Immune complex deposition in the choroid plexus of patients with acquired immunodeficiency syndrome.

We identified immune complex deposits in the choroid plexus of approximately 75% of patients with acquired immunodeficiency syndrome (AIDS) who had either normal brains or human immunodeficiency virus encephalitis. Since circulating immune complexes are common in AIDS patients, and since local choroid plexus pathology usually was absent, their likely origin is from the bloodstream. Choroid plexus deposits of immune complexes have been implicated in altering the function of this structure or in enhancing its vulnerability to infection. Therefore, immune complex deposition in the choroid plexus of AIDS patients may be responsible for some of the common alterations in the cerebrospinal fluid and for the frequency of opportunistic infections in this region.

Histochemical localization of enzyme activity in the kidneys of male marmosets (Callithrix jacchus and Callithrix penicillata).

The distribution of several hydrolases and oxidoreductases was studied in the renal parenchyma of adult male marmosets (Callithrix jacchus and Callithrix penicillata). The oxidative enzymes showed a high reactivity in the proximal and distal tubules, whereas the hydrolases reacted strongly in the proximal tubules but only weakly or not at all in the thick limb of Henle's loop, distal tubules and collecting ducts. The NAD-dependent enzymes (except alpha-GPDH) showed a stronger reactivity in the proximal tubules, while the NADP-dependent ones were more reactive in the thick limb of Henle's loop and distal convoluted tubules. Two groups of interstitial cells were found in the medulla. A first group inside the outer medulla, showing cells rich in acid phosphatase and nonspecific esterases and a second group, close to the papilla, reactive to a certain number of oxidative enzymes. A different reactivity in cells of the distal convoluted tubules, thick limb of Henle's loops and collecting ducts (dark cells) was seen in the case of some enzymes like nonspecific esterase, alpha-GPDH and SDH.