1. Utilizing Lectin Binding
Specificities for Diagnosis of
IgA Nephropathy
A Less Invasive Approach to Diagnosing IgA Nephropathy
Bridgette Nikisher- Yorktown High School
Dr. Carl V. Hamby- New York Medical College

2. 0
Abstract
Utilizing Lectin Binding Specificities for Diagnosis of IgA Nephropathy
IgA Nephropathy is the most common form of glomerulonephritis in the world, and there
is only one widely accepted diagnostic test for the disease: renal biopsy. The goal of this research
was to create a serum-based diagnostic test for IgA Nephropathy that would rule in or out
patients that need renal biopsies. Previous studies have shown that Helix Aspersa agglutinin
(HAA) binds better to the IgA1 of IgAN patients vs. healthy control, so it was hypothesized that
IgA/HAA ratios would be the best differentiator of IgAN vs. healthy samples. Serum samples
were collected from IgAN patients and healthy volunteers. IgA1 from the serum was purified
and used in ELISA and Jacalin bead experiments. The ELISA IgA/IgG ratios were the best
indicator of whether or not a sample was IgAN or not (AUC=0.76, sensitivity = 65% , specificity
= 75%). The ELISA IgA/HAA ratios were next best (AUC = 0.42, sensitivity= 65%, specificity=
40%), and the Jacalin bead IgA/IgG were the worst (AUC = 0.32, sensitivity= 43%, specificity=
50%). However, the sensitivity and specificity are not good enough to be considered a successful
diagnostic test, so there is more research needed to create a successful serum-based diagnostic
test.

3. 1
I. Introduction
IgA Nephropathy is the most common form of glomerulonephritis worldwide, though it
is listed as a rare disease. IgA Nephropathy (IgAN) affected 61,423 people in the USA in 1996.
IgAN affects the glomeruli of the kidneys; glomeruli act as the filters of the kidney, so over time,
the kidneys of IgAN patients lose function, causing
hematuria. Eventually, IgA Nephropathy can result
in chronic kidney disease (CKD), requiring the
patient to undergo a kidney transplant due to the
problems illustrated in Image 1. The disease is often
not caught in early stages, therefore IgAN is very
difficult to diagnose. This difficulty results from
there being only one widely accepted diagnostic
test: renal biopsy. The problem is that renal biopsies are very invasive procedures, so a non-
invasive diagnostic test would be very beneficial. Renal
biopsies require the patient to lie on their stomach so the
doctor can locate the area for the biopsy to take place. Then,
the skin is cleaned and the patient is given anesthesia either
just on the area, or as an injection to make them sleep. From
there, an incision is made and an ultrasound is used to find the
exact location to insert the needle. The needle is then inserted
to remove the tissue needed for the biopsy. The insertion of the needle through the skin into the
kidney is shown in image 3. Biopsies are not necessary for all patients that undergo the
Image 1: Differences between a healthy
kidney and a kidney affected by CKD
Source: www.healthandfitnesstalk.com
Image 3: insertion of a biopsy
needle through the skin into
the kidney
Source: www.riversideonline.com

4. 2
procedure, so another problem is the amount of people that are put through the painful process
without a real need for it.
As mentioned earlier, IgA Nephropathy is very difficult to diagnose, as the symptoms
typically present themselves later into the progression of the disease, or not at all. Alternative
methods of diagnoses that have been attempted by many researchers include testing lectin-
binding specificities. A lectin is a plant or animal protein that possessed the ability to recognize a
specific group of carbohydrates. Specificity is how effective a test is at not producing false
positives. High specificity, or a specificity approaching 100%, means that the test does not
produce many false positives and therefore is an effective diagnostic test. For this experiment, a
high specificity would successfully address the goal as it would create a reliable diagnostic test.
Previous Research
IgA Nephropathy is the most common form of glomerulonephritis worldwide
(Novak 2005, Oortwijn 2006, Mestecky). IgA Nephropathy is also known as Berger’s Disease
and “is defined by the predominant deposition of IgA in the glomerular mesangium” (Barratt
2005). This means that the disease causes
buildup of immunoglobulin A (IgA)
antibodies in the kidney. In Image 3, the
green indicates the locations where IgA
antibodies have clustered together in the
mesangial cells, leading to IgA
Nephropathy. The disease leads to loss of
renal function, and hematuria. Hematuria is
Image 3: The green fluorescent shows buildup of IgA
antibodies in the mesangial cell of an IgAN patient
Source: www.med.niigata-u.ac.jp

