Clinical Potential of Genetically Modified Antibodies: A Report

This report explores the clinical potential of genetically modified antibodies, focusing on their application in treating various diseases. The report begins by discussing the use of genetically modified antibodies like rituximab in treating conditions such as mediastinal B-cell lymphoma, highlighting the benefits over traditional therapies. It then delves into the complement system, explaining its pathways and the role of C1 esterase inhibitor in regulating immune responses. The report further presents a case study of a patient with hereditary angioedema (HAE), analyzing the symptoms, diagnosis, and potential treatments, including the importance of C1 esterase inhibitor in managing the condition. The report also discusses the genetic and molecular basis of B-cell lymphoma and the implications of C1 esterase inhibitor deficiency. This report provides a comprehensive overview of the clinical significance of genetically modified antibodies and their role in modern healthcare.

Running head: CLINICAL POTENTIAL OF GENETICALLY MODIFIED ANTIBODIES
CLINICAL POTENTIAL OF GENETICALLY MODIFIED ANTIBODIES
Name of the Student:
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Author Note:

1CLINICAL POTENTIAL OF GENETICALLY MODIFIED ANTIBODIES
ANSWER TO QUESTION NO. 1
Individuals with hypersensitivity towards a particular drug can experience hazardous
side effects on generalized implementation of a medication, and could encounter increased
health risks through a cascade of side effects initiated by that drug. Using genetically
modified antibodies, accounting the sensitivity of the patient could optimize the outcome of
the medication. Genetically engineered monoclonal antibodies are prescribed worldwide for
treating variety of cancers, autoimmune disorders and inflammatory diseases.
Anti-CD 20 antibody rituximab is an example of such genetically modified antibody,
which is used to treat patients with mediastinal B-cell lymphoma. Clinical trials have
reflected that using rituximab to young patients having primary mediastinal B-cell lymphoma
could suspend the obvious need of radiotherapy in those patients (Dunleavy et al. 2013).
Mutation in BCL6 gene results in mediastinal B-cell lymphoma arising from the thymus,
which is closely associated with sclerosis resulted from Hodgkin’s lymphoma. Patients with
mediastinal B cell lymphoma typically have localized aggregation of medistinal mass in their
chest region. BCL6 mutation along with somatic mutation in immunoglobulin heavy chain,
leads to defective immunoglobulin expression on B cell receptors. Patients with B-cell
lymohoma are found to express defective cellular-Rel (encoded by REL proto-oncogene) and
defective production of JAK 2 protein (JAK 2 is an essential tyrosine kinase protein involved
in JAK-STAT pathway), which is also found in Hodgkin’s lymphoma. Genes that are found
to be overexpressed in B cell lymphoma, also show elevated levels of expression in
Hodgkin’s lymphoma. Hence, it can be inferred that B cell lymphoma and Hodgkin’s
lymphoma are probably related (Rosenwald et al. 2003). Limitation of immunochemotherapy
and concomitant side effects of routine radiotherapy deliver severe health risks on the patient
and are unable to cure the disease entirely. Rituximab is used in combination with EPOCH

2CLINICAL POTENTIAL OF GENETICALLY MODIFIED ANTIBODIES
(Etoposide, Prednisone, Oncovin or Vincristine sulfate, Cyclophosphamide, Doxorubicin) to
treat mediastinal B cell lymphoma patients that promotes better results than radiotherapy and
associated side effects. Rituximab mediated EPOCH treatment also inhibits further
progression of B cell lymphoma. Thus, R-EPOCH has greater effectiveness in comparison to
conservative use of immune-chemotherapy and radiotherapy and could be additionally used
as a potential treatment for Hodgkin’s lymphoma.
ANSWER TO QUESTION NO. 2
Complement system pathway is a form of innate immune response activated as a first
line of defense in response to invading microorganisms leading to antibody-dependent
cellular cytotoxicity or phagocytosis of the foreign organism. Complement system acts via
three major pathways namely, classical, alternative and lectin pathway. Nine major proteins
(C1-C9) are involved in this pathway, which facilitates the formation of membrane attacking
complex (MAC) via a cascade of reactions, which binds to the extracellular matrix of the
invading organism. Activation of classical complement system is achieved by cleavage of the
inactive calcium-bound C1 complex. C1 protein has three subunits-C1q, C1r, C1s. Binding of
C1q to the antigen-antibody (Ag-Ab) complex, exposes the proteolytic domain of C1r, which
in turn activates C1s complex. C1s activates C4 complex to liberate C4b and conversion of
C2 to C2b and forms C4b2a complex. Inflammatory response initiates the alternative
complement system by cleavage of C3 to C3b, which binds with the Factor B of blood
plasma to form C3bBb complex. C4b2a complex and C3bBb leads to the formation of C3
convertase enzyme complex, which is a quintessential component of the complement system.
C3 convertase incorporates further complement proteins (C5, C6, C7, C8), which ultimately
results in the formation of MAC.

