CELLULAR, TISSUE AND GENE THERAPIES ADVISORY COMMITTEE

47^th Meeting, May 14-15, 2009

Gaithersburg, MD

 

Issue Summary

 

Topic I.:  Potential for Chlamydia trachomatis and Neisseria gonorrhoeae transmission by human cells, tissues, and cellular and tissue-based products (HCT/Ps) that are recovered from the reproductive system, gestational tissues, or other sources.

 

Issue:  FDA seeks discussion by the Committee on the current scientific data as it relates to the potential for infectious disease transmission of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) by human cells, tissues, and cellular and tissue-based products (HCT/Ps) that are recovered from the reproductive system or gestational tissues (e.g., amniotic membrane and placenta, cells recovered from menstrual blood, foreskin, and placental/umbilical cord blood derived cell products), or other sources.  The recent increased use of these HCT/Ps in transplantation, and increased research to evaluate potential stem cells from these HCT/Ps for use in development of cellular therapy products, has raised questions regarding the potential for infectious disease transmission that have not been previously considered. 

 

Regulatory Background:

 

The Office of Cellular, Tissue and Gene Therapies (OCTGT) within CBER regulates human cells, tissues, and cellular and tissue-based products (HCT/Ps) in order to prevent the introduction, transmission, or spread of communicable diseases.  HCT/Ps cover a broad range of individual products.  The regulations define HCT/Ps (21 CFR 1217.3(d)) as articles containing or consisting of human cells or tissues that are intended for implantation, transplantation, infusion, or transfer into a human recipient.  Donors of HCT/Ps may be either living or deceased (i.e., cadaveric).  Examples of HCT/Ps include bone, ligament, skin, dura mater, heart valve, and cornea from deceased donors; hematopoietic stem cells derived from peripheral and cord blood, manipulated autologous chondrocytes, epithelial cells on a synthetic matrix, and semen or other reproductive tissue from living donors.   

 

The following articles are not considered HCT/Ps:

 

·         Vascularized human organs for transplantation;

·         Whole blood or blood components or blood derivative products subject to listing under 21 CFR § 607 and 207, respectively;

·         Secreted or extracted human products, such as milk, collagen, and cell factors; except that semen is considered an HCT/P;

·         Minimally manipulated bone marrow for homologous use and not combined with a drug or a device (except for a sterilizing, preserving, or storage agent, if the addition of the agent does not raise new clinical safety concerns with respect to the bone marrow);

·         Ancillary products used in the manufacture of HCT/P;

·         Cells, tissues, and organs derived from animals other than humans; and

·         In vitro diagnostic products as defined in 21 CFR §809.3(a).

 

Relevant Communicable Disease Agents or Diseases and Donor Screening

 

HCT/Ps carry the risk of communicable disease transmission from the donor to the recipient.  To minimize this risk, FDA has established regulatory requirements designed to prevent the introduction, transmission, or spread of communicable disease by screening and testing the donor, and ensuring that the cells or tissues are not contaminated during recovery, processing, storage or distribution. 

Individuals who have communicable diseases that their donated tissues can transmit to transplant recipients are not eligible to serve as donors.  In accordance with the risk-based approach developed for 21 CFR Part 1271 certain exceptions are made for use of HCT/Ps from donors who are determined to be ineligible.  These include HCT/Ps from a:

 

• First degree or second degree blood relative for hematopoietic stem cell donors,
• Directed (known) reproductive  donors
• Donors where there is a documented urgent medical need

 

In order for there to be a requirement to screen or test HCT/P donors for an infectious agent, that agent must be considered by FDA to be a relevant communicable disease agent or disease (RCDAD).  RCDADs are designated two ways in the regulations; some diseases are specifically listed in the regulation 21 CFR §1271.3(r)(1), while others must meet certain criteria, listed in 21 CFR §1271.3(r)(2) to be considered a RCDAD.  The provisions in 1271.3(r)(2) were established to allow FDA to address emerging infectious diseases. 

