Investigation of cytokines and intracellular bacteria in relation to the administration of lactoferrin in women with infertility

Objectives Accumulating evidence suggests an association between high levels of IL-6 in the amniotic fluid and threatened preterm delivery, recurrent miscarriage, pre-eclampsia. The role of lactoferrin (LF) was evaluated in order to assess the levels of IL-6 in cervical-vaginal secretions (CVS) and to establish the existence of a correlation between IL-6 and the intracellular microorganisms Mycoplasma hominis (Mh) and Ureaplasma urealyticum (UU) and C. trachomatis (CT), potentially implicated in the pathogenesis of infertility and miscarriage. LF is an iron binding glycoprotein of 80 kDa, member of the transferrin's family which is considered a component of first-line host defense against pathogens, because of its antimicrobial, anti-inflammatory and immunomodulatory properties. Methods. 25 outpatients with idiopathic infertility observed at Unit of Pathophysiology of Human Reproduction of University of Ferrara from March 2011 to March 2012 were enrollled. Women underwent CVS sampling in the peri-ovulatory phase for dosage of IL -6 by ELISA assay and microbiological and molecular (Reverse Transcriptase - PCR [RT- PCR]) 16 s rRNA gene examination for, Mh, UU and CT, respectively. The patients were administered LF 300 mg (DIFESAN Progine Pharmaceuticals, Italy) intravaginally for 7 days. After 12 hours of discontinuation of therapy, women were subjected to a second sampling of SVC for the execution of the same tests. Results. Our results showed a reduction of the mean values of IL- 6 concentration after therapy with Lf [58.2 (± 80.9) pg/ml vs 77.2 (± 150) pg/ml] before therapy. This difference was not statistically significant (p= 0.8). The microbiological examination for UU showed a significant reduction of positive samples for the microorganism after therapy (6 vs 2; p = 0.2). With RT-PCR, there was also a significant reduction of positive samples for UU (4 vs 2; p = 0.5) as well as for Mh, after therapy, (6 vs 4; p=0.4). A statistically significant correlation was also found between Mh and cervical-vaginal IL-6 (p=0.04; t=2.15) concentration. CT wasn’t detected in any sample. Conclusion. LF seems to confirm its role as anti-inflammatory molecule while its antimicrobial efficacy is limited in numeric values given the small sample. These results could be justified assuming that Mh and UU can take advantage of LF as a source of iron, which is necessary for their survival and proliferation, property already owned by other microorganisms through siderophores, bindings and lytic enzymes, which utilize LF as a donor of iron. There was a statistically significant correlation between a high concentration of IL-6 and positivity for Mh; moreover, a dose of 300 mg of LF given for 7 days intravaginally, results in a reduction of the cytokine level and UU and Mh and UU by RT-PCR, although not statistically significant. A larger sample size is needed to verify the potential immunomodulatory and therapeutic properties of LF, for a possible employment in infertility with potential infectious pathogenesis.