Is immunity in diabetic patients influencing the susceptibility to infections? Immunoglobulins, complement and phagocytic function in children and adolescents with type 1 diabetes mellitus.

OBJECTIVE: Previous reports suggest an increased susceptibility of diabetes patients to infections, but little information is available on possible underlying immunologic dysfunctions. The aim of this study was to evaluate humoral factors in pediatric patients with type 1 diabetes mellitus. METHODS: There were 66 diabetic patients (39 males:27 females; 5-17 yr) classified into two groups according to levels of glycohemoglobin (limit 9%): Group C - controlled (n = 33) and Group UC - uncontrolled (n = 33). We evaluated five patients in C and six in UC who reported previous infections. Immunologic analysis included measurement of plasma concentrations of immunoglobulins (Ig), C3, and C4 levels (turbidimetry); functional hemolytic assays for complement evaluation (CPH for classical and APH for alternative pathways), quantification of C4 isotypes C4A and C4B (ELISA), phagocytosis assays, measurement of bactericidal activity against Staphylococcus aureus, as well as tests of fungicidal capacity for Candida albicans. RESULTS: The UC Group had higher mean age, received higher insulin doses, and had higher concentrations of glycohemoglobin than the C Group. No significant differences in duration of the disease or nutritional conditions were detected between the groups. Lower IgA values in C (10/33) and lower IgG levels in UC (23/33) were detected, and there were inverse relationship with HbA1c values. Analysis of CPH, APH, C3, and C4 showed normal levels in both groups and no statistical correlation with the HbA1c. However, 9/33 children of the UC Group had decreased C3 values. C4B levels were below the normal range in 8/20 and correlated with higher HbA1c. Both phagocytic assays for S. aureus and Candida albicans were within normal limits. CONCLUSIONS: Low IgG concentrations and to some degree reduction in C4B levels were related to impaired metabolic control. No strong link between the immunological alterations was found in diabetic patients and the occurrence of infections.

IGA1 proteases: ocorrência em agentes estiológicos de meningite / IgA1 proteases: ocurrence in meningitis etiological agents

Dentre os fatores de virulência em bactérias investigados na Seçäo de Bacteriologia do Instituto Adolfo Lutz, tem sido avaliada a ocorrência de proteases à imunoglobulina A (IgA1 proteases) em agentes etiológicos de meningite. Estas enzimas extracelulares säo produzidas por diferentes patógenos de mucosa, incluindo os três principais agentes das meningites bacterianas: Neisseria menigitidis, Haemophilus influenzae e Streptococus pneumoniae. IgA1 proteses foram detectadas por imunoeletroforese em 28 de 39 cepas estudadas, bactérias e leveduras. Com exceçäo de 7 bactérias obtidas de coleçäo de cultura, todos os microrganismos foram isolados de líquido cefalorraquidiano. Nos três agentes etiológicos mais frequentes de meningite foi observada a presença de IgA1 proteases, como também em quatro outras bactérias, das quais duas de coleçäo, e näo citadas na literatura como produtoras destas enzimas