5. 3
blood in the urine, and for IgAN patients, it can be macroscopic or microscopic (UNC). The
disease can also cause increased proteinuria, or protein in the urine (Tomana 1999). IgAN is
typically a slow progressing disease, with 30-50% of patients reaching end stage renal disease
(ESRD) within a range of 20 years (Radford 1996). ESRD is the last stage of chronic kidney
disease (CKD), and once a patient reaches ESRD, they cannot live unless they undergo dialysis
or a kidney transplant. According to the IgA Nephropathy Support Network, 50% of IgA
Nephropathy patients progress into ESRD, which is a problem because kidney transplants are
very difficult procedures to both perform and find a proper organ donor. IgA Nephropathy
causes ESRD because the influx of IgA in the kidney leads to inflammation (Satake 2014).
However, the disease is quite hard to detect as there is only one standard diagnostic test. IgAN
patients are diagnosed by renal biopsy, as it is the current gold standard for diagnosis of IgAN
(Haubitz 2005). As described earlier and demonstrated in Image 2, renal biopsies are very
invasive, so another reliable, non-invasive diagnostic test would be useful for diagnosis,
particularly if it could rule out the disease and thereby avoid unnecessary biopsies (Moldoveanu
2007). The problem with the new diagnostic test that was evaluated in this experiment is that it is
very time consuming; however, the test is non invasive, which was the goal.
Studies done by multiple scientists such as Moldoveanu and Gomes have suggested that
lectin binding specificities can be utilized determine whether or not the patient would have to
undergo a renal biopsy as they can determine whether or not there is even a possibility of the
patient having IgA Nephropathy. Helix aspersa agglutinin (HAA) is a GalNAc-specific lectin
that has been found to be the “best lectin for recognizing the glycosylation of IgA1 from IgAN
patients” (Gomes 2010). In a study done by Moldoveanu et al (2007), the results showed HAA-
IgA levels to vary significantly from IgAN patients and healthy controls, suggesting that HAA

6. 4
has a stronger affinity to IgA in IgAN patients than in healthy controls. Another study done by
Shimozato et al (2008) also had results in which the IgAN patients had higher HAA-IgA binding
levels than normal controls (p=0.0025). Shimozato et al’s study (2008) also had a specificity of
89% and a sensitivity of 66%, both of which are values that can support the data. In addition to
Moldoveanu et al (2007) and Shimozato et al (2008), Moore et al has also suggested that HAA
can be useful in detecting Gal-deficient IgA1 in IgAN patients (Gomes 2010). Utilizing these
lectins would help reduce the number of patients undergoing renal biopsies when they do not
have IgA Nephropathy.
Purpose and Hypothesis
Renal biopsies are very invasive and painful, as they require a tissue removal from the kidney
through a biopsy needle. Creating a new diagnostic test with the HAA-IgA ratios as a basis
would reduce the invasiveness of IgAN diagnostic tests; however, it may take more time as the
ELISA takes time to develop. The goal of this research was to evaluate lectin-binding
specificities of IgA1 antibodies as new diagnostic tests for IgAN that can be performed with a
simple blood draw. The higher the specificity or sensitivity of the lectin, the more effective it
was at differentiating between IgAN patients and healthy controls. The most effective lectin
could be used to form the basis of a serum-based diagnostic test that would be non invasive and
prevent unnecessary renal biopsies. The hypothesis was that HAA-IgA ratios will be useful in
creating this new diagnostic test, as previous results have shown that HAA binds to IgA more in
patients with IgAN than in patients without IgAN. HAA binds to the IgA more in patients with
IgAN than in patients without because it recognizes the glycosylation of IgA1 in patients with
IgA Nephropathy, but not those without. Therefore, the results from patients with IgA

