Molecular Immunology and Immunogenetics

The aetiology of Crohn’s disease and paratuberculosis are the subjects of intensive study and also frequently, of dispute. However, a number of other nosological entities have a similar history, namely type 1 diabetes, multiple sclerosis, sarcoidosis, asthma, psoriasis, spondylarthritis, Blau syndrom etc. The zoonotic risk of Mycobacterium avium subsp. paratuberculosis (MAP) has been discussed for more than one hundred years. „The problem remains open, further research is needed“, is the sentence which seems to be obligatory in the conclusions
of many scientific articles. A number of hypotheses have been suggested, all with a grain of truth in them. The infection hypothesis has many supporters and opponents, but it does not fit to all Crohn’s disease cases. The contribution of the genetic factor has been admitted a long time ago and has been experimentally confirmed by recent excellent studies. An environmental factor is expected and has been often mentioned, but has yet to be discovered. Muramyl dipeptide, derived from peptidoglycans of the bacterial cell wall is one of the triggers, mentioned in connection with chronic inflammatory diseases. The immunomodulatory ability of this compound has been recognised for decades and is exploited in Freund’s adjuvant. A critical amount of muramyl dipeptide can
affect immunity during some bacterial infections but the long latent period between infection and onset of the clinical form of the disease could explain why a causative relationship between the primary infection and chronic inflammation is not considered. Different species of mycobacteria can be found in the environment, in water, dust, soil and aerosol. Although severe infections with mycobacteria have been described, these species are not thought to be typical zoonotic pathogens. Muramyl dipeptide derived from mycobacteria obviously plays a starring role as a bacterial trigger in the aetiology of many autoimmune and autoinflammatory diseases. Paratuberculosis in cattle and other ruminants is a source of enormous contamination of the environment but also of milk and meat by MAP. Muramyl dipeptide from mycobacteria, namely MAP, and Crohn’s disease as a representative of diseases often called civilization threats, are important pieces of the gigantic puzzle. Mycobacteria in the environment and foodstuffs have to be acknowledged as a public health risk, which can never be completely eliminated. There is no reason to push the panic button, but we must learn how to live  together with this microorganism, how the pool of immunomodulator sources can be diminished, and how the pathogenic relationship between triggers and target tissues can be disrupted. The dissemination of knowledge, the availability of rapid and inexpensive tools for identification of mycobacteria in different matrices, and the establishment of a maximal allowed limit for mycobacteria in milk and meat should contribute to food safety and consumer protection.

Enhanced leukocyte recruitment is an inflammatory process that occurs during early phases of the vascular dysfunction that characterises atherosclerosis. We evaluated the impact of anti-TNF-α (adali-mumab, infliximab and etanercept) and anti-IL-12/23 (ustekinumab) on interactions between human leukocytes and endothelial cells in a flow chamber that reproduced in vivo conditions. Clinical concentrations of anti-TNF-α were evaluated on the leukocyte recruitment induced by a variety of en-dothelial (TNF-α, interleukin-1β, lymphotoxin-α and angiotensin-II) and leukocyte (PAF, IL-12 and IL-23) stimuli related to inflammation and atherosclerosis. Treatment with anti-TNF-α, even before or after establishing the inflammatory situation induced by TNF-α, diminished leukocyte–endothelial cell interactions induced by this stimuli. Our results also implicated adhesion molecules (ICAM-1, VCAM-1 and E-selectin) in the actions of anti-TNF-α in terms of leukocyte adhesion to endothelium. However, anti-TNF-α drugs did not influence the actions of interleukin-1β, but prevented those of lymphotoxin-α and angiotensin-II. However, once established, inflammatory response elicited by the latter three stimuli could not be reversed. Pre-treatment with anti-TNF-α, also prevented leukocyte actions induced by IL-23 on PBMC rolling flux and rolling velocity and by IL-12 on PMN adhesion. Ustekinumab exhibited a more discreet profile, having no effect on leukocyte recruitment induced by any of the endothelial stimuli, while blocking the effects of IL-23 on leukocyte activation and those of IL-12 on PMN adhesion and PAF on PBMC rolling velocity. These findings endorse the idea that biological anti-inflammatory drugs, in particular anti-TNF-α, have the capacity to influence cardiovascular risk accompanying psoriasis and rheumatoid arthritis by ameliorating vascular inflammation.

Glioma is one of the most aggressive and most common tumors of the central nervous system (CNS) in humans. The exact causes of glioma are not well known, but evidence suggests the involvement of genetic factors in addition to environmental risk factors. The present study aimed to determine whether polymorphisms in IL-10-1082A/G, IL-12p40 1188C/A, and IL-13+2044G/A (rs20541) are associated with the incidence of glioma in Iraqi patients. Ninety-six patients with different grades of glioma and 40 apparently healthy individuals were recruited. A blood sample and genomic DNA were collected from all subjects. The amplification refractory mutation system and sequence-specific primer polymerase chain reaction (PCR) were used for genotyping of IL-10-1082A/G and IL-12p40 1188C/A, respectively; whereas, the IL-13+2044G/A was detected by DNA sequencing after amplification of the genes by PCR.