Lymphocyte count decline

Tuberculin skin testing is an important part of the care of all HIV-1-infected patients or persons at risk for HIV-1 infection. Tuberculin skin testing should be done using the Mantoux method. A tuberculin reaction of >5 mm of induration is classified as positive in persons known to have or suspected of having HIV-1 infection. Unfortunately, as the CD4 lymphocyte count declines with progression of HIV-1 disease, many patients no longer react to delayed-type hypersensitivity testing. More than 60% of persons with CD4 lymphocyte counts of <200 cells/pl may have skin test reactions of <5 mm. Thus, it is impossible to detect the presence of tuberculous infection in many HIV-l-infected individuals. 

Inhibition of the normal immune response results from a gradual destruction of lymphoid tissue, followed by a decline in antibody production and a decrease in the numbers of eosinophils, basophils, and lymphocytes. The reduction in T-lymphocyte counts by glucocorticoids can occur acutely as a result of the redistribution of these cells from the intravascular space to the spleen, lymph nodes, and bone marrow. Thus an increase in the neutrophil count is commonly observed after glucocorticoid administration. The major suppressive effects of glucocorticoids on the inflamniatory response and the immune system appear to be through the modulation of cytokine production via an inhibition of nuclear factor kappa B (NF-kB) expression and nuclear translocation. Cytoldnes released from immunocompetent cells mediate both the acute and chronic phases of inflammation and participate in the control of the immune response (see Chapter 22). 

Significant suppression of peripheral lymphocyte counts was observed in beagle dogs that were exposed by inhalation to 90Sr fused-clay particles (Jones et al. 1976). Lymphocytes declined gradually over time in all exposed groups (initial lung burdens 5 pCi/kg 185 kBq/kg), and remained more than 50% lower than controls after 2 years. 

Eventually, the CD4 lymphocyte count begins a steady decline, accompanied by a rise in the plasma HIV RNA concentration. Once the peripheral CD4 count falls to <200 ceU per mm, there is an increasing risk of opportunistic infection. Sexual acquisition of CCR5-tropic HIV-1 is associated with a median time to clinical disease—usually an opportunistic infection such as Pneumocystis carinii pneumonia—of 8-10 years. Occasional patients can harbor HIV for more than two decades without significant decline in CD4 count or clinical immunosuppression this may reflect a combination of favorable host immunogenetics and immune responses. 

Lau, B., Gange, S.J., Phair, J.P., Riddler, S.A., Detels, R., and Margolick, J.B. 2003. Rapid declines in total lymphocyte counts and hemoglobin concentration prior to AIDS among HIV-1-infected men. AIDS 17 2035-2044. 

A 46-year-old man was treated with ceftaroline 600 mg IV every 8 h for a surgical site infection and bacteraemia secondary to MRSA. On day 39 of ceftaroline, the patient became hypoxic and presented with fever and chills. On physical exam, the surgical site was healed. Laboratory results revealed an elevated white blood cell count (12,000 cells/mm ) with an absolute eosinophil count of 1500 cells/mm. CT scan showed diffuse bilateral infiltrates with bilateral hilar and mediastinal adenopathy. On admission, the patient was switched to tigecycline and aztreonam. The patient s respiratory status continued to decline. A bronchoalveolar lavage (BAL) was performed on hospifal day 3 and fluid analysis showed 16% eosinophils, 62% neutrophils and 20% lymphocytes. BAL culture was negative. Methylprednisolone was initiated, and the patient s clinical status improved within 24 h [65 ]. 

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