[Serum activity of the lactate dehydrogenase enzyme in patients with human immunodeficiency virus infection]

Many patients with infection by the HIV show an increase in the levels of the lactodehydrogenase (LCH) enzyme. In most of these cases, such increase has been associated to the presence of pneumonia by Pneumocystis carinii. In order to analyze other possible causes of this increase, we conducted a study in which the clinical, analytical and immunological condition of a group of HIV+ patients with increased levels of LDH was compared to another group whose values were within normal limits.

The clinical records of 200 patients with HIV infection were retrospectively reviewed. The patients were divided into two groups depending if their LDH values were greater than (group A) or lower than (group B) the upper limit considered as normal in our laboratory (230-460 UI/L). Group A included 150 patients and Group B, 50.

Both groups were similar with respect to age, sex risk group for HIV infection, hemoglobin level, platelet count and renal function. The number of patients fulfilling AIDS criteria was significantly greater (p < 0.05) among those with LDH above 460 UI/L. Leukocytes and lymphocytes CD4+ values were significantly greater (p < 0.05) among group B. The diseases more frequently diagnosed in group A were: tuberculosis in 41 cases (27%), pneumonia by P. carinii in 31 (21%), bacterial pneumonia in 19 (13%), disseminated disease by cytomegalovirus in 14 (9%) and by Mycobacterium avium in 12 (8%). Among the patients with increased LDH, their levels were similar in the patients with tuberculosis, pneumocystosis and in the patients with AIDS and those which were in the first stages of the HIV infection.

The increase in LDH among the patients with HIV infection in the era of the prophylaxis against P. carinii must be carefully interpreted. Greater levels of this enzyme are little specific, but have a high sensitivity in the case of tuberculosis and pneumocystosis.