Neutralizing antibody production against Rebif® and ReciGen® in Relapsing-Remitting Multiple Sclerosis (RRMS) patients and its association with patient's disability.

INTRODUCTION: Human recombinant interferon beta (IFN-ß) is one of the first line treatments for Relapsing-Remitting Multiple Sclerosis (RRMS). However, the production of neutralizing antibodies (NAb) can impair its function. The aim of this study was to investigate the production of neutralizing antibodies against Rebif® and ReciGen® (two brands of IFN-ß-1a) and to evaluate its correlation with Expanded Disability Status Scale (EDSS). MATERIALS AND METHODS: Serum samples of 71 RRMS patients (34 in ReciGen®, 37 in Rebif® group) were collected. Neutralizing antibody was measured by Myxo-virus resistance protein A (MxA) assay using A549 cell line. The MxA concentration was measured by enzyme-linked immunosorbent assay (ELISA) kit. RESULTS: The median period of treatment with IFN-ß-1a was 18 months in ReciGen® and 24 months in Rebif® arms. The percentage of patients with positive titer of neutralizing antibody (NAb+) had no statistically significant difference between groups (P = 0.6). In both ReciGen® and Rebif® groups, the increase in EDSS score was significantly higher in NAb+ patients compared to NAb- patients (p ≤ 0.05). The duration of using ReciGen® or Rebif® for >24 months was influential in the NAb positivity (OR = 3.78). CONCLUSION: Receiving interferon beta-1a for >24 months is correlated with higher possibility of NAb production. The type of IFN-ß used in the study had no significant impact on NAb positivity. In addition, both groups had comparable EDSS score changes, and NAb status of patients was correlated with their EDSS score.

A high prevalence of tylosin resistance among Staphylococcus aureus strains isolated from bovine mastitis.

The macrolides appear to have considerable effects for treatment of bovine mastitis because of excellent diffusion into the mammary gland, long half-life, low protein binding, high intracellular concentration and lipid solubility. Acquired resistance to macrolides in Staphylococcus aureus is primarily related to target-site modification through acquisition of an erm gene. In the present study the prevalence of both phenotypic and genotypic tylosin resistance in S. aureus isolates (n = 103) from subclinical mastitis in nine dairy farms belonging to three different province of Iran were investigated. Overall, ermA, ermB and ermC was found in 7.80%, 32.00%, and 20.40% of S.aureus isolates, respectively. A very high percent of isolates (56.90%) were resistant to tylosin. MIC90 and MIC50 values were 64 and 32 µg mL-1, respectively. Most of tylosin resistant isolates did not harbour any erm gene but ermB was dominant gene among 58 tylosin resistant isolates of S. aureus. In overall, tylosin resistance was prevalent in S. aureus isolates obtained from bovine mastitis in Iran.