Reasons: I see three potential symptoms of RRD/RRv:
the hyperthorniness when the other canes are nothing like
the fringe on the stipules at the bottom of one of the leaves is so overgrown compared to 'normal' leaves
the edges of new leaves are irregular and much wider toothed than the much smoother toothed edges of other leaves

Good eye for the things that were irregular in the worst way.

"Apply a possible immune system booster. Until controlled scientific studies disprove these "possibilities", after cutting off the suspected cane, one could try boosting the immune system of the rose by either of the two methods below:

1) By applying hydrogen peroxide.

"In spite of the enormous information from research on genetics of plant disease resistance, the question still remains unresolved: what is directly inhibiting or killing pathogens and suppressing symptoms in resistant plants? This is particularly true for resistance to viral infections. Here we show that externally applied reactive oxygen species (ROS) such as hydrogen peroxide (H2O2) or ROS-producing (O 2�− [superoxide] and H2O2) chemical systems infiltrated into tobacco leaves 2 hours after inoculation suppress replication of Tobacco mosaicvirus (TMV) in the susceptible Samsun (nn) cultivar. This was determined by a biological and a real-time PCR method. Infiltration of leaves of the resistant Xanthi (NN) cultivar with the ROS-producing chemicals and H2O2 significantly suppressed local necrotic lesions (i.e. the hypersensitive response) after inoculation of tobacco leaves with TMV. Accordingly, an early accumulation or external application of ROS, such as O 2�− and H2O2, in tobacco may contribute to the development of resistance to TMV infection."

The above is taken from the following 2011 reviewed scientific published paper (there are other papers, this is just one example)

: http://www.akademiai.com/content/q055880253up3p57/

2) By applying aspirin.

"Salicylic acid (SA) is an inducer of systemic acquired resistance (SAR) and could be a potential candidate in the control of plant virus diseases...................................................................... ......The results obtained confirm that SA promotes major changes in the induction of resistance in tomato plants and suggest that treatment with exogenous SA could be considered to reduce the infections caused by PVX."

The above is taken from the following 2014 reviewed scientific published paper (there are other papers, this is just one example)

http://link.springer.com/article/10.1007/s10658-013-0333-1

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The recommendations are based on results in the scientific literature for plants with other virus infections.

Examples for hydrogen peroxide:
http://forums2.gardenweb.com/forums/load/roses/msg0417381111236.html

http://forums2.gardenweb.com/forums/load/rosesant/msg0518594226728.html
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Example for aspirin:
http://forums2.gardenweb.com/forums/load/roses/msg1011110221766.html

See the following Google Scholar search for Aspirin:
http://scholar.google.com/scholar?hl=en&q=plant+virus+aspirin&btnG=&as_sdt=136&as_sdtp=