Serum from a thrombocytopenic patient who was refractory to the transfusions of HLA-matched platelets contained a platelet-specific alloantibody, anti-Nak^a. Immunofluorescence analyses revealed that the Nak^a antigen defined by the serum was expressed exclusively on platelets and its distribution was different from P1^A1, Bak^a Yuk^a or Yuk^b. Analysis by Dr. von dem Borne’s group revealed the Nak^a was also different from Ko^a, Ko^b or Zw^b. Family studies showed that the Nak^a antigen was inherited as an autosomal codominant trait. Its antigen frequency in the Japanese population was over 97%. The results of the enzyme immunoassay using monoclonal antibodies for antigen immobilization showed that the Nak^a epitope did not appear to reside on GPIIb/IIIa or Ib. The transfusions of Nak^a-compatible platelets improved the patient’s thrombocytopenia.

Serum from a thrombocytopenic patient who was refractory to the transfusions of HLA-matched platelets contained a platelet-specific alloantibody, anti-Naka. Immunofluorescence analyses revealed that the Naka antigen defined by the serum was expressed exclusively on platelets and its distribution was different from P1A1, Baka, Yuka or Yukb. Analysis by Dr. von dem Borne's group revealed the Naka was also different from Koa, Kob or Zwb. Family studies showed that the Naka antigen was inherited as an autosomal codominant trait. Its antigen frequency in the Japanese population was over 97%. The results of the enzyme immunoassay using monoclonal antibodies for antigen immobilization showed that the Naka epitope did not appear to reside on GPIIb/IIIa or Ib. The transfusions of Naka-compatible platelets improved the patient's thrombocytopenia.

The present data showed that the serum ferritin level of the female donors decreased the most with increasing frequency of apheresis donation. The cumulative RBC left in the collecting chamber and for the laboratory test is discussed in relation to a possible cause of iron deficiency in frequent apheresis donors.

Background and Objectives: To ascertain the safety of repeat apheresis donation, hematological and biochemical tests were performed on 511 donors with a donation rate of over 6 times per year for a period of 12–19 months. Materials and Methods: Repeat donors who had apheresis more than 6 times in the previous year were chosen. Data for the repeat donors at the start of the experiments were compared with those at the end of the study. Blood samples were taken prior to donation. Serum protein, albumin, immunoglobulin G, A, and M, serum ferritin levels were determined by biochemical tests. Results: When compared to prospective donors of 400 ml, WBC, lymphocytes, and serum ferritin levels were lower in a roughly frequency–dependent manner in female and male donor groups at the beginning of the study. All the data for the male group remained almost constant with increasing frequency of apheresis donation. However, in the female group, ferritin levels significantly decreased with over 21 donations. Conclusions: The present data showed that the serum ferritin level of the female donors decreased the most with increasing frequency of apheresis donation. The cumulative RBC left in the collecting chamber and for the laboratory test is discussed in relation to a possible cause of iron deficiency in frequent apheresis donors.

Predonation measurement of haemoglobin concentration, combined with the referral of those with abnormal values, provided a health benefit to that population.