A case report, published in the peer-reviewed journal Frontiers in Medicine, has found that the researchers’ observations suggest vaccination with the Pfizer mRNA vaccine might “induce rapid progression of AITL”, a rare cancer.
However, researchers have cautioned that this is one case, and that further studies are required, saying “dedicated studies are needed to determine whether this case can be extrapolated to populations of patients with AITL” or other peripheral T cell lymphomas. Health authorities, including the HSE, have described the Pfizer vaccine as safe, and recommend that cancer patients receive a Covid-19 vaccine unless contra-indicated.
AITL, or Angioimmunoblastic T-cell lymphoma, is a rare and often, but not always, aggressive form of lymphoma, more likely to be seen in elderly patients. Symptoms of AITL include high fever, night sweats, skin rash, and autoimmune disorders. As a result of these autoimmune disorders, the body’s immune system attacks its own cells and tissues.
The authors of the report, including experts working in pathology, haematology and nuclear medicine (the use of imaging to determine the severity of a disease), said that since the mRNA vaccines “strongly activate T follicular helper cells”, it was important to explore the possible impact of mRNA vaccines approved for use against Covid-19 on the growth of abnormal tissue affecting the T cells.
Specifically, the case study reported and discussed “unexpected rapid progression of lymphomatous lesions after administration of a BNT162b2 mRNA vaccine booster in a man recently diagnosed with AITL”. BNT162b2 is the vaccine manufactured by Pfizer-BioNTech.
The researchers said that the “remarkable efficiency” of the Covid mRNA vaccines has been “related to their ability to induce a potent stimulation of T follicular helper cells” but that, clinically, “this might translate into reactive lymphadenopathy [swelling of the lymph nodes]”.
This “sometimes may raise a differential diagnosis with a lymphoproliferative disorder ” – a disease characterized by uncontrolled production of lymphocytes – they stated.
They believed several arguments support this possibility. “First, the dramatic speed and magnitude of the progression manifested on two [tumour imaging] 18F-FDG PET-CT performed 22 days apart,” they said.
“Such a rapid evolution would be highly unexpected in the natural course in the disease,” they said.
“Since mRNA vaccination is known to induce enlargement and hypermetabolic activity of draining lymph nodes, it is reasonable to postulate that it was the trigger of the changes observed.”
“Indeed, the increase in size and metabolic activity was higher in axillary lymph nodes draining the site of vaccine injection as compared to their contralateral counterparts. However, pre-existing lymphomatous nodes were also clearly enhanced as compared to the first test. Moreover, new hypermetabolic lesions most likely of lymphomatous nature clearly appeared at distance of the injection site,” the case report found.
“Our case first raises the question of the COVID-19 prevention strategy to be used in this patient which is currently poorly protected against COVID-19. On the short term, the only option is to recommend strict masking and social distancing, and to offer him anti-SARS-CoV-2 antibody therapy in case of high-risk contact.
“If he gets infected, he might benefit from early treatment with a monoclonal antiviral antibody or oral antiviral drugs (molnupiravir, Paxlovid) when they become available. On the longer term, the use of mRNA vaccines should clearly be avoided while other types of vaccines might be considered,” the researchers said.
This was the first observation suggesting that administration of a Covid-19 vaccine “might induce AITL progression”, the researchers believed, although 3 other cases of post-vaccination T cell lymphoma flares were reported in the medical literature.
The Field Chief Editor of Frontiers in Medicine, Dr Michel Goldman, who is also an author of the case report, told Gript.ie that the case report seemed to escaped media attention to date because of “ the fear to fuel vaccine hesitancy.”
However, the researchers cautioned that more research was required. “At this time, extrapolation of the findings of this case to other patients with AITL or other peripheral T cell lymphoma involving TFH cells is premature,” they said. They are aware of ongoing clinical studies that may identify additional cases and of experiments in mice expressing the mutations characteristic of AITL.
If the causal relationship between vaccine shots and lymphoma flares is supported by these investigations, this might indeed have consequences in the clinical practice. They remind that the rare cases of cerebral thromboses induced by the AstraZeneca and Johnson &Johnson vaccines came first to light because of a few isolated cases reports.
“AITL patients are rare and their mutation profile is heterogeneous. Furthermore, their immune reactions might be affected by their treatment. It is therefore unlikely that existing pharmacovigilance systems will be efficient to identify extremely rare cases like ours. Prospective studies involving systematic PET/CT imaging after SARS-CoV-2 vaccination in AITL patients with specified mutation profiles might eventually be needed.”
And they upheld the overall “favorable benefit-risk ratio” of what they described as “much-needed vaccines.”
Whatever the result of such studies, it should not affect the overall favorable benefit-risk ratio of these much-needed vaccines,” they wrote.
Dr Goldman told Gript.ie that the patient central to the case was “still under treatment ” and that “interim evaluation demonstrated good therapeutic response.”