Invalidation of antiglobulin tests by a high thermal amplitude cryoglobulin

A multiply transfused patient was referred for evaluation of a transfusion reaction. The direct and indirect antiglobulin tests (DAT, IAT) for alloantibody were negative. However, IgG-coated control cells failed to agglutinate in the negative reactions, casting doubt on their validity. At 4 degrees C, the patient's serum exhibited a large cryoprecipitate (2.9 mg/mL), made up predominantly of an IgG kappa paraprotein and having trace amounts of IgM and C3. Clear serum separated at 37 degrees C became cloudy within 10 minutes at room temperature (RT); within 4 hours, approximately 60 percent of the total precipitable cryoprotein had precipitated. Red cells (RBCs) incubated in fresh serum that had cooled to RT or RBCs obtained from RT or refrigerated samples contained cryoprecipitate that sedimented with the RBCs during washing with RT saline. On resuspension, enough IgG cryoglobulin redissolved to neutralize completely the commercial anti-IgG reagents. If the patient's samples were maintained at 37 degrees C, cryoprecipitate did not form, and RBCs washed four times at 37 degrees C gave valid DAT and IAT reactions. The removal of all cryoprecipitate from the patient's serum by centrifugation after overnight incubation at 4 degrees C also made possible valid antibody screening and compatibility tests.     

A dichotomy between the expression of IgD on B cells and its requirement for triggering such cells with two T-independent antigens

The majority of adult B lymphocytes in the mouse bear two immunoglobulin isotypes, IgM and IgD (μ(+)δ(+) cells) (1). A small population of IgM-bearing cells lacks, or expresses very low levels of IgD (μ- predominant [μp] cells) (1). These cells are believed to constitute a less mature subset of B cells analogous to neonatal B cells (2). Based on the time during ontogeny when responses to T-independent (TI) and T-dependent (TD) antigens appear (3, 4) and the ability to block in vitro responses with anti- μ or anti-δ (5, 6, D. Mosier, personal communication), it has been suggested that the precursors of two TI-1 responses, trinitrophenyl (TNP)- Brucella (TNP-BA) and TNP-lipopolysaccharide (TNP-LPS) are μp cells (5, 6), whereas the precursor for a TD response, TNP-sheep erythrocytes (TNP-SRBC), bears both IgM and IgD (6). However, the possibility cannot be excluded that IgD is present on some or all of the TI precursors, but that it is not obligatory for triggering. In the present experiments we have examined the phenotypes of TI and TD precursors by treating cells with C’ and either anti-μ or anti-δ before stimulation with antigen. Our results suggest that the majority of B cells that respond to TNP-BA, TNP-LPS, and TNP-SRBC bear IgD, even though in the case of the two TI antigens, IgD is not required for triggering.     

In vitro and in vivo persistence of reticulocytes from donor red cells

BACKGROUND: Reticulocytes are important in the phenotyping of transfused patients. Reticulocytes can persist in blood units for the shelf life of the unit. STUDY DESIGN AND METHODS: Temperature dependence of reticulocyte persistence was examined in vitro at 4, 24, and 37 degrees C by using thiazole orange staining and flow cytometric analysis. Two-color flow cytometric analysis was used to evaluate the persistence of donor reticulocytes in transfused patients. RESULTS: Flow cytometric analysis using thiazole orange demonstrated that persistence of reticulocytes in units of stored CPDA-1 blood was temperature-dependent. Reticulocytes disappeared over 13 and 6 days at 24 degrees C and 37 degrees C, respectively, but at 4 degrees C the reticulocyte count changed little over 35 days. Two-color flow cytometric analysis of reticulocyte antigens was used to follow donor reticulocytes in 14 transfusion events in nine different patients. Donor reticulocytes persisted through 24 hours in 75 percent of the patients and were detectable at 48 hours in three patients. CONCLUSION: This study demonstrates that reticulocytes persist during refrigerated storage; they are detectable in the circulation of most recipients for the first 24 hours after transfusion and in the circulation of a few recipients after 48 hours. These findings may have relevance for separation techniques based on reticulocyte density in samples drawn shortly after transfusion and for evaluation of reticulocyte counts in patients with hematologic abnormalities.     

Coexistence of diffuse plane normolipaemic xanthoma and amyloidosis in a patient with monoclonal gammopathy

Diffuse plane normolipaemic xanthomatosis (DPNX) is a well-defined clinicopathological entity that characteristically presents with yellow–orange plaques in the periorbital areas, the neck, the upper trunk and the flexural folds. DPNX has been reported in association with lymphoproliferative disorders and, occasionally, with miscellaneous, probably coincidental disorders. A case of DPNX in a patient with an IgGλ monoclonal gammopathy and systemic amyloidosis is reported. Clinical and histopathological findings revealed typical features of DPNX and amyloidosis coexisting in the cutaneous lesions. To our knowledge this is the first reported case showing coexistence of xanthoma and amyloidosis in cutaneous lesions in a patient with a monoclonal gammopathy.