Insulin antibody response to bovine insulin therapy: functional significance among insulin requiring young diabetics in India

The importance of anti-insulin antibody in patients with type 1 diabetes mellitus treated with continuous subcutaneous insulin infusion or multiple daily insulin injections therapy

To investigate the influence of two insulin administration modalities, continuous subcutaneous insulin infusion (CSII) and multiple daily insulin injections (MDI) therapy with insulin analogues, on the development of insulin antibodies (IAs) in patients with type 1 diabetes mellitus and to assess the impact of IAs on glucose control and hypoglycaemia. 96 patients with type 1 diabetes mellitus treated with CSII (n = 48) or MDI (n = 48) were included in the study. Age, duration of diabetes, A1c, preprandial and postprandial blood glucose and hypoglycaemic events were compared between IA positive and negative patients. IA levels were higher in the CSII group (% 24.6 ± 14.2) than the MDI group (% 13.2 ± 9.9). Duration of diabetes and age were not associated with IA positiveness. While A1c, preprandial blood glucose and the frequency of hypoglycaemic events were similar in two groups, postprandial blood glucose was lower in IA positive group (P = 0.03). Patients with type 1 diabetes mellitus treated with CSII with insulin analogues had higher IA levels when compared to MDI therapy. However, the development of IAs did not impair the glycaemic control.

Immunogenicity of human and bovine insulin in type 1 diabetes mellitus patients

BACKGROUND

The advantages of synthetic insulin (human insulin) over bovine insulin in the treatment of type 1 diabetes mellitus (DM) are much debated in terms of potency and purity. Immunogenicity is one of several factors that determine potency and safety. This study was designed to investigate and study the difference in immunogenicity of human and bovine insulin. We investigated anti-insulin antibody (AIAB) status in 69 type 1 DM patients receiving insulin therapy. Group 1 had 33 patients treated with bovine insulin, and group 2 had 32 patients treated with human insulin. All patients had received their respective insulin therapy for a minimum period of 1 year and had no history of change in insulin type. Forty-three subjects from the normal population were the control group.

METHODS

AIABs were assayed in serum samples of all subjects using a semiquantitative radioimmunoassay kit. The Kruskal-Wallis non-parametric and Mann-Whitney U tests were used to study the difference in immunogenicity of human and bovine insulins.

RESULTS

The Kruskal-Wallis test showed that antibody titers in the three groups significantly differed (P<0.001). The Mann-Whitney U test showed no significant difference in AIAB titer between the treatment groups. AIAB titers in the two treatment groups differed significantly from that of the control group, independently (P<0.001). High titers of AIABs are present in patients receiving bovine and human insulin compared to that of the normal population.

CONCLUSIONS

Bovine and human insulins are antigenic, and there is no significant difference in AIAB titer. Prospective studies are required to determine the long-term clinical significance of these antibodies.

Immunological responses to exogenous insulin

Regardless of purity and origin, therapeutic insulins continue to be immunogenic in humans. However, severe immunological complications occur rarely, and less severe events affect a small minority of patients. Insulin autoantibodies (IAAs) may be detectable in insulin-naive individuals who have a high likelihood of developing type 1 diabetes or in patients who have had viral disorders, have been treated with various drugs, or have autoimmune disorders or paraneoplastic syndromes. This suggests that under certain circumstances, immune tolerance to insulin can be overcome. Factors that can lead to more or less susceptibility to humoral responses to exogenous insulin include the recipient's immune response genes, age, the presence of sufficient circulating autologous insulin, and the site of insulin delivery. Little proof exists, however, that the development of insulin antibodies (IAs) to exogenous insulin therapy affects integrated glucose control, insulin dose requirements, and incidence of hypoglycemia, or contributes to beta-cell failure or to long-term complications of diabetes. Studies in which pregnant women with diabetes were monitored for glycemic control argue against a connection between IAs and fetal risk. Although studies have shown increased levels of immune complexes in patients with diabetic microangiopathic complications, these immune complexes often do not contain insulin or IAs, and insulin administration does not contribute to their formation. The majority of studies have shown no relationship between IAs and diabetic angiopathic complications, including nephropathy, retinopathy, and neuropathy. With the advent of novel insulin formulations and delivery systems, such as insulin pumps and inhaled insulin, examination of these issues is increasingly relevant.

Pattern of Candida species isolated from patients with diabetes mellitus and vulvovaginal candidiasis and their response to single dose oral fluconazole therapy

OBJECTIVE

Patients with diabetes mellitus are at increased risk of vulvovaginal candidiasis (VVC). Besides Candida albicans, they often have infection due to non-C. albicans Candida species such as C. glabrata. Oral single dose fluconazole (150 mg) is commonly used to treat VVC in non-diabetic individuals with response rate varying from 70 to 90%. However, there is paucity of related information in diabetic women with VVC. Present study has been conducted to systematically assess the effect of fluconazole therapy among diabetic patients with clinically symptomatic VVC.

