Following a 32-year career in plant pathology R&D for agricultural and biosecurity applications I was well-versed in DNA-based diagnostic technologies. But I never imagined that at 68-years of age, I would be the topic of a difficult diagnostic investigation which required innovations in proteomics diagnostics.
While undergoing prostate cancer treatment in 2015, amyloid deposits were detected in my prostate gland biopsy. This chance finding led to further investigation and a diagnosis of early systemic amyloidosis with heart involvement.
I was fortunate to be referred to the haematologist and director of the PAH amyloidosis Centre, Dr Peter Mollee, who is at the forefront of systemic amyloidosis diagnosis techniques in Australia.
Dr Mollee found that I had a monoclonal lambda immunoglobulin free light chain in my blood which can be the causative problem underlying AL amyloidosis. However, there was a possibility that the amyloid deposits could be of transthyretin (ATTR) type. Or that the circulating monoclonal immunoglobulin lambda free light chains was unrelated to the amyloidosis but was due to a condition called MGUS.
Because treatment is different for each type of amyloidosis It was extremely important to establish what type of amyloidosis I had before any treatment plan could be formed.
In my case the current standard method of diagnosis concluded with a negative result. Dr Mollee then, using a section of my prostate tissue, carried out laser-capture microdissection-coupled with tandem mass spectrometry. A typing method available at the Princess Alexandra Hospital (PAH) Amyloidosis Centre in Brisbane.
Using this tissue, the proteomics method identified immunoglobulin lambda light chain, as well as signature amyloid associated proteins (ApoE, SAP, ApoA4, vitronectin and clusterin). Dr Mollee then concluded that a confident diagnosis of lambda light chain amyloidosis could be made and appropriate treatment was able to commenced on October 28, 2015 following a whole body bone and cardiac nuclear scan.
Read: Proteomics to the rescue – Precision diagnosis for precision medicine
My treatment consisted of a sixteen-week course of chemotherapy, bortezomib (Velcade), cyclophosphamide and dexamethasone. The bortezomib was administered by IV in the hospital haematology day care unit while the cyclophosphamide and dexamethasone were taken orally. I also have a drug called Zometa given by IV regularly to improve or maintain my bone density
The anti-viral drug valaciclovir (Valtrex) was also prescribed to be taken every day to reduce the risk of getting shingles, a disease I had in 2001, which was fortunately diagnosed early and treated with an anti-viral drug.
I had very few side effects during the course of treatment, apart from the effects of dexamethasone causing insomnia for a couple of days each treatment cycle. There were some minor episodes of intermittent peripheral neuropathy as well as some intermittent random bone pain.
After the fourth weekly treatment there was a dramatic decrease in my Lambda (L) reading, down to 24 mg/L, with the Kapa (k) reading down to 6 mg/L, with the K/L ratio at 0.25 (still just outside the normal ratio range listed as 0.31-1.56). As the treatment continued, the K/L ratio went on dropping and moved into the normal range by the completion of treatment on 9 Feb 2017. The K/L ratio remained in the normal range until September 2018, but the L readings had been slowly rising for several months before and continued to rise slowly during 2019 The L levels were much lower than those before my velcade treatment started but they were still heading in the wrong direction.