 

Disease agents specifically listed in 21 CFR 1271.3(r)(1) include the following for all HCT/Ps:

 

•     Human immunodeficiency virus (HIV), types 1 and 2;

•     Hepatitis B virus (HBV);

•     Hepatitis C virus (HCV);

•     Human transmissible spongiform encephalopathy (TSE), including Creutzfeldt-Jakob disease (CJD); and

•     Treponema pallidum (syphilis).

 

In addition to the above list of RCDADs for all HCT/Ps, a communicable disease agent or disease meeting the following criteria (Sec. 1271.3(r) (2)), but not specifically listed, is relevant if it is one:

 

a.   For which there may be a risk of transmission by an HCT/P, either to the recipient of the HCT/P or to those people who may handle or otherwise come in contact with the HCT/P, such as medical personnel, because the disease agent or disease:

 

i.       is potentially transmissible by an HCT/P; and

 

ii.      either (1) has sufficient incidence and/or prevalence to affect the potential donor population (Sec. 1271.3(r)(2)(i)(B)(1)), or (2) may have been released accidentally or intentionally in a manner that could place potential donors at risk of infection (Sec. 1271.3(r)(2)(i)(B)(2));

 

b.   That could be fatal or life-threatening, could result in permanent impairment of a body function or permanent damage to body structure, or could necessitate medical or surgical intervention to preclude permanent impairment of body function or permanent damage to a body structure (Sec. 1271.3(r)(2)(ii)); and

 

c.       For which appropriate screening measures have been developed and/or an appropriate screening test for donor specimens has been licensed, approved, or cleared for such use by FDA and is available (Sec. 1271.3(r)(2)(iii)).

 

The following are additional RCDADs for all HCT/Ps that were added according to the 1271.3(r)(2) definition:

 

·         West Nile Virus;

·         Sepsis; and

·         Vaccinia (the virus used in smallpox vaccine).

 

Current requirements for Donor Screening and Testing

 

Relevant communicable disease agents or diseases for which a donor must be screened or screened and tested include:

 

 

^* Including CJD and variantCJD

^**  Although CMV is not a relevant communicable disease agent or disease, donors of viable, leukocyte-rich HCT/Ps must be tested for evidence of infection due to CMV in order to adequately and appropriately reduce the risk of transmission

 

Examples of viable, leukocyte-rich HCT/Ps include hematopoietic stem/progenitor cells and semen.  FDA interprets reproductive HCT/Ps to include semen, oocytes, and embryos to which the donor contributed the spermatozoa or oocyte. 

 

The term “donor screening” has a specific meaning in the context of HCT/Ps.  In some circumstances, the term donor screening may also encompass donor testing.  However, the HCT/P regulations distinguish between donor screening (medical history interview, physical assessment and medical record review) and donor testing.  HCT/P donors are  tested using donor screening tests. 

 

The screening process includes:

 

• Physical assessment or examination
• Review of potential donor’s medical records
• Interviewing donor (if the donor is living) about his or her social behavior
• Interviewing person who is knowledgeable about the donor’s social behavior (if the donor is non-living)

 

The key information needed to determine donor eligibility is:

 

·         Relevant risk factors (e.g., non-medical drug injection during the past five years)

·         Clinical or physical evidence of communicable disease agents that could be transferred to a recipient of donated HCT/Ps

·         Results of testing for relevant communicable disease agents

 

This discussion focuses on issues related to testing donors of HCT/Ps that are recovered from the human reproductive system, gestational tissues, or other sources for CT and NG.  The current donor screening and testing requirements for these HCT/Ps do not require evaluation for CT and NG.  

 

 

Discussion and Literature Review:

 

There has been a recent increase in the research and use of cells and tissues that are derived from the reproductive system or gestational tissues.  Because of their anatomical location, HCT/Ps collected from the reproductive system or from gestational tissues raises questions regarding the potential for infection or contamination with CT and NG.  FDA will provide information about the HCT/Ps under consideration and review relevant infectious disease literature.  In addition, the Committee will hear presentations from CDC regarding CT and NG, and from product experts who will describe the recovery and use of amniotic membrane and cord blood. 

