Progression of HIV disease is associated with increased expression of FcγRI and CR1 on alveolar macrophages

The expression of receptors for complement and the Fc region of immunoglobulin by alveolar macrophages (AM) constitutes a valuable aid to effector function of these cells. However, during HIV infection such expression may also act to increase binding of immune complexes, thus facilitating viral infection of these cells. This study was designed to determine whether changes in the expression of these receptors occurs in situ during HIV infection. Lung macrophages were isolated by bronchoalveolar lavage in groups of HIV⁺ subjects segregated on the basis of peripheral CD4 count. A group of normal subjects was also investigated. Expression of CR1 and FcγRI was quantified by measuring the optical density of reaction product following controlled immunoperoxidase staining with MoAbs CD35 and CD64. Both CR1 and FcγRI were increased over normal in all HIV⁺ subjects. This increase was progressive with advancing disease as determined by correlation with declining peripheral CD4 count. Comparison of asymptomatic and symptomatic subjects with HIV infection showed no difference in CR1 expression but a rise in FcγRI expression in the latter group. An overall inverse correlation was also found between peripheral CD4 count and FcγRI expression, but not CR1 expression. These data demonstrate a significant increase in the expression of these receptors on AM from HIV⁺ subjects, and show that this increase may occur before any symptoms in these patients.     

OSTEOLYTIC PROPERTIES OF THE SYNOVIAL-LIKE TISSUE FROM ASEPTICALLY FAILED JOINT PROSTHESES

Relationships were found between the bone-resorbing abilityof conditioned media (CMs) from cultures of peri-prosthetictissues and their levels of bone-remodelling agents. Bone-resorbingactivity was measured by ⁴⁵Ca release from pre-labelled mousecalvaria and 23 of 40 CMs exhibited bone-resorbing activity.Cytokine and prostanoid levels in the CMs were measured by immunoassay,and the levels of interleukin (IL)-1ß, IL-6, tumournecrosis factor (TNF) and prostaglandin E₂ (PGE₂) correlatedwith each other, except for the latter two. Significantly higherlevels of IL-6 were present in those CMs with bone-resorbingactivity than in those without, and a similar pattern was observedfor PGE₂ and IL-1ß. However, some CMs with high levelsof IL-1ß, IL-6, TNF and PGE₂ failed to induce resorption,whereas a few CMs with low levels of these agents induced resorption.Moreover, neither dialysis of CMs nor addition of neutralizingantisera to IL-1 and IL-1ß to CMs, either alone orin combination, reduced the bone-resorbing activity of the CMs.It is considered that these agents may act synergistically tomediate osteolysis around failed joint implants, but that otherunidentified bone-resorbing agent(s) must be involved. KEY WORDS: Implant failure, Pseudosynovial membrane, IL-1ß, IL-6, TNF, TGFß1, Prostaglandins, Bone resorption, Leucocytes     

AN ALGOMETER FOR THE AUTOMATED MEASUREMENT OF PAIN THRESHOLD

An automated device is described which enables operator independentmeasurement of pain threshold. Pressure is applied across ajoint of the digit by means of a controlled pneumatic actuator.Testing 10 normal subjects indicated good reproducibility (r²=0.75,one-way analysis of variance). KEY WORDS: Pain, Measurement     

THE USE OF DOLORIMETRY IN THE ASSESSMENT OF POST-TRAUMATIC ALGODYSTROPHY OF THE HAND

We have investigated the use of dolorimetry in the assessmentof algodystrophy of the hand. Findings in 12 affected patientsfollowing Colles' fracture were compared with age- and sex-matchednormal controls. Algodystrophy was associated with a significantincrease in tenderness of both the finger joints and bones.Tenderness of the whole hand was quantified by summing the dolorimetryreadings at each site within the hand and the ratio of the summedreadings for the two hands was defined as the dolorimetry ratio.This ratio was highly reproducible and independent of externalvariables. It was significantly lower in patients with algodystrophythan in controls and may provide a method for the diagnosisand serial assessment of the disorder. KEY WORDS: Pain, Colles'fracture, Reflex sympathetic dystrophy, Sudeck's atrophy ^*Current address: Department of Orthopaedic Surgery, BristolRoyal Infirmary, Bristol BS2 8HW.     

Studies on tuberculin fever. I. The mechanism of fever in tuberculin hypersensitivity

Evidence has been presented that the fever elicited by intravenous administration of old tuberculin (O.T.) in BCG-infected rabbits is a specific property of this hypersensitivity system and is probably not due to contamination of tuberculin with bacterial endotoxins. Daily injections of O.T. in sensitized animals resulted in a rapid tolerance to its pyrogenic effect. Tuberculin tolerance can be differentiated from that occurring with endotoxins and was invariably associated with the development of a negative skin test. The mechanism of this tolerance would thus appear to be desensitization. A circulating pyrogen found during tuberculin fever was indistinguishable in its biologic effects from endogenous pyrogens obtained in several other types of experimental fever. This material produced fevers in normal recipients and therefore may be clearly differentiated from O.T. itself which was pyrogenic only to sensitized animals. Since the titer of serum pyrogen was directly proportional to the degree of fever induced by injection of O.T. in the donor animals, a causal relation is suggested. On the basis of these findings, it is postulated that tuberculin fever is due to a circulating endogenous pyrogen released by a specific action of O.T. on sensitized cells of the host.