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B cells are being recognized as one of the major players in the pathogenesis of multiple sclerosis (MS). The B cell activating factor (BAFF) system plays an essential role in B cell homeostasis and function in the periphery. Mycobacterium avium subspecies paratuberculosis (MAP) has been previously associated to MS in Sardinia. Antibodies against a MAP surface protein, MAP_2694, have been found significantly associated to MS patients, and this response was modified by interferon-β therapy. Increased BAFF levels following IFN-β therapy have been also described in MS patients. In this study, we evaluated whether soluble BAFF levels are comparable in men and women affected by MS and performed a correlation of the reported BAFF increase in MS patients under IFN-β therapy with changes of humoral response against MAP_2694. For these reasons, we investigated 44 MS patients before and after IFN-β therapy. A significant difference of BAFF levels was found between men and women with MS; moreover, we confirmed that IFN-β therapy strongly induces BAFF serum levels, but this was not related to the modification of immunological response against MAP_2694. In conclusion, our study highlights that IFN-β therapy induces the potent B cell survival factor BAFF without alterations of the humoral immune response against MAP.

Background: Amongst Sardinians the human leukocyte antigen (HLA) DRB1-DQB1 haplotypes *15:02-*06:01, *16:01-*05:02, *14:01-4-*05:03 are protective for multiple sclerosis (MS), while *13:03-*03:01, *04:05-*03:01, *03:01-*02:01, *15:01-*06:02 and Mycobacterium avium subspecies paratubercolosis (MAP) are predisposing factors. We studied the correlation between MAP and HLA., Methods: Five hundred thirty-one patients were searched for anti-MAP2694 antibodies, DRB1-DQB1 genotyping was performed. The haplotypes were classified as predisposing, neutral or protective., Results: Anti-MAP2694 were found in 23 % of subjects carrying one protective HLA versus 32 % without (p = 0.04)., Conclusions: We showed a lower frequency of Abs in patients with protective HLA. These haplotypes could have a protective role for both MS and MAP.

Background. The prevalence of allergies is steadily increasing worldwide; however, the pathogenesis is still unclear. We hypothesized that Mycobacterium avium subsp. paratuberculosis (MAP) may contribute to allergy development. This organism can be present in dairy foods, it can elicit an immunomodulatory switch from a Th1 to a Th2 response, and it has been speculated that it is linked to several human autoimmune diseases. To determine the contribution, sera from 99 individuals with various atopic disorders and 45 healthy nonallergic controls were assessed for total IgE levels and successively for MAP-specific IgE by ELISA. Results. The mean total serum IgE level in allergic patients was 256±235 IU/mL, and in the healthy controls it was 62±44 IU/mL (AUC = 0.88; p<0.0001). Among the patient groups, 50 of the 99 subjects had increased IgE total level ≥ 150 IU/mL, while 49 subjects had IgE ≤ 150 IU/mL (mean level: 407±256 IU/mL versus 106±16 IU/mL; p<0.0001). Additionally, 6 out of 50 subjects (12%) with IgE ≥ 150 IU/mL and none (0%) with IgE ≤ 150 IU/mL were positive for specific MAP IgE (AUC = 0.63; p=0.03). Conclusion. The present study revealed that MAP has the ability to induce specific IgE and might contribute to the induction of allergic inflammation in genetically predisposed individuals. [ABSTRACT FROM AUTHOR]

Background and purpose: Infectious mononucleosis (IM) caused by Epstein- Barr virus (EBV) has been associated with increased risk of multiple sclerosis (MS). However, the mechanism linking these pathologies is unclear. Different reports indicate the association of EBV, and recently Mycobacterium avium subsp. paratuberculosis (MAP), with MS. For a better understanding of the role of these pathogens, the host response induced by selected antigenic peptides in subjects with a history of IM that significantly increases the risk of MS was investigated. Methods: Both humoral and cell-mediated response against peptides able to induce a specific immune activation in MS patients deriving from lytic and latent EBV antigens BOLF1305-320, EBNA1400-413, from MAP MAP_402718-32, MAP_0106c121-132 and from human proteins IRF5424-434 and MBP85-98 in subjects with current and past IM were examined. Results: EBNA1 and MAP_0106c peptides were able to induce a humoral immune response in subjects with a history of clinical IM in an independent manner. Moreover, these peptides were capable of inducing pro-inflammatory cytokine interferon γ by CD4+ and CD8+ T lymphocytes and interleukin 6 and tumour necrosis factor α by CD14+ monocyte cells. Conclusion: Our results highlight that EBV and MAP may be involved independently in the same causal process leading to MS in subjects with a history of IM. [ABSTRACT FROM AUTHOR]

Little is known regarding the environmental factors at play in igniting rheumatoid arthritis (RA) autoimmunity, although an association between Mycobacteria and RA has been documented. This pilot study focused on examining a possible involvement of Mycobacterium tuberculosis (MTB) and Mycobacterium avium ss. paratuberculosis (MAP) in RA. We measured out the serum levels of IgG antibody against different mycobacterial antigens in Sardinian patients and controls, by an enzyme-linked immunosorbent assay. The population study was composed of 61 RA patients under different therapies and 52 healthy controls, whereas the antigens tested were MTB lipoarabinomannan (ManLAM), MAP heath shock protein 70, and MAP protein tyrosine phosphatase. The frequencies of anti-ManLAM antibodies were higher in the RA group (23 %) compared to the healthy controls (5.7 %) (AUC = 0.7; p < 0.0001), whereas serum reactivity to MAP antigens was not observed. ManLAM antigen was also detected in the plasma of three RA patients (which were anti-ManLAM antibody positive) by Western blot analysis using anti-Man-LAM monoclonal antibodies. The data produced corroborate the hypothesis of a potential association between MTB ManLAM and RA disease, but so far, further studies are necessary to understand its role in RA pathogenesis. [ABSTRACT FROM AUTHOR]