Saturday, December 14, 2013

CD4 Count Fluctuation

Why did my CD4 decrease?  I tried to research on CD4 fluctuations. And below (in green) is what I've found.

I'm worried about the 14% decline on my CD4 count (about 1% decline on my CD4 percentage), because this could mean ARV treatment failure. But, as mentioned below, CD4 count normally fluctuates. And my change in CD4 count is NOT significant, because the change is less than 30% (or less than 3 percentage point change in CD4%). Another thing, as mentioned below, it is HIV Viral Load that best determines whether an ARV regimen is effective or a failure. My doc asked me to have my viral load test 3-4 weeks ago. But I haven't done it yet since it's not available at PGH. I guess, it's a must for me now to go to RITM to have this test.

I hope the decrease is just due to common factors affecting CD4 like: 

  • Stress or lack of sleep. We've had a problem at work the night before my test, so I stayed at the office until 10pm, ate dinner at 10:45 PM, and slept late due to insomnia.
  • I haven't eaten and drunk water for 9 hours before the test, because of the fasting required for lipid test. 
  • I fought with my partner the night before. 
  • Testing error. I heard the nurse at my HIV hub say that the med tech extracting blood who also read the CD4 result, was new. 

I'll see what my doctor will say next week about my test results. For the meantime, I should stop worrying, since anxiety also lowers CD4!

Here's what I've read from the internet. 

Use of CD4 Count for Monitoring Therapeutic Response
An adequate CD4 response for most patients on therapy is defined as an increase in CD4 count in the range of 50 to 150 cells/mm3 per year, generally with an accelerated response in the first 3 months of treatment. Subsequent increases in patients with good virologic control average approximately 50 to 100 cells/mm3 per year until a steady state level is reached.3 Patients who initiate therapy with a low CD4 count4 or at an older age5 may have a blunted increase in their counts despite virologic suppression.

Frequency of CD4 Count Monitoring 
ART now is recommended for all HIV-infected patients. In untreated patients, CD4 counts should be monitored every 3 to 6 months to determine the urgency of ART initiation. In patients on ART, the CD4 count is used to assess the immunologic response to ART and the need for initiation or discontinuation of prophylaxis for opportunistic infections (AI).

The CD4 count response to ART varies widely, but a poor CD4 response is rarely an indication for modifying a virologically suppressive antiretroviral (ARV) regimen. In patients with consistently suppressed viral loads who have already experienced ART-related immune reconstitution, the CD4 cell count provides limited information, and frequent testing may cause unnecessary anxiety in patients with clinically inconsequential fluctuations. Thus, for the patient on a suppressive regimen whose CD4 cell count has increased well above the threshold for opportunistic infection risk, the CD4 count can be measured less frequently than the viral load. In such patients, CD4 count may be monitored every 6 to 12 months, unless there are changes in the patient’s clinical status, such as new HIV-associated clinical symptoms or initiation of treatment with interferon, corticosteroids, or anti-neoplastic agents (CIII). 

Another website mentions this:

The normal values for CD4 count vary considerably among different laboratories. The mean normal value for most laboratories is approximately 500-1,300 cells/µL. This calculated value is subject to more fluctuations than the CD4 cell percentage. Illness, vaccination, diurnal variation, laboratory error, and some medications can result in transient CD4 cell count changes, whereas the CD4 percentage remains more stable. Because CD4 counts may vary, treatment decisions generally should not be made on the basis of a single CD4 value. When results are inconsistent with previous trends, tests should be repeated, and treatment decisions usually should be based on two or more similar values. A change between two test results is considered significant if it is a 30% change in absolute CD4 count or 3 percentage point change in CD4 percentage.

Once a patient has started ART, the viral load is used to monitor the response to therapy. A key goal of ART is to achieve a viral load that is below the level of detection (e.g., <40 copies/mL). Because CD4 and clinical responses may lag behind changes in viral load, viral load testing is essential for detecting virologic failure in a timely manner. With an effective ARV regimen, a 10-fold decline (1 logarithm) is expected within the first month, and suppression to undetectable levels should be achieved within 3-6 months after initiation of therapy. Isolated low-level elevations (typically <400 copies/mL) in viral load may occur in patients on ART; these "blips" generally do not predict subsequent virologic failure. (Additionally, some viral load assays appear to produce low-level positive results (<200 copies/mL) more commonly than others; as with blips, these do not appear to increase the risk of virologic failure.) To avoid confusing virologic failure with blips or test variability, current guidelines define virologic failure as repeated HIV RNA levels >200 copies/ mL. If the viral load does not reduce to an undetectable level (or at least <200 copies/mL), or if it rebounds after suppression, virologic failure has occurred, and possible causes should be investigated (e.g., poor ARV adherence, resistance to ARVs, or reduced drug exposure).