Introduction

Human leucocytes possess A and B antigens ₁,₂,₃,₄,₅. By absorption and elusion tests and also by mixed cell agglutination test, the agglutination results have been confirmed. According to Dausset ₆, the A and B antigens are intrinsic in leucocytes and not merely absorbed from the plasma. Lectin – leucocyte interactions have been studied by Sharon ₇, Sehrt and Luther ₈, Culina et al ₉ and Carlin et al ₁₀.

The anti-LH lectin (Erythrina lithosperma extract) was successfully used to discriminate human red blood cells as LH-positive (firm agglutination) and LH-negitive (weak agglutination) types, initially by Shrivastava et al₁₁. Recently, this lectin was used to differentiate diabetic red blood cells from those of normal individuals ₁₂,₁₃. Following the earlier report ₁₄, in the present study, an attempt has been made, considering larger sample size, to observe the reaction patterns of the anti-LH lectin and leucocytes in patients with diabetes mellitus.

Materials And Methods

A total of 109 blood samples from patients with diabetes mellitus (type II) were obtained from District Hospital, Sagar, and Varny Pathology Clinic, Sagar, Madhya Pradesh. Control samples were obtained from 98 unrelated normal healthy individuals from the same area. The samples comprised both males and females.

For the ABO typing, standard serological procedures were followed. The anti-LH lectin (Erythrina lithosperma extract) was prepared in the laboratory as described by Shrivastava et al ₁₁. The seeds of Erythrina lithosperma were procured from the Botanical Survey of India, Kolkata.

The separation of leucocytes was done following Widmann ₁₅, with minor modifications. For leucocyte agglutination tests, 25 µl leucocyte suspensions and an equal amount of anti-LH lectin were mixed in a cavity of a tile. Saline control was also made for comparison. After 20 minutes, readings were recorded both macroscopically and microscopically. Thereafter, titration tests were performed and results were recorded after 30 minutes.

Results

Table 1 shows the anti-LH lectin –leucocyte reactions in diabetic and control samples at different titres. The lectin Erythrina lithosperma reacted at titre 1:16 with the leucocytes of diabetic A cells (06.42%), B cells (19.27%), O cells (01.83%) and AB cells (02.75%) and with control leucocytes of A cells (07.14%), B cells (13.26%), O cells (04.08%) and AB cells (05.10%). The lectin reacted at titre 1:32 with the leucocytes of diabetic A cells (13.76%), B cells (22.94%), O cells (28.44% ) and AB cells (04.59%) and with control leucocytes of A cells (13.26%), B cells (22.45%), O cells (32.65%) and AB cells (02.04).

The distribution of titre scores in patients with diabetes mellitus and controls pooling all the four blood groups is given in table 2. The lectin reacted at titre 1:16 slightly more with diabetic cells (30.27% and) than controls (29.59%) and at titre 1:32 slightly less (69.72%) than controls (70.41%), showing no significant differences (P> 0.05) statistically between the diabetic and control samples.

Figure 1

Table 1: The anti-LH lectin – leucocyte reactions and titre scores in patients with diabetes mellitus.

Figure 2

Table 2: Distribution of titre-scores (pooled for all the four blood groups) in patients and controls.

Discussion

The results indicateed that the lectin Erythrina lithosperma reacted with the leucocytes from both diabetic as well as normal individuals in almost equal strength. However, unlike erythrocytes where clear cut differentiation regarding the reaction patterns (LH-negative for weak reaction and LH-positive for strong reaction) occurs in diabetic and control samples ₁₂,₁₃, the anti-LH lectin Erythrina lithosperma fails to differentiate diabetic leucocytes from normal ones on the basis of the intensity of their agglutination. Nonetheless, it follows the findings of the earlier study ₁₄. It appears therefore that the variable expression of the LH antigen is a unique property only of erythrocytes.