J.P. van de Merwe

The resident faecal flora is determined by genetic characteristics of the host. Implications for Crohn's disease?

Recently, an “abnormal” faecal flora has been associated with Crohns disease, a disease of unknown origin but with pertinent genetic predisposition. Therefore, it was investigated whether the faecal flora is under genetic influence in groups of monozygotic and dizygotic twins. Faecal floras of monozygotic twin siblings were found to be much more alike than those of dizygotic twin siblings. It is concluded that the resident faecal flora is under genetic influence and may be a useful parameter to study possible genetic backgrounds of other diseases.

The Obligate Anaerobic Faecal Flora of Patients with Crohn's Disease and Their First-Degree Relatives

The obligate anaerobic faecal floras of patients with Crohns disease, their first-degree relatives, and healthy control subjects were compared. The flora of Crohns patients contained more anaerobic gram-positive coccoid rods and gram-negative rods than that of healthy subjects; on this basis patients and healthy subjects formed two clusters with minor overlap. Nine of 26 children of Crohns patients were also included within the Crohns disease cluster. During 5 to 7 years of follow-up study 3 of them presented with remitting abdominal pain, diarrhoea, or weight loss, and in 1 of them Crohns disease was diagnosed; none of the 17 children with a normal flora showed symptoms possibly due to Crohns disease. It is concluded that the abnormal flora may be indigenous to subjects predisposed to Crohns disease, suggesting a direct or indirect relationship between the abnormal faecal flora and Crohns disease.

Interstitial cystitis: a review of immunological aspects of the aetiology and pathogenesis, with a hypothesis

In ̄ammation of the bladder is a common disease mainly affecting women. Patients may complain of suprapubic pain, urinary frequency and urgency with or without haematuria on repeated occasions. In many cases, urine analysis reveals white and red blood cells, while a positive bacteriological culture will con®rm an infectious cause of the cystitis. However, if the culture is negative, with or without cells, interstitial cystitis (IC) should be suspected. IC is a poorly understood syndrome that, like bacterial cystitis, occurs primarily in women. Lack of awareness of IC by the physician or the use of an inappropriate diagnostic approach may result in a lengthy period for many patients between the onset of symptoms and diagnosis of IC. IC is a chronic in ̄ammatory bladder disorder of unknown aetiology. Bladder histology, showing in®ltrates of mast cells, eosinophilic leukocytes and T lymphocytes, suggests that the disease is mediated by the immune system. The clinical association of IC with thyroid disorders and systemic autoimmune diseases such as systemic lupus erythematosus [1] and SjoÈgrens syndrome [2], has led to the hypothesis that IC may be an autoimmune disease of the bladder. However, the triggering factor that leads to disease is still unknown, as is the case with the associated autoimmune diseases. The most prevalent aetiological theories of IC are:

Increased frequency of CD16+ monocytes and the presence of activated dendritic cells in salivary glands in primary Sjögren syndrome

Objectives: In the salivary glands of patients with primary Sjögren Syndrome (pSjS) an accumulation of dendritic cells (DCs) is seen, which is thought to play a role in stimulating local inflammation. Aberrancies in subsets of monocytes, generally considered the blood precursors for DCs, may play a role in this accumulation of DCs. This study is aimed at determining the level of mature CD14lowCD16+ monocytes in pSjS and their contribution to the accumulation of DCs in pSjS. Methods: Levels of mature and immature monocytes in patients with pSjS (n = 19) and controls (n = 15) were analysed by flow cytometry. The reverse transmigration system was used for generation of DCs generated from monocyte subsets. The phenotype of DCs in pSjS salivary glands was analysed using immunohistochemistry. In vivo tracking of monocyte subsets was performed in a mouse model. Results: Increased levels of mature CD14lowCD16+ monocytes were found in patients with pSjS (mean (SD) 14.5 (5.5)% vs 11.4 (3.4)%). These cells showed normal expression of chemokine receptor and adhesion molecules. Mature monocytes partly developed into DC-lysosome-associated membrane glycoprotein (LAMP)+ (19.6 (7.5)%) and CD83+ (16 (9)%) DCs, markers also expressed by DCs in pSjS salivary glands. Monocyte tracking in the non-obese diabetic (NOD) mouse showed that the homologue population of mature mouse monocytes migrated to the salivary glands, and preferentially developed into CD11c+ DCs in vivo. Conclusions: Mature monocytes are increased in pSjS and patient and mouse data support a model where this mature monocyte subset migrates to the salivary glands and develops into DCs.

Induction of chronic arthritis in rats by cell wall fragments of anaerobic coccoid rods isolated from the faecal flora of patients with Crohn's disease

Crohns disease and ulcerative colitis are accompanied by seronegative arthritis in about one fifth of the cases. In the present study, cell wall fragments from major residents such as Eubacterium, Coprococcus and Peptostreptococcus species, isolated from the faecal flora of patients with Crohns disease, were tested for properties to induce chronic arthritis in Lewis rats. Cell wall fragments from Eubacterium contortum strains Me44 and Me47 were found to induce chronic arthritis; Peptostreptococcus productus strain C 18 cell wall fragments induced acute self-limiting arthritis. Coprococcus comes strain Me46 cell walls, on the other hand, were found to be lethal to the majority of rats inoculated, whereas those which survived did not develop acute or chronic arthritis. The results indicate that intraperitoneal injection of a single dose of cell wall fragments from bacteria that are major residents of the human anaerobic faecal flora can induce chronic inflammatory joint disease in the rat.