7. 5
Nephropathy and patients without the disease were expected to have significant variation that
would be used to create a cut off for future diagnostic purposes.
II. Methodology
Overview of Methodology: Collaboration between Mentor and Student
In order to address the goal of developing a cost and time effective diagnostic test, an
enzyme-linked immunoabsorbent assay (ELISA) was designed by the supervising scientist prior
to experimentation to test patient/control binding to of the antibodies Immunoglobulin A (IgA),
Immunoglobulin G (IgG) and the lectin HAA. The purpose of the experiment was to see which
lectin had the highest binding to IgA1 antibodies in IgAN patients. Whichever lectin had the
highest binding would produce the best sensitivity and specificity, and therefore be the most
useful in determining which samples were IgAN patients and which samples were healthy
patients. It was hypothesized that HAA would be the best lectin for binding. This ELISA was
performed by the student in the mentor’s lab, biosafety level 2, with all proper personal
protection equipment (PPE) including, but not limited to, lab coats and biosafety cabinets. In
addition to the ELISA, the student also performed a Jacalin bead experiment that was run
through a flow cytometer. The Jacalin bead experiment was performed for two reasons: 1) it
would be a slightly more time effective option, and 2) the mentor had attempted a Jacalin bead
approach previously, and wanted to re-address it from a new angle. Both the ELISA and the flow
cytometry assay were serum based assays, so they only required a blood sample, addressing the
problem that the current diagnostic test, a renal biopsy, is invasive enough to be considered an
outpatient surgery, and could be unnecessary for some patients to undergo. Both experiments
were performed by the student with training and supervision by the mentor, who also designed

8. 6
the experiments. Results from both assays were analyzed by the mentor and the student, side by
side, using the Number Cruncher Statistical Software (NCSS).
Step 1: Obtaining serum samples: Done by Mentor
Blood samples were obtained with permission from both patients of IgA Nephropathy as well
as healthy control volunteers. Healthy control volunteers are defined as people who do not have
IgA Nephropathy that volunteered to have blood samples taken from them for the experiment.
This was done with assistance from the Department of Medicine. The purpose of this was to be
able to run the diagnostic test with known IgAN patients and healthy controls to see how
effectively the test was able to discriminate between the two cohorts.
Step 2: Jacalin purification of IgA1 from patient serum: Done by Mentor
In order to to purify the IgA1 that would be used to coat the wells in the ELISA assay,
Jacalin purification of IgA1 from the patient serum had to be done. This was necessary as the
next step requires purified IgA1 for other antibodies to bind to. First, patient and healthy control
serum was diluted 1:1 with 0.1 M PBS binding buffer (pH 7.4)
and passed over Jacalin-conjugated agarose beads in 1 ml
affinity columns. The columns were washed with 5 volumes of
binding buffer to remove unbound proteins. Finally, purified
IgA1 was eluted from columns with 0.1M melibiose dissolved
in binding buffer. This purified IgA1 would then be used in
the next step of the experiment, the Enzyme-Linked
Immunosorbent assay (ELISA), which would be used as a possible diagnostic test.
96-well plate filled with jacalin-
purified IgA1
Picture by B. Nikisher

9. 7
Step 3: Enzyme-Linked Immunosorbent Assay (ELISA): Done by Student
The ELISA was performed in a biosafety level 2 (BSL-2) lab. The assay required the use
of 96-well plates, a micro plate reader, various volume pipettes, phosphate buffered saline (PBS),
patient serum, OPD substrate, bio-tinylated HAA, goat anti-human IgA, goat anti-human IgG,
and 1M sulfuric acid. The purpose of the assay was to bind IgA1 antibodies to HAA or IgG
antibodies. To start the ELISA, 50 μL of patient and healthy control volunteer Jacalin-purified
IgA was added each well of a 96 well plate at a concentration of 10μg/mL. The plate was then
incubated overnight in a refrigerator at 4°C to coat wells with the IgA antibodies. This was done
to bind the wells with patient serum so the antibodies would have something to bind themselves
to. The next morning, the plates were blocked by 1 hour incubation with 2% dry milk dissolved
in PBS. Then, plates were washed 3 times with the “flip and slap” method using PBS to remove
all unbound antibodies. The flip and slap method is performed by “flipping” liquid out of plate
into sink, slap 3x on paper towel, fill with PBS buffer solution, repeat. After the plates were
completely washed, 50μL of PBS or bio-tinylated HAA were added to appropriate wells and
incubated for 30 minutes. This was done to initiate binding of HAA to patient IgA1 antibodies.
After incubation, the “flip and slap” method was again used to wash the plates 3 times using
PBS. After cleaning, 50μL of a 1:10,000 dilution of horse radish peroxidase conjugated (HRP)
anti-IgA or anti-IgG were added to wells that had previously contained PBS and 50μL of a
1:1,000 dilution of HRP-streptavidin were added to wells that previously contained HAA. After
30 minutes of incubation, plates were washed 3 times with PBS by the “flip and slap method”
once again. To initiate color development, 200 μL/well of OPD substrate was added to all wells.
After color was sufficiently developed, 50 μL/well of 1M sulfuric acid was added as the stop
solution to stop color development. Finally, the plate was read at 490 nm on a micro plate reader

