Variation of cold agglutinin levels

Cold Agglutinins and Cryoglobulins Associate With Clinical and Laboratory Parameters of Cold Urticaria

Mast cell-activating signals in cold urticaria are not yet well defined and are likely to be heterogeneous. Cold agglutinins and cryoglobulins have been described as factors possibly associated with cold urticaria, but their relevance has not been explained. We performed a single-center prospective cohort study of 35 cold urticaria patients. Cold agglutinin and cryoglobulin test results, demographics, detailed history data, cold stimulation test results, complete blood count values, C-reactive protein, total immunoglobulin E levels, and basal serum tryptase levels were analyzed. Forty six percent (n = 16) of 35 tested patients had a positive cold agglutinin test and 27% (n = 9) of 33 tested patients had a positive cryoglobulin test. Cold agglutinin positive patients, when compared to cold agglutinin negative ones, were mainly female (P = 0.030). No gender-association was found for cryoglobulins. A positive cold agglutinin test, but not a positive cryoglobulin test, was associated with a higher rate of reactions triggered by cold ambient air (P = 0.009) or immersion in cold water (P = 0.041), and aggravated by increased summer humidity (P = 0.007). Additionally, patients with a positive cold agglutinin test had a higher frequency of angioedema triggered by ingestion of cold foods or drinks (P = 0.043), and lower disease control based on Urticaria Control Test (P = 0.023). Cold agglutinin levels correlated with erythrocyte counts (r = −0.372, P = 0.028) and monocyte counts (r = −0.425, P = 0.011). Cryoglobulin concentrations correlated with basal serum tryptase levels (r = 0.733, P = 0.025) and cold urticaria duration (r = 0.683, P = 0.042). Results of our study suggest that cold agglutinins and cryoglobulins, in a subpopulation of cold urticaria patients, are linked to the course and possibly the pathogenesis of their disease.

RBC alloantibody specificity and antigen potency in Olmsted County, Minnesota

BACKGROUND

While RBC antigen frequencies for whites of Northern European ancestry are known, the relative frequencies of RBC antibodies within this population have not been determined. The distribution of RBC alloantibodies by sex and age was studied, as were the immunogenicity of RBC antigens and the occurrence of RBC alloantibody clusters in a geographically defined population.

STUDY DESIGN AND METHODS

RBC alloimmunization among patients and donors in Olmsted County, MN, was determined for the period from 1975 to 1995. Alloantibody frequencies were used to calculate the potency of each antigen relative to K. Cluster analysis was applied to the data to identify natural groupings of antibodies.

RESULTS

The frequency and potency of 33 alloantibodies from 1345 alloimmunized subjects were estimated. The most frequent alloantibodies were E (20.8%), Le(a) (18.6%), K (14.7%), D (12.9%), Le(b) (9.4%), M (7.2%), P(1) (6.7%), Fy(a) (6.3%), C (6.8%), and c (3.5%). The most potent antigens were Wr(a) (0.363), C(w) (0.078), Le(a) (0.03), E (0.028), V (0.025), Js(a) (0.023), Kp(b) (0.023), Go(a) (0.023), JMH (0.023), and Rd (0.023). Greater frequency of overall alloimmunization (M:F = 1:2.7), anti-D (p<0.0001), and anti-Le(a) (p = 0.003) was seen among females. Warm autoantibodies were more frequent among males with positive antibody screens (p<0.0001). No other gender differences were observed. Alloimmunization increased with age for K, Kp(a), Fy(a), D, C, E, and warm autoantibodies. Frequencies of alloimmunization to Le(a), Le(b), M, and P(1) decreased with age. The cluster analysis showed grouping of the antibodies to C and D as well as to Le(a) and Le(b), but the other RBC alloantibodies did not form clusters.

CONCLUSION

Less than 1 percent of residents tested had positive antibody screens. Anti-E and anti-Le(a) were more common than anti-K. Wr(a) and C(w) were more potent antigens than K. Most antibodies showed an increase in frequency with increasing age. Except for anti-C and -D and anti-Le(a) and -Le(b), RBC alloantibodies did not occur in clusters.

Immunoglobulin VH gene expression in human aging

Immune responses change in aging humans, but it is not known whether there is an age-associated change in the expressed B cell repertoire. We compared Ig VH cDNA libraries from circulating B cells of five elderly and three young human adults. As in young persons, nearly two-thirds of the cDNA clones from older subjects had zero to three V(H) mutations, although there was more individual variation among the elderly. V(H)4 family expression increased in older subjects, both in unmutated and in mutated cDNA clones, whereas V(H)3 family expression predominated in young adults. To test for bias toward activated cells in the cDNA libraries, we studied two older persons by both cDNA library analysis and single-cell RT-PCR. In one subject, more than 85% of VH segments were unmutated by either analysis. In the second, mutated Ig segments were much more frequent in cDNA clones than in consecutive single cells; however, V(H) family usage and high representation of particular genes were similar in both analyses. While aging humans continue to produce naive B cells with unmutated Ig genes, a shift to greater use of the V(H)4 family members and expression of particular genes may reflect changes in selection of developing B cells before affinity maturation toward reactivity with foreign antigen.

Red blood cell cold agglutinins and B lymphocyte cytotoxins in breast cancer sera

Cytotoxic activity towards B-lymphocytes in sera from individuals with breast carcinoma was related to red blood cell cold agglutinin levels and IgM values. The control group consisted of 32 females with a similar age distribution. Significant increases in red blood cell cold agglutinin levels were found in the group of cancer patients and the group with the histological category of mucin-producing carcinoma with lymphocyte cytotoxins (p less than 0.025, respectively), in comparison to the control group and cancer patients without lymphocyte cytotoxins. Serum IgM concentrations were significantly increased in the group of cancer patients (p less than 0.025) and the group with mucin-producing carcinoma (p less than 0.01) with lymphocyte cytotoxins, in comparison to cancer patients and controls without lymphocyte cytotoxins. The lymphocyte cytotoxins were completely or partially adsorbed by red blood cells in 58% of the positive sera. These results suggest that red blood cell cold agglutinins constitute a portion of cytotoxic anti-B lymphocyte antibodies. At present it is unknown whether the lymphocytotoxic antibodies in breast cancer patients are of importance in immunologic host defenses.