Mannan-binding protein—levels in plasma and upper-airways secretions and frequency of genotypes in children with recurrence of otitis media

Abstract

SUMMARYWe have investigated a possible association beiween recurrence of otitis media and low concentrations of mannan-binding protein (MBP) in plasma and upper-airway secretions. The protein eoncentration was measured in plasma (H = 76). nasopharyngeal secretions (/j = 83) and middle ear effusions (« -73) from otitis-prone children, children wilh less recurrence of acule otitis media, children with no previous history of acute olitis media, but suffering from seeretory otitis media, and healthy children. Moreover, genetic polymorphistrts associated with low MBP plasma levels were investigated in DNA from nasopharyngeal tonsils of S9 children with recurrence of otitis media. A wide rangeof MBP plasma concentrations was found. No statistically significant differences in MBP plasma concetitralion were observed between patients and controls. Nor was there any increased frequency of the genotypes associated with low MBP plasma concentrations. Thus, our resulls do nol support the assumption thai low eoncenlration and/or MBP deficiency alone predispose to recurrence of otitis media in Caucasian children. MBP was detecicd in bolh nasopharyngeal secretions (1/175 of plasma level) and middleear effusions (1/4 of plasma level), suggesting a role for the protein in the local mucosal immune defence system at these locations. In contrast, MBP was undetectable in 53 samples of mixed-saliva.

Mannose-Binding Lectin and Upper Respiratory Tract Infections in Children and Adolescents

“…Three studies did not find an association between MBL polymorphisms and URI. Garred et al 18 were admitted to the hospital for ventilating tubes and/or adenoidectomy with healthy controls. 18 The frequency of the B allele did not differ between groups, but a trend was shown toward more homozygosity of the B allele in the patient group.…”

Functional polymorphisms in the mannan-binding lectin 2 gene: Effect on MBL levels and otitis media

“…[40][41][42][43][44][45] In addition, several studies showed an association of upper respiratory tract infections and/or AOM with aberrant MBL levels and/or genotypes, 11,46-48 but this was not confirmed by others. 49,50 These conflicting results might be caused by variation in age of subjects under study, because in one prospective study in children from Greenland, the maximal effect of MBL deficiency was observed in children between 6 and 17 months of age, whereas the effect could not be demonstrated in younger or older children. 11 The fact that we find MBL relevance only below the age of 24 months makes sense, because adaptive immunity against polysaccharide encapsulated bacteria, a main group of causative pathogens for AOM, matures around this age.…”

“…20 Finally, the studies that did not find an association between OM and MBL2 genotype were rather small (n 5 73, n 5 89), especially when looking at OM subgroups. 49,50 Probably large and well characterized cohorts of defined ethnicity are necessary to establish the effect of a single gene in a multifactorial disease like OM. Overall, our data show that both recognized and new MBL2 polymorphisms influence functional MBL serum levels and are of clinical relevance in young children with recurrent AOM.…”

Mannan‐Binding Lectin in Children with Chronic Gastritis

“…MBL being in general an acute phase serum protein was reported to be present also in sites where inflammatory processes develop (i.e. bronchoalveolar lavage fluid from patients with recurrent respiratory infections [24], exudate from children with otitis media [39], synovial fluid from patients suffering from rheumatoid arthritis [40], glomeruli of patients with IgA nephropathy [41] and intestinal fluid of AIDS patients infected with Cryptosporidium parvum [42]). MBL is known to be synthesized in the liver; however, there is some evidence of its extra‐hepatic production, mainly in animal models [43–46].…”