 

The following table summarizes information about the specific HCT/Ps under consideration:

 

Examples of HCT/Ps Recovered From the  Reproductive System or Gestational Tissues

 

Tissue	Description	Examples of Products/Uses
Amniotic Membrane & cells recovered from amniotic membrane	Innermost layer of the placental membrane; often used decellularized, either as a surgical patch, or as a rich substrate for seeding other cell types (Ref. 1); decellularized amnion contains collagen fibers, glycosaminoglycans and elastin fibers	Wound dressing, treatment for leg ulcers, skin loss, reconstruction of the pelvic floor, vaginal epithelialization, oral cavity reconstruction, replacement of nasal mucosa, ear surgery, and in otolaryngology procedures (Ref. 2), ocular repair, stem cells (Ref. 3)
Placenta & cells recovered from placenta	Fetomaternal organ connected to the fetus by a fetal cord; has a role in transfer of gases and nutrients to the fetus and endocrine function	Used to replace or supplement damaged or inadequate integumental tissue; Stem cells (Refs. 4-5)
Cells recovered from menstrual blood	Shed menstrual blood collected into a container processed for long-term storage, and banked/stored	Stem cells (Refs. 6-8)
Foreskin & cells recovered from foreskin	Usually from infant foreskin but also may use adult foreskin	Fibroblast cells used as component of a cell/scaffold product (Refs. 9-10); Research ongoing re: potential for stem cells (Refs. 11-12)
Umbilical cord blood (HPC-C)	Blood which remains in the  umbilical cord of a newborn, after clamping, is collected, processed for long-term storage, and banked/stored (Ref. 13)	Hematopoietic stem cells derived from cord blood used for reconstitution of the hematopoietic system during the treatment of malignant and nonmalignant diseases, most commonly in pediatric patients (Refs. 14-15)
Placental blood derived stem cells	Extracted from placenta after placental/umbilical cord blood is recovered (Ref. 16)	Used in conjunction with cord blood for hematopoietic reconstitution (Refs. 17-19)

 

Anatomic Relationships among the Maternal and Fetal Gestational Tissues

 

 

http://www.merck.com/mmpe/sec18/ch258/ch258a.html

 

Possible Routes of Intrauterine Infection

 

 

 

 

Possible routes of intrauterine infection (Ref. 20).  Microorganisms can colonize intrauterine cavity through one of the following routes: ascending from the vagina (the most common route), spreading hematogenously through placenta, by accidental contamination during an invasive medical procedure, and through fallopian tubes.

 

Animal Studies

 

CT:  The pig and mouse have been used to show genital infection with CT. The following is a summary studies on tissue colonization after infection of CT, cited in the literature:

 

• Specific pathogen-free pig genital infection model was used to characterize colonization of CT serovar E strains, the most prevalent serovar. Chlamydiae could ascend in the genital tract and replicate in the superficial epithelial layer of uterus, oviducts, ovaries, cervix, and the urethra. Tissue samples from spleen, liver, and local draining lymph nodes were negative for the presence or replication of Chlamydia (Ref. 21).

• Infection parameters were assessed in mice intravaginally infected with human genital isolates of CT serovar E. Infection, assessed by culture and PCR on day 14, was observed to progress to the upper cervix and uterine horns. There were no infections in the ovaries, tubes and lymph nodes.  All upper genital tract material was negative on day 56 (Ref. 22).
• Female mice were inoculated intravaginally with CT and the infection assessed by culture. The primary infection peaked after 4 to 10 days and resolved in all mice after 28 to 35 days (Ref. 23).
• Mice were inoculated intraperitoneally (ip) only or intravenously (iv) and intravaginally (ivag) combined (iv + ivag), with a human CT serovar E, 14 days before pregnancy or one to nine days after pregnancy. On day 18 of pregnancy, the mice were killed and the contents of the uterus examined. Placental colonization was observed in mice challenged by ip route (6/8), but placental colonization was observed in 1 out of 9 mice challenged via the iv + ivag combined route. Chlamydia was not recovered from fetal tissue even in situations of heavy placental colonization, Chlamydia did not cross the placenta (Ref. 24).