10. 8
Step 4: Flow Cytometry: Done by Student with Mentor Assistance
The flow cytometry test was performed with Jacalin beads. This
test was run because unlike the ELISA assay, Jacalin purification of IgA1
from serum is unnecessary, again addressing the “time and cost effective”
goal. To start, 200 μL of a 5% suspension of Jacalin beads in binding
buffer were pelleted and resuspended with 200 μL of patient serum
diluted 1:1 with binding buffer. The beads were incubated in the serum for
30 minutes to bind the patient serum to the beads. Samples were then divided into 2 tubes
(100μL each) and washed with PBS. The washing process was as follows: spin tubes in
centrifuge; aspirate off serum/buffer; resuspended in PBS; repeat twice. After washing, samples
were incubated with a 1:1000 dilution of either Goat anti-IgG or goat anti-IgA for 30 minutes to
initiate binding. The beads were washed with PBS and
incubated with a 1:10 dilution of FITC-labeled anti-goat IgG.
After 20 minutes of incubation, the beads were washed and run
on a flow cytometer. The flow cytometer produced a flow figure
which contains (for this experiment), the amount of IgA
detected, the amount of IgG detected, and the Mean
Fluorescence Intensity (MFI). The MFI measures a shift in
fluorescence in a group of cells, or how much an antigen is
expressed, in this case, either IgA or IgG. The numbers from
the flow figure were then used to create IgA/IgG ratios, create graphs, and form cutoffs for
statistical analysis in NCSS, as described later.
Jacalin beads
spun down
Photo by B.
Nikisher
Flow cytometer that was used for
the experiment
Photo by B. Nikisher

11. 9
III. Results
ELISA Assay
An ELISA was performed as it could be a non invasive serum-based diagnostic test for
IgA Nephropathy. The results from the ELISA showed that IgG/IgA ratios were more effective
in determining which samples were healthy controls and which samples were IgAN patients. As
shown in Figure 1, the cutoff between healthy samples and IgAN samples was 0.4. This cutoff is
the number at which a line can be drawn on the graph and separate most of the IgAN samples
from most of the healthy controls. The cutoff line was determined by drawing a line on the graph
and counting how many healthy controls are above/below the line and how many IgAN samples
are above/below the line; a technique used by the mentor in previous studies. The line that was
most successful in separating IgAN samples from healthy control samples was the cutoff line
that was chosen for the statistical analysis. As shown in Figure 2, the Receiver Operating Curve
(ROC) generated an AUC of 0.76, sensitivity of 65% and specificity of 75%. Figure 3 shows the
results when the ratios of HAA/IgA were taken. It was hypothesized that IgAN patients
(represented in blue) would have much higher ratios of HAA/IgA than healthy volunteers
(shown in red) because previous research has shown that HAA binds to the IgA1 of IgAN
patients more than it binds to the IgA1 of healthy controls.. The cutoff line was drawn at 3.5
because this split the patients, and the ROC produced an AUC of 0.42, sensitivity of 65% and
specificity of 40%; as shown in Figure 4. The AUC and specificity are much lower than those
from the IgG/IgA graph, but the sensitivity remains the same. However, the IgG/IgA ratios are
the best indicator [based off sensitivity and specificity] of which patients are IgA Nephropathy

12. 10
and which are healthy volunteers, although the AUC, sensitivity and specificity all are not as
high as needed to be considered a consistent diagnostic test.
Figure 2: Receiver Operating Curve
from IgG/IgA ratios assuming cutoff
at 0.4
Area under curve (AUC) = 0.76
Sensitivity= 65%
Specificity= 75%.
Figure 3: Ratios of IgA to
HAA – IgAN patients (blue)
were expected to have
higher binding and therefore
higher ratios than the
control patients (red).
0
1
2
3
4
5
6
7
8
1 2 3 4 5 6 7 9 10 11 29 A B C D E F G IS CH
Ratio
Patient Sample
IgA:HAA Ratios
Figure 1: The ratios of
Immunoglobulin G
(IgG) over
Immunoglobulin A
(IgA) as received from
the ELISA assay. IgAN
patients (blue) were
expected to have higher
ratios than controls
(red).
0
0.5
1
1.5
2
2.5
3
3.5
1
2
3
4
5
6
7
9
10
11
29
A(RA)
B
C
D
E
F
G
IS
CH
Ratio
Patient Sample
IgG:IgA Ratios
ROC Curve of Cond_Value
TruePositiveRate-Sensitivity
False Positive Rate - Specificity

