How Chlamydia Avoids the Immune System

Chlamydia or Chlamydia trachomatis is the most common sexually transmitted infection on a worldwide level. At this point, 7-8% of UK people aged under 25 are infected with the bacteria. Furthermore, 70% of all infected women and 50% of men with the infection do not experience any symptoms when infected. Therefore, the risk of getting the disease is very high, and it keeps growing as the number of infected people increases every year.

If you do not get tested regularly and treated for chlamydia right away, you will just continue spreading the disease to your sexual partner/s. People with multiple sex partners are at highest risk, especially if they do not practice safe sex.

Do not just assume that you are healthy. Chlamydia is a tricky disease that creeps out on people and hides until it is too late. Since it does not have any symptoms in most cases, it is one of the most rapidly spread STDs known to people.

Life Cycle of Chlamydia

The chlamydia trachomatis is a gram-negative bacterium that can be found in two forms:

  • The intracellular reticulate body or RB
  • The infectious elementary body or EB

Its life cycle is the following – EBS attach to the cell’s membrane, on the inner layer or epithelium of the human’s urogenital tract. Afterwards, the EBS enters the cells and transform into RBs within two hours. Then, the RBs grow and start dividing over the following hours, multiplying rapidly.

At this point, the RBs transform back into EBs. And since this is a rapid process, it only takes two to three days after the initial infection for the host cell to burst and release the created infectious EBs.

The Nature of Chlamydia

Chlamydia trachomatics has various serovars that can cause different pathology types. For example, the serovars A to C cause ocular infections, or trachoma, and are the biggest cause of blindness in the developing world. Serovars from D to K cause the common chlamydia sexually transmitted infection, while L1 and L2 cause the lymphogranuloma venereum’s severe pathology.

Chlamydia in Men

When a man is infected with the bacterium, this infection can cause a variety of infections that range from mild to severe. Men can suffer from urethritis, as well as chronic prostatitis. In addition to this, several researchers have proven that men diagnosed with chlamydia have decrease in sperm quality when compared to their healthy counterparts.

Chlamydia in Women

The infection is more detrimental to the woman’s health. In women, the chlamydia infection can have long-term, devastating effects on the reproductive health. This bacterium is closely associated with pelvic inflammatory disease, urethritis, pelvis scarring and adhesions, and severe fertility complications. These complications include ectopic pregnancy, miscarriage, infertility and premature membrane rupture, all of which often result to be fatal for the baby, and sometimes even the mother.

Immune Response Mechanism to Chlamydia Trachomatis in Women

The female reproductive tract normally has the macrophages, dendritic cells and several resident lymphocytes throughout the four main epithelial areas: the cervix, vagina, uterus and Fallopian tubes. Normally, the reproductive tract does not have organized lymphoid tissue.

Knowing this, where does the Ct infection occur?

Chlamydia trachomatis builds up in the lower genital tracts. When a person is infected, this bacterium attracts a variety of immune cells that include macrophages, lymphocytes and dendritic cells that infiltrate its epithelium.

At the infected site, there is usually a strong inflammation. This inflammatory reaction to the bacterium is mainly mediated by the CD4+ T cells, in combination with a Th1 phenotype that clears the infection. These cells produce the IFN or interferon-y, known to inhibit the reproduction of chlamydia.

However, evidence suggests that the IFN-y concentration in the body is critical to the infection’s outcome. According to experts, when the levels of IFN-y are high in the body, this is associated with the infection clearance. In the case where the IFN-y levels are low, the bacteria can remain in the body and persist without replicating.

Since it neither goes away, nor replicates, the Ct infection can remain in the infected person’s body for several years. During these years, reinfection is very common, and since symptoms are barely noticeable, a person can carry the infection in their body for a long time, infecting other people they have unprotected sex with.

Reinfection as a result of improper or no treatment can result in a secondary immune response. In addition to this, the inflammation is increasing with each reinfection, causing further damage to the patient’s reproductive tract. This is where the complications and serious health problems arise.

Reports list this as the main cause of chronic pelvic inflammatory disease, a serious effect of untreated chlamydia in women. If the chlamydia infection keeps spreading higher up the tract of a woman and reaches the Fallopian tubes and uterus, this can also cause an ectopic pregnancy and even infertility.

Tubal damage is very serious and common in untreated chlamydia patients, but it remains unclear whether and how much damage Ct causes, and how much the host immune response.

Chlamydia Treatment, Diagnosis and Prevention

People who practice unsafe sex or change sexual partners often are recommended to get tested more often than those who do not. However, testing is crucial for the sexual health of everyone who has sexual relations, even if they do not switch partners. Seeing that most sexually transmitted diseases do not show symptoms until there is bigger damage in the body, you must be smart about your sexual health and do regular checkups.

Your doctor can diagnose Ct by genital swab and urinary testing. If diagnosed, a patient is treated with an antibiotic therapy such as doxycycline or azithromycin.

According to latest findings, the widespread use of these antibiotics that treat chlamydia reduces the ability of the individual to make a good protective immune response. Still, since the correlates of the immunity are not well understood yet, antibiotics are the best choice for people infected with this bacterium.

Since there is no vaccine for this infection just yet, testing should show whether a person is infected or not, and proper treatment is highly recommended to avoid damage to the body and the person’s health.