 

NG:   The lack of a good animal model that simulates NG infection in humans limits the understanding of the pathogenesis of gonococcal infection. Various animal models of infection have been used to study the distribution and interaction of the gonococci bacteria with(in) tissues. The value of such studies, though limited, has provided information on the tissue colonization characteristics of gonococcal infection.  The following is a summary of relevant animal studies cited in the literature:

 

• In earlier studies, the chimpanzee model was shown to be the only animal species in which gonococcal urethral infection could be established for 3-6 weeks. In these studies, researchers were unable to colonize the genital tracts of several other animal species, including baboons, pig-tailed macaques, rabbits, macaques, monkeys (rhesus, squirrel, owl, and capuchin), marmosets, and guinea pigs (Ref 25). Other investigators have also demonstrated that gonococci are able to attach, damage and invade the oviduct of baboons (Refs. 26-27). 
• Sprague-Dawley rats have been used to demonstrate transmission of NG from transmission from mother to fetus during pregnancy (Ref.28). The rats were infected intraperitoneally (not the usual route of infection in humans) on day 20 of pregnancy.  Disseminated gonococcal infection and pelvic inflammatory disease were able to spread from pregnant rat to fetus and resulted in fetal mortality.
• Mice infected intravaginally with NG develop endometritis (Ref. 29).
• The 17β-estradiol-treated mouse infection model, the only small animal model for gonococcal genital tract infection, was used to characterize the distribution of NG bacteria within the genital tract tissue of infected mice. Mice were intravaginally infected with NG and at days 2 and 5 post infection, the genital tracts were examined for bacterial distribution by immunohistochemistry.  Gonococci were detected in the vaginal lumen, vagina and cervical tissue and lamina propria. No bacteria were detected in upper genital tract (Ref. 30).  
• After vaginal inoculation of mice with NG, the bacteria reached and invaded the upper female reproductive tissues and elicited a T-cell specific immune response (Ref. 31).

 

Human Studies

 

CT in amniotic fluid/amniotic membrane, human placenta and fetal cord blood:

 

• Several studies showed evidence that CT could cross placental membrane, since infected newborn infants were delivered by C-section, sometimes prior to the rupture of the membranes (Refs. 32-36).  In most of the cases mothers had CT genital infection; however in one case the mother had serum antibody against CT, but a negative cervical culture (Ref. 33).
• CT has been isolated from amniotic fluid on several occasions and one group of authors specified that CT antigen was identified in the epithelial cells of the amnion (Refs. 38-41).  Although the authors of some of the above referenced papers indicated that the presence of antigen in epithelial cells was significantly lower in C-section groups than in the vaginal delivery groups, there were a small number of cases in which the presence of antigen occurred even without premature rupture of membranes in C-section deliveries. 
• A study on the role of bacterial and viral infections in miscarriages identified a CT infection existed in one placenta of a miscarried fetus, out of 108 examined (Ref. 42).
• CT can infect placental trophoblast cells in vitro (Ref. 43).
• Infection of the placenta with CT was reported in a stillborn fetus delivered by C-section (Ref. 44).  The mother was likely CT-infected at the time of delivery as she had high IgG antibody titers to CT and a positive cervical swab to CT three years before the pregnancy (no cervical swabs were performed during the pregnancy).
• Human amniotic membrane is susceptible to infection by CT, as cultured primary amniotic epithelial cells have been used for in vitro studies of these bacterial species (Refs. 37, 45).
• CT was detected in the lungs of a stillborn fetus that died of intrauterine pneumonia (Ref. 46).  In this reported case, the amniotic membranes were found to be intact, indicating that CT could cross amniotic membranes and cause the fatal disease in fetus.
• The presence of antichlamydial IgG antibodies were detected in samples of infant cord blood using micro-immunofluorescence test (Ref. 47).
• CT DNA was detected in 10.34% (3 out of 29) fetal cord blood samples in a study using quantitative PCR technique (Ref. 48).  In the same study, CT DNA was detected in only 3.45% (1 out of 29) maternal blood samples.