13. 11
Jacalin Beads/Flow Cytometry Results
It was hypothesized that the ratios of IgG/IgA would be higher for IgAN patients than
healthy volunteers because IgA1 binds better to IgAN patients than healthy controls; however,
when the flow cytometer was run, the results varied all over (Figure 5). As seen in Figure 6, the
AUC was 0.32, sensitivity of 43%, specificity of 50%. This assay turned out to be the least
effective indicator of what samples came from IgAN patients and what samples came from
healthy volunteers because the analysis generated the lowest AUC, sensitivity and specificity. It
is important to keep in mind that the samples used for the flow cytometer experiment were not
the same as the samples used for the ELISA. This variation in samples could sway the results,
but it shouldn’t have too much of an effect as the samples in this set were also those of IgA
Nephropathy patients and healthy controls. Both the ELISA and Flow Cytometer experiments
were performed on similar samples, as far as whether or not the disease was present in the
sample or not.
Figure 4: Receiver Operating Curve
(ROC) from the ratios of IgA to HAA,
assuming a cutoff at 3.5
AUC = 0.42
Sensitivity= 65%
Specificity= 40%.
False Positive Rate - Specificity
ROC Curve of Cond_ValueTruePositiveRate(Sensitivity)

14. 12
Overview of Analysis
All statistical analyses were performed in the Number Cruncher Statistical Software
(NCSS) program available in the mentor’s laboratory. The data was entered into a Microsoft
Excel spreadsheet which was used to create graphs. These graphs would then be used to
formulate a cutoff, or a line at which the patients were separated from the healthy volunteers.
These cutoffs would be the number entered into the NCSS to see if the cutoff was actually viable
or not. The primary analysis was the receiver operating curve (ROC) which was performed in the
Number Cruncher Statistical Software (NCSS) in collaboration between the student and the
0
1
2
3
4
5
23 CP BR 24 25 22 28 20 KW CH RA
41.64706 10.36364
Ratio
Patient Sample
Bead IgG:IgA Ratios Figure 5: IgG/IgA ratios
from the flow cytometer
assay. The IgAN patients
(blue) were expected to
have a higher ratio average
than the control patients
(red). The patient samples
in this assay were different
than the patient samples
used for the ELISA assay.
Figure 6: ROC analysis of
the Bead IgG/IgA ratios,
assuming a cutoff at 1.5
AUC = 0.32
Sensitivity= 43%
Specificity= 50%
ROC Curve of Cond_Value
TruePositiveRate(Sensitivity)
False Positive Rate (Specificity)

15. 13
mentor. The results suggested that an ELISA IgA/IgG ratio
test would be the best diagnostic test of the three attempted
because the ELISA IgA/IgG presented the highest AUC,
sensitivity and specificity (0.76, 65%, 75%, respectively).
The ELISA IgA/HAA was the second best at determining
whether or not a sample was a healthy control or an IgA
Nephropathy patient with an AUC of 0.42, sensitivity of
65% and specificity of 40%. The Jacalin bead
experiment was the worst differentiator of IgAN from
healthy, with an AUC of only 0.32, sensitivity of 43% and specificity of 50%.
IV. Discussion
These results were derived using a Receiver Operating Curve (ROC) analysis on the
Number Cruncher Statistical Software (NCSS). The ROC analysis was used to generate an AUC,
as an AUC analysis approaching 1 indicates less false positives, and therefore the ratio is a better
indicator. The ROC also generated the sensitivity and specificity. Sensitivity and specificity are
best when they are closest to 100%, as they are measures of how effective the test is.
Receiver operating curve (ROC) analysis produced each ratio set with an area under curve,
sensitivity and specificity. The area under curve is an indicator of false positives, and a number
approaching a value of one is more effective at diagnosing. Sensitivity is how well the test was
able to correctly diagnose the IgAN patients with IgAN. Specificity is how effective the test is at
not producing false positives. Just like the AUC, where a number approaching one is the best, a
sensitivity or specificity approaching 100% is better. IgG:IgA ratios from the ELISA had the best
Figure 7: Sample of data entered in excel

