Final answer:
The serum protein fractions most likely to be elevated in patients with nephrotic syndrome are alpha-2 globulin and beta globulin.
Step-by-step explanation:
In patients with nephrotic syndrome, the most likely elevated serum protein fractions are alpha-2 globulin and beta globulin. Nephrotic syndrome results in a damaged glomerulus, causing significant protein, especially albumin, to spill into the urine. Due to the loss of albumin, there is a compensatory increase in other serum proteins, notably alpha-2 globulin and beta globulin, which are involved in transport functions and the acute phase reactant response, respectively. Additionally, gamma globulins may also be elevated due to the stimulatory effect on the immune system.