 

NG in amniotic fluid/amniotic membrane, human placenta and fetal cord blood:

 

• Gonorrhea is sometimes associated with the amniotic infection syndrome, called gonorrhea amnionitis.
• Studies indicated that NG had pili structure that could effectively attach to both epithelial cells and connective tissue cells (Ref. 49).
• Human amniotic membrane is susceptible to infection by NG, as cultured primary amniotic epithelial cells have been used for in vitro studies of these bacterial species (Ref. 50).
• A case of gonococcal chorioamnionitis in a patient with intact membranes suggested the transplacental spread of bacteria (Ref. 51).
• In a small-case study NG was isolated from two placentas of the infants born through vaginal deliveries, where the NG infections likely occurred before rupture of the membranes (Ref. 52).  In these two cases both mothers had positive cervical cultures for NG.
• Infection of CT in the placenta often coincides with  infection of NG.  However, a small study indicated that chlamydial infections of placenta are less common than gonnococal infections of placenta (Ref. 53).  The same group of authors also refers to another study (unpublished observation) that examined 205 infants with ophthalmia neonatorum (neonatal conjunctivitis) and found that only one out of 38 chlamydial ophthalmia neonatorum was delivered by C-section, while four of 19 NG caused ophthalmia neonatorum were delivered by C-section.
• NG DNA was detected in 3.45% (1 out of 29) infant cord blood samples using quantitative PCR technique (Ref. 48).  In the same study, the authors did not detect NG DNA in any of the 29 maternal blood samples using the same PCR technique.  The authors reasoned that the discrepancy between the results obtained from the cord blood and maternal blood was either due to the low levels of the pathogen in the maternal blood or due to a possible contamination of the cord blood sample.

 

 

Closing:

 

To date, FDA has not had a public discussion regarding donor testing for CT and NG in donors of HCT/Ps that are recovered from reproductive system, gestational tissues, or other sources.  Although we are not aware of any specific cases of HCT/P transmission of CT or NG to date, we must consider the available scientific information that relates to the potential for transmission via HCT/Ps.  While placenta has anti-microbial properties against various bacterial species (Ref. 54), including NG (Mlyneck 1988), the review of the literature indicates a basis for concern that placenta and amniotic membrane may have the potential to be infected with these bacteria either in vivo or at the time of birth.  

 

The scientific and medical literature also includes reports of NT and GC colonization and/or infection of the urinary tract (e.g. bladder and kidney) (Refs. 55-57).  HCT/Ps recovered from bladder or kidney cells are of research interest in the development of cellular therapy products for bladder and kidney disease.  The potential for HCT/Ps recovered from bladder and kidney to transmit CT or NG is unknown. 

 

The processing of HCT/Ps ranges from relatively unprocessed to extensively processed, and there are no available data specific to the ability of any processing methods to definitively eliminate CT or NG if present. There is no available literature to specifically inform as to the transmissibility, if present, of CT or NG via these HCT/Ps.  Absent specific available literature, it is sometimes necessary for FDA to make public health decisions based upon the best available information. 

 

We bring this issue to the Committee so that we can obtain the Committee’s expert scientific input on this topic. 

 

Questions to the Committee: 

 

1. Please comment on the potential for transmission of C. trachomatis and N. gonorrhoeae by HCT/Ps that are recovered from the reproductive system or gestational tissues, for example:

 

·         Amniotic membrane and placenta, or cells recovered from these tissues 

·         Cells recovered from menstrual blood

·         Foreskin

·         Placental/umbilical cord blood derived cell products

 

2.      Please comment on whether additional HCT/Ps should be considered for potential risk for transmission of C. trachomatis and N. gonorrhoeae (e.g., cells recovered from bladder and kidneys).

 

 

References:

 

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This briefing document for the CTGTAC meeting first session on May 14 is publicly releasable without redaction.