Serum agglutinins to Eubacterium and Peptostreptococcus species in Crohn's and other diseases.

Sera from patients suffering from Crohns and other diseases and from healthy subjects were tested for agglutinins to anaerobic, gram-positive coccoid rods belonging to species of Eubacterium and Peptostreptococcus. Four strains labelled Eubacterium contortum (two strains), Eubacterium rectale and Peptostreptococcus productus were agglutinated by a higher percentage of sera from patients with Crohns disease than from healthy subjects and from patients with liver and intestinal diseases (including ulcerative colitis), ankylosing spondylitis, granulomatous diseases, diseases of immunity and malignancies. The agglutinins were of the IgG and IgM classes and strain-specific; the titres were low. The results obtained with sera from patients with Crohns disease and healthy people were subjected to discriminant analysis to estimate the probability, based on the combined results with the four strains, that a patient suffers from Crohns disease. When sera giving an a posteriori probability greater than or equal to 0.95 (a priori probability = 0.5) were considered positive, the test with four strains had a sensitivity of 54% and a specificity of nearly 100%. The results with sera submitted for diagnosis showed that positive reactions in patients with a diagnosis apparently incompatible with Crohns disease were within acceptable limits.

Binding to faeces and influence on human anaerobes of antimicrobial agents used for selective decontamination

The degree of binding of ampicillin, cephradine, co-trimoxazole, gentamicin, nalidixic acid, neomycin, polymyxin B and tobramycin by faecal substance as well as the influence of these antibiotics on human intestinal obligate anaerobes was investigated. In contrast to ampicillin, cephradine, co-trimoxazole and nalidixic acid, the nonabsorbable antibiotics polymyxin B and neomycin were bound to a considerable degree by human faeces. The binding of tobramycin and gentamicin to the solid part of faeces was less effective. The inhibitory effect of co-trimoxazole, gentamicin, nalidixic acid, neomycin, polymyxin B and to-bramycin on the human obligate anaerobes was weak as compared with ampicillin and cephradine.Drugs which effectively eliminate Enterobacteriaceae from the gastrointestinal tract and which have a moderate effect on obligate anaerobes, like polymyxin B, are particularly suitable for selective decontamination of the gastrointestinal tract. The strong inactivating binding of aminoglycosides and polymyxin B to faeces accounts for the relatively high oral dose needed for a suitable faecal concentration.

An International Study of Agglutinins to Eubacterium, Peptostreptococcus and Coprococcus Species in Crohn’s Disease, Ulcerative Colitis and Control Subjects

The world-wide occurrence of agglutinating antibodies to four coccoid anaerobes belonging to Eubacterium, Peptostreptococcus and Coprococcus spp. was investigated in 937 coded sera from patients suffering from Crohns disease, ulcerative colitis, various other diseases and from healthy controls. Positive results were found in 59% of patients with Crohns disease, 29% of patients with ulcerative colitis, and 8% of both diseased and healthy control subjects. Patients with Crohns disease of the colon had more positive tests (67%) than patients with disease confined to the small bowel (46%). The results show that agglutinating antibodies to the coccoid anaerobes occur more frequently in patients with Crohns disease than in other subjects in widely varying geographic regions.

Effect of antibiotics on the human intestinal flora in mice

Antibiotics used during selective decontamination were studied for their effect on the human intestinal flora in mice. Polymyxin B and neomycin were found to eliminate Escherichia coli from the gastrointestinal tract but did not alter total numbers of obligate anaerobes. Neomycin induced an increase of the percentage of gram-negative obligate anaerobes. Cephradine did not affect the numbers of obligate and facultative anaerobes but increased the percentage of gram-negative obligately anaerobic rods in the flora.The selective effect of polymyxin B and neomycin on the flora is accounted for by a relative insusceptibility of the anaerobic flora as compared with E. coli. Low concentrations of polymyxin B and neomycin were detected in caecal supernatants. This was found to be due to strong binding of both antibiotics to the solid fraction of intestinal contents.

Serum Antibodies to Peptidoglycan-Polysaccharide Complexes from the Anaerobic Intestinal Flora in Patients with Crohn’s Disease

Soluble peptidoglycan-polysaccharide complexes (PPC) isolated from feces of a healthy subject shared antigens with 22 out of 40 anaerobic intestinal bacteria and, therefore, these could be considered as flora derived. IgG, IgA and IgM antibodies against PPC were found in sera from healthy subjects, patients with Crohns disease (CD) and other patients. In sera of CD patients with agglutinating antibodies to 4 anaerobic intestinal bacteria (used as an aid for diagnosis of CD) IgG and IgA levels to PPC were higher than in CD patients without these antibodies.