3CLINICAL POTENTIAL OF GENETICALLY MODIFIED ANTIBODIES
C1esterase inhibitor is a typical serine protease or serpin family of proteins, produced
by monocytes, hepatocytes and several other cells in response to pro-inflammatory cytokines.
C1EINH acts on C1 protein by binding with C1 protease, which inactivates the C1rs
complex. Subsequent inactivation of C1r and C1s complex, inhibits further activation of C4
and C2 complex. Hence, C1EINH plays an essential role in regulation of classical and lectin
complement pathway (Owen, Punt and Stanford 2013).
Inhibition of plasmin by C1EINH plays another crucial role in fluid homeostasis.
Plasmin is the activated form of plasminogen produced by hepatocytes, which cleaves blood
clot via fibrinolytic pathway. Plasmin also acts as an activator of pre-Kallikrein to plasma
Kallikrein complex, thus initiating Kallikrein-kinin cascade, which liberates bradykinin from
activated plasma kallikrein-HMWK complex. Bradykinin is a potent vasodilator and
mediator of vascular permeability. Bradykinin binds to the B2 receptors of the endothelial
cells present in the inner layer of the vascular space, which introduces gaps between cellular
junctions, which releases internal fluid and proteins from the inner space of the blood vessel
to the surrounding tissues. Pre-Kalllikrein is also activated by the blood plasma factor XIIa,
which releases Bradykinin into the bloodstream via the similar pathway initiated by plasmin.
C1EINH binds to pre-Kallikrein complex and activated factor XII, thus inhibiting production
of bradykinin and excess fluid loss.
Angel, a 17-year-old patient, who was admitted to the hospital primarily with
painless, non-pruritic swelling in her left hand. She also had urticaria, a typical kind of skin
rash due to allergic response towards a certain compound. However, there are possibilities of
other complications related to Scabies, Henoch-Schonlein Purpura as well as the Erythema
Multiforme. As per Ashton, Leppard and Cooper (2014), all of these complications are
associated with the complications of skin and occur due to the type IV hypersensitivity, in
which, no foreign antibodies or antigens initiates the hypersensitive reactions and occurs due

4CLINICAL POTENTIAL OF GENETICALLY MODIFIED ANTIBODIES
to the presence of the self-cell components, initiating severe hypersensitive reactions
(Ashton, Leppard and Cooper 2014).Erythema Multiforme is a health complication in which
the patient suffer from critical allergic reactions and increases the health complication,
whereas, in Henoch-Schonlein Purpura, patient suffer from allergic reaction that arises due to
the increased amount of the IgA and affects the kidney, lungs and central nervous system of
the patient. Hence, these are the differential diagnoses that the patient suffer from and hence,
these apects should also be assessed prior to identification of the actual healthcare
complications (2014 2014). Urticaria can be cured by anti-histamine medication, as the
doctor had prescribed (oral anti-histamines).
The patient primarily enrolled in the hospital notifying pain in abdomen and vomiting
after 1 year, which escalated to diarrhea after 2 days. These aforementioned symptoms imply
excessive fluid loss, which worsened the condition of vomiting prevailing diarrhea.
Disruption of C1 esterase inhibitor function increased bradykinin-mediated vasodilation and
vascular permeability, which might be the cause of swelling of abdominal tissues, reflected
by initial pain and a prolonged effect of this phenomenon and additional consequence of
other potent vasodilators like prostacyclin, Nitrous oxide (NO), could have contributed to
uncontrolled fluid loss from the body, causing diarrhea. Analyzing the previous medical
history and these symptoms, the probable cause indicates hereditary angioedema (HAE).
Studies elaborated HAE relapses after short periods, typically 9-12 months with frequent
swelling of lips, palms, intestinal walls, subcutaneous layers and abdominal pain (Bork et al.
2003). Mutation or insufficient production of C1 esterase inhibitor (C1EINH) is abbreviated
as type 2 and type 1 HAE respectively. Although, it is named ‘hereditary’, this disease can be
inherited or may appear de-novo (i.e. neither of the parents has HAE).
Six months later of this incident, Angel was again admitted in the hospital with
swelling of her lips and tongue, followed by dental extraction. In this scenario, dental

