Thanks for your post.
Cases like these are very challenging, and there is little evidence-based literature to provide clear guidance. Patients with very low CD4 count nadirs are often at risk for having attenuated CD4 count rises on HAART.
First, it's worth thinking about secondary causes of CD4 lymphopenia-- ie, leukopenia, bone marrow suppression. Is there evidence of supprssion of other hematopoetic lines? In such cases (especially among those patients with very low CD4 counts), a bone marrow biopsy and culture would seem prudent.
If this is not the case, then it's natural to ask if there could be an unusual adverse drug reaction to either the components of Truvada (tenofovir+FTC) or Kaletra (lopinavir+ritonavir). There are clearly case reports of tenofovir+ddI causing CD4 lymphopenia; some have asked the question (based on usually unpublished anecdotes) if tenofovir with 3TC or FTC might have the same effect in rare cases. This is effect difficult to ascertain with certainty, since TDF-based regimens are used so widely; this could be an association that is not causal.
That said, a next strategy might be to switch NRTIs from Truvada to perhaps Epzicom (Kivexa, with HLA testing); alternatively a switch from Kaletra to an alternative 3rd agent could be considered. In the later case, it's relevant to note that several studies and meta analyses have shown boosted PIs to cause a greater increase in CD4 levels than NNRTIs. Typically (ie, median changes) this is not thought to be of any clinical significance, but may be a negative aspect to a proposed change.
In any event, with the undetectable viral load, I'll typically be very patient with my expectations of CD4 count increase. More often than not, CD4 absolute counts and percentages do eventually show increases.
Thanks again for your post. I hope that this is helpful.
BY