METHODS

Study subjects included 85 consecutive patients with diabetes mellitus (type 2=70 and type 1=15) and 62 non-diabetic women who had clinical signs and symptoms of VVC and in whom evidence of candidiasis was documented by presence of yeast on direct microscopy followed by culture. Single dose fluconazole (150 mg) was given orally to all the subjects in a supervised manner. Subjects were reassessed on 14th day after fluconazole therapy and a repeat high vaginal swab was taken for direct microscopy and fungal culture. Total glycosylated haemoglobin (HbA1) was measured to assess glycaemic control.

RESULTS

There were no significant differences in the frequency of pruritus (55.9 vs. 56.7%), vaginal discharge (63.8 vs. 69.0%), dyspareunia (25.0 vs. 20.0%), and percentage yeast positivity (67.5 vs. 54.7%) between diabetic and control groups before the start of fluconazole therapy. Following fluconazole therapy, vaginal discharge on examination and yeast positivity on direct microscopy continued to remain positive in higher percentage of subjects in the diabetic group as compared to non-diabetic subjects (52.5 vs. 36.4%; P =0.22 and 50.7 and 29.0%, respectively, P =0.07, respectively). Overall 67.1% of patients with diabetes and 47.3% of controls continued to show persistence of Candida growth on high vaginal swab culture following fluconazole treatment (P=0.042). Candida glabtara was the most common species isolated in patients with diabetes mellitus and its frequency was significantly higher in them when compared to control group (54.1 vs. 22.6%, P<0.001). C. albicans was the most common species isolated in controls. Species-specific response to fluconazole showed that 81.3% of patients in the diabetic group and 78.6% of the non-diabetic controls continued to show fungal growth when C. glabrata was the organism grown (P=0.99). However, in case of C. albicans, 45.4% of the patients in the diabetic group and only 21.5% of the controls had persistent Candida growth following fluconazole therapy (P=0.22).

CONCLUSION

Overall only one third of patients with diabetes mellitus and VVC respond to single dose 150 mg of fluconozole therapy. Limited response in the clinical symptoms and culture negativity following single dose fluconazole therapy in diabetic subjects with VVC is explained by the high prevalence of C. glabrata in them. The present study involved only 85 patients and majority of them had type-2 diabetes mellitus. There is need to perform similar study in large number of diabetics subjects including patients with type-1 diabetes mellitus and assess various alternative treatment protocol which are also effective in C. glabrata infection.

Glycaemic control and microvascular complication among patients with youth onset diabetes in India using differing types of insulin and methods of glucose monitoring

We assessed whether insulin types and monitoring methods were relevant to glycaemic control, microvascular complications as well as costs of management in 208 patients with youth onset diabetes in India. The type of insulin and monitoring method used made no difference to the glycaemic and complication status. Cost considerations support bovine insulin use along with urine glucose monitoring as an appropriate approach to diabetes self care in developing countries.

Species-specific prevalence of vaginal candidiasis among patients with diabetes mellitus and its relation to their glycaemic status

OBJECTIVES

Non- C. albicans Candida species are increasingly being recognized as the cause of vulvo-vaginal candidiasis. These species are often less susceptible to antifungal agents. Patients with diabetes mellitus are at risk for vulvo-vaginal candidasis. We assessed the species-specific prevalence rate and risk of candidiasis in patients with diabetes mellitus and healthy controls.

METHODS

Genital tract examination, direct microscopy and fungal cultures of discharge collected by high vaginal swab were undertaken among 78 consecutive patients with diabetes mellitus (mean (+/-sd) age 32+/-12 years and body mass index (BMI) 22.3+/-5.5kg/m(2)) and 88 age- and BMI-matched healthy females. Glycaemic control in the diabetic cohort was assessed by measuring total glycosylated haemoglobin.

RESULTS

Candida species were isolated in 36 of 78 (46%) subjects with diabetes mellitus and in 21 of 88 (23%) healthy subjects (Chi-squared 9.11, P=0.0025). The predominant Candida species isolated in diabetics with vulvo-vaginal candidiasis were Candida glabrata (39%), C. albicans (26%) and C. tropicalis (17%). In contrast, in the control group, C. albicans, C. glabrata and C. hemulonii comprised 30% each, with none having C. tropicalis infection (for C. tropicalis: diabetic vs. control; 17% vs. nil, P=0. 05). Among the diabetic group, subjects with vulvo-vaginal candidiasis had significantly higher mean HbA1 when compared to those who had no such infection (12.8+/-2.6% vs. 9.7+/-1.7% respectively, P=0.001). The overall accuracy of direct microscopy and clinical examination for predicting vulvo-vaginal candidiasis was only 77% and 51%, respectively, in the diabetic group, and 83% and 65% in the control group.

CONCLUSIONS

Patients with diabetes mellitus had a high prevalence rate (46%) of vulvo-vaginal candidiasis with relative risk of 2.45. The non- C. albicans species such as C. glabrata and C. tropicalis were the predominant species isolated among them. There seems to be a significant link between hyperglycaemia and vulvo-vaginal candidiasis.