Chorionic Tissue and Peripheral Blood as Potential Reservoir of Pathogens Responsible of Reccurent Spontaneous Miscarriage in Women. Preliminary Results

Background Recurrent spontaneous miscarriages (RSMs) are attributed to “unexplained” factors, the majority of which are genetic or immune factors, while infections can account for 10-15% of all abortions. Recently, it has been shown that silent infections caused by emerging viruses such as HPV, Merkel cell polyomavirus (MCPyV) as BK and JC, as well as bacterial agents (Chlamydia trachomatis, Mycoplasma spp and Ureaplasma spp), can assume importance in the occurrence of early abortions. We investigated the role of some pathogens potentially involved in the RSM, in the absence of obvious symptoms. The study population consisted of 28 women; of these, 8 had RSMs (28.6%; Group 1) and 20 (71.4 %; Group 2) were controls (voluntary interruption of pregnancy [VIP]). For both groups, the age was between 18 and 42 years (mean age of 35.4 yr), with a gestational age less than or equal to 12 weeks. The number of pregnancies was the same for both groups, from a minimum of 1 to a maximum of 6. All women underwent PBMC extraction from peripheral whole blood and chorionic tissue (Ct) specimens obtained after curettage of uterine endometrial that were analyzed by PCR and Reverse-Transcriptase-PCR (RT-PCR) to investigate for bacteria (C. trachomatis, U. parvum, U. urealyticum [U.U], M. hominis) and virus DNA (HPV, BK, JC, MCPyV). Results. In Group 1 (n. 8, including 5 Italian, one Romanian, one Moldovan, 1 Cameroonian), the positivity rate for bacterial DNA was respectively 0 and 2 (25%; U.U) in PBMCs and in CT samples [16% confirmed by RT-PCR], respectively; for the virus, positive samples were 2 (25%; MCPyV) and 0 in both, respectively. In Group 2, the positivity rate for bacterial DNA was respectively 1 and 2 (5% and 10% for U.U, respectively,) in both PBMCs and in CT, respectively; while for the virus, this rate was 3 (15%) and 1 (5%) for MCPyV and HPV, in both PBMC and CT, respectively. These rates were found not statistically significant (p> 0.05; Fisher's exact test). Conclusions. So far, bacteria and virus have been never searched in both Ct and PBMCs from women with miscarriage or abortion. The detection of U.U DNA in Ct specimens from Group 1, shows that this pathogen is potentially responsible of RSM, as shown by the RT-PCR results which testify its metabolical viability as well as its potential harmful action in inducing abortion, although the limited sample size hampers a statistical association between U.U and abortion. MCPyV was observed in PBMCs from Group 1 and 2, but not in the Ct samples. This is not of particular significance because this virus is ubiquitous with a seroprevalence of around 80%. Further studies will be necessary to expand knowledge of this virus and bacteria in RSM.