A 28-year old man who is HIV seropositive has been lost to follow-up for six years. He now has proteinuria (3.5 g/24 hr) and azotemia (serum creatinine of 2.2 mg/dL). His CD4 lymphocyte count is 150/mm3, and plasma viral load is 120,000 RNA copies/mL. Kidney biopsy shows collapsing FSGS, microcystic dilatation of tubules, and an interstitial infiltrate. Highly active antiretroviral therapy (HAART) is initiated. If the HIV infection responds to HAART, which of the following is the most likely outcome?
A. Progression of chronic kidney disease, with rapid development of ESRD in less than six months
B. Improvement of chronic kidney disease, with a reduction in proteinuria and serum creatinine
C. Transition into a membranous glomerulonephropathy
D. No effect on course of renal disease