T lymphocyte subpopulations in leprosy patients and their relation with circulating immune complexes.

The possible relationship between circulating immune complexes (CIC) and peripheral T lymphocyte populations was studied in thirteen active multibacillary leprosy (10 lepromatous--LL--and 3 borderline lepromatous--BL--) and 19 matched controls. Theophylline-resistant T cells (The-R, a lymphocyte subpopulation displaying helper activity on B cells) and total T cells were assessed by means of the E rosette technique, with and without previous theophylline incubation, 1h 37 degrees C, respectively. CIC were quantified by 125I-C1q binding test. Although leprosy patients showed a statistical non significant light depression in total T cells the remarkable variability in circulating levels of The-R T cells enabled us to separate them into two well delineated groups (in relation to this variable p less than 0.001) with no difference in age, sex and bacteriologic state: a) leprosy patients with The-R T cells proportionally conserved (6LL and 2BL); b) leprosy patients with The-R T cells proportionally depressed (4LL and 1BL). Patients belonging to the latter group showed the highest statistically significant levels of CIC. Even though we do not discard an unknown factor being responsible for our findings, we believe that this inverse relationship between elevated CIC and depressed The-R circulating T cells might be representing a lower helper activity on antibody synthesis intending to reduce its excessive production.

[Isolation and characterization of immune complexes associated with malignant tumors and leprosy]. / Aislamiento y caracterización de complejos inmunes asociados a tumores malignos y a lepra.

We are dedicated to the study of circulating immune complexes (CIC) associated with different diseases: malignant tumors, leprosy and rheumatoid arthritis. Immune complexes were evaluated by various methods: 125I-Clq binding assay, 125I-IgG binding test, 125I-bovine conglutinin binding assay and polyethylene glycol precipitation test (3.5% and 2.5%). Techniques for the isolation and splitting of CIC in their components were performed in sera from patients with tumors and with leprosy. These methods consisted in the combination of CIC with protein A followed by elution with different buffers. CIC splitting techniques were first applied on immune complexes formed in vitro (BSA-aBSA, OVA-aOVA). The analysis of CIC fractions was done by SDS-PAGE, immunoelectrophoresis and immunoblotting techniques. Results were as follows: CIC levels correlated with active stages of disease, decreasing during remission so that CIC detection can be useful to evaluate response to treatment. The isolation and splitting of immune complexes into their components resulted in the obtention of immunologically active fractions, especially in sera from patients with gastrointestinal and breast cancer and with leprosy.

Aislamiento y caracterización de complejos inmunes asociados a tumores malignos y a lepra. / [Isolation and characterization of immune complexes associated with malignant tumors and leprosy]

We are dedicated to the study of circulating immune complexes (CIC) associated with different diseases: malignant tumors, leprosy and rheumatoid arthritis. Immune complexes were evaluated by various methods: 125I-Clq binding assay, 125I-IgG binding test, 125I-bovine conglutinin binding assay and polyethylene glycol precipitation test (3.5

and 2.5

). Techniques for the isolation and splitting of CIC in their components were performed in sera from patients with tumors and with leprosy. These methods consisted in the combination of CIC with protein A followed by elution with different buffers. CIC splitting techniques were first applied on immune complexes formed in vitro (BSA-aBSA, OVA-aOVA). The analysis of CIC fractions was done by SDS-PAGE, immunoelectrophoresis and immunoblotting techniques. Results were as follows: CIC levels correlated with active stages of disease, decreasing during remission so that CIC detection can be useful to evaluate response to treatment. The isolation and splitting of immune complexes into their components resulted in the obtention of immunologically active fractions, especially in sera from patients with gastrointestinal and breast cancer and with leprosy.

Evaluation of circulating immune complexes in leprosy.

Circulating immune complexes (CIC) were evaluated in leprosy by 4 methods: the 125I-C1q binding assay (C1q), the platelet aggregation test (PAT), the 3.5% polyethylene glycol (PEG) precipitation test and the 2.5% PEG precipitation assay. Serum samples belonged to lepromatous leprosy bacilloscopy positive (LL+), lepromatous leprosy bacilloscopy negative (LL-), tuberculoid (TT) and first grade contact group (Co). Studies performed by the 3 first methods showed higher CIC levels in LL+ group (p less than 0.01) and lower values in the 3 others, all of them when compared to normals. On the contrary, the 2.5% PEG precipitation test gave less discriminative results giving only p less than 0.01 in LL+. CIC values obtained in the contact group showed significant results compared to normals but similar to LL- and TT groups. The C1q binding assay and the PAT were the most discriminative methods giving r = 0.90; C1q versus 3.5% PEG, r = 0.36; C1q vs 2.5% PEG, r = 0.14. The PAT compared to 3.5% PEG, r = 0.48 and PAT vs. 2.5% PEG, r = 0.24. Therefore it may be concluded as follows: a) The radioiodinated C1q binding assay and the PAT are recommended for the study of CIC in leprosy; b) The 2.5% PEG precipitation assay offers less sensitivity since it gave similar value in LL-, TT, Co and controls; c) CIC levels observed in LL+ patients may be induced by the antigenic overload demonstrated by the positive bacilloscopy; d) The contacts have CIC levels significantly different from the normal population possibly caused by a subclinical infection.

Evaluation of circulating immune complexes in leprosy.

Circulating immune complexes (CIC) were evaluated in leprosy by 4 methods: the 125I-C1q binding assay (C1q), the platelet aggregation test (PAT), the 3.5

polyethylene glycol (PEG) precipitation test and the 2.5

PEG precipitation assay. Serum samples belonged to lepromatous leprosy bacilloscopy positive (LL+), lepromatous leprosy bacilloscopy negative (LL-), tuberculoid (TT) and first grade contact group (Co). Studies performed by the 3 first methods showed higher CIC levels in LL+ group (p less than 0.01) and lower values in the 3 others, all of them when compared to normals. On the contrary, the 2.5

PEG precipitation test gave less discriminative results giving only p less than 0.01 in LL+. CIC values obtained in the contact group showed significant results compared to normals but similar to LL- and TT groups. The C1q binding assay and the PAT were the most discriminative methods giving r = 0.90; C1q versus 3.5

PEG, r = 0.36; C1q vs 2.5

PEG, r = 0.14. The PAT compared to 3.5

PEG, r = 0.48 and PAT vs. 2.5

PEG, r = 0.24. Therefore it may be concluded as follows: a) The radioiodinated C1q binding assay and the PAT are recommended for the study of CIC in leprosy; b) The 2.5

PEG precipitation assay offers less sensitivity since it gave similar value in LL-, TT, Co and controls; c) CIC levels observed in LL+ patients may be induced by the antigenic overload demonstrated by the positive bacilloscopy; d) The contacts have CIC levels significantly different from the normal population possibly caused by a subclinical infection.