An assessment of polymorphonuclear leukocyte rigidity in HIV-infected individuals after immune recovery.

Purpose: To determine whether polymorphonuclear leukocytes (PMNs) remain rigid after immune reconstitution in human immunodeficiency virus (HIV)-infected individuals with a history of severe immunosuppression.

Methods: PMN rigidity was measured in vitro in three groups: (1) HIV-infected individuals with a history of CD4+ T-lymphocyte counts of less than 50/microL, but with current counts of more than 200/microL attributable to potent antiretroviral therapy (group 1); (2) HIV-infected individuals whose CD4+ T-lymphocyte counts had always been more than 200/microL (group 2); and (3) HIV-negative control subjects. Rigidity was determined with a cell transit analyzer (containing a micropore filter with 30 identical, 8-microm diameter pores), representing a simple in vitro model of a capillary bed. A longer PMN pore transit time reflects increased PMN rigidity.

Results: PMN transit time (median) in group 1 (n = 11) was 3.34 ms, in group 2 (n = 9) was 3.19 ms, and in control subjects (n = 15) was 2.66 ms. PMN rigidity was significantly greater in groups 1 (P = 0.014) and 2 (P = 0.046) than in control subjects (Wilcoxon rank-sum test). A significant difference was not identified between groups 1 and 2 (P = 0.518).

Conclusions: The increased PMN rigidity known to occur in severely immunosuppressed HIV-infected individuals persists after immune reconstitution. Furthermore, PMN rigidity is increased in those HIV-infected individuals who do not have a history of severe immunosuppression. Because PMN rigidity can alter microvascular blood flow, HIV-infected individuals may remain at risk for retinal vascular damage in the era of potent antiretroviral therapy.