5CLINICAL POTENTIAL OF GENETICALLY MODIFIED ANTIBODIES
extraction could have triggered trauma-induced activation of complement cascade and
coagulation pathway, and resulted in acute HAE response. Dental extraction is found to be
associated with facial edema, which further developed into laryngeal edema, causing
asphyxiation (Bork et al. 2003). Immediate intubation was required to prevent asphyxiation;
otherwise, it could have resulted in death of the patient. Dysfunctional C1 esterase inhibitor
in hereditary angioedema is found to be the principal reason of spontaneous swelling of
subcutaneous tissues, face, abdomen, upper respiratory tract, genitalia and peripheral limbs.
Hence, laryngeal swelling of the patient could have exacerbated into erythmatous pharyngeal
edema and swelling of the oropharynx.
The doctor should have ordered a test for C3 and C4 protein levels of the patients.
Normal levels of C3 and low levels of C4 indicates stable function of the alternative pathway,
but a dysfunction in classical component pathway, as C4 is an indicator of this cascade. For
further confirmation, tests checking C1q levels should also be carried out to distinguish
between acquired and hereditary angioedema. Low levels of C1q stipulates acquired
angioedema, whereas, normal levels of C1q could be inferred with possible inherited
angioedema. To characterize between type 1 and type 2 angioedema, C1EINH and C1 levels
should be checked. Low levels of both C1 and C1 esterase inhibitor implies type 1 hereditary
angioedema, with a decreased production of C1EINH than normal. Low levels of C1 EINH
but normal or high levels of C1 protein indicates type 2 hereditary angioedema, which states
a possible mutation in C1EINH gene, causing low levels of the protein, and unregulated C1
levels (Markovic et al. 2000).
Possible treatment for hereditary angioedema could be treatment with reconstituted
C1 esterase inhibitor solution, via injection. Low levels of C1EINH causes acute swelling of
limbs, intestine, abdomen, pharynx due to excessive fluid loss from the intravascular space.

6CLINICAL POTENTIAL OF GENETICALLY MODIFIED ANTIBODIES
Isolated C1EINH therapy is commonly used worldwide to treat C1 esterase inhibitor
deficiency in patients with hereditary angioedema.

7CLINICAL POTENTIAL OF GENETICALLY MODIFIED ANTIBODIES
References
Ashton, R., Leppard, B. and Cooper, H., 2014. Differential diagnosis in dermatology. CRC
Press. Retrieved from: https://content.taylorfrancis.com/books/download?dac=C2015-0-
75338-1&isbn=9781498784733&format=googlePreviewPdf
Bork, K., Hardt, J., Schicketanz, K.H. and Ressel, N., 2003. Clinical studies of sudden upper
airway obstruction in patients with hereditary angioedema due to C1 esterase inhibitor
deficiency. Archives of Internal Medicine, 163(10), pp.1229-1235.
Dunleavy, K., Pittaluga, S., Maeda, L.S., Advani, R., Chen, C.C., Hessler, J., Steinberg, S.M.,
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Medicine, 368(15), pp.1408-1416.
Markovic, S.N., Inwards, D.J., Frigas, E.A. and Phyliky, R.P., 2000. Acquired C1 esterase
inhibitor deficiency. Annals of internal medicine, 132(2), pp.144-150.
Owen, J.A., Punt, J., Stranford, S.A. and KUBY, I., 2013. 7th.
Rosenwald, A., Wright, G., Leroy, K., Yu, X., Gaulard, P., Gascoyne, R.D., Chan, W.C.,
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