients and 101 healthy controls. Genotype and allele frequencies of MBL2 A/O polymorphism were significantly different between patients and controls, and the O allele was associated with an increased risk of SLE. An association between low mannose binding lectin (MBL) producer combined genotypes and increased risk for SLE was also reported. Furthermore, when stratifying SLE patients according to clinical and laboratory data, an association between the A/O genotype and nephritic disorders and between the X/Y genotype and antiphospholipid syndrome was evident. Combined genotypes responsible for low MBL production were more frequently observed in SLE patients with nephritis. Our results indicate MBL2 polymorphisms as possible risk factors for SLE development and disease-related clinical manifestations. [Copyright &y& Elsevier]

Abstract: Although genetic variants in tumor necrosis factor (TNF), mannose binding lectin (MBL), and the vitamin D receptor (VDR) have been associated with leprosy clinical outcomes, these findings have not been extensively validated. We used a case-control study design with 933 patients in Nepal, which included 240 patients with type I reversal reaction (RR), and 124 patients with erythema nodosum leprosum (ENL) reactions. We compared genotype frequencies in 933 cases and 101 controls of seven polymorphisms, including a promoter region variant in TNF (G −308A), three polymorphisms in MBL (C154T, G161A and G170A), and three variants in VDR (FokI, BsmI, and TaqI). We observed an association between TNF −308A and protection from leprosy with an odds ratio of 0.52 (95% confidence interval = 0.29–0.95, p = 0.016). MBL polymorphism G161A was associated with protection from lepromatous leprosy (odds ratio = 0.33, 95% confidence interval = 0.12–0.85, p = 0.010). VDR polymorphisms were not associated with leprosy phenotypes. These results confirm previous findings of an association of TNF −308A with protection from leprosy and MBL polymorphisms with protection from lepromatous leprosy. The statistical significance was modest and will require further study for conclusive validation. [Copyright &y& Elsevier]

Our purpose was to investigate a possible relationship between occurrence of type I diabetes and polymorphism of the mannose binding lectin gene. Polymorphism of codon 54 of the mannose binding lectin (MBL) gene, whose presence of the minority allele leads to significant reduction of serum MBL concentration, was investigated in 128 Japanese patients with type I diabetes and 78 healthy volunteers by restriction fragment length polymorphism method. Frequencies of the minority allele were compared between the patient group and the control group. Frequency of the minority allele was 24.2% in the patient group and 19.9% in the control group. The probability of being heterozygous or homozygous for the minority allele was 41.4% in the patient group and 33.3% in the control group. Patients with DRB1*0405-DQB1*0401 and/or DRB1*0901-DQB1*0303 haplotypes, the two major type I diabetes–prone human leukocyte antigen haplotypes, showed a slightly higher probability of being heterozygous or homozygous for allele B of the MBL gene. Possession of the minority allele of the MBL gene may be a minor risk factor for having type I diabetes. [Copyright &y& Elsevier]