16. 14
results with an area under the curve (AUC) = 0.76; sensitivity = 65; specificity = 75%.
HAA:IgA ratios were next best, but not great, with AUC = 0.42; sensitivity = 65%; specificity =
40%. IgG:IgA ratios from the Jacalin bead experiment had the lowest results, showing an AUC =
0.32; sensitivity = 43%; specificity = 50%. The IgG:IgA ratios from ELISA were most effective
in determining differences between healthy volunteer samples and IgAN patient samples.
The results shown demonstrate the difference in ratios between the IgAN patients and
healthy control subjects. The analysis intended to find a ratio that was able to successfully
differentiate between IgAN patients and healthy controls. This was to determine which was the
most useful in ruling in or out patients that need to undergo renal biopsy. For each graph, the
IgAN patient columns were expected to be higher, showing more binding between IgG/IgA and
HAA/IgA. It was hypothesized that HAA/IgA would have more significant results (i.e.; higher
AUC, higher sensitivity, higher specificity) because HAA has been reported to detected Gal-
deficient IgA1 proteins, which are a marker of IgAN (Moldoveanu, Shimozato 2008, Gomes
2010). Instead, the IgG/IgA ratios had higher specificity, sensitivity, and AUC; this shows that
the IgG/IgA ratios performed better at separating between IgAN and healthy control samples.
V. Conclusion
IgA Nephropathy is the most common form of glomerulonephritis; however, it is also
very difficult to diagnose. Currently, the only definitive diagnostic test is a renal biopsy, which is
very invasive as it requires a biopsy needle to be inserted through the skin into the kidney to graft
a sample for biopsy, which is very painful. The goal of this research was to develop a serum
based test that would be able to rule in or out patients that need to undergo renal biopsy. The test
created through this experiment would not necessarily be a diagnostic test, but rather would be

17. 15
an indication test of whether or not a renal biopsy is needed as it would tell whether or not the
sample had a chance of being an IgA Nephropathy patient or not. Eventually, a serum-based
diagnostic test may gain enough support by the medical community to be as widely accepted as a
renal biopsy, but as of now, the only fully supported diagnostic test is a renal biopsy. It was
hypothesized that, due to the ability of HAA to detect Gal-deficient IgA1 proteins in IgAN
patients, HAA: IgA ratios would be the best indicator of IgAN patients against healthy controls.
This was tested through an ELISA assay where the samples were incubated with IgG and HAA,
and a Jacalin bead experiment with the same coating in order to reduce the time and materials
put into the experiment.
Receiver operating curve (ROC) analysis demonstrated that IgG:IgA ratios obtained by
ELISA performed best as diagnostic tests with an area under the curve (AUC) of 0.76, and
sensitivity of 65%, specificity of 75%. HAA:IgA ratios were next best with an AUC of 0.42 and
sensitivity of 65% and specificity of 40%. IgG:IgA ratios obtained by flow cytometery with
Jacalin beads performed worst with an AUC of 0.32 and sensitivity of 43% and specificity of
50%. The IgG:IgA ratios generated from the ELISA were the most effective in separating IgAN
patients from healthy controls; therefore, the best indicator of whether or not a patient would
have to undergo renal biopsy. Despite these conclusions, none of the diagnostic tests performed
for this project are quite at the acceptable specificity and sensitivity (to become the next gold
standard the new test simply has to have a higher specificity and sensitivity than the previous
test) to become a widely accepted and common practice diagnostic test.
Future Research

18. 16
With the medical field advancing the way it is, it is critical to have the most effective
diagnostic tests for each disease. However, it is also important that these diagnostic tests are fast
and relatively easy to perform. Currently, the only widely accepted diagnostic test for IgA
Nephropathy is a highly invasive renal biopsy. The results from this project can establish a basis
for a new, serum based diagnostic test for IgAN. This would make diagnosing the disease less
invasive for patients. A serum-based diagnostic test would benefit all involved in the diagnosis,
and therefore there should be more emphasis put on the development of a serum based diagnostic
test. Eventually, if a good enough serum based test is discovered (sensitivity and specificity
above at least 85%, preferably higher), renal biopsies may no longer be needed for diagnosis of
IgA Nephropathy, saving patients from a lot of pain and excess spending.

19. 